Discovery of Osivelotor (GBT021601): A Potent, Next-Generation Sickle Hemoglobin Polymerization Inhibitor.
Zhe Li, Carsten Alt, Kobina Dufu...
https://pubmed.ncbi.nlm.nih.gov/40832524/Actively Recruiting
Led by Pfizer · Updated on 2026-03-20
389
Participants Needed
49
Research Sites
104 weeks
Total Duration
Researchers are evaluating the safety, tolerability, effectiveness, and how the body processes and responds to osivelotor in people with sickle cell disease SCD. This multicenter, Phase 23 study focuses on both adults and adolescents with SCD, aiming to determine the best dose and assess the drugs effects over time. The study has three parts. Part A tests safety, tolerability, and dose-finding in adults with SCD, starting with randomization to different daily doses of osivelotor, ranging from 100 mg to potentially 200 mg, over 12 weeks. Part B compares osivelotor to placebo in adults and adolescents over 48 weeks, with adults receiving an initial 300 mg daily dose for 7 days followed by 150 mg daily, while adolescent dosing will be defined later. The Open Label Extension OLE offers long-term open-label osivelotor treatment for up to two years after Part B. Participants will be monitored throughout the study with regular visits to assess safety, blood responses, and how well they tolerate the medication. The main results will be reviewed through 12 weeks in Part A, 48 weeks in Part B, and approximately 24 months in the OLE. The study includes blood tests, monitoring of vaso-occlusive crises, and other health evaluations to understand osivelotors effects and safety over time.
CONDITIONS
A Phase 2/3 Study in Adult and Adolescent Participants With SCD
P
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Lead Sponsor
This table compares participation in this trial with other options available for this condition. The information is drawn from published research and the trial’s study details and is provided for educational purposes only.
| Factors | Osivelotor tablets | Placebo tablets (with stable background therapy) | Hydroxyurea (current standard therapy) |
|---|---|---|---|
| What it is | Osivelotor tablets are a next-generation inhibitor of sickle hemoglobin polymerization designed to reduce sickling and vaso-occlusive events in SCD. | Matching placebo tablets are provided along with stable background therapy to allow comparison with osivelotor. | Hydroxyurea is a guideline-endorsed oral therapy that raises fetal hemoglobin and reduces the frequency of vaso-occlusive crises. |
| Role in trial | Osivelotor is the investigational drug being evaluated for its effects on SCD symptoms and crisis frequency. | Placebo tablets are used as the control to measure the effects of osivelotor against no active new therapy. | Hydroxyurea is not assigned in this trial but serves as the external current-care benchmark for comparison. |
| Primary use | Investigational treatment to reduce sickling and vaso-occlusive episodes in sickle cell disease. | Comparator for assessing changes in vaso-occlusive crisis rates and symptoms in participants not receiving the active drug. | Established therapy for reducing painful crises and improving quality of life in SCD patients. |
| How it is given or performed | Oral tablets taken daily, per trial protocol. | Matching placebo tablets taken orally, same schedule as osivelotor arm. | Oral therapy prescribed once daily, with dose adjusted to clinical response, as per guideline and standard practice. |
| Evidence status | Clinical efficacy not yet established; results from this trial will determine effectiveness in crisis reduction. | Placebo arm serves as a control group; no expected disease-modifying effect. | Hydroxyurea efficacy well-established; reduces crisis frequency, pain events, and improves survival based on guideline-supported studies. |
| Important limitations | Long-term safety and effectiveness unknown; trial enrollment limited to ages 12+; results not yet available. | Placebo does not provide disease-modifying benefit; trial results may not generalize beyond controlled setting. | Hydroxyurea may cause cytopenias or require dose adjustments; not all patients tolerate or respond; rare adverse events occur. |
Disclaimer: This comparison is created with the help of artificial intelligence(AI) and may contain errors or missing information. It is not medical advice and does not mean one option is better or safer than another. Clinical trials are still being studied, and joining a trial is your choice. Please consult your healthcare professional before making any decisions.
You may qualify if you...
You will not qualify if you...
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
Duration - Up to 12 weeks
Participants receive daily doses of osivelotor to evaluate safety, tolerability, and efficacy and determine the optimal dose.
Duration - 48 weeks
Participants receive osivelotor or placebo to evaluate efficacy over a 48-week period.
Duration - Up to approximately 24 months
Participants receive open-label osivelotor to evaluate long-term safety and hematologic responses.
Study Type
INTERVENTIONAL
Masking
QUADRUPLE
Allocation
RANDOMIZED
Model
PARALLEL
Primary Purpose
TREATMENT
Number of Arms
3
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Zhe Li, Carsten Alt, Kobina Dufu...
https://pubmed.ncbi.nlm.nih.gov/40832524/Mofiyin Obadina, Sam Wilson, Vimal K Derebail...
https://pubmed.ncbi.nlm.nih.gov/37254256/Pfizer
Lead Sponsor