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M5049 low dose

Phase 2

Systemic Lupus Erythematosus | Small molecule | Immunology |Merck & Company, Inc.|Last Updated: Jul 20, 2026

Success Probability

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Trial Design

RandomizedDouble-BlindCONTROLLED
Total Trials1
Total Enrollment379

FDA Designations

No designations recorded

Clinical trial landscape

M5049 low dose · 1 trial · 1 indication

Phase 2 1
NCT05540327The Willow LTE Study With M5049 in Participants With SCLE, DLE and/or SLE (WILLOW LTE)Systemic Lupus Erythematosus
ACTIVE NOT_RECRUITING379 Analytics
PHASE2ACTIVE NOT_RECRUITING
The Willow LTE Study With M5049 in Participants With SCLE, DLE and/or SLE (WILLOW LTE)
Systemic Lupus ErythematosusUnlock trial analytics

Study Endpoints

Primary Endpoints

Part 1: Safety Profile as Assessed by Incidence of Treatment-Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs), Adverse Event of Special Interest (AESIs)
Baseline up to Week 50 (Long Term Extension Part 1)
Part 2: Safety Profile as Assessed by Incidence of Treatment-Emergent Adverse Events (TEAEs), Serious Adverse Events (SAEs), Adverse Event of Special Interest (AESIs)
Baseline up to Week 194 (LTE Part 1 and LTE Prolongation Part 2))

Secondary Endpoints

Part 1 and Part 2: Number of Participants with Abnormalities in Laboratory Parameters and QT Interval Corrected
Baseline up to Week 50 and LTE Prolongation up to Week 194 (Part 2)
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Study Design & Arms

AllocationRANDOMIZED
MaskingQUADRUPLE
ModelPARALLEL
PurposeTREATMENT

Treatment Arms

ArmTypeDescription
M5049 low dose + PlaceboEXPERIMENTALParticipants with CLE (active SCLE and/or DLE) or SLE who received low dose of M5049 in WILLOW study will continue to receive M5049 low dose and matching placebo.
M5049 medium dose+ PlaceboEXPERIMENTALParticipants with CLE (active SCLE and/or DLE) or SLE who received medium dose of M5049 in WILLOW study will continue to receive M5049 medium dose and matching placebo.
M5049 high dose + PlaceboEXPERIMENTALParticipants with CLE (active SCLE and/or DLE) or SLE who received M5049 matched placebo or high dose of M5049 in WILLOW study will receive M5049 high dose .

Interventions

NameTypeDescription
M5049 low doseDRUGParticipants will receive film-coated tablets of M5049 at a low dose orally, twice a day (BID) for up to 194 weeks.
M5049 medium doseDRUGParticipants will receive film-coated tablets of M5049 at a medium dose orally, BID for up to 194 weeks.
M5049 high doseDRUGParticipants will receive film-coated tablets of M5049 at a high dose orally, BID for up to 194 weeks.
PlaceboDRUGParticipants will receive M5049 matching placebo orally, BID for up to 194 weeks.
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Eligibility Criteria

Age Range18 Years to 76 Years
SexALL
Healthy VolunteersNo
Study Sites122

Inclusion Criteria: * Are SCLE, DLE and/or SLE that have completed the 24 week Treatment of the Willow Study * Have a Body Mass Index (BMI) within the less than or equal to (\<=) 40 kilograms per meter square (inclusive) at Screening * Participants who had successfully completed Week 48 of the Part...

Countries:United StatesArgentinaAustraliaBrazilBulgariaChileChinaColombiaGreeceIsraelJapanMauritiusMexicoMoldovaPhilippinesPolandRomaniaSerbiaSouth AfricaSouth KoreaSpainTaiwan
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Recent Changes (Last 90 Days)

LOWJul 20, 2026NCT05540327lastUpdatePostDate: changed
LOWJul 20, 2026NCT05540327lastUpdatePostDate: changed

Frequently asked questions about M5049 low dose

What is M5049 used for?

M5049 is an investigational small molecule being studied for Systemic Lupus Erythematosus, Coronavirus Disease 2019, and in healthy volunteers. It is developed by Merck & Company, Inc. (MRK) and is currently in Phase 2 clinical development. The drug is not approved and remains under investigation.

What does M5049 target?

M5049 is a small molecule therapeutic developed by Merck & Company, Inc. (MRK). Its specific molecular target has not been disclosed in available clinical trial information. The drug is being evaluated in Phase 2 trials for Systemic Lupus Erythematosus and COVID-19 pneumonia.

Who makes M5049?

M5049 is developed by Merck & Company, Inc., a pharmaceutical company traded on the New York Stock Exchange under the ticker MRK. The company is conducting clinical trials of M5049 in multiple countries, including the United States, for conditions such as Systemic Lupus Erythematosus and COVID-19.

What phase is M5049 in?

M5049 is in Phase 2 clinical development. It has completed a Phase 2 trial in COVID-19 pneumonia and a Phase 1 trial in healthy volunteers. An additional Phase 2 long-term extension study in Systemic Lupus Erythematosus is active but not recruiting participants.

What clinical trials is M5049 in?

M5049 has been studied in three clinical trials. NCT04448756 was a Phase 2 study in COVID-19 pneumonia. NCT04880213 was a Phase 1 study in healthy Japanese and Caucasian participants. NCT05540327 is an active Phase 2 long-term extension study in Systemic Lupus Erythematosus, with 379 participants enrolled.

Is M5049 the same as M5049 low dose?

M5049 is also known as M5049 low dose. The drug is being investigated by Merck & Company, Inc. (MRK) for Systemic Lupus Erythematosus and other conditions. Clinical trials reference the drug under the name M5049, and the low dose formulation is part of its development program.