 CAMBRIDGE, Mass., June 23, 2021 GLOBE NEWSWIRE -- Rubius Therapeutics, Inc. Nasdaq:RUBY, a clinical-stage biopharmaceutical company that is genetically engineering red blood cells to create an entirely new class of cellular medicines called Red Cell TherapeuticsTM, today announced that the first patient has been dosed in a new Phase 1 arm of the ongoing Phase 12 clinical trial of RTX-240 in combination with KEYTRUDA pembrolizumab1 for the treatment of patients with relapsedrefractory or locally advanced solid tumors. To be eligible for the trial, patients must have disease that is relapsed or refractory to an anti-PD-1 or PD-L1 therapy. 