Inducible T-cell co-stimulatory (ICOS) receptor agonist, feladilimab (fela), alone and in combination (combo) with pembrolizumab (P): Results from INDUCE-1 urothelial carcinoma (UC) expansion cohorts (ECs).
Authors: Arjun Vasant Balar, Victor Moreno, Eric Angevin, Hui Kong Gan, Maria Vieito, Antoine Italiano, Riccardo Danielli, Erminia Massarelli, Frans Opdam, Michael Jon Chisamore, Debra Rogan, Xiao Ji, Courtney Henry, Catherine Elizabeth Ellis, Marc S. Ballas, Axel Hoos, Francesco Ricci
Journal: Journal of Clinical Oncology (2021)

4519 Background: INDUCE-1 is a first-in-human trial evaluating fela, an IgG4 ICOS agonist non-T-cell depleting mAb, as monotherapy (mono) and in combo with P. ECs include tumor types, such as UC, with high ICOS expression and immunotherapy-favorable features. Fela induced IFNγ, increased PD-1/L1 expression, and enhanced antitumor activity in combo with PD-1 blockade nonclinically. We report preliminary efficacy, safety, and biomarker data of fela ± P in INDUCE-1 UC ECs. Methods: Eligible patients (pts) had recurrent/metastatic (R/M) UC of the upper or lower urinary tract, ≤6 prior systemic therapy lines in the advanced setting, measurable disease, and no active autoimmune disease. Pts received 0.3 or 1 mg/kg fela (mono EC; anti-PD-1/L1–experienced [exp] pts) or 0.3 mg/kg fela + 200 mg P (combo EC; anti-PD-1/L1–naïve pts) every 3 wks, up to 35 cycles until disease progression or unacceptable toxicity. Disease was assessed every 9 wks through wk 54, then every 12 wks. Archival and/or fresh biopsy tumor tissue was collected for biomarker analyses and safety assessed. Results: By Nov 6 2020, 13 anti-PD-1/L1–exp and 32 anti-PD-1/L1–naïve pts were evaluable in the mono and combo ECs, respectively. In the mono EC, median age was 69 yrs (range: 47–82), 92% of pts were male, and 85% received ≥2 prior therapy lines in the metastatic setting. In the combo EC, median age was 70 yrs (range: 42–84), 75% of pts were male, and 72% received ≥1 prior therapy line in the metastatic setting. In the mono EC, median duration of follow-up (mDoF) was 10.6 mo (range: 1.1–22.8); overall response rate (ORR) was 8% (1 partial response [PR]; 95% CI: 0.2, 36.0) with a duration of response (DoR) of 6.1 mo; disease control rate (DCR [response or stable disease for ≥9 wks]) was 23% (95% CI: 5.0, 53.8), and median overall survival (mOS) was 14.5 mo (95% CI: 2.8, NR), with 74% of pts alive at 6 mo. In the combo EC, mDoF was 9.6 mo (range: 0.9–28.3); ORR was 22% (7 PRs; 95% CI: 9.3, 40.0) with a median DoR of 8.3 months (range: 3.5–23.3+); DCR was 63% (95% CI: 43.7, 78.9), and mOS was 10.7 mo (95% CI: 5.2, 18.1), with 64% of pts alive at 6 mo. Grade ≥3 treatment-related AEs were reported for 0% and 9% of pts in the mono (N = 16) and combo (N = 44) safety populations, respectively. PD-L1 expression and ICOS-specific biomarkers are being evaluated, with promising trends observed in enrichment of clinical activity in preliminary analyses. Conclusions: Fela is the first ICOS agonist with reported single-agent activity in anti-PD-1/L1–exp relapsed/refractory UC. Fela + P in combo shows promising clinical activity and manageable safety in PD-1/L1–naïve R/M UC. Further study is warranted. Updated data to be presented. Funding: Study 204691 (NCT02723955) funded by GlaxoSmithKline in collaboration with Merck Sharp &amp; Dohme Corp, a subsidiary of Merck &amp; Co, Inc, Kenilworth, NJ, USA. Clinical trial information: NCT02723955.