A Study to Evaluate the Efficacy, Safety, and Tolerability of IMVT-1402 in Adult Participants With Active, Difficult to Treat Rheumatoid Arthritis

This Phase 2b, multicenter, double-blind, placebo-controlled, randomized withdrawal study is designed to assess the efficacy and safety of IMVT-1402 in adult participants with active, difficult-to-treat, anti-citrullinated protein autoantibody (ACPA) positive rheumatoid arthritis (RA). The primary objective is to evaluate the effects of IMVT-1402 compared to placebo, as measured by the American College of Rheumatology 20% (ACR20) response.

The study consists of several periods. During the Screening Period (5 weeks) participants will undergo screening procedures to determine eligibility. In Period 1 (Open-Label Treatment), all eligible participants will receive open-label treatment with IMVT-1402 at a dose of 600 mg subcutaneous (SC) once weekly (QW) for 16 weeks. Participants who meet the ACR20 response criteria at Weeks 14 and 16 will be randomized in a 1:1:1 ratio to receive blinded treatment with either IMVT-1402 600 mg SC QW, IMVT-1402 300 mg SC QW, or placebo SC QW for 12 weeks in Period 2 (Randomized Withdrawal). Eligible participants who complete Period 2 at Week 28 will have the option to receive IMVT-1402 for an additional 48 weeks in Period 3 (Long -Term Extension). A follow-up visit will occur 4 weeks after the last dose of study treatment to monitor safety.

The primary endpoint of the study is the proportion of participants achieving an ACR20 response at the end of Period 2. Secondary objectives include evaluating the safety and tolerability of IMVT-1402, as well as its effects on other efficacy measures. This study aims to provide valuable data on the use of IMVT-1402 in treating adults with active, difficult-to-treat, ACPR-positive RA.

Eligibility Criteria:
Inclusion Criteria:

* Diagnosis of 'definite RA' according to the 2010 ACR/ European Alliance of Associations for Rheumatology (EULAR) Rheumatoid Arthritis Classification Criteria.
* Greater than or equal to 6/68 TJC and ≥ 6/66 SJC at both Screening and Baseline visits.
* C-reactive protein ≥ 1.5 × upper limit of normal (ULN) at Screening Visit.
* DAS28-CRP \> 4.1 at the Screening Visit.
* Elevated immunoglobulin G (IgG) + ACPA at the Screening Visit.
* Inadequate response to at least 2 classes of biologic/targeted synthetic DMARDs.

Additional inclusion criteria are defined in the protocol.

Exclusion Criteria:

* Have received rituximab and experienced insufficient efficacy or loss of efficacy
* History of any chronic inflammatory arthritis with onset prior to age 18 or history of acute inflammatory joint disease of different origin from RA.
* Active malignancy or history of malignancy within 5 years prior to Screening Visit.
* Medical history of primary immunodeficiency, T cell or humoral, including common variable immunodeficiency.
* Used any non-immunosuppressive Fc-based therapeutic protein (e.g., mAb or Fc-fusion protein) within 4 weeks prior to or at Screening Visit.
* Used any anti-FcRn treatment within 2 months prior to or at Screening Visit or have a documented history of non-response to prior anti-FcRn treatment.

Other, more specific exclusion criteria are defined in the protocol.