A phase II trial of cabozantinib and erlotinib for patients with EGFR and c-Met co-expressing metastatic pancreatic adenocarcinoma (PDAC).

Abstract

e16764 Background: Both EGFR and the c-MET receptors are overexpressed in a majority of PDACs. Inhibition of both receptors simultaneously may be required for anti-tumor activity. Erlotinib, an EGFR inhibitor, has modest activity in metastatic PDAC and is approved by the FDA in combination with gemcitabine. Cabozantinib is a tyrosine kinase inhibitor targeting AXL, FLT-3, KIT, MER, MET, RET, ROS1, TIE-2, TRKB, TYRO3, and VEGFR-1, -2, and -3. Preclinical data suggests that the addition of cabozantinib to erlotinib leads to tumor shrinkage and improvement in survival in a KPC PDAC mouse model compared to gemcitabine alone. This phase II study tests this hypothesis in patients with metastatic PDAC that co-express c-MET and EGFR. Methods: Key eligibility includes patients (pts) with metastatic PDAC with EGFR and c-MET overexpression (as determined by centrally tested IHC of 2+ or greater) that have progression on one prior chemotherapy regimen. Patients were treated with cabozantinib (40mg daily) and erlotinib (100mg daily) continuously. This dosing is based on previous combination data in NSCLC. This is a single arm two-stage phase II study with a primary endpoint of overall response rate. Secondary endpoints include of PFS, DCR and OS. Results: From October 2017 to October 2019, 43 pts were screened with 7 pts (median age 62 [range 51-76)] enrolled and treated on study. Pts had a median of 1 line of prior systemic chemotherapy. Most common reason for screen failure was due to lack of co-expression of c-MET and EGFR. EGFR IHC expression was +2 in 4 pts, +3 in 3 pts; c-MET IHC expression was +2 in 5 pts and +3 in 2 pts. Most common any-grade adverse events attributable to cabozantinib and erlotinib include: diarrhea (71%), AST increase (43%), fatigue (43%), nausea (43%), and rash (43%). Only one grade 3 event of fatigue occurred. All pts had clinical and/or radiographic progression within 1-2 months after initiating study therapy. Conclusions: The combination of cabozantinib and erlotinib was well tolerated with manageable toxicity. Due to lack of clinical responses, this study has been terminated due to futility. Clinical trial information: NCT03213626 .