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

17 août 2026 mis à jour par: Primmune Therapeutics, Inc.

A Phase 2 Study to Investigate the Activity of Neoadjuvant PRTX007 Combined With Pembrolizumab in Participants With Stage III Melanoma (INFLECTION-003)

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.

Aperçu de l'étude

Statut

Recrutement

Les conditions

Description détaillée

This study investigates whether combining the TLR7 agonist PRTX007 with pembrolizumab enhances immune-mediated tumor response in the neoadjuvant setting for Stage III melanoma, with the goal of improving pathologic response rates and clinical outcomes while maintaining an acceptable safety profile.

Design This is a Phase 2, multi-center, open-label, single-arm study conducted in Australia. The study will enroll approximately 48 participants with resectable Stage III melanoma.

The study consists of two parts:

  • Part A: 24 participants will be enrolled, including an initial dose-escalation safety run-in using a 3+3 design to evaluate tolerability and dose-limiting toxicities.
  • Part B: An additional 24 participants will be enrolled if sufficient activity is observed in Part A.

Treatment Plan

Participants will receive neoadjuvant therapy consisting of:

  • PRTX007: Oral administration for 3 days on and 4 days off per week for 9 cycles (7-day cycles)
  • Pembrolizumab: 200 mg intravenous infusion every 3 weeks for 3 cycles Following completion of neoadjuvant therapy, participants will undergo definitive surgical resection.

Post-surgical treatment will be response-adapted:

  • Participants achieving MPR may receive observation or pembrolizumab alone
  • Participants without MPR will receive adjuvant PRTX007 in combination with pembrolizumab

Type d'étude

Interventionnel

Inscription (Estimé)

48

Phase

  • Phase 2

Contacts et emplacements

Cette section fournit les coordonnées de ceux qui mènent l'étude et des informations sur le lieu où cette étude est menée.

Coordonnées de l'étude

Lieux d'étude

    • New South Wales
      • Waratah, New South Wales, Australie, 2298
        • Recrutement
        • Calvary Mater Newcastle
    • Queensland
      • Cairns, Queensland, Australie, 4870
        • Pas encore de recrutement
        • Cairns And Hinterland Hospital And Health Service
      • Greenslopes, Queensland, Australie, 4120
        • Pas encore de recrutement
        • Gallipoli Medical Research
      • Woolloongabba, Queensland, Australie, 4102
        • Pas encore de recrutement
        • Princess Alexandra Hospital
    • Victoria
      • Melbourne, Victoria, Australie, 3000
        • Pas encore de recrutement
        • Peter MacCallum Cancer Centre
    • Western Australia
      • Nedlands, Western Australia, Australie, 6009
        • Pas encore de recrutement
        • Sir Charles Gairdner Hospital
      • Nedlands, Western Australia, Australie, 6009
        • Recrutement
        • One Clinical Research Pty Ltd

Critères de participation

Les chercheurs recherchent des personnes qui correspondent à une certaine description, appelée critères d'éligibilité. Certains exemples de ces critères sont l'état de santé général d'une personne ou des traitements antérieurs.

Critère d'éligibilité

Âges éligibles pour étudier

  • Adulte
  • Adulte plus âgé

Accepte les volontaires sains

Non

La description

Inclusion Criteria:

  • Adults aged 18 years or older
  • Histologically confirmed, resectable Stage III cutaneous melanoma.
  • Candidate for curative-intent surgical resection
  • Eastern Cooperative Oncology Group (ECOG) performance status of 0-2
  • Adequate organ function
  • Able to provide written informed consent

Exclusion Criteria:

  • Prior systemic therapy for melanoma, including immunotherapy
  • Uveal melanoma or mucosal melanoma.
  • Active autoimmune disease requiring systemic treatment
  • Primary immunodeficiency or use of systemic immunosuppressive therapy
  • Women who are pregnant or breastfeeding
  • Recent treatment with another investigational therapy
  • Any condition that, in the opinion of the investigator, would interfere with study participation or safety

Plan d'étude

Cette section fournit des détails sur le plan d'étude, y compris la façon dont l'étude est conçue et ce que l'étude mesure.

Comment l'étude est-elle conçue ?

Détails de conception

  • Objectif principal: Traitement
  • Répartition: N / A
  • Modèle interventionnel: Affectation à un seul groupe
  • Masquage: Aucun (étiquette ouverte)

Armes et Interventions

Groupe de participants / Bras
Intervention / Traitement
Expérimental: 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.

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 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

Que mesure l'étude ?

Principaux critères de jugement

Mesure des résultats
Description de la mesure
Délai
Major Pathologic Response (MPR) Rate
Délai: At time of surgical resection (approximately 9 weeks after initiation of treatment)
Major pathologic response (MPR) is defined as ≤10% residual viable tumor cells in the resected tumor specimen following completion of neoadjuvant therapy, as assessed by central pathology review.
At time of surgical resection (approximately 9 weeks after initiation of treatment)

Mesures de résultats secondaires

Mesure des résultats
Description de la mesure
Délai
Incidence of Adverse Events (AEs), Serious Adverse Events (SAEs), Immune-Related AEs (irAEs), and Dose-Limiting Toxicities (DLTs)
Délai: From first dose of study treatment through end of study (approximately up to 52 weeks)
Number and severity of adverse events, serious adverse events, immune-related adverse events, and dose-limiting toxicities, graded according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) version 6.0.
From first dose of study treatment through end of study (approximately up to 52 weeks)
Number of participants with abnormal physical examination findings, abnormal vital signs, abnormal Eastern Cooperative Oncology Group (ECOG) performance status, and abnormal clinical laboratory parameters
Délai: Baseline through end of study (approximately up to 52 weeks)
Baseline through end of study (approximately up to 52 weeks)
Pathologic Complete Response (pCR) Rate
Délai: At time of surgical resection (approximately 9 weeks after initiation of treatment)
Pathologic complete response (pCR) is defined as the absence of residual viable tumor cells (0%) in the resected tumor specimen following neoadjuvant therapy, as assessed by central pathology review.
At time of surgical resection (approximately 9 weeks after initiation of treatment)
Event-Free Survival (EFS)
Délai: From first dose up to 1 year
Event-free survival (EFS) is defined as the time from first dose of study treatment to any of the following events: disease progression or toxicity preventing surgery during neoadjuvant treatment; recurrence of disease after surgery; failure to achieve complete resection (R0 or R1); or death from any cause.
From first dose up to 1 year
Overall Survival (OS)
Délai: From first dose through end of study (approximately up to 52 weeks or longer if followed)
Overall survival is defined as the time from first dose of study treatment to death from any cause.
From first dose through end of study (approximately up to 52 weeks or longer if followed)
Pharmacokinetics of PRTX007
Délai: During treatment period (multiple time points from baseline through approximately 9 weeks and selected later time points)
Plasma concentrations of PRTX007 and its active metabolite will be measured to characterize pharmacokinetic parameters using validated analytical methods.
During treatment period (multiple time points from baseline through approximately 9 weeks and selected later time points)
Changes in cytokine, chemokine and soluble PD-1/PD-L1 biomarkers
Délai: Baseline through treatment period (up to approximately 9 weeks and selected later time points)
Baseline through treatment period (up to approximately 9 weeks and selected later time points)
Changes in mRNA expression
Délai: Baseline through treatment period (up to approximately 9 weeks and selected later time points)
Baseline through treatment period (up to approximately 9 weeks and selected later time points)
Changes in immune cell activation and proliferation markers
Délai: Baseline through treatment period (up to approximately 9 weeks and selected later time points)
Baseline through treatment period (up to approximately 9 weeks and selected later time points)

Collaborateurs et enquêteurs

C'est ici que vous trouverez les personnes et les organisations impliquées dans cette étude.

Dates d'enregistrement des études

Ces dates suivent la progression des dossiers d'étude et des soumissions de résultats sommaires à ClinicalTrials.gov. Les dossiers d'étude et les résultats rapportés sont examinés par la Bibliothèque nationale de médecine (NLM) pour s'assurer qu'ils répondent à des normes de contrôle de qualité spécifiques avant d'être publiés sur le site Web public.

Dates principales de l'étude

Début de l'étude (Réel)

1 juillet 2026

Achèvement primaire (Estimé)

1 décembre 2027

Achèvement de l'étude (Estimé)

1 juin 2029

Dates d'inscription aux études

Première soumission

20 avril 2026

Première soumission répondant aux critères de contrôle qualité

27 avril 2026

Première publication (Réel)

4 mai 2026

Mises à jour des dossiers d'étude

Dernière mise à jour publiée (Réel)

19 août 2026

Dernière mise à jour soumise répondant aux critères de contrôle qualité

17 août 2026

Dernière vérification

1 août 2026

Plus d'information

Termes liés à cette étude

Plan pour les données individuelles des participants (IPD)

Prévoyez-vous de partager les données individuelles des participants (DPI) ?

NON

Description du régime IPD

Individual participant data will not be shared because the study involves an investigational product and the sponsor has not established a data sharing plan at this time.

Informations sur les médicaments et les dispositifs, documents d'étude

Étudie un produit pharmaceutique réglementé par la FDA américaine

Non

Étudie un produit d'appareil réglementé par la FDA américaine

Non

Ces informations ont été extraites directement du site Web clinicaltrials.gov sans aucune modification. Si vous avez des demandes de modification, de suppression ou de mise à jour des détails de votre étude, veuillez contacter register@clinicaltrials.gov. Dès qu'un changement est mis en œuvre sur clinicaltrials.gov, il sera également mis à jour automatiquement sur notre site Web .

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