Exelixis (EXEL -3.8%) has announced interim analysis from ongoing Phase 1b (COSMIC-021) trial of Cabometyx (cabozantinib) in combination with Roche’ Tecentriq (atezolizumab), for the treatment of locally advanced or metastatic solid tumors. Data from two expansion cohorts was presented during the European Society for Medical Oncology Congress.
Interim results from cohort 1 (clear cell Renal Cell Cancer expansion cohort) included 70 patients. Median follow-up of 25.8 months in cabozantinib 40 mg dose group, the objective response rate (ORR) was 53%; disease control rate was 94%. Median progression-free survival (PFS) was 19.5 months. At median follow-up of 15.3 months for the cabozantinib 60 mg dose group, ORR was 58%, with four complete responses; disease control rate was 92%. Median PFS was 15.1 months. Median duration of response for all responding patients was 15.4 months.
In the 40 mg dose group, treatment-related serious adverse events occurring in ≥5% of patients were diarrhea (9%), fatigue (6%), hypertension (24%) and hypophosphatemia (15%); 24% of the patients discontinued either study treatment for treatment-related AEs, and and 15% discontinued both study treatments for treatment-related AEs.
In the 60 mg dose group, serious AEs observed included diarrhea (19%), fatigue (6%), hypertension (14%), alanine aminotransferase (ALT) increased (14%), aspartate aminotransferase (AST) increased (6%), lipase increased (8%) and mucosal inflammation (6%); discontinuation rate of 19% for either study treatment, and 6% discontinued both study treatments due to treatment-related AEs.
Initial results from the non-clear cell expansion cohort ((cohort 10)) included 30 patients. At a median follow-up of 13 months, ORR was 33%, and disease control rate was 93%, with Median PFS was 9.5 months, and median duration of response was 8.3 months.
On the safety front, 17% of patients discontinued either study treatment for treatment-related AEs, and 3% discontinued both study treatments for treatment-related AEs.