Trial results for a Phase 1b/2 study (NCT03473756) investigating atezolizumab in combination with rogaratinib for patients with urothelial carcinoma were posted on ClinicalTrials.gov on 2025-04-09. The study's Phase 1b part, focusing on safety, identified 1 dose-limiting toxicity (DLT) in the rogaratinib 800 mg BID + atezolizumab group and 4 DLTs in the rogaratinib 600 mg BID + atezolizumab group.
Background
The study, titled "Phase 1b/2 Study of Rogaratinib (BAY1163877) in Combination With Atezolizumab in Urothelial Carcinoma," aimed to evaluate the safety, tolerability, recommended Phase 2 dose (RP2D), and pharmacokinetics of rogaratinib in combination with atezolizumab in patients with untreated FGFR-positive urothelial carcinoma. The trial was designed with two parts: Phase 1b (Part A) and Phase 2 (Part B), with Part A specifically addressing safety and tolerability.
Trial design
The study (NCT03473756) was a Phase 1b/2 trial that enrolled 37 participants diagnosed with urothelial carcinoma. The interventions included rogaratinib and atezolizumab. The primary objectives for the Phase 1b (Part A) portion of the study were to determine the safety, tolerability, RP2D, and pharmacokinetics of rogaratinib in combination with atezolizumab in this patient population.
Key results
Safety and preliminary efficacy data were reported for participants receiving the combination therapy:
- For the outcome of "Number of Participants With Dose-limiting Toxicities (DLTs)":
- In the Rogaratinib 800 mg BID + Atezolizumab group, 1 participant experienced DLTs.
- In the Rogaratinib 600 mg BID + Atezolizumab group, 4 participants experienced DLTs.
- Regarding "Number of Participants With Treatment-emergent Adverse Events (TEAEs)":
- The Rogaratinib 800 mg BID + Atezolizumab group had 11 participants with TEAEs.
- The Rogaratinib 600 mg BID + Atezolizumab group had 26 participants with TEAEs.
- For "Number of Participants With Drug-related TEAEs":
- The Rogaratinib 800 mg BID + Atezolizumab group had 11 participants with drug-related TEAEs.
- The Rogaratinib 600 mg BID + Atezolizumab group had 26 participants with drug-related TEAEs.
- For "Number of Participants With Treatment-emergent Serious Adverse Events (TESAEs)":
- The Rogaratinib 800 mg BID + Atezolizumab group had 8 participants with TESAEs.
- The Rogaratinib 600 mg BID + Atezolizumab group had 14 participants with TESAEs.
- For "Objective Response Rate (ORR)" (reported as number of participants):
- In the Rogaratinib 800 mg BID + Atezolizumab group, 1 participant achieved an objective response.
- In the Rogaratinib 600 mg BID + Atezolizumab group, 10 participants achieved an objective response.
What this means
The results from the Phase 1b portion of this study provide initial safety and tolerability data for the combination of rogaratinib and atezolizumab in patients with urothelial carcinoma. The observation of dose-limiting toxicities in both dose groups, with a higher number at the 600 mg BID dose of rogaratinib, is a key finding for determining the appropriate dosing strategy. The reported adverse events and serious adverse events will inform the overall safety profile of this combination. The preliminary objective response rates offer an early indication of potential efficacy, which would typically be further explored in subsequent trial phases.
Source
The information regarding these trial results was obtained from ClinicalTrials.gov, a public database of clinical studies. The results for study NCT03473756, titled "Phase 1b/2 Study of Rogaratinib (BAY1163877) in Combination With Atezolizumab in Urothelial Carcinoma," were posted on 2025-04-09 on clinicaltrials.gov.