First-line FOLFOX plus panitumumab versus 5FU plus panitumumab in RAS-BRAF wild-type metastatic colorectal cancer elderly patients: The PANDA study.

Abstract

4002 Background: Data on first-line treatment efficacy in elderly patients are limited. Many analyses adopt a questionable cut-off of 65 years and specific evidence with anti-EGFRs is low. FOLFOX-panitumumab (pan) is an option for RAS wild-type (wt) untreated mCRC patients. Guidelines recommend considering fluoropyrimidine monotherapy as an option for elderly patients, but no randomized studies have ever explored the role of the combination with an anti-EGFR. Methods: This is a prospective, open-label, multicenter phase II randomized trial. Unresectable and previously untreated RAS- BRAF wt mCRC patients aged ≥70 were randomized to receive FOLFOX-pan (arm A), or 5FU/LV-pan (arm B) for up to 12 cycles followed by pan maintenance until PD. The primary EP was PFS in both arms. Stratification criteria were age (≤75 vs > 75 years), ECOG PS (0–1 vs 2) and geriatric assessment with G8 Score (≤14 vs > 14). In each treatment arm, the null hypothesis for median PFS was set at ≤6 months. Assuming an expected median PFS time ≥9.5 months with both experimental regimens, a sample size of 90 patients in each arm granted to the study a power of 90%, with a type I error rate equal to 5% (1-sided Brookmeyer-Crowley test) for rejecting the null hypothesis. No formal comparison between the two arms was planned. Results: From Jul 2016 to Apr 2019 a total of 394 patients were screened, 211 were deemed eligible for inclusion and 185 were randomized (92 arm A and 93 arm B). Main pts’ characteristics were (arm A/B): males 66%/61%; median age 77/77y; PS≥1 49%/55%; right colon 23%/21%; G8 > 14 31%/30%. At a median follow up of 20.5 mos, 135 (arm A/B: 64/71) PD events were collected. Median PFS was 9.6 (95% CI 8.8-10.9) in arm A with FOLFOX-pan and 9.1 (95% CI 7.7-9.9) in arm B with 5FU/LV-pan. Response rates were (arm A/B): 65%/57%. Grade 3-4 toxicities were (arm A/B): neutropenia 9.8%/1.1%; diarrhea 16.3%/1.1%; stomatitis 9.8%/4.4%; neurotoxicity 3.3%/0%; fatigue 6.5%/4.4%; skin rash 25%/24.2%, hypomagnesemia 3.3%/7.7%. Conclusions: Large prospective randomized studies in molecularly selected elderly mCRC are feasible with multicenter collaborative efforts. Primary EP was met in both treatment arms. 5FU/LV plus panitumumab for up to 12 cycles followed by panitumumab maintenance until PD might be a reasonable option in elderly mCRC patients with RAS/BRAF wt tumors deserving further investigations in phase III trials. Clinical trial information: NCT02904031 .