The Efficacy and Safety of PRTX007-003 Combined With Pembrolizumab in Resectable Stage III Melanoma

Sponsor
Primmune Therapeutics, Inc.
Study ID
NCT07565285
Phase
PHASE2
Status
Not Yet Recruiting

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Conditions

  • Melanoma Stage III

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Not accepted

Interventions

  • PRTX007 — DRUG
    PRTX007 is an orally administered prodrug of PRX034, a Toll-like receptor 7 (TLR7) agonist designed to activate innate and adaptive immune responses. NEOADJUVANT REGIMEN * 600 mg orally once daily (safety run-in participants) or * 750 mg orally once daily (subsequent participants) * Administered 3 days on, 4 days off (7-day cycle) * Total of 9 cycles (9 weeks) ADJUVANT REGIMEN (IF NO MPR) * 750 mg orally once daily * Administered 3 days on, 4 days off * Total of 12 cycles (12 weeks)
  • Pembrolizumab — DRUG
    Pembrolizumab is a programmed cell death protein-1 (PD-1) blocking antibody administered by intravenous infusion NEOADJUVANT REGIMEN * 200 mg IV every 3 weeks (Q3W) * Total of 3 cycles (9 weeks) ADJUVANT REGIMEN * 400 mg IV every 6 weeks (Q6W) for 7 cycles OR * 200 mg IV every 3 weeks (Q3W) for 14 cycles * Total duration: approximately 42 weeks

Study Details

This Phase 2, multi-center, single-arm study evaluates the safety, tolerability, and activity of neoadjuvant PRTX007 in combination with pembrolizumab in participants with resectable Stage III melanoma. Neoadjuvant immunotherapy has demonstrated improved clinical outcomes compared with adjuvant-only approaches, but there remains a need to enhance pathologic response rates without significant added toxicity. Participants will receive oral PRTX007, a Toll-like receptor 7 (TLR7) agonist prodrug, administered in combination with intravenous pembrolizumab prior to surgical resection. The primary objective is to determine the major pathologic response (MPR) rate following neoadjuvant therapy. Secondary objectives include evaluation of safety, pathologic complete response, event-free survival, overall survival, pharmacokinetics, and immune-related biomarkers. This study aims to determine whether the addition of PRTX007 to pembrolizumab improves antitumor immune responses and clinical outcomes in patients with Stage III melanoma.

Key Dates

Start date
May 31, 2026
Status verified
Apr 2026
Primary completion
Dec 31, 2027
Completion
Jun 30, 2029

Study Design

Enrollment
48 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT

Arms

  • Experimental: Neoadjuvant PRTX007 + Pembrolizumab (Response-Adapted Adjuvant Therapy)
    Participants with resectable Stage III melanoma will receive neoadjuvant treatment with PRTX007 in combination with pembrolizumab prior to definitive surgical resection. Following surgery, participants will receive response-adapted adjuvant therapy based on pathologic response. Participants achieving a major pathologic response (MPR) may receive observation or pembrolizumab alone, while participants without MPR will receive adjuvant PRTX007 in combination with pembrolizumab.

Primary Outcome Measure

Major Pathologic Response (MPR) Rate [ Time Frame: At time of surgical resection (approximately 9 weeks after initiation of treatment) ]

Central Contacts

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