Capecitabine-based Chemoradiotherapy in Combination With the IL-1 Receptor Antagonist Anakinra for Rectal Cancer Patients

Anakinra 100 mg s.c. (Kineret) will be administered from day -10 (i.e. 10 days before initiation of RT) to the last day of RT.

Capecitabine will be administered using a 3+3 dose escalation design (500 mg/m2 bid, 650 mg/m2 bid and 825 mg/m2 bid po, respectively) from day 1 to day 40 of RT including weekends.

PTV: 1.8 Gy to 45 Gy (#28 fractions) to the primary tumor and pelvic lymph nodes; followed by a sequential boost of 1.8 Gy to 9 Gy (#5 fractions) to the gross tumor volume

Restaging to evaluate tumor response will be conducted 10 weeks after completion of CRT. For patients achieving a clinical complete response (cCR), a Watch and Wait (W\&W) option with close follow-up is scheduled. In case of non-cCR, immediate total mesorectal excision (TME) surgery is recommended. According to the current German S3-guidelines, adjuvant chemotherapy is optional.