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LY3871801

Phase 2

Rheumatoid Arthritis | Small molecule | Immunology |Eli Lilly and Company|Trials Updated: May 22, 2026

LY3871801 development status

Highest phase Phase 2
Registered trials 4 across 1 sponsor since Feb 2022

LY3871801 target and mechanism

ModalitySmall molecule

Also known as [14C]-LY3871801

Success Probability

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Market & Valuation

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Trial Design

RandomizedDouble-BlindPLACEBO_CONTROLLEDDMC
Total Trials1
Total Enrollment164

FDA Designations

No designations recorded

LY3871801 clinical trials

LY3871801 · 1 trial · 1 indication

Phase 2 1
NCT05848258An Adaptive Phase 2a/2b Study of LY3871801 in Adult Participants With Rheumatoid ArthritisRheumatoid Arthritis
COMPLETED164 Analytics
PHASE2COMPLETED
An Adaptive Phase 2a/2b Study of LY3871801 in Adult Participants With Rheumatoid Arthritis
Rheumatoid ArthritisUnlock trial analytics

Study Endpoints

Primary Endpoints

Phase 2a: Change from Baseline in Disease Activity Score - high-sensitivity C-reactive protein (DAS28-hsCRP)
Baseline, Week 12
Phase 2b: Percentage of Participants Achieving American College of Rheumatology (ACR)50
Baseline to Week 12

Secondary Endpoints

Phase 2a: Percentage of Participants Achieving ACR20/50/70
Baseline to Week 12
Phase 2b: Change from Baseline in DAS28-hsCRP
Baseline, Week 12
Phase 2b: Percentage of Participants Achieving ACR20/70
Week 12
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Study Design & Arms

AllocationRANDOMIZED
MaskingDOUBLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
LY3871801 Phase 2aEXPERIMENTALParticipants will receive LY3871801 administered orally.
Placebo Phase 2aPLACEBO_COMPARATORParticipants will receive placebo.
LY3871801 Dose 1 Phase 2bEXPERIMENTALParticipants will receive LY3871801 administered orally.
LY3871801 Dose 2 Phase 2bEXPERIMENTALParticipants will receive LY3871801 administered orally.
LY3871801 Dose 3 Phase 2bEXPERIMENTALParticipants will receive LY3871801 administered orally.
Placebo Phase 2bPLACEBO_COMPARATORParticipants will receive placebo.

Interventions

NameTypeDescription
LY3871801DRUGAdministered orally
PlaceboDRUGAdministered orally
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Eligibility Criteria

Age Range18 Years to N/A
SexALL
Healthy VolunteersNo
Study Sites54

Inclusion Criteria: * Have a diagnosis of adult-onset RA for at least 3 months prior to screening as defined by the 2010 ACR/European League Against Rheumatism (EULAR) classification criteria. * Have moderately-to-severely active RA at screening and baseline, defined by the presence of * ≥6 swol...

Countries:United StatesArgentinaCzechiaFranceGermanyHungaryIndiaMexicoPolandUnited Kingdom
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Frequently asked questions about LY3871801

What is LY3871801 used for?

LY3871801 is being developed for the treatment of rheumatoid arthritis, an inflammatory autoimmune condition affecting the joints. It is an investigational small molecule studied in adults with rheumatoid arthritis. Eli Lilly and Company is developing the drug, and it has not been approved for any use.

Who is developing LY3871801?

LY3871801 is being developed by Eli Lilly and Company, which trades on the New York Stock Exchange under the ticker LLY. Lilly is the sponsor of the clinical program evaluating the drug in rheumatoid arthritis.

What phase is LY3871801 in?

LY3871801 is in Phase 2 development. It has completed one Phase 2a/2b clinical trial in adults with rheumatoid arthritis. The drug remains investigational and has not been approved by the FDA or any other regulatory agency.

What clinical trials is LY3871801 in?

LY3871801 has been studied in one clinical trial, NCT05848258, titled An Adaptive Phase 2a/2b Study of LY3871801 in Adult Participants With Rheumatoid Arthritis. The trial enrolled 164 participants across the United States, Argentina, Czechia, France, Germany, Hungary, India, Mexico, Poland, and the United Kingdom, and it is now completed.

Is LY3871801 the same as [14C]-LY3871801?

Yes, [14C]-LY3871801 is an alternative name for LY3871801. The [14C] label refers to a carbon-14 radiolabeled version of the same molecule, typically used in studies to track how the drug is absorbed, distributed, metabolized, and excreted.

How was the Phase 2 trial of LY3871801 designed?

The Phase 2a/2b trial NCT05848258 was a randomized, double-blind, placebo-controlled study in adults with rheumatoid arthritis. It enrolled 164 participants aged 18 years and older, included both sexes, and did not enroll healthy volunteers. The trial has been completed.