What is osivelotor studying for sickle cell disease?

Osivelotor is being studied to evaluate its safety, how well patients tolerate it, its effectiveness, and how it affects the body in people with sickle cell disease. Pfizer is sponsoring this research to find out if osivelotor can help manage this condition. Participants can expect careful monitoring throughout the trial to assess these factors.

Who may be eligible for this sickle cell disease clinical trial?

People aged 12 to 65 with sickle cell disease who have had between 2 and 10 vaso-occlusive crises in the past year may be eligible. Both males and females can join, but pregnant or breastfeeding women are excluded. Participants should have stable blood counts and stable doses if taking hydroxyurea or L-glutamine. Please review eligibility criteria for more details.

Is there any cost to participate in this sickle cell disease clinical trial?

Study-related care, including the study drug and all trial visits, is provided at no cost. However, personal costs like travel to the study site may not be covered and can vary. Participants should prepare for these possible expenses before joining.

Actively Recruiting

Phase 2

Phase 3

Age: 12Years +

All Genders

ID05431088

Phase 23 Study of Oral Osivelotor for Treating Sickle Cell Disease in Adolescents and Adults

Led by Pfizer · Updated on 2026-03-20

389

Participants Needed

Research Sites

104 weeks

Total Duration

AI-Summary

What this Trial Is About

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

Brief Title

A Phase 2/3 Study in Adult and Adolescent Participants With SCD

Who Can Participate

Age: 12Years +

All Genders

Eligibility Criteria

You may qualify if you...

Male or female with sickle cell disease
Participants with stable hemoglobin value as judged by the Investigator
Stable dose of hydroxyurea and/or L-glutamine for at least 90 days prior to consent, with no planned dose changes
Age between 12 and 65 years inclusive (for Part B)
Experienced 2 to 10 vaso-occlusive crises within 12 months of screening
Completed Part B to be eligible for Open Label Extension

You will not qualify if you...

More than 10 vaso-occlusive crises within 12 months of screening
Pregnant or breastfeeding female participants
Regular or recent (within 90 days) red blood cell transfusion therapy
Hospitalization for sickle cell crisis or vaso-occlusive event within 14 days before consent or during screening

Research Team

Pfizer Pfizer CT.gov Call Center

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