Safety and efficacy of intratumoural anti-CTLA4 with intravenous anti-PD1
- Lambros Tselikas
- Sandrine Susini
- Matthieu Texier
- Andrey Yurchenko
- Emilie Routier
- Mona Amini-Adle
- Edi Tihic
- Séverine Mouraud
- François-Xavier Danlos
- Samy Ammari
- Thibault Raoult
- Séverine Roy
- Delphine Bredel
- Siham Farhane
- Lydie Cassard
- Irma Molinaro
- Alexander Eggermont
- Jean-Charles Soria
- Laurence Zitvogel
- Christophe Massard
- Angelo Paci
- Thierry de Baere
- Jean-Yves Scoazec
- Nathalie Chaput
- Sergey Nikolaev
- Nicolas Meyer
- Céleste Lebbé
- Stéphane Dalle
- Caroline Robert
- Aurélien Marabelle
2026-04-29
Intravenous administration of anti-CTLA4 with anti-PD1 provides durable tumour responses but causes severe treatment-related adverse events in patients with cancer 1 . Intratumoural administration at lower doses but high local concentrations could enhance antitumour efficacy while minimizing systemic exposure and toxicity. Here we report the randomized multicentre phase 1b NIVIPIT trial (ClinicalTrials.gov: NCT02857569 ), which enrolled 61 patients with untreated metastatic melanoma, randomly assigned 2:1 to receive intravenous nivolumab (anti-PD1; 1 mg kg −1 ) combined with either intratumoural ipilimumab (anti-CTLA4; 0.3 mg kg −1 ) or intravenous ipilimumab (3 mg kg −1 ). The primary end-point was met with significantly lower incidence of grade 3 or 4 treatment-related adverse events at 6 months in the intratumoural versus intravenous arm (22.6% versus 57.1%), equivalent to anti-PD1 monotherapy. RECIST (response evaluation criteria in solid tumours) best objective response rate reached 65.7% for anti-CTLA4 injected lesions and 50% for uninjected lesions, confirming the relationship between intratumoural exposure to anti-CTLA4 and efficacy. Baseline tumour immune profiling revealed that protumoural activated regulatory T (T reg ) cells and M2 macrophages predict durable clinical benefit, regardless of the anti-CTLA4 administration route. A decrease in activated intratumoural T reg cells occurred only in patients who showed durable clinical benefit, who also presented high intratumoural Fcγ receptor (FcγR) expression. Our results provide a rationale for intratumoural anti-CTLA4 strategies in oligometastatic and early-stage cancers and indicate that high intratumoural activated T reg cell and FcγR + M2 macrophage numbers are prerequisites for efficacy of combined anti-CTLA4 and anti-PD1.