Second-line therapy with nivolumab plus ipilimumab for older patients with oesophageal squamous cell cancer (RAMONA): a multicentre, open-label phase 2 trial oleh Matthias P Ebert, ProfMD, Nadja M Meindl-Beinker, PhD, Tobias Gutting, MD, Martin Maenz, PhD, Johannes Betge, MD, Nadine Schulte, MD, Tianzuo Zhan, MD, Philip Weidner, MD, Elke Burgermeister, PhD, Ralf Hofheinz, ProfMD, Arndt Vogel, ProfMD, Stefan Angermeier, MD, Claus Bolling, MD, Maike de Wit, ProfMD, Ralf Jakobs, ProfMD, Meinolf Karthaus, ProfMD, Gertraud Stocker, MD, Peter Thuss-Patience, MD, Tobias Leidig, PhD, Timo Gaiser, ProfMD, Jakob N Kather, ProfMD, Nicolai Haertel, MD