Neoadjuvant Chemoradiotherapy Plus Tislelizumab Followed by TME for LARC.

Rationale and Design of a Prospective, Multicenter Phase Ⅱ Clinical Trial of Safety and Efficacy Evaluation of Long Course Neoadjuvant Chemoradiotherapy Plus Tislelizumab Followed by TME for LARC.

Long course radiotherapy plus neoadjuvant chemotherapy followed by resection total mesorecta excision has accepted widespread recognized in the treatment of locally advanced rectal cancer (LARC). Tislelizumab, an anti-PD1(programmed death 1) humanized IgG4 (Immunoglomin G4) monoclonal antibody, has been demonstrated with clinical activity and is approved for treating recurrent/refractory classical Hodgkin lymphoma and locally advanced/metastatic urothelial carcinoma in China.

The aim of This NCRT-PD-1-LARC trial is to evaluate the efficacy and safety of long course neoadjuvant chemoradiotherapy plus tislelizumab followed by total mesorecta excision for LARC. This NCRT-PD-1-LARC trial will be a prospective, multicenter and phase Ⅱ clinical trial designed to evaluate the safety and efficacy of LARC patients treated with long course neoadjuvant chemoradiotherapy plus tislelizumab followed by total mesorecta excision. It will consecutively enroll 50 stage II/III LARC patients (cT3N0M0 and cT1-3N1-2M0) with the tumor distal location ≤ 10cm from anal verge at 7 centers in China. The enrolled patients will receive long course radiotherapy (50 Gy/25 f, 2 Gy/f, 5 days/week) and three 21-day cycles capecitabine (1000 mg/m2, bid, po, day1-14) plus three 21-day cycles tislelizumab (200 mg, iv.gtt, day8), followed by total mesorecta excision 6-12 week after the end of radiotherapy. The primary efficacy endpoint will be the pathological complete response (pCR) rate, which is defined as absence of viable tumor cells in the primary tumor and lymph nodes.

Inclusion criteria:

• Patients have been fully aware of the content of this study and signed the informed consent voluntarily;
• Patients with rectal cancers must satisfied all the following conditions: Stage II/III LARC (cT1-3N1-2M0)；Tumor distal location ≤10 cm from anal verge (MRI diagnosed);
• Patients regardless of gender with aged ≥18 years and ECOG score of 0 or 1;
• Physical and viscera function of patients can withstand major abdominal surgery;
• Patients are willing and able to follow the study protocol during the study;
• Patients give consent to the use of blood and pathological specimens for study;
• Within 28 days prior to enrolment, we must confirm a negative serological pregnancy test for child-bearing age women and they agree to use effective contraception for the duration of drug use and for 60 days after the last dose.

Exclusion criteria:

• Patients have a present or previous active malignancy except the diagnosis of rectal cancer this time;
• Patients underwent major surgery within 4 weeks prior to study treatment;
• Patients have any condition affects the absorption of capecitabine through gastrointestinal tract;
• Patients have severe uncontrolled recurrent infections, or other severe uncontrolled concomitant diseases;
• Patients who are allergic to any of the ingredients under study;
• Patients with severe concomitant diseases with estimated survival ≤ 5 years;
• Patients with present or previous moderate or severe liver and kidney damage presently or previously;
• Patients have received other study medications or any immunotherapy currently or in the past;
• Patients preparing for or previously received organ or bone marrow transplant;
• Patients who received immunosuppressive or systemic hormone therapy for immunosuppressive purposes within 1 month prior to the initiation of study therapy;
• Patients with congenital or acquired immune deficiency (such as HIV infection);
• If patients with a history of uncontrolled epilepsy, central nervous system disease or mental disorder, the investigator will determine whether the clinical severity prevents the signing of informed consent or affects the patient's oral medication compliance;
• Patients with other factors that may affect the study results or cause the study to be terminated midway, such as alcoholism, drug abuse, other serious diseases (including mental illness) requiring combined treatment and severe laboratory examination abnormalities.
• Pregnant or lactating women