S. Peters, J.-L. Pujol, U. Dafni, M. Dómine, S. Popat, M. Reck, J. Andrade, A. Becker, D. Moro-Sibilot, A. Curioni-Fontecedro, O. Molinier, K. Nackaerts, A. Insa Mollá, R. Gervais, G. López Vivanco, J. Madelaine, J. Mazieres, M. Faehling, F. Griesinger, M. Majem, J.L. González Larriba, M. Provencio Pulla, K. Vervita, H. Roschitzki-Voser, B. Ruepp, P. Mitchell, R.A. Stahel, C. Le Pechoux, D. De Ruysscher, R. Stahel, A. Hiltbrunner, M. Pardo-Contreras, A. Gasca-Ruchti, N. Giacomelli, R. Kammler, N. Marti, R. Pfister, A.C. Piguet, S. Roux, S. Troesch, M. Schneider, R. Schweri, I. Zigomo, Z. Tsourti, P. Zygoura, S. Tsouprou, M. Kassapian, G. Dimopoulou, C. Andriakopoulou, F. Morin, E. Amour, G. Mariaule, N. Archirel, M. Fernandez, E. Pereira, L. Benito, K. Lopez, A. Hernández, S. Chinchen, H. Jurkovic, A. Livingstone, J. Mitchell, M. Walker, S. Ng, C. Steer, K. Briscoe, A. Saqib, E. Abdi, B. Houghton, K. O’Byrne, B.R. Chittajallu, B.G. Hughes, A. Black, H. Werner, G. Zalcman, F. Vaylet, P. Merle, I. Monnet, N. Girard, P.-J. Souquet, F. Barlesi, D. Debieuvre, H. Senellart, M. Poudenx, A. Dixmier, D. Pouessel, J. Cadranel, H. Lena, E. Quoix, S. Friard, C. Audigier-Valette, E. Pichon, K. Kokowski, H. Kirchen, A. Tufman, C. De-Colle, J. de Langen, A. Insa, B. Massutí, M.P. Pulla, S.P. Aix, N. Villanueva, G.L. Vivanco, K. Franks, R. Califano, RS: GROW - R3 - Innovative Cancer Diagnostics & Therapy, Radiotherapie, Pulmonary medicine, CCA - Cancer Treatment and quality of life, CCA - Cancer biology and immunology, University of Zurich, and Stahel, R A
BACKGROUND: Concurrent chemotherapy and thoracic radiotherapy followed by prophylactic cranial irradiation (PCI) is the standard treatment in limited-disease small-cell lung cancer (LD-SCLC), with 5-year overall survival (OS) of only 25% to 33%. PATIENTS AND METHODS: STIMULI is a 1:1 randomised phase II trial aiming to demonstrate superiority of consolidation combination immunotherapy versus observation after chemo-radiotherapy plus PCI (protocol amendment-1). Consolidation immunotherapy consisted of four cycles of nivolumab [1 mg/kg, every three weeks (Q3W)] plus ipilimumab (3 mg/kg, Q3W), followed by nivolumab monotherapy (240 mg, Q2W) for up to 12 months. Patient recruitment closed prematurely due to slow accrual and the statistical analyses plan was updated to address progression-free survival (PFS) as the only primary endpoint. RESULTS: Of the 222 patients enrolled, 153 were randomised (78: experimental; 75: observation). Among the randomised patients, median age was 62 years, 60% males, 34%/65% current/former smokers, 31%/66% performance status (PS) 0/1. Up to 25 May 2020 (median follow-up 22.4 months), 40 PFS events were observed in the experimental arm, with median PFS 10.7 months [95% confidence interval (CI) 7.0-not estimable (NE)] versus 42 events and median 14.5 months (8.2-NE) in the observation, hazard ratio (HR)= 1.02 (0.66-1.58), two-sided P= 0.93. With updated follow-up (03 June 2021; median: 35 months), median OS was not reached in the experimental arm, while it was 32.1 months (26.1-NE) in observation, with HR= 0.95 (0.59-1.52), P= 0.82. In the experimental arm, median time-to-treatment-discontinuation was only 1.7 months. CTCAE v4 grade =3 adverse events were experienced by 62% of patients in the experimental and 25% in the observation arm, with 4 and 1 fatal, respectively. CONCLUSIONS: The STIMULI trial did not meet its primary endpoint of improving PFS with nivolumab-ipilimumab consolidation after chemo-radiotherapy in LD-SCLC. A short period on active treatment related to toxicity and treatment discontinuation likely affected the efficacy results.