Safety and Efficacy of Efavaleukin Alfa in Subjects With Steroid Refractory Chronic Graft Versus Host Disease

"Phase 1: This study will be conducted as a multiple ascending dose (MAD) study. Each dosing cohort will consist of between 3 and 6 subjects who will receive efavaleukin alfa subcutaneously (SC) either every week or every 2 weeks plus protocol permitted background therapy for 52 weeks. At the discretion of the Sponsor, following discussion and agreement between the principal investigator and medical monitor, subjects responding to efavaleukin alfa (as assessed by the end of week 50), who wish to continue treatment, may continue to receive efavaleukin alfa treatment at their current dosing regimen for up to an additional 208 weeks through an extended dosing period. All subjects who continue to receive efavaleukin alfa during the extended dosing period will be reevaluated every 6 months for their response to treatment.~Phase 2: All subjects will receive the recommended phase 2 dose (RP2D) of efavaleukin alfa for 52 weeks."