A Research Guide for
Sickle Cell Disease

Newborn screening for SCD uses a small blood sample (the “heel stick”) collected in the first 24 to 48 hours of life. The sample is analyzed using one or more of these methods:

• High-Performance Liquid Chromatography (HPLC): Separates hemoglobin types by their chemical properties. The most widely used initial screening method.
• Isoelectric Focusing (IEF): Separates hemoglobin types by electrical charge. Often used as a confirmatory method.
• Capillary Electrophoresis: A newer method that combines speed and accuracy.

The screening result will show which hemoglobin types are present. A result of “FS” (fetal hemoglobin predominant, with hemoglobin S detected) suggests HbSS or HbS-beta-zero-thalassemia. “FSC” suggests HbSC disease. “FAS” indicates sickle cell trait (carrier status).

Important: A positive newborn screen is a screening result, not a final diagnosis. It must be confirmed with follow-up testing, typically hemoglobin electrophoresis or HPLC at around 3 to 6 months of age, sometimes supplemented by DNA analysis to distinguish between genotypes.

After a positive newborn screen, confirmatory testing determines the exact type of sickle cell disease. Hemoglobin electrophoresis is the standard confirmatory test — it provides a detailed breakdown of hemoglobin types and their relative percentages in the blood.

Key values to understand from your electrophoresis results:

• HbS percentage: The amount of sickle hemoglobin. In HbSS, this is typically 80–90% or higher (once fetal hemoglobin has declined).
• HbF percentage: The amount of fetal hemoglobin. Higher levels are generally protective. This is also how we track hydroxyurea’s effect.
• HbA percentage: Normal adult hemoglobin. Absent in HbSS and HbS/β0, present in variable amounts in HbSC and HbS/β+.
• HbC percentage: Present in HbSC disease.
• HbA2 percentage: Can help distinguish beta-thalassemia variants.

In some cases, DNA-based testing (molecular genotyping) is needed to confirm the exact mutation, particularly to distinguish HbSS from HbS/β0-thalassemia, which can look identical on electrophoresis.

SCD severity is not simply determined by genotype. While HbSS is generally the most severe and HbSC generally milder, there is enormous variability within each genotype. Several factors influence severity:

• Fetal hemoglobin level: The single strongest predictor of milder disease. People with naturally high HbF (or those boosted by hydroxyurea) tend to have fewer pain crises and complications.
• Co-inherited alpha-thalassemia: About one-third of African Americans carry one or more alpha-thalassemia gene deletions. Co-inheriting alpha-thalassemia with SCD tends to reduce hemolysis and raise hemoglobin levels, potentially reducing some complications while possibly increasing others (like VOCs due to increased blood viscosity).
• Genetic modifiers: Multiple other genes influence disease severity. Research is ongoing to identify all of them.
• Environmental factors: Access to healthcare, hydroxyurea adherence, hydration, infection prevention, and altitude exposure all affect outcomes.

The practical implication: even within the same genotype, one person’s experience may be very different from another’s. Treatment should be individualized, not based on genotype alone.

A sickle cell diagnosis has implications beyond the individual patient. Genetic counseling is recommended for:

• Parents of a child with SCD: Both parents are carriers (or one has SCD themselves). Understanding the inheritance pattern helps with family planning for future pregnancies.
• Siblings: Brothers and sisters should be tested to determine if they have SCD, are carriers, or are unaffected.
• Extended family: Aunts, uncles, and cousins may be carriers without knowing it.
• Adults with SCD considering having children: If your partner is also a carrier or has SCD, each pregnancy carries a risk of the child having SCD. Genetic counselors can discuss reproductive options including preimplantation genetic diagnosis (PGD) with IVF, prenatal testing, and natural conception with newborn screening.

Sickle cell trait testing is a simple blood test and is available at most laboratories. Carrier testing should be offered to all partners of people with SCD or sickle cell trait, regardless of their racial or ethnic background.

While universal newborn screening catches most cases in the U.S., some adults may not have been diagnosed in infancy — particularly immigrants from countries without screening programs, individuals who were born before screening was universal in their state, or people who were told they had sickle cell trait but actually have a compound heterozygous form of SCD.

If you are an adult with chronic anemia, unexplained pain episodes, or a family history of SCD and have never been tested, request a hemoglobin electrophoresis from your primary care doctor. It is a routine, inexpensive test.

Globally, newborn screening programs are expanding but remain inconsistent. India’s National Sickle Cell Elimination Mission (NSCEM), launched in July 2023, had screened over 42 million people by September 2024 — a massive public health initiative. In sub-Saharan Africa, pilot screening programs are growing, but the majority of affected newborns are still not screened, leading to devastating early mortality.

A VOC, also called a pain crisis or sickle cell crisis, occurs when sickled red blood cells block small blood vessels, cutting off oxygen to tissues. The pain can be excruciating — often described as worse than post-surgical pain. Common locations include the back, chest, arms, legs, and abdomen, though pain can occur anywhere.

Home management strategies (for mild to moderate crises):

• Hydrate aggressively: Drink plenty of water and other non-caffeinated fluids. Dehydration is one of the most common VOC triggers.
• Pain medication: Take prescribed pain medications early — do not wait for the pain to become unbearable. Many patients have a written pain management plan from their hematologist that includes both non-opioid (ibuprofen, acetaminophen) and opioid medications for home use.
• Warmth: Apply warm (not hot) compresses or heating pads to the painful area. Avoid cold, which can worsen sickling.
• Distraction and relaxation: Breathing exercises, meditation, music, or other coping techniques can complement medication.
• Rest, but gentle movement: Complete immobility increases risk of blood clots. Gentle repositioning and light movement are beneficial.

When to go to the emergency department:

• Pain not controlled by your home medications within 1–2 hours
• Fever above 101.3°F (38.5°C) — this is always an emergency in SCD
• Chest pain or difficulty breathing
• Any neurological symptoms (weakness, numbness, confusion, speech changes)
• Pale or gray appearance, rapid heart rate, extreme fatigue
• Inability to keep fluids down

Evidence-based guidelines from the American Society of Hematology (ASH) and the National Heart, Lung, and Blood Institute (NHLBI) are clear: the first dose of pain medication should be administered within 60 minutes of emergency department arrival. Pain should be reassessed every 15 to 30 minutes, with dose adjustments as needed.

Unfortunately, SCD patients frequently experience delays, undertreated pain, and implicit bias in emergency settings. Studies consistently show that SCD patients wait longer for pain medication than patients with other painful conditions. This is a health equity issue with life-or-death consequences.

What you can do to advocate for yourself or your loved one:

• Carry a letter from your hematologist detailing your diagnosis, baseline labs, medication list, and individualized pain protocol.
• Know the ASH guideline standard: first pain dose within 60 minutes.
• Ask the triage nurse to contact your hematologist if there is any question about your care.
• If your pain is being undertreated, calmly state: “My hematologist’s pain protocol calls for [specific medication and dose]. Can we please follow that plan?”
• Request a patient advocate if you feel your concerns are not being heard.
• Document your experience — times, medications, and responses — for follow-up with your care team.

A note on opioid concerns: SCD patients require opioids for acute pain crises. The opioid crisis has paradoxically worsened pain treatment for SCD patients, as some providers have become reluctant to prescribe adequate doses. Addiction rates in SCD patients taking prescribed opioids for acute pain are actually very low. Physical dependence (needing higher doses over time) is not the same as addiction. Pseudoaddiction — drug-seeking behavior caused by undertreated pain — is commonly misinterpreted as true addiction.

Acute chest syndrome (ACS) is the leading cause of death in adults with SCD and the second leading cause of hospitalization. It occurs when sickled cells block blood vessels in the lungs, often combined with infection, fat embolism from bone marrow, or fluid overload.

Warning signs:

• New chest pain (especially with breathing)
• Fever
• Cough
• Rapid or labored breathing
• Decreasing oxygen levels

ACS often starts during a pain crisis. Up to 10–20% of patients hospitalized for a VOC develop ACS. This is why every pain crisis admission should include close monitoring of respiratory status.

Treatment includes: Oxygen therapy, IV antibiotics (to cover bacterial infection), simple or exchange blood transfusion, bronchodilators, and incentive spirometry (a device that encourages deep breathing). In severe cases, exchange transfusion — removing some of the patient’s sickle cells and replacing them with normal donor red blood cells — is life-saving.

Prevention: Incentive spirometry (10 deep breaths every 2 hours while awake) during any hospitalization for pain crisis is one of the most important preventive measures. Hydroxyurea significantly reduces ACS risk.

Children with HbSS disease have a stroke risk 200 to 400 times higher than children without SCD. Approximately 11% of children with HbSS will have a clinically apparent stroke by age 20, and silent cerebral infarcts (strokes without obvious symptoms that cause cognitive damage) are even more common, affecting 27–39% of children by age 14.

Transcranial Doppler (TCD) screening: This painless ultrasound test measures blood flow velocity in the brain’s major arteries. High velocity indicates narrowed arteries and elevated stroke risk. TCD screening is recommended:

• Starting at age 2 years
• Annually through at least age 16
• For children with HbSS and HbS/β0-thalassemia

If TCD is abnormal (high velocity): Chronic transfusion therapy, maintaining HbS below 30%, reduces stroke risk by approximately 90%. The STOP trial demonstrated this conclusively and transformed SCD stroke prevention.

Recognizing stroke in SCD: Use the FAST acronym — Face drooping, Arm weakness, Speech difficulty, Time to call 911. In children, also watch for sudden severe headache, vision changes, confusion, seizures, or sudden difficulty walking.

Critical point: A stroke in SCD is treated the same as any stroke — it is a medical emergency. Call 911 immediately. Do not drive to the hospital.

Splenic sequestration occurs when the spleen suddenly traps large volumes of blood, causing it to enlarge rapidly. This can lead to life-threatening hypovolemia (dangerously low blood volume) within hours.

Most common in: Children with HbSS between ages 6 months and 5 years (before the spleen has auto-infarcted). It can also occur in older patients with HbSC or HbS/β+-thalassemia, whose spleens remain functional longer.

Signs to watch for:

• Sudden left-sided abdominal pain or fullness
• Rapidly enlarging spleen (parents should learn to palpate)
• Sudden pallor (pale or gray appearance)
• Rapid heart rate, weakness, lethargy
• Hemoglobin drop of 2 g/dL or more below baseline

Treatment: Immediate blood transfusion to restore blood volume. After a second episode, splenectomy (surgical removal of the spleen) is typically recommended due to high recurrence risk.

Parent action: Check your child’s spleen size regularly. Your hematologist should teach you how to feel the spleen’s edge. Know your child’s baseline hemoglobin. If the spleen suddenly feels larger and the child looks pale or is lethargic, go to the emergency department immediately.

Priapism: A prolonged, painful erection caused by sickled cells blocking blood outflow from the penis. Affects up to 35% of males with SCD. Episodes lasting more than 2 hours (major priapism) require emergency treatment — aspiration and irrigation by a urologist. Delay can cause permanent erectile dysfunction. Short episodes (“stuttering priapism”) lasting under 2 hours may resolve at home with hydration, pain management, light exercise, and warm baths, but should be reported to the hematologist.

Aplastic crisis: Caused by parvovirus B19 (“fifth disease”) infection, which temporarily shuts down red blood cell production. Because sickled cells already have a shortened lifespan, even a brief pause in production causes a rapid, severe drop in hemoglobin. Treatment is transfusion support. The illness is usually self-limited (1–2 weeks), and patients develop lifelong immunity after one episode.

Infections: People with SCD have functional asplenia — their spleen either auto-infarcted from repeated sickling or was surgically removed. Without a functioning spleen, they are highly vulnerable to encapsulated bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis). This is why penicillin prophylaxis and complete vaccination are life-saving. Fever in SCD is treated as an emergency until infection is ruled out — blood cultures, immediate antibiotics, close monitoring.

Racial bias in pain management is not a theory — it is documented in dozens of studies. SCD patients, who are predominantly Black, systematically receive less pain medication, wait longer for treatment, have their pain reports doubted, and are labeled as “drug-seeking” at higher rates than patients with other equally painful conditions.

A landmark 2016 study found that a significant proportion of medical trainees held false biological beliefs about racial differences in pain sensitivity. These biases directly affect treatment decisions.

What this means for SCD patients and families:

• You are not imagining the problem. It is real and measurable.
• Self-advocacy is not optional — it is a survival skill in SCD care.
• Carry your individualized pain protocol from your hematologist.
• Ask your hematologist to add their contact information to your emergency plan so ED staff can call them directly.
• If you experience discrimination, file a complaint with the hospital’s patient relations department and your state’s medical board.
• Consider connecting with SCD advocacy organizations that work on health equity issues.

Comprehensive sickle cell centers and day hospitals (specialized units where SCD patients receive acute care without going through the general ED) are one solution to this problem. Ask your hematologist if one is available in your area.

Hydroxyurea (also called hydroxycarbamide) is the most extensively studied and proven disease-modifying therapy for SCD. It works primarily by reactivating fetal hemoglobin (HbF) production, which interferes with hemoglobin S polymerization and reduces sickling. It also reduces white blood cell counts, decreases red blood cell adhesion to blood vessel walls, and increases red blood cell hydration.

Proven benefits (from the landmark MSH trial and subsequent studies):

• 44% reduction in pain crises (VOCs)
• Significant reduction in acute chest syndrome episodes
• Reduced need for blood transfusions
• Reduced hospitalizations
• Improved survival — long-term follow-up shows hydroxyurea-treated patients live longer

Who should take it: Hydroxyurea is FDA-approved for children aged 2 and older (Siklos, 2017). ASH guidelines recommend starting as early as 9 months of age for all patients with HbSS and HbS/β0-thalassemia, regardless of severity. This is a change from earlier recommendations that reserved it for patients with frequent crises. The BABY HUG trial showed clear benefits even in infants aged 9 to 17 months.

Dosing: Starting dose is typically 15–20 mg/kg/day, with dose escalation every 8 weeks to maximum tolerated dose (MTD), aiming for a target fetal hemoglobin increase and adequate blood count response. MTD is the dose that produces the greatest HbF increase without unacceptable drops in blood counts.

Monitoring: Complete blood counts (CBCs) are checked regularly (every 2–4 weeks during dose escalation, then every 2–3 months at stable dose) to watch for excessive drops in white blood cells, platelets, or hemoglobin.

The adherence crisis: Despite overwhelming evidence, hydroxyurea is dramatically underused. Only about 29.5% of eligible U.S. children fill their prescriptions. Reasons include provider unfamiliarity, family concerns about side effects (particularly fertility — data is reassuring but not definitive for males), pharmacy access barriers, and inadequate dose optimization. If you or your child is eligible and not on hydroxyurea, have an honest conversation with your hematologist about why.

Common side effects: Generally well-tolerated. Most common is mild reduction in blood counts (expected and monitored). Mild headache, nausea, and skin/nail changes may occur. Long-term cancer risk has been studied extensively — no increased risk has been demonstrated after decades of use.

L-glutamine oral powder (brand name Endari) was FDA-approved in 2017 for patients aged 5 and older to reduce acute complications of SCD. It is thought to work by reducing oxidative stress in sickle red blood cells.

Efficacy: Modest — approximately 25% reduction in pain crises. Less impressive than hydroxyurea but can be used alongside it for additional benefit.

Practical considerations: It is a powder that must be mixed with food or liquid twice daily. Some patients find this inconvenient, and the taste can be challenging. Insurance coverage has been inconsistent.

L-glutamine is not a replacement for hydroxyurea — it is a supplementary option, typically considered when hydroxyurea alone is not providing adequate control.

Voxelotor was originally FDA-approved in 2019 and worked by increasing hemoglobin’s oxygen affinity to reduce sickling. While it did improve hemoglobin levels and reduce hemolysis markers, the improvement in hemoglobin did not translate to reduced clinical events, and the safety concerns led to withdrawal.

Crizanlizumab is a monoclonal antibody that blocks P-selectin, a molecule involved in the adhesion of sickle cells to blood vessel walls. It was FDA-approved in 2019 based on the SUSTAIN trial, which showed reduced pain crises.

Current status: The evidence for crizanlizumab has been significantly weakened:

• The STAND Phase 3 confirmatory trial failed to meet its primary endpoint.
• The European Medicines Agency (EMA) revoked marketing authorization in August 2023.
• The drug remains FDA-approved in the U.S., but many experts now question the strength of the evidence supporting its use.

Furthermore, inclacumab, a second P-selectin inhibitor (from Roche), also failed its Phase 3 trial (THRIVE-131, August 2025), raising broader questions about whether P-selectin inhibition alone is sufficient to prevent VOCs.

Discuss with your hematologist whether continuing or starting crizanlizumab makes sense given this evolving evidence landscape.

Two pyruvate kinase (PK) activators have been in development for SCD, and one has delivered very promising results:

Etavopivat (Novo Nordisk) — the most promising pipeline drug:

• Mechanism: Activates pyruvate kinase, an enzyme that helps red blood cells maintain their shape and energy. This reduces sickling by improving red blood cell health from the inside.
• HIBISCUS Phase 3 trial (results: April 2026): Met both co-primary endpoints.
• 27% reduction in VOC rate (statistically significant)
• Hemoglobin response: 48.7% of patients vs. 7.2% on placebo
• Oral, once-daily pill
• Regulatory submission expected in the second half of 2026
• If approved, this would be the first new oral therapy for SCD in years and would fill a major gap between hydroxyurea and gene therapy

Mitapivat (Agios):

• Also a PK activator, evaluated in the RISE UP trial
• The RISE UP trial met the hemoglobin response endpoint but VOC reduction was not statistically significant
• This means mitapivat improved anemia markers but did not demonstrate a meaningful reduction in pain crises
• Still under evaluation but less promising than etavopivat for clinical event reduction

Ask your hematologist about clinical trials for these and other pipeline agents.

Chronic (regular, scheduled) red blood cell transfusions are used in SCD for specific indications:

• Stroke prevention: Following abnormal TCD or a prior stroke. Goal is to maintain HbS below 30%. This is the most common indication and is usually lifelong.
• Severe or recurrent acute chest syndrome
• Severe symptomatic anemia not responsive to hydroxyurea
• Organ failure prevention

Transfusions can be given as simple transfusions (adding donor blood) or exchange transfusions (removing the patient’s blood and replacing it with donor blood, using a machine called an apheresis device). Exchange transfusion avoids iron overload but requires venous access and is more resource-intensive.

Iron chelation: Patients on chronic simple transfusion therapy accumulate iron, which deposits in the liver, heart, and endocrine glands, causing serious damage. Iron chelation therapy removes excess iron:

• Deferasirox (Exjade/Jadenu): Oral, once daily. Most commonly used. Requires kidney function monitoring.
• Deferoxamine (Desferal): Subcutaneous or IV infusion, 8–12 hours/day, 5–7 days/week. Effective but burdensome.
• Deferiprone (Ferriprox): Oral, three times daily. Particularly effective at removing cardiac iron.

Iron levels are monitored by serum ferritin (every 3 months) and liver iron concentration by MRI (annually). Cardiac MRI (T2*) monitors cardiac iron loading.

Even between acute events, SCD silently damages organs over time. By adulthood, most patients with HbSS have evidence of damage to one or more organs. Regular screening catches problems early, when intervention can make a difference.

Recommended surveillance includes:

• Kidneys: Annual urinalysis for proteinuria starting at age 10. Sickle nephropathy is the most common cause of chronic kidney disease in SCD. Early use of ACE inhibitors may slow progression.
• Eyes: Annual dilated eye exams starting at age 10 (some experts recommend earlier). Sickle retinopathy — particularly proliferative retinopathy in HbSC disease — can cause blindness if untreated. Laser photocoagulation is the treatment.
• Lungs: Pulmonary function tests periodically. Pulmonary hypertension is a serious complication; echocardiography can screen for elevated pressures.
• Heart: Echocardiography to monitor for diastolic dysfunction and pulmonary hypertension.
• Hips and shoulders: Avascular necrosis (bone death from blocked blood supply) affects up to 50% of adults with HbSS. Report persistent joint pain promptly; early MRI can catch it before joint destruction.
• Liver: Monitor liver function, especially in patients on chronic transfusion therapy (iron overload) or with sickle hepatopathy.
• Spleen: Ultrasound in young children. Most adults with HbSS have auto-infarcted spleens by adolescence.

Infection prevention is a cornerstone of SCD management, particularly in children. Functional asplenia makes SCD patients vulnerable to overwhelming sepsis from encapsulated bacteria.

Penicillin prophylaxis:

• Start by age 2 months
• Dose: Penicillin V 125 mg twice daily for children under age 3; 250 mg twice daily from age 3 to 5
• After age 5: can consider stopping in children who have not had a serious pneumococcal infection and who have been fully vaccinated, though some experts recommend continuing longer, especially in HbSS
• The PROPS study showed an 84% reduction in pneumococcal sepsis with penicillin prophylaxis

Vaccinations (in addition to the standard childhood schedule):

• Pneumococcal vaccines: Both PCV15 or PCV20 (conjugate) AND PPSV23 (polysaccharide) are recommended. Discuss exact schedule with your hematologist.
• Meningococcal vaccines: Both MenACWY and MenB series
• Haemophilus influenzae type b (Hib): Standard schedule
• Annual influenza vaccine
• COVID-19 vaccines: Recommended and up to date
• Hepatitis B: Especially important for patients receiving transfusions

Keep a current vaccination record and bring it to every appointment.

While not a substitute for medical treatment, daily wellness habits meaningfully affect SCD outcomes:

• Hydration: Dehydration is one of the most preventable VOC triggers. Sickle red blood cells are more likely to polymerize in a dehydrated environment. Aim for generous fluid intake throughout the day — water is best. Avoid excessive caffeine and alcohol, which promote dehydration.
• Avoid temperature extremes: Both extreme cold and overheating can trigger crises. Dress warmly in cold weather. Avoid unheated swimming pools. Stay cool in heat but avoid air conditioning set too cold.
• Altitude: Low-oxygen environments (high altitude, unpressurized aircraft cabins) can trigger sickling. Commercial aircraft cabins are pressurized to approximately 6,000–8,000 feet, which is usually tolerable but may require supplemental oxygen for some patients. Discuss air travel with your hematologist.
• Exercise: Moderate exercise is encouraged but avoid extreme exertion and dehydration during activity. Stay well-hydrated before, during, and after exercise. Listen to your body.
• Nutrition: Folate supplementation (1 mg/day) is commonly recommended to support red blood cell production. A balanced, nutritious diet supports overall health. Vitamin D supplementation may be needed, as deficiency is common in SCD.
• Sleep: Adequate sleep is important. Sleep apnea is more common in SCD and can worsen nocturnal oxygen levels — report snoring or daytime sleepiness to your doctor.

Depression and anxiety are significantly more common in people with SCD than in the general population. Living with chronic pain, unpredictable crises, frequent hospitalizations, limitations on activities, and the burden of a stigmatized disease takes a profound psychological toll.

Key points:

• Depression affects an estimated 25–30% of adults with SCD
• Anxiety is similarly prevalent
• Pain catastrophizing (a pattern of negative cognitive and emotional responses to pain) worsens both pain perception and outcomes
• PTSD can develop from repeated traumatic pain experiences and hospitalizations
• Social isolation is common, especially in adolescents and young adults

What helps:

• Cognitive behavioral therapy (CBT) has the strongest evidence for chronic pain and depression in SCD
• Ask your SCD team about psychology/psychiatry referrals — mental health support should be integrated into SCD care, not an afterthought
• Peer support groups (in-person or online) reduce isolation
• Mindfulness and relaxation techniques complement medical pain management
• Antidepressant medications, when indicated, are safe and effective in SCD
• For children: school accommodations (504 plans or IEPs) reduce academic stress

Mental health is physical health. Do not dismiss emotional suffering as “just part of having SCD.”

The transition from pediatric to adult SCD care is one of the most dangerous periods in a patient’s life. Data consistently shows:

• Mortality increases 2.3 times between ages 15–19 and 20–24
• A gap of more than 6 months between the last pediatric visit and first adult visit doubles the hospitalization risk
• ED utilization spikes during the transition period
• Medication adherence (especially hydroxyurea) drops significantly

Why it is so dangerous: Pediatric hematology programs typically provide comprehensive, team-based care with social workers, psychologists, and transition coordinators. Adult hematology care often lacks these wrap-around services. Young adults lose the familiarity of their childhood medical team. Insurance coverage may change. Mental health, social, and economic stressors all peak during this period.

Best practices for a safe transition:

• Start transition planning at age 12–14 — do not wait until 18
• Use a structured transition readiness assessment tool
• Identify an adult hematologist with SCD expertise well before the transfer date
• Arrange a “warm handoff” — a joint visit or direct introduction between pediatric and adult teams
• Ensure the young adult has health insurance secured before leaving pediatric care
• Transfer complete medical records, including imaging, lab trends, and complication history
• Continue follow-up contact for 6–12 months after transition to ensure engagement

Pregnancy in SCD is high-risk but achievable with proper planning and monitoring. The World Health Organization published its first global guideline on SCD in pregnancy in June 2025, reflecting growing recognition of this critical area.

Key facts:

• Women with SCD face 4 to 11 times the maternal mortality risk compared to women without SCD
• Increased risks of preeclampsia, preterm delivery, low birth weight, and pain crises during pregnancy
• Acute chest syndrome risk is elevated during pregnancy and the postpartum period
• VTE (blood clot) risk is also elevated

Before pregnancy:

• Hydroxyurea must be stopped before conception — it is a known teratogen (can cause birth defects). Ideally, stop at least 3 months before trying to conceive.
• Partner testing: The father should be tested for hemoglobin disorders. If both parents carry abnormal hemoglobin genes, genetic counseling is essential.
• Baseline health assessment: Kidney function, blood pressure, cardiac status, and current hemoglobin level should all be evaluated.
• Folic acid supplementation: Higher dose (4 mg/day) is recommended starting before conception.

During pregnancy:

• Co-management by a high-risk obstetrician (maternal-fetal medicine specialist) AND a hematologist with SCD expertise
• Prophylactic transfusions may be recommended to maintain hemoglobin and reduce HbS percentage
• Close monitoring for preeclampsia, fetal growth, and pain crises
• Low-dose aspirin for preeclampsia prevention starting in the first trimester
• Venous thromboembolism prophylaxis
• Delivery planning at a center with SCD expertise and blood bank capability

Contraception: Progesterone-only methods (IUDs, implants, progesterone-only pills) are generally preferred. Combined estrogen-containing contraceptives are used with caution due to VTE risk. Long-acting reversible contraception (LARC) is particularly appropriate for women who want to delay pregnancy while ensuring reliable protection.

Casgevy, developed by Vertex Pharmaceuticals and CRISPR Therapeutics, is the world’s first CRISPR-based gene therapy approved for any disease. It was FDA-approved on December 8, 2023, for patients aged 12 and older with sickle cell disease and a history of recurrent vaso-occlusive crises.

How it works: Casgevy uses CRISPR/Cas9 gene editing to modify the BCL11A enhancer in the patient’s own blood stem cells. BCL11A is the genetic switch that turns off fetal hemoglobin (HbF) production after birth. By disrupting this switch, Casgevy permanently reactivates fetal hemoglobin, which prevents hemoglobin S from polymerizing and sickling. The patient’s own stem cells are collected, edited in a laboratory, and then infused back after myeloablative conditioning chemotherapy (busulfan).

Clinical trial results (combined CLIMB SCD analysis):

• 100% of evaluable patients (45 out of 45) were free of vaso-occlusive crises with a mean VOC-free duration of 35.3 months
• Durable fetal hemoglobin production
• Patients reported dramatic improvements in quality of life, pain, fatigue, and daily functioning

Real-world rollout (2025 data):

• 50 active treatment sites globally
• 301 patients started the treatment process in 2025
• 111 infusions completed in 2025
• 90% of U.S. patients have reimbursed insurance access
• 10 ex-U.S. countries have coverage

Expansion to younger children: Data on patients aged 5–11 was presented at ASH in December 2025, with regulatory submissions for this age group expected in the first half of 2026.

Cost: Approximately $2.2 million per treatment.

Key risks and considerations:

• Myeloablative conditioning (busulfan): Required to destroy the patient’s existing bone marrow to make room for the edited cells. This is intense chemotherapy with risks including infections, mucositis, and infertility.
• Fertility: Busulfan conditioning is highly likely to cause infertility. Fertility preservation (egg, sperm, or ovarian/testicular tissue cryopreservation) should be discussed and offered before treatment. For pre-pubertal children, experimental tissue banking is the only option.
• Hospitalization: Typically 4–6 weeks in the hospital during conditioning and engraftment, with several months of recovery before returning to normal activities.
• Long-term unknowns: CRISPR is a new technology. While results so far are extremely promising, the longest follow-up is still under 5 years. Patients will need lifelong monitoring.
• No cancer signal: Unlike Lyfgenia (see below), Casgevy has not shown any signal of blood cancers. The CRISPR editing mechanism is considered less likely to cause insertional mutagenesis than viral vectors.

Lyfgenia, developed by bluebird bio, was FDA-approved on December 8, 2023, the same day as Casgevy. It is approved for patients aged 12 and older with sickle cell disease and a history of recurrent vaso-occlusive crises.

How it works: Unlike Casgevy’s gene editing approach, Lyfgenia uses a lentiviral vector (a modified virus) to add a new gene to the patient’s stem cells. This gene produces an anti-sickling beta-globin called HbA-T87Q (βA-T87Q), which functions like normal hemoglobin and prevents sickling. The patient’s stem cells are collected, the gene is added in the laboratory, and the modified cells are infused back after myeloablative conditioning.

Clinical trial results: Patients showed significant increases in anti-sickling hemoglobin, reduced pain crises, and improved quality of life.

Cost: Approximately $3.1 million per treatment.

Practical reality: Given the cancer risk associated with Lyfgenia and the excellent safety and efficacy profile of Casgevy, many transplant centers now recommend Casgevy over Lyfgenia when both are available. The decision should be made through a detailed discussion with your treatment team, considering availability, individual risk factors, and personal preferences.

Feature	Casgevy	Lyfgenia
Mechanism	CRISPR gene editing — reactivates fetal hemoglobin	Lentiviral gene addition — adds anti-sickling globin
VOC-free rate	100% of evaluable patients (45/45)	Significant reduction (varies by measure)
Cancer risk	No signal detected	Boxed warning: 2 AML deaths + 1 MDS case
Conditioning	Myeloablative busulfan (required)	Myeloablative busulfan (required)
Fertility impact	High infertility risk (from busulfan)	High infertility risk (from busulfan)
Monitoring	Long-term follow-up (15 years recommended)	Minimum 15 years cancer surveillance (required)
Cost	~$2.2 million	~$3.1 million
Current age range	≥12 years (ages 5–11 under review)	≥12 years

Several next-generation gene therapies are in clinical trials, aiming to improve on current options:

BEAM-101 (risto-cel) — Beam Therapeutics:

• Mechanism: Base editing — a more precise form of gene editing that changes a single DNA letter without making a double-strand cut (unlike CRISPR/Cas9). This is theoretically safer because it avoids the risk of unintended chromosomal rearrangements.
• BEACON Phase 1/2 trial: 31 patients treated
• Results: Fetal hemoglobin (HbF) levels above 60%, sickle hemoglobin (HbS) below 40%. No severe VOCs after engraftment. Published in the New England Journal of Medicine.
• Significance: If the safety and efficacy hold up in larger trials, base editing could offer a refined alternative to CRISPR cutting.

Reduced-intensity conditioning gene therapy:

• A Phase 1/2 trial using a GbGM lentiviral vector with a modified gamma-globin gene (HbFG16D) was published in Nature Medicine in 2025.
• Key advantage: Uses reduced-intensity conditioning instead of the full myeloablative busulfan used by Casgevy and Lyfgenia. This means less toxicity, potentially preserving fertility, and expanding eligibility to patients who cannot tolerate intensive conditioning.
• Early results showed greater than 80% reduction in VOC events.
• If successful in larger trials, reduced-intensity approaches could make gene therapy accessible to a much broader population, including older adults and those with organ damage.

Hematopoietic stem cell transplant (HSCT) has been the only established cure for SCD for over 30 years. It replaces the patient’s sickle cell-producing bone marrow with healthy donor marrow.

Matched sibling donor (MSD) transplant:

• The gold standard when a fully matched sibling donor is available
• Cure rates above 90% in children
• Graft rejection rates are low
• Graft-versus-host disease (GVHD) — where donor immune cells attack the recipient’s body — is the main risk
• The limitation: Only about 15–20% of SCD patients have a fully matched sibling donor

Haploidentical (half-matched) donor transplant:

• Uses a parent, sibling, or child as a half-matched donor — dramatically expanding the donor pool since nearly every patient has a haploidentical donor
• The modified Hopkins platform with post-transplant cyclophosphamide (PTCy) has improved outcomes significantly:
• Overall survival: 91%
• Graft failure: 7%
• Acute GVHD: 4%
• Chronic GVHD: 11%
• Still carries higher risks than matched sibling transplant but has become a viable option for many more patients

Matched unrelated donor (MUD) transplant:

• Uses a donor from the national bone marrow registry
• Historically higher complication rates than matched sibling transplant
• Donor registries have limited diversity, making it harder to find well-matched donors for patients of African descent

Transplant vs. gene therapy: Both are curative, but transplant uses someone else’s stem cells (with risk of GVHD), while gene therapy uses the patient’s own modified cells (no GVHD risk but different unknowns). The choice depends on donor availability, patient age, organ function, personal preferences, and center expertise. A transplant specialist can help navigate this decision.

Gene therapy is not a single event — it is a months-long process. Understanding the timeline helps patients and families prepare.

1. Evaluation and eligibility (weeks 1–4): Comprehensive health assessment including heart, lung, liver, and kidney function. Infectious disease screening. Psychological evaluation. Insurance authorization. Fertility counseling and preservation.
2. Stem cell collection (weeks 4–8): The patient receives injections of a medication (plerixafor, sometimes with G-CSF) to mobilize stem cells from the bone marrow into the bloodstream. Stem cells are then collected through a process called apheresis — blood is drawn from one arm, stem cells are separated out by a machine, and the remaining blood is returned through the other arm. This may take multiple sessions.
3. Manufacturing (6–16 weeks): The collected stem cells are shipped to the gene therapy manufacturer, where they are edited (Casgevy) or transduced with the viral vector (Lyfgenia). This takes several weeks to months. The patient returns home during this period and continues their usual SCD management.
4. Conditioning chemotherapy (about 4 days): Once the modified cells are ready, the patient is admitted to the hospital and receives myeloablative busulfan chemotherapy over approximately 4 days. This destroys the existing bone marrow to create space for the new cells. This is the most physically challenging part of the process.
5. Infusion (day 0): The edited stem cells are infused through an IV, similar to a blood transfusion. The cells find their way to the bone marrow and begin growing.
6. Engraftment and recovery (2–6 weeks in hospital): The patient has very low blood counts during this period and is highly vulnerable to infection. Close monitoring, antibiotics, and transfusion support are required. Neutrophil engraftment (white blood cells recovering to safe levels) typically occurs 2–4 weeks after infusion.
7. Post-discharge recovery (months 2–6): Gradual return to normal activities. Frequent clinic visits to monitor blood counts, hemoglobin composition, and organ function. Avoiding crowded places and sick contacts until immune recovery is complete.
8. Long-term follow-up (years 1–15+): Regular monitoring to confirm durability of the treatment and screen for any late complications.

The cost of gene therapy — $2.2 million for Casgevy, $3.1 million for Lyfgenia — would be prohibitive for nearly all patients without insurance coverage and innovative payment models.

CMS Cell and Gene Therapy (CGT) Access Model:

• Launched to address the access challenge for Medicaid patients (who make up a large proportion of SCD patients in the U.S.)
• 33 states plus D.C. and Puerto Rico are participating
• Uses outcomes-based payment — the manufacturer receives full payment only if the therapy achieves defined clinical outcomes
• Reduces financial risk for state Medicaid programs and increases willingness to cover these expensive therapies

Private insurance: Most major private insurers are covering gene therapy for SCD, though prior authorization, center-of-excellence requirements, and appeals processes may be involved. According to Vertex, 90% of U.S. patients now have reimbursed access to Casgevy.

Practical barriers beyond cost:

• Limited number of authorized treatment centers (50 active sites globally as of 2025)
• Travel and housing costs for patients who must relocate near a treatment center for several months
• Lost wages for the patient and a caregiver during the treatment and recovery period
• Childcare for other children in the family
• Many treatment centers have social workers and patient navigators who can help with these practical challenges

Both gene therapy (due to busulfan conditioning) and bone marrow transplant carry a high risk of infertility. This conversation must happen before treatment begins — there is no going back after conditioning chemotherapy.

Options for fertility preservation:

• Post-pubertal males: Sperm banking is straightforward and highly effective. Multiple samples should be collected and cryopreserved before starting any conditioning regimen.
• Post-pubertal females: Egg freezing (oocyte cryopreservation) or embryo freezing. Requires 2–3 weeks of ovarian stimulation with hormonal injections, followed by an egg retrieval procedure. Should be initiated well before the planned treatment date.
• Pre-pubertal children: Options are more limited. Experimental ovarian tissue cryopreservation (for girls) and testicular tissue cryopreservation (for boys) are available at some academic centers. These are research-level procedures, and successful fertility restoration from prepubertal tissue is not yet proven, but the tissue is preserved for future use as techniques advance.

Insurance coverage: Many states now mandate insurance coverage for fertility preservation before medical treatments that may cause infertility. Ask your treatment center’s social worker about coverage and financial assistance programs.

This is not a minor issue. For many young patients and families, fertility preservation is a decisive factor in whether to pursue curative therapy. Have this conversation early, honestly, and with a reproductive endocrinologist.

• Sickle Cell Disease Association of America (SCDAA): The oldest and largest patient advocacy organization for SCD in the U.S. Provides education, connects patients with local chapters, advocates for research funding and policy changes, and offers community programs. Website: sicklecelldisease.org
• American Society of Hematology (ASH): Publishes evidence-based clinical guidelines for SCD management. Their 2020 guidelines cover pain management, transfusion, cerebrovascular disease, and more. Available free online.
• National Heart, Lung, and Blood Institute (NHLBI): Part of the NIH. Funds SCD research and publishes clinical guidelines. Maintains a registry of SCD clinical trials.
• Sickle Cell Foundation of Georgia (SCFG): One of the most active state-level foundations, offering newborn screening follow-up, transition support, and comprehensive patient services.
• Sick Cells: Patient advocacy organization focused on health equity, research funding, and amplifying patient voices in SCD policy discussions.
• Global Alliance of Sickle Cell Disease Organizations (GASCDO): International umbrella organization connecting SCD organizations worldwide.

Sickle cell disease has long been one of the most underfunded and under-researched genetic diseases relative to its burden. The numbers are stark:

• NIH research funding per patient: Cystic fibrosis receives approximately $2,807 per patient per year. Sickle cell disease receives approximately $812 per patient per year. That is a 3.4-fold disparity for a disease that affects three times more Americans.
• Cystic fibrosis, which affects primarily white populations, has had a well-funded research pipeline, strong pharmaceutical partnerships, and a network of accredited care centers for decades. SCD, which primarily affects Black populations, has historically received a fraction of that investment.
• SCD was the first molecular disease ever characterized (1949). Despite 75+ years of understanding the molecular basis, the pace of therapeutic development lagged far behind other genetic diseases until very recently.

What is changing: Advocacy organizations have brought these disparities to national attention. The SCDAA, ASH, and patient-led groups have pushed for increased NIH funding, expanded Medicaid coverage, and the CMS Gene Therapy Access Model. The approval of two gene therapies in 2023 was a landmark. But disparities in access, research funding, and care quality persist.

What you can do:

• Contact your congressional representatives to advocate for SCD research funding and care access
• Share your story — patient testimonies are among the most powerful advocacy tools
• Participate in clinical trials when appropriate — SCD research depends on patient enrollment
• Join or donate to SCD advocacy organizations
• Support health equity initiatives in your community

Utah has a smaller SCD population than many states, which can make finding experienced providers more challenging. Key resources include:

• University of Utah Health — Hematology: The academic medical center in Salt Lake City offers hematology services and can coordinate SCD care. While Utah does not have a large dedicated sickle cell center, the university’s hematology division can manage patients and refer to larger centers for specialized procedures like gene therapy or transplant.
• Primary Children’s Hospital (Intermountain Healthcare): Provides pediatric hematology services for children with SCD in the Intermountain region. Connected to the University of Utah’s pediatric department.
• Intermountain Healthcare: The largest healthcare system in Utah. While SCD expertise is more limited than at major SCD centers on the East Coast or in the South, Intermountain providers can manage routine care and escalate appropriately.
• Telehealth options: For patients in Utah who need access to SCD specialists at larger centers, telehealth consultations with institutions like St. Jude, NIH, or Emory University may be available. Ask your local hematologist about establishing a virtual co-management arrangement.
• Altitude considerations: Utah’s high elevation (Salt Lake City is at approximately 4,226 feet, and many areas are higher) can trigger sickling in some patients. Discuss altitude precautions with your hematologist, especially before traveling to higher-elevation areas of the state.

Clinical trials are how new SCD treatments reach patients. Participating in a trial can provide access to cutting-edge therapies and contributes to knowledge that helps future patients.

Where to search:

• ClinicalTrials.gov: The U.S. government registry of clinical trials. Search for “sickle cell disease” and filter by location, age, and phase. As of 2026, there are hundreds of active SCD trials.
• ASH Clinical Trials Search: The American Society of Hematology maintains a searchable database focused on blood diseases.
• NHLBI Cure Sickle Cell Initiative: A collaborative research initiative accelerating development of genetic therapies for SCD.
• Your SCD care team: Your hematologist should proactively discuss trial eligibility with you at each visit.

Questions to ask about any trial:

• What phase is the trial? (Phase 1 = first in humans; Phase 2 = does it work; Phase 3 = comparison to standard care)
• Is there a chance I will receive placebo instead of the experimental treatment?
• What are the known risks and side effects?
• How often will I need to visit the study site?
• Are travel, lodging, and other expenses covered?
• Can I continue my current SCD medications while on the trial?
• What happens to my care after the trial ends?

SCD imposes significant financial burdens: frequent hospitalizations, expensive medications, lost work days, and travel to specialized care.

Insurance programs:

• Medicaid: Many SCD patients qualify for Medicaid, which covers most SCD-related care. The CMS Gene Therapy Access Model specifically addresses gene therapy coverage for Medicaid beneficiaries.
• Medicare: SCD patients with end-stage renal disease or who have received Social Security Disability for 24 months may qualify.
• ACA Marketplace: Cannot deny coverage based on SCD as a pre-existing condition.
• Supplemental Security Income (SSI) and Social Security Disability Insurance (SSDI): SCD patients with significant functional limitations may qualify. The Compassionate Allowances program can expedite SCD disability claims.

Medication assistance programs:

• Hydroxyurea is generic and generally affordable, but if cost is a barrier, Patient Assistance Programs (PAPs) from generic manufacturers may help.
• L-glutamine (Endari): Emmaus Medical offers a patient assistance program.
• Gene therapy: Vertex (Casgevy) and bluebird bio (Lyfgenia) both have patient support programs to help with insurance navigation and out-of-pocket costs.

Other resources:

• SCDAA local chapters may offer emergency financial assistance
• Hospital social workers can connect you to local aid programs
• United Way 211: Call 211 for local assistance with housing, food, utilities, and transportation

The psychological burden of SCD is substantial, and specialized mental health support is critical.

• Comprehensive SCD centers: Many larger centers have psychologists and social workers integrated into the SCD team. Ask if yours does.
• SCDAA support groups: Both in-person (through local chapters) and online. Connecting with other SCD patients and families who truly understand the experience is powerful.
• Therapy options: Cognitive behavioral therapy (CBT) has the strongest evidence base for chronic pain conditions, including SCD. Acceptance and commitment therapy (ACT) is another evidence-based option. Look for therapists who have experience with chronic illness.
• Crisis resources: If you or someone with SCD is experiencing a mental health crisis, the 988 Suicide and Crisis Lifeline (call or text 988) is available 24/7. The Crisis Text Line (text HOME to 741741) is another option.
• Caregiver support: Caregiver burnout is real. The National Alliance for Caregiving and the Family Caregiver Alliance offer resources specifically for caregivers of people with chronic illness.
• School-based support for children: Children with SCD benefit from 504 plans that accommodate absences, pain episodes, hydration needs, bathroom access, and activity modifications. School psychologists can help develop these plans.

The global SCD landscape is changing rapidly:

• WHO recognition: The World Health Organization has increasingly prioritized SCD, including publishing its first global guideline on SCD in pregnancy (June 2025). The 2006 World Health Assembly resolution recognized SCD as a global health priority.
• Newborn screening expansion: India’s National Sickle Cell Elimination Mission (NSCEM) screened over 42 million people in its first 14 months. Countries across sub-Saharan Africa are expanding pilot screening programs, though reaching all newborns remains a formidable challenge.
• Hydroxyurea in Africa: The REACH trial demonstrated that fixed-dose hydroxyurea (20 mg/kg) is safe and feasible in malaria-endemic sub-Saharan Africa, opening the door to broader use in the regions with the highest disease burden.
• Gene therapy access globally: Currently concentrated in high-income countries. Efforts are underway to develop more affordable gene therapy platforms and to establish treatment centers in Africa and India, but this remains years away.
• United Nations General Assembly: SCD advocacy groups are pushing for a UN high-level meeting on SCD, similar to those held for HIV/AIDS, tuberculosis, and non-communicable diseases.

The progress of the past five years is remarkable. For the first time, we have approved cures, a strong pipeline of new therapies, global momentum on screening and treatment access, and a growing community of empowered patients and advocates. The future for people with sickle cell disease is brighter than it has ever been.

The following clinical guidelines and landmark studies form the evidence base for this guide. You do not need to read these yourself, but your medical team should be familiar with them. If a recommendation in this guide is questioned, these are the sources to reference.

• ASH 2020 Guidelines for Sickle Cell Disease — Published in Blood Advances. Covers pain management, transfusion, cerebrovascular disease, cardiopulmonary and kidney disease. Available free at hematology.org.
• NHLBI Evidence-Based Management of SCD (2014) — Expert panel report. Remains the foundation for many care recommendations.
• MSH Trial (Charache et al., NEJM 1995) — Landmark trial proving hydroxyurea reduces pain crises and acute chest syndrome in adults with HbSS.
• BABY HUG Trial (Wang et al., Lancet 2011) — Proved hydroxyurea benefit in infants aged 9–17 months with HbSS.
• STOP Trial (Adams et al., NEJM 1998) — Proved that chronic transfusion prevents first stroke in children with abnormal TCD.
• CLIMB SCD / CLIMB-121 (Casgevy) — Combined analysis and registration trial data presented at ASH and published.
• BEACON (BEAM-101) — Phase 1/2 base editing trial. Published in NEJM.
• HIBISCUS (Etavopivat) — Phase 3 results reported April 2026. First PK activator to meet both co-primary endpoints.
• WHO Guideline on SCD in Pregnancy (June 2025) — First global guideline on this topic.
• REACH Trial (Hydroxyurea in Africa) — Fixed-dose hydroxyurea feasibility in malaria-endemic settings.

• Voxelotor (Oxbryta) — Approved by the FDA in 2019, voxelotor worked by increasing hemoglobin’s oxygen affinity to reduce sickling. While it improved hemoglobin levels on blood tests, the HOPE-KIDS 2 pediatric trial revealed more deaths in the treatment arm than placebo. Pfizer voluntarily withdrew the drug from the global market on September 25, 2024. Patients should not refill or continue taking this medication. WITHDRAWN
• Inclacumab (Pfizer) — A second anti–P-selectin monoclonal antibody (similar mechanism to crizanlizumab) tested in the THRIVE-131 Phase 3 trial. The trial failed to meet its primary endpoint in August 2025, marking the second P-selectin inhibitor to fail in a confirmatory trial and raising fundamental questions about whether blocking P-selectin alone is sufficient to prevent pain crises. FAILED
• Crizanlizumab (Adakveo) — weakened evidence — Originally approved by the FDA in 2019 based on the Phase 2 SUSTAIN trial, the Phase 3 STAND confirmatory trial failed to meet its primary endpoint. The European Medicines Agency revoked marketing authorization in August 2023. The drug remains FDA-approved in the U.S. but its evidence base is significantly weakened. Discuss with your hematologist whether continuing or starting this medication is appropriate. DE-ADOPTED (EU)
• Mitapivat (RISE UP trial) — A pyruvate kinase activator tested in the RISE UP Phase 3 trial. While it met the hemoglobin response endpoint, the trial did not demonstrate a statistically significant reduction in vaso-occlusive crises — the outcome that matters most to patients. Without proven VOC reduction, the clinical utility for SCD is limited compared to etavopivat, which met both endpoints. FAILED (VOC endpoint)
• Chronic transfusion as sole secondary stroke prevention replacement — The SWiTCH trial tested whether hydroxyurea plus phlebotomy could replace chronic transfusion plus chelation for secondary stroke prevention (preventing recurrent stroke). The trial was stopped for futility — hydroxyurea did not reduce stroke recurrence in this setting. Chronic transfusion remains the standard for secondary stroke prevention and should not be replaced with hydroxyurea alone. FAILED
• Senicapoc (ICA-17043) — A Gardos channel blocker that aimed to reduce red blood cell dehydration and sickling. While Phase 2 data showed improved hemoglobin and reduced hemolysis markers, the Phase 3 trial was terminated early for futility in 2008 after it failed to reduce pain crisis frequency. The drug was never approved. FAILED
• Prasugrel (antithrombotic approach) — Tested in the DOVE Phase 3 trial (children and adolescents with SCD), prasugrel, an antiplatelet agent, failed to reduce VOC rate compared to placebo despite a rationale based on platelet activation in sickle cell vaso-occlusion. FAILED

Why this matters: These failures are not wasted effort. Each one teaches the scientific community something about the biology of SCD and narrows the path toward treatments that actually work. If someone recommends a therapy that appears on this list, ask your hematologist for the latest evidence before proceeding.

• United States (FDA) — Hydroxyurea, L-glutamine (Endari), and crizanlizumab (Adakveo) are approved disease-modifying therapies. Both Casgevy and Lyfgenia gene therapies were approved December 8, 2023. Voxelotor (Oxbryta) was withdrawn September 2024. Etavopivat is expected to be submitted for approval in the second half of 2026.
• European Union (EMA) — Hydroxyurea is approved. Crizanlizumab marketing authorization was revoked in August 2023. Casgevy received conditional marketing authorization for SCD (approved). Voxelotor was withdrawn. Gene therapy access is expanding but varies by member state reimbursement.
• United Kingdom (NICE/MHRA) — Casgevy was recommended by NICE (Technology Appraisal TA1044) for SCD patients aged 12 and older with recurrent VOCs. Lyfgenia was not recommended by NICE for SCD. Hydroxyurea is available. Crizanlizumab approval was withdrawn.
• Japan (PMDA) — SCD is rare in Japan, and most SCD-specific therapies have not been submitted for approval there. Patients with SCD in Japan typically access care through university hospital hematology departments.
• Canada (Health Canada) — Hydroxyurea is approved. Gene therapy access is being evaluated. Crizanlizumab was approved but evidence concerns apply. Treatment is primarily coordinated through academic medical centers in Toronto, Montreal, and other major cities.
• Australia (TGA) — SCD prevalence is low but growing due to migration from endemic regions. Hydroxyurea is available. Gene therapy has not yet been approved. Major SCD care is centralized at children’s hospitals and hematology departments in Sydney and Melbourne.
• India — Hydroxyurea is available and increasingly used through the National Sickle Cell Elimination Mission (NSCEM). Gene therapy is not yet available domestically. The NSCEM, launched July 2023, had screened over 42 million people by September 2024.
• Sub-Saharan Africa — The region with the highest SCD burden faces the greatest access challenges. Hydroxyurea is becoming more available through WHO and national programs, supported by the REACH and NOHARM trials showing safety in malaria-endemic settings. Gene therapy remains years away from broad access in Africa.

At present, most approved SCD therapies originated from U.S.-based development programs. There are no major SCD-specific therapies approved exclusively outside the United States. However, access to approved therapies differs by country:

• Casgevy is approved in the U.S., EU, UK, Bahrain, and Saudi Arabia (among others), with 10 countries having some form of access or reimbursement as of 2025.
• Hydroxyurea is available globally but is underused in many low- and middle-income countries due to supply chain, monitoring capacity, and awareness barriers.
• Bone marrow transplant is more widely available globally than gene therapy and remains the primary curative option in most countries outside the U.S. and Europe.

If you are traveling internationally with SCD, carry a medical summary letter from your hematologist (translated if necessary), a list of your medications with generic names, and information about your nearest SCD-capable facility at your destination. Some airline carriers may require a fitness-to-fly letter for SCD patients.