Safety summary from the dose-escalation and dose-expansion parts
| Events, n (%) | Dose-escalation part | Dose-expansion part | ||||
| Avelumab 10 mg/kg Q2W | Avelumab 800 mg QW→Q2W** plus M9241 16.8 µg/kg (n=7) | Avelumab 800 mg QW→Q2W** plus M9241 16.8 µg/kg (n=16) | ||||
| M9241 4 µg/kg (n=9) | M9241 8 µg/kg (n=7) | M9241 12 µg/kg (n=7) | M9241 16.8 µg/kg (n=6) | |||
| AE, any grade | 9 (100) | 7 (100) | 7 (100) | 6 (100) | 7 (100) | 16 (100) |
| Grade ≥3 | 6 (66.7) | 5 (71.4) | 6 (85.7) | 4 (66.7) | 4 (57.1) | 14 (87.5) |
| TRAE, any grade | 8 (88.9) | 5 (71.4) | 6 (85.7) | 5 (83.3) | 6 (85.7) | 15 (93.8) |
| Grade ≥3 | 0 | 1 (14.3) | 1 (14.3) | 1 (16.7) | 0 | 8 (50.0) |
| Avelumab-related, any grade | 2 (22.2) | 4 (57.1) | 3 (42.9) | 4 (66.7) | 5 (71.4) | 15 (93.8) |
| Grade ≥3 | 0 | 1 (14.3) | 1 (14.3) | 0 | 0 | 8 (50.0) |
| M9241-related, any grade | 8 (88.9) | 4 (57.1) | 6 (85.7) | 5 (83.3) | 6 (85.7) | 12 (75.0) |
| Grade ≥3 | 0 | 1 (14.3) | 1 (14.3) | 1 (16.7) | 0 | 6 (37.5) |
| AE leading to discontinuation of either study drug | 6 (66.7) | 2 (28.6) | 3 (42.9) | 2 (33.3) | 1 (14.3) | 3 (18.8) |
| TRAE leading to discontinuation of study drug | ||||||
| Avelumab-related | 2 (22.2) | 0 | 1 (14.3) | 0 | 0 | 0 |
| M9241-related | 1 (11.1) | 0 | 1 (14.3) | 0 | 0 | 0 |
| AE leading to death | 0 | 1 (14.3) | 0 | 1 (16.7) | 1 (14.3) | 2 (12.5) |
| TRAE leading to death | 0 | 0 | 0 | 0 | 0 | 0 |
| Infusion-related reaction | 2 (22.2) | 2 (28.6) | 0 | 2 (33.3) | 2 (28.6) | 7 (43.8) |
| Immune-related AE | 2 (22.2) | 1 (14.3) | 2 (28.6) | 0 | 1 (14.3) | 1 (6.3) |
| Cytokine release syndrome | 0 | 0 | 0 | 1 (16.7) | 3 (42.9) | 3 (18.8) |
| Avelumab-related | 0 | 0 | 0 | 1 (16.7) | 3 (42.9) | 3 (18.8) |
| M9241-related | 0 | 0 | 0 | 1 (16.7) | 3 (42.9) | 3 (18.8) |
| Grade ≥3 | 0 | 0 | 0 | 0 | 0 | 0 |
*Avelumab QW for 12 weeks then Q2W thereafter.
AE, adverse event; QW, once a week; Q2W, every 2 weeks; TRAE, treatment-related adverse event.