Exelixis, Inc. announced results for cabozantinib (CABOMETYX®) in combination with immunotherapies in patients with advanced colorectal cancer, including encouraging data from cohort 16 of the phase 1b COSMIC-021 trial of cabozantinib in combination with atezolizumab in patients with metastatic colorectal cancer who were previously treated with fluoropyrimidine-containing chemotherapy. Results from cohort 2 of the phase 2 CAMILLA trial of cabozantinib in combination with durvalumab in patients with advanced mismatch repair proficient/micro satellite stable (pMMR/MSS) colorectal cancer patients who were chemotherapy-refractory were also announced. The data from these studies are being presented during Poster Session C: Cancers of the Colon, Rectum, and Anus on Saturday, January 22 at the 2022 American Society of Clinical Oncology's Gastrointestinal Cancers Symposium (ASCO GI).
At a median follow-up of 28.1 months, the primary endpoint of objective response rate (ORR) by investigator per Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 in cohort 16 (n=31) was 10%. The disease control rate (DCR; complete response + partial response + stable disease) was 71%. Median progression-free survival (PFS) was 3.0 months (95% confidence interval [CI]: 2.7-5.4), and median overall survival (OS) was 14.0 months (95% CI: 5.5-16.7). Median duration of response was 7.6 months (95% CI: 4.2-not estimable [NE]). A post-hoc exploratory analysis showed that patients with wild-type RAS (n=12) had longer PFS and OS compared with patients with RAS mutations (n=19): median PFS was 5.8 months (95% CI: 2.8-11.0) compared with 2.7 months (95% CI: 1.6-4.1), respectively, and median OS was 16.7 months (95% CI: 8.4-NE) compared with 8.7 months (95% CI: 4.7-15.9), respectively. ORR was 25% for patients with wild-type RAS and 0% for patients with RAS mutations.