Abstract No : Abstract #1089P
Indication : Merkel cell carcinoma
Intervention : Retifanlimab
Company : Macrogenics
Technology : PD-1/PD-L1 inhibitor
As of January 8, 2020, 27 pts with MCC had received retifanlimab 500 mg IV Q4W (22 chemo-naïve, 5 refractory, all stage IV). Of the 22 chemo-naïve pts enrolled, 18 have had ≥1 on-study tumor assessment or discontinued. There are 10 (56%) responders (investigator assessed) with 2 (11%) complete responses and 8 (44%) partial responses. Of these, 6 are confirmed and 4 are unconfirmed ongoing responses. Three pts (17%) have stable disease. Among all treated pts (n=27), 16 (59%) had a treatment-emergent adverse event (TEAE); 6 (22%) were ≥Grade 3, 11 (41%) had a treatment-related TEAE (TRAE), 3 (11%) of which were ≥Grade 3. The most common TRAEs were asthenia and pruritus (n=3 each). Seven (26%) had a TEAE of special interest (the only immune-related AE occurring in >1 pt was hypothyroidism [n=2]). Two pts (7%) discontinued treatment due to TEAEs (radiculopathy and polyarthritis). No fatal TEAEs have been reported
Initial results demonstrate promising activity and safety of retifanlimab in pts with advanced or metastatic chemo-naïve MCC. Updated results from a preplanned analysis for futility will be presented at the meeting.