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Osivelotor

Phase 2

Sickle Cell Disease | Small molecule | Hematology |Pfizer, Inc.|Last Updated: Aug 18, 2026

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment389

FDA Designations

No designations recorded

Clinical trial landscape

Osivelotor · 3 trials · 3 indications

Phase 2 1Phase 1 2
NCT05431088A Phase 2/3 Study of Osivelotor in Adult and Adolescent Participants With SCDSickle Cell Disease
RECRUITING389 Analytics
PHASE2RECRUITING
A Phase 2/3 Study of Osivelotor in Adult and Adolescent Participants With SCD
Sickle Cell DiseaseUnlock trial analytics

Study Endpoints

Primary Endpoints

Part A
Through week 12

Number of adult participants with change from baseline in hemoglobin (Hb) through week 12 as measured by change in osivelotor concentrations from baseline or percentage change from baseline of clinical measures of anemia Hb and hemolysis (including indirect bilirubin, reticulocytes and lactate dehydrogenase).

Part B
Through week 48

Co-primary endpoints: Hb response (increase from baseline of \>1 g/dL) at Week 48 (based on average of Hb levels at Week 40 and Week 48) and the Annualized rate of VOC through end of Week 48. A VOC is defined as an acute episode of pain that: * Has no medically determined cause other than a vaso-occlusive event, and * Results in a visit to a medical facility (hospitalization, emergency department, urgent care center, outpatient clinic, or infusion center), and * Requires parenteral narcotic agents, parenteral nonsteroidal anti-inflammatory drugs (NSAIDs), or an increase in treatment with oral narcotics. Complicated VOCs of acute chest syndrome (ACS), hepatic sequestration, splenic sequestration, priapism, and dactylitis that meet the requirements listed above will be included in this co-primary endpoint.

OLE
Approximately 24 months after last patient enrolled

Incidence of Treatment Emergent Adverse Events: * Incidence of SAEs * Incidence of AEs leading to discontinuation * Change from baseline in laboratory parameters.

Part 1: Mouth Feel Effect
1, 5, 10, 20 minutes post dose

Mouth feel visual analogue scale (VAS) assesses the participant's global perception of mouth feel (that is, effects over the whole course of the drug experience including any carryover effects). A 100-point VAS is used to assess response based on a score ranging from 0 points to 100 points (0 points = " Bad Mouth feel ", 50 points = "neither bad nor good mouth feel", and 100 points = "Good Mouth feel ").

Part 1: Bitter effect
1, 5, 10, 20 minutes post dose

Bitter visual analogue scale (VAS) assesses the participant's global perception of bitterness (that is, effects over the whole course of the drug experience including any carryover effects). A 100-point VAS is used to assess response based on a score ranging from 0 points to 100 points (0 points = " extremely bitter ", 50 points = "neither bad nor good bitterness", and 100 points = "not bitter").

Part 1: Tongue/mouth burn effect
1, 5, 10, 20 minutes post dose

Tongue/mouth burn visual analogue scale (VAS) assesses the participant's global perception of tongue/mouth burn (that is, effects over the whole course of the drug experience including any carryover effects). A 100-point VAS is used to assess response based on a score ranging from 0 points to 100 points (0 points = "extreme burn", 50 points = "neither bad nor good burn", and 100 points = "no burn").

Part 1:Overall liking effect
1, 5, 10, 20 minutes post dose

Overall liking visual analogue scale (VAS) assesses the participant's global perception of overall liking (that is, effects over the whole course of the drug experience including any carryover effects). A 100-point VAS is used to assess response based on a score ranging from 0 points to 100 points (0 points = "bad", 50 points = "neither bad nor good", and 100 points = "good").

Part 2: Area under the Concentration-Time Curve (AUC 0-144) of osivelotor, as data permits
0, 2, 4, 6, 8, 12, 24, 48, 72, 96, 144 hours post-dose

AUC from 0 to 144 hours is a measure of the whole blood concentration of the drug over time. It is used to characterize drug absorption; if AUC0-144 not available, then AUClast will be calculated.

Area under the whole blood and plasma concentration versus time curve (AUC) from time zero (pre-dose) to the last quantifiable concentration (AUClast) of osivelotor
0 hours (pre-dose) to 84 days post-osivelotor dose
Area under the whole blood and plasma concentration versus time curve (AUC) from time zero (pre-dose) to extrapolated infinite time (AUCinf) of osivelotor
0 hours (pre-dose) to 84 days post-osivelotor dose
Maximum observed whole blood and plasma concentration (Cmax) of osivelotor
0 hours (pre-dose) to 84 days post-osivelotor dose

Secondary Endpoints

Part 1: Number of Participants With Treatment-Emergent Adverse Events (AEs)
Day 1 to 28
Part 2: Number of Participants With Treatment-Emergent Adverse Events (AEs)
Day 1 to 84
Part 1 and 2: Number of participants with clinically significant laboratory abnormalities.
Day 1 to Day 2 for Part 1, Day 1 to Day 7 for Part 2.
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
Part BPLACEBO_COMPARATORStudy drug arm: Adult participants will receive osivelotor at 300 mg QD loading dose for 7 days followed by 150 mg QD through Week 48. Adolescent participant dose will be defined in a future protocol amendment. Placebo arm: Participants will receive placebo tablets for 48 weeks.
OLEEXPERIMENTALAdult Participants will receive 150 mg open-label osivelotor up to 2 years after the last participant's visit in Part B or when the drug is commercially available in that region. The appropriate doses for adolescents will be defined in a future protocol amendment.
Part AACTIVE_COMPARATORInitially, participants will be randomized 1:1 to 100 mg and 150 mg daily. Upon review of the 150 mg safety data from at least 6 participants, there will be 1:1:1 randomization: 100 mg, 150 mg, and up to 200 mg. Participants will then receive maintenance once daily doses through Week 12.
Part 1 Sequence 1 - PalatabilityEXPERIMENTALParticipants will receive 4 preparations (Treatments A, B, C, D) of osivelotor pellet/granules at least 2 hours apart on Day 1 which they will put in their mouth and then spit it out.
Part 1 Sequence 2 - PalatabilityEXPERIMENTALParticipants will receive 4 preparations (Treatments B, C, D, A) of osivelotor pellet/granules at least 2 hours apart on Day 1 which they will put in their mouth and then spit it out.
Part 1 Sequence 3 - PalatabilityEXPERIMENTALParticipants will receive 4 preparations (Treatments C, D, A, B) of osivelotor pellet/granules at least 2 hours apart on Day 1 which they will put in their mouth and then spit it out.
Part 1 Sequence 4 - PalatabilityEXPERIMENTALParticipants will receive 4 preparations (Treatments D, A, B, C) of osivelotor pellet/granules at least 2 hours apart on Day 1 which they will put in their mouth and then spit it out.
Part 2 Pharmacokinetics - Treatment EEXPERIMENTALParticipants will receive 1 preparation (Treatment E) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow.
Part 2 Pharmacokinetics - Treatment FEXPERIMENTALParticipants will receive 1 preparation (Treatment F) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow. They might have a dose on Day 7 which they will put in their mouth and then spit it out; afterwards they will complete the taste questionnaire.
Part 2 Pharmacokinetics - Treatment GEXPERIMENTALParticipants will receive 1 preparation (Treatment G) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow.
Part 2 Pharmacokinetics - Treatment HEXPERIMENTALParticipants will receive famotidine and afterwards preparation (Treatment H) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow.
Part 2 Pharmacokinetics - Treatment IEXPERIMENTALParticipants will receive 1 preparation (Treatment I) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow.
Part 2 Pharmacokinetics - Treatment JEXPERIMENTALParticipants will receive 1 preparation (Treatment J) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow. They might have a dose on Day 7 which they will put in their mouth and then spit it out; afterwards they will complete the taste questionnaire.
Part 2 Pharmacokinetics - Treatment KEXPERIMENTALParticipants will receive 1 preparation (Treatment K) of osivelotor pellet/granules on Day 1 which they will put in their mouth and swallow.
Group 1EXPERIMENTALParticipants with moderate hepatic impairment will receive a single dose of osivelotor, administered orally under fasted conditions.
Group 2EXPERIMENTALParticipants with mild hepatic impairment will receive a single dose of osivelotor, administered orally under fasted conditions.

Interventions

NameTypeDescription
OsivelotorDRUGTablets which contain drug substance
FamotidineOTHERFamotidine is a marketed medicine which decreases the amount of acid made in the stomach and is used to prevent and treat heartburn.
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Eligibility Criteria

Age Range12 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites80

Inclusion Criteria: Part A and Part B: * Male or female with SCD, HbSS and HbSB-zero * Participants with Hemoglobin ≥ 5.5 and ≤ 10.5 g/dL during Screening and considered stable by the Investigator. * For participants taking hydroxyurea and/or L-glutamine, the dose must be stable for at least 90 da...

Countries:United StatesBrazilIndiaKenyaNigeriaSaudi ArabiaUnited Kingdom
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Recent Changes (Last 90 Days)

LOWAug 18, 2026NCT05431088lastUpdatePostDate: changed
LOWAug 18, 2026NCT05431088lastUpdatePostDate: changed

Frequently asked questions about Osivelotor

What is Osivelotor used for?

Osivelotor is an investigational small molecule being studied for sickle cell disease, liver diseases, and in healthy adults. It is being developed by Pfizer, Inc. (NYSE: PFE). The drug is currently in Phase 1 clinical development and is not yet approved by the FDA.

What does Osivelotor target?

The molecular target of Osivelotor has not been disclosed in available information. The drug is a small molecule being studied for its effects in sickle cell disease and liver diseases, but its specific mechanism of action is not publicly detailed.

Who makes Osivelotor?

Osivelotor is being developed by Pfizer, Inc., a pharmaceutical company traded on the New York Stock Exchange under the ticker symbol PFE. Pfizer is conducting clinical trials to evaluate the drug's safety and efficacy in sickle cell disease and liver diseases.

What phase is Osivelotor in?

Osivelotor is in Phase 1 clinical development. It is being studied in early-stage trials to assess how the body processes the drug in people with liver impairment and healthy adults. The drug is investigational and has not received FDA approval.

What clinical trials is Osivelotor in?

Osivelotor is being studied in three clinical trials. NCT05431088 is a Phase 2/3 study in sickle cell disease, NCT06340347 is a Phase 1 study in liver diseases, and NCT06507904 is a Phase 1 study in healthy adults. These trials are conducted in multiple countries including the United States.

Is Osivelotor the same as PF-07940367?

Yes, Osivelotor is also known as PF-07940367. In clinical trial NCT06340347, the study medicine is referred to as Osivelotor (PF-07940367), confirming that these names refer to the same investigational drug being developed by Pfizer.