Combination therapy with vibostolimab and pembrolizumab exhibited encouraging antitumor activity and a tolerable safety profile in patients with advanced non-small cell lung cancer (NSCLC) and no previous anti–PD-1/PD-L1 therapy, according to study results presented at the ESMO Virtual Congress 2020.
Vibostolimab, an anti–TIGIT (T-cell immunoreceptor with immunoglobulin and ITIM domains) monoclonal antibody, demonstrated promising efficacy and was well tolerated in a phase 1 dose-finding and dose-escalation study of heavily pretreated patients with advanced solid tumors.
In a dose-expansion/confirmation study, researchers enrolled 41 patients with advanced NSCLC naive to anti–PD-1/PD-L1 therapy, irrespective of PD-L1 status (median age, 62 years; 68% men).
Seventy-three percent of study participants had received at least 1 previous line of therapy, and 83% had an Eastern Cooperative Oncology Group Performance Status of 1.
Patients were assigned to vibostolimab (200 or 210 mg) plus pembrolizumab (200 mg) on day 1 of a 3-week cycle. Treatment continued for up to 35 cycles.
Safety and tolerability served as the primary endpoints. Secondary endpoints included overall response rate (ORR), duration of response (DOR) and progression-free survival (PFS) by investigator assessment.
Median follow-up was 11 months (range, 7-18).
In total, 83% (n = 34) of the study population developed a treatment-related adverse event. The most common treatment-related adverse events were pruritus (34%), hypoalbuminemia (29%) and pyrexia (20%).
Grade 3-4 treatment-related adverse events occurred in 15% (n = 6) of the study population. There were no treatment-related adverse events leading to death.
The ORR for all patients was 29% (95% CI, 16-46), and the median DOR was not reached (range, 4-17+). The median PFS for all patients by investigator assessment was 5.4 months (95% CI, 2.1-8.2).
PD-L1 data were available for 25 patients. The ORR for patients with a Tumor Proportion Score (TPS) ≥1% (n = 13) was 46% (95% CI, 19-75), and the median PFS was 8.4 months (range, 3.9-10.2). The ORR for patients with a TPS <1% (n = 12) was 25% (95% CI, 5-57), and the median PFS was 4.1 months (95% CI, 1.9 to not reached).
