Results of monoclonal antibodies against EGFR-receptors application in patients with metastatic colorectal cancer (mCRC).

Abstract

e14701 Background: Monoclonal antibodies against the epidermal growth factor receptor(EGFR)are standard components of treatment in mCRC.This study was designed to evaluate the tolerability and efficacy of the combinations of Panitumumab(P) and Cetuximab(C) with chemotherapy in patients with wild type(WT) KRAS tumors mCRC. Methods: Mutation analysis of KRAS(codons12,13) was done on samples at diagnosis. Key elegibility criteria included measurable mCRC stage IV, ECOG ≤2, adequate liver,kidney and bone marrow function, no brain metastases. P was administered 6mg/ kg 1 day q2w. C was administered 400mg/m² 1day and 250mg/m² q1w. Combination with FOLFOX-6 or FOLFIRI pegimens was allowed. Endpoints include response rate, OS, PFS and safety. Results: Of 38 testable samples there were 21(55.3%) WT KRAS tumors. All of these 21 (13male and 8female) pts were recruited. Mean age was 58.1±12.3. Synchronous metastases had 33.3%(7pts). Majority of pts benefited from anti-EGFR combined with cytotoxic chemotherapy 80.9% (17), mostly FOLFIRI – 57,1%(12).There were23.8%(5) in the 1st line CT, 76.1%(16) in the 2nd line CT. 6 mos of the treatment were analyzed. Overall RR was76.1 %(16) including 6PR(28.5%) and 10SD(47.6%). Med OS= 9.1mo, Med PFS= 4.3mo. 8 pts(38.1%) are alive till the abstract submission. Most common toxicities were:skin rash 2/3Gd.-90.5%(19), xeroderma 2Gd.-42.9%(9),skin itch 1/3Gd.-42.9%(9), paronychia 2Gd. -14.2%(3), purulent psorophthalmia 2Gd.-14.2%(3). All kinds of toxicities were controlled by symptomatic medication if necessary and did not lead to anti-EGFR agents dalay. Besides,diarrhea 1/2Gd.- 66.7%(14), 3Gd.-14.3%(3), neutropenia 1/2Gd.-28.6%(6), 3/4Gd.-9.5%(2), nausea 3/4Gd.- 14.3%(3), vomiting 1/2Gd.- 42.9%(9), fatigue 1/2Gd.-47.6%(10). Conclusions: These results consider significant efficacy of anti-EGFR agents combined with CT in pts with mCRC. Controlled toxicity of the therapy allows to use it widely.