A First-in-Human, Phase 1, Open-Label, Single and Multiple Ascending Dose Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of CPTX2309 by Intravenous Administration in Healthy Volunteers and Subjects With Moderate to Severe Rheumatoid Arthritis (RA) or Systemic Lupus Erythematosus (SLE)

Capstan Therapeutics3 sites in 1 country64 target enrollmentStarted: April 9, 2025Last updated: July 16, 2026

Conditions

Interventions

Drugs

Trial Snapshot

Phase: Phase 1
Status: Recruiting
Sponsor
Enrollment: 64
Locations: 3
Primary Endpoint: Part C and D: Change from baseline in vaccination-induced antibody titers

Study Overview Study Design Eligibility Criteria Arms & Interventions Outcomes Investigators Sites Records & Identifiers Similar Trials

Study Overview

Brief Summary

The purpose of this study is to assess the safety and tolerability of CPTX2309 in healthy adult participants and adult participants with moderate to severe rheumatoid arthritis or systemic lupus erythematosus.

Detailed Description

A first-in-human Phase 1, open label study to evaluate safety and tolerability of a single ascending dose (SAD) and multiple ascending dose (MAD) of CPTX2309 intravenously administered to healthy adult participants and adult participants with moderate to severe rheumatoid arthritis or systemic lupus erythematosus.

Study Design

Study Type: Interventional
Allocation: Non Randomized
Intervention Model: Sequential
Primary Purpose: Treatment
Masking: None

Eligibility Criteria

Ages: 18 Years to 65 Years (Adult, Older Adult)
Sex: All
Accepts Healthy Volunteers: Yes

Inclusion Criteria

•Male and female participants who are healthy as determined by the investigator based on review of medical history, physical examination, and clinical laboratory tests obtained during the screening period.
•Participant is willing and able to adhere to the study visit schedule and other protocol requirements.
•Clinical diagnosis of RA and fulfilling the 2010 ACR/EULAR classification criteria for RA
•Presence of rheumatoid factor or ACPA above the ULN
•Confirmation of at least moderate active disease at screening with the presence of at least 6 swollen and 6 tender joints at screening using the 68 (tender)/66 (swollen) joint count OR the presence of at least 3 joints with active synovitis via MRI assessment.
•Clinical diagnosis of SLE and fulfilling the 2019 EULAR/ACR classification criteria for SLE
•Positive ANA>=1:80 and the presence of at least one of the following autoantibodies above the upper limit of normal (ULN): anti-double standard DNA (dsDNA) or anti-Smith (Sm).

Exclusion Criteria

•Evidence of organ dysfunction or any clinically significant deviation from normal in physical examination, vital signs, or clinical laboratory tests beyond what is consistent with a healthy population in the region in which the study is conducted.
•Use of any investigational medical device or investigational drug within 30 days or 5 half-lives of the investigational drug (whichever is longer) prior to the first administration of CPTX
•- Participants diagnosed with Felty's syndrome
•Active neuropsychiatric SLE, as defined by the CNS portion of SLEDAI at Screening, or signs of symptoms of neuropsychiatric SLE within 6 months prior to Screening (lupus headache permissible)
•Note: Other protocol-defined inclusion/exclusion criteria apply

Arms & Interventions

Part A: SAD Cohorts

Experimental

Escalating single doses of CPTX2309 on a specified day to healthy adult participants.

Intervention: CPTX2309 (Drug)

Part B: MAD Cohorts

Experimental

Escalating multiple doses of CPTX2309 on specified days to healthy adult participants.

Intervention: CPTX2309 (Drug)

Part D: MAD Cohorts

Experimental

Escalating multiple doses of CPTX2309 on specified days to adult participants with moderate to severe RA or SLE.

Intervention: CPTX2309 (Drug)

Part C: SAD Cohorts

Experimental

Escalating single doses of CPTX2309 on a specified day to adult participants with moderate to severe RA or SLE.

Intervention: CPTX2309 (Drug)