Induction Therapy With Panitumumab + mFOLFOX-6 in Rectal Cancer and Quadruple Wild-type Mutation Before Surgery

Patients with rectal adenocarcinoma of intermediate risk (defined by magnetic resonance imaging \[MRI\]), without mutations in KRAS, BRAF, NRAS and PI3KCA, who are candidates for preoperative treatment, will receive a preoperative Induction therapy with 12 weeks of panitumumab with mFOLFOX-6 to evaluate the efficacy in terms of pathologic complete response (pCR)

Phase II, nonrandomized single-arm trial of preoperative treatment with mFOLFOX-6 and panitumumab in an enriched population of patients with rectal adenocarcinoma of intermediate risk, screened by MRI, without mutations in KRAS, BRAF, NRAS and PI3K. All patients enrolled in the study will receive 12 weeks of the investigational product (mFOLFOX-6 with panitumumab) every 14 days for six cycles, unless unacceptable toxicity occurs or progression is detected. After this treatment, response will be evaluated by diffusion-weighted MRI and endoscopy. In the absence of disease progression, patients eligible for R0 resection will undergo total mesorectal excision (TME). After surgery, patients will receive mFOLFOX6 x 6 cycles. In the case of intolerance to FOLFOX-panitumumab, disease progression or ineligibility for R0 resection, patients will receive chemoradiotherapy with capecitabine 825 mg/m2 every 12 hours concomitantly with radiotherapy (RT) with a total dose of 50.4 Gy. At the end of this treatment, patients will undergo TME between 6-8 weeks after finishing the CRT. If a patient has received 4 or more neoadjuvant cycles of FOLFOX-panitumumab before unacceptable toxicity or progression, it will be considered that the neoadjuvant treatment has been completed and the patient will have no additional neoadjuvant treatment but surgery. If the patient has received \<4 cycles of neoadjuvant treatment, neoadjuvant CRT will be administered. If a patient has an acceptable toxicity or disease progression or a R0 surgery is not possible to be performed and the patient received CRT, the patient will be followed up for 24 months, from the enrollment of the last patient in the trial, or until progression occurs, in order to assess progression-free survival and all the data regarding surgery and CRT will be recorded in the eCRF. If a patient withdraws consent and refuses to continue participating in the study, follow-up evaluations must be discontinued.