A Phase 1 dose-escalation study to evaluate safety, pharmacokinetics, and pharmacodynamics of OSE-279, an anti-PD-1 monoclonal antibody in patients with advanced solid tumours

  • Eur J Cancer. 2026 Jun 3:240:116729. doi: 10.1016/j.ejca.2026.116729.
Marie Robert  1 ,  Nuria Kotecki  2 ,  Carlos Gomez-Roca  3 ,  Christophe Massard  4 ,  Sophie Postel-Vinay  5 ,  Judith Raimbourg  1 ,  Mariana Brandao  2 ,  Iphigénie Korakis  3 ,  Thibaut de la Motte Rouge  4 ,  Silvia Comis  6 ,  Karima Imadalou  6 ,  Caroline Chevalier  6 ,  Laurie Cordonnier  6 ,  Constant Josse  7 ,  Géraldine Teppaz  6 ,  Margaux Seité  6 ,  Justine Durand  6 ,  Virginie Thepenier  6 ,  Caroline Mary  6 ,  Vanessa Gauttier  6 ,  Mylène Derame  6 ,  Aurore Morello  6 ,  Nicolas Poirier  6 ,  Philippe Alexandre Cassier  8
Affiliations
  • 1. Institut de Cancérologie de l'Ouest, Saint-Herblain, ARPEGO Network, France.
  • 2. Institut Jules Bordet, Brussels, Belgium.
  • 3. IUCT-Oncopole Claudius Régaud, Toulouse, France.
  • 4. Centre Eugène Marquis, Rennes, France.
  • 5. Institut Gustave Roussy, Villejuif, France.
  • 6. OSE Immunotherapeutics, Nantes, France.
  • 7. Exystat, Malakoff, France.
  • 8. Centre Léon Bérard, Lyon, France. Electronic address: [email protected].
PMID: 42034003 DOI: 10.1016/j.ejca.2026.116729
Abstract

Background: OSE-279 is a high affinity humanized monoclonal bivalent antibody against PD-1 with potent antitumor activity in vivo in syngeneic non-clinical models.

Methods: This phase I study assessed the safety, pharmacokinetics, pharmacodynamics and antitumor activity of OSE-279 in advanced solid tumours.

Results: Twenty patients received OSE-279 intravenously at 100 mg q3w (n = 2), 300 mg q3w (n = 7) and 600 mg q6w (n = 11). Median age was 61.5 (range 3-81) years, 50% were female, median number of prior metastatic lines was 2 (range 1-6). Most frequent tumour types were soft tissue sarcoma (n = 4) and anal squamous cell carcinoma (n = 3). OSE-279 monotherapy was safe. Two recommended phase 2 doses were established: 300 mg q3w and 600 mg q6w. The most common (≥10%) related TEAEs were diarrhoea, dry mouth, pruritus, chills, fatigue, headache, dysgeusia and hyperthyroidism. OSE-279 PK exhibited linear dose proportionality and mean receptor occupancy was maintained above 80% in all tested doses. There were 1 CR at 300 mg q3w, 4 PRs at 600 mg q6w and 7 SD with response duration ranging from 6.8 to 18.4 months.

Conclusion: OSE-279 monotherapy was well tolerated with durable responses in patients with advanced solid tumours. The trial is continuing with OSE-279 combined with OSE2101, a therapeutic Cancer vaccine in 1st line HLA-A2 positive PD-L1 ≥ 50% NSCLC. CLINICAL TRIAL REGISTRATION (NCT NUMBER: NCT05751798).

Keywords
Immune checkpoint inhibitor; OSE-279; PD-1; Phase I; Solid tumours.
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