A Clinical Study of MK-1045 in People With Lupus or Rheumatoid Arthritis (MK-1045-004)

NCT07363590 | Recruiting Phase 1 FDA Drug

• 5 other identifiers: 1045-004U1111-1326-48162025-523412-36-00MK-1045-004jRCT2031250748
• Study Type: interventional
• Target: 21
• Locations: 6 countries
• Sites: 8

Brief Summary

This study looks at a study medicine called MK-1045 in people with lupus and rheumatoid arthritis (RA). The main goal of the study is to learn about the safety of MK-1045 and if people tolerate it when they receive it at different dose levels (amounts).

Conditions

Rheumatoid Arthritis; Systemic Lupus Erythematosus

Outcome Measures

Primary Outcomes (4)

• Part 1: Number of Participants with One or More Adverse Events (AEs)

  An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.

  Up to approximately 12 weeks

• Part 1: Number of Participants who Discontinue Study Drug Due to an AE

  An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.

  Up to approximately 4 weeks

• Part 2 and Part 3: Number of Participants with One or More AEs

  An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.

  Up to approximately 52 weeks

• Part 2 and Part 3: Number of Participants who Discontinue Study Drug Due to an AE

  An AE is defined as any unfavorable and unintended sign, symptom, disease, or worsening of preexisting condition temporally associated with study treatment and irrespective of causality to study treatment.

  Up to approximately 2 weeks

Secondary Outcomes (6)

• Part 1: Maximum Serum Concentration (Cmax) of MK-1045

  At designated time points up to 12 weeks

• Part 1: Area Under the Concentration-Time Curve from Time 0 to Infinity (AUC0-Inf) of MK-1045

  At designated time points up to 12 weeks

• Part 1: Percentage of Participants with a Peripheral B Cell Count Less Than the Lower Limit of Quantitation (LLOQ) at the End of Each Treatment Period

  At designated time points up to 12 weeks

• Part 2 and Part 3: Cmax of MK-1045

  At designated time points up to 52 weeks

• Part 2 and Part 3: Area Under the Concentration-Time Curve From Time 0 to the End of the Dosing Interval (AUCtau) of MK-1045

  At designated time points up to 52 weeks

Study Arms (3)

Part 1 Prime Dose Escalation Panels

EXPERIMENTAL

Participants will receive single intravenous (IV) doses of MK-1045 at varying dose levels.

Biological: MK-1045

Part 2 Step-up Dose Escalation Panels

EXPERIMENTAL

Participants will receive 3 step up doses of MK-1045 as a prime, step-up and target dose over a 3-week dosing interval.

Biological: MK-1045

Part 3 Dose Expansion Panels (Optional)

EXPERIMENTAL

Participants will receive 3 step up doses of MK-1045 as a prime, step-up and target dose over a 3-week dosing interval.

Biological: MK-1045

Interventions

MK-1045 BIOLOGICAL

IV infusion

Also known as: CN201

Part 1 Prime Dose Escalation Panels; Part 2 Step-up Dose Escalation Panels; Part 3 Dose Expansion Panels (Optional)

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Has a body mass index between 18 and 32 kg/m\^2, inclusive
• Systemic lupus erythematosus (SLE): Has a diagnosis of SLE for at least 6 months and met the European Alliance of Associations for Rheumatology (EULAR)/ American College of Rheumatology (ACR) 2019 classification criteria
• SLE: Is taking at least one background therapy for SLE
• RA: Has a diagnosis of RA for at least 6 months and meets the 2010 ACR-EULAR classification criteria for RA

You may not qualify if:

• Has a known active infection (excluding fungal infection of nail beds), or any major episode of infection requiring hospitalization or treatment with anti-infectives within 8 weeks prior to the Day 1 dosing
• History of serious recurrent or chronic infection
• Is known to be infected with hepatitis B virus, hepatitis C virus, or human immunodeficiency virus
• Has evidence of active tuberculosis (TB), latent TB, or inadequately treated TB
• Has a significant or uncontrolled medical disease in any organ system not related to RA or SLE
• For RA participants, has a history of any arthritis with onset before age 17 years
• Has a current inflammatory condition other than SLE or RA that could interfere with disease activity assessments
• History of cancer (except fully treated nonmelanoma skin cancers or cervical carcinoma in situ after complete surgical removal) and is disease free for \<5 years before Day 1 dosing
• Has had a major surgery within 3 months prior to Screening or has a major surgery planned during the study.
• Has symptomatic heart failure (New York Heart Association class III or IV) or myocardial infarction or unstable angina pectoris within 6 months prior to Screening
• Has a severe chronic pulmonary disease requiring oxygen therapy
• Has current active lymphoproliferative disease, including lymphoma, or signs and symptoms suggestive of possible lymphoproliferative disease

Sponsors & Collaborators

• Merck Sharp & Dohme LLC: lead

Study Sites (8)

Anima Diepenbeek ( Site 0601)

Diepenbeek, Limburg, 3590, Belgium

RECRUITING

Arensia Exploartory Medicine ( Site 1301)

Tbilisi, 0112, Georgia

RECRUITING

Istituto Clinico Humanitas- IRCCS ( Site 1902)

Rozzano, Milano, 20089, Italy

RECRUITING

The University of Tokyo Hospital ( Site 0301)

Bunkyo, Tokyo, 113-8655, Japan

RECRUITING

Keio University Hospital ( Site 0302)

Shinjyuku, Tokyo, 160-8582, Japan

RECRUITING

PMSI Republican Clinical Hospital "T.Mosneaga" ( Site 1001)

Chisinau, 2025, Moldova

RECRUITING

ARENSIA Clinics ( Site 0902)

Bucharest, Bucharest, 011658, Romania

RECRUITING

ARENSIA Exploratory Medicine-Country Emergency Hospital- Arensia,Cluj-Napoca ( Site 0901)

Cluj-Napoca, Cluj, 400006, Romania

RECRUITING

Related Links

• Merck Clinical Trials Information
• Plain Language Summary

MeSH Terms

Conditions

Lupus Erythematosus, Systemic; Arthritis, Rheumatoid

Condition Hierarchy (Ancestors)

Connective Tissue Diseases; Skin and Connective Tissue Diseases; Autoimmune Diseases; Immune System Diseases; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases

Study Officials

• Medical Director

  Merck Sharp & Dohme LLC

  STUDY DIRECTOR

Central Study Contacts

Toll Free Number

CONTACT

1-888-577-8839; Trialsites@msd.com

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SEQUENTIAL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 16, 2026
• First Posted: January 23, 2026
• Study Start: February 19, 2026
• Primary Completion (Estimated): July 16, 2029
• Study Completion (Estimated): July 16, 2029
• Last Updated: May 4, 2026

Record last verified: 2026-04

Data Sharing

• IPD Sharing: Will share

Locations

RO (2); JP (2); IT (1); BE (1); GE (1); MO (1)