A recent phase 2 trial has revealed encouraging three-year survival rates for patients with locally advanced rectal cancer (LARC) treated with neoadjuvant short-course radiotherapy (SCRT) followed by camrelizumab (Airuika) in conjunction with oxaliplatin and capecitabine (CAPOX). The study, published in BMC Medicine, suggests a potential new treatment approach for this challenging disease.

The trial followed 30 patients, with a median follow-up of 40.8 months. Among the 27 patients who underwent total mesorectal excision (TME) after receiving at least one dose of camrelizumab plus CAPOX, the median disease-free survival (DFS) was not reached. The estimated three-year DFS rate for this group was an impressive 80.2%.

Subgroup analyses further highlighted the benefits of this treatment regimen. Patients who achieved a pathological complete response (pCR) demonstrated a 100% three-year DFS rate, compared to 63.5% for those who did not. Similarly, patients with postoperative pathological node-negative status (pN0) had a 94.4% three-year DFS rate, while those with node-positive status had a 50% rate.

The study also identified additional factors associated with improved outcomes. Patients with negative baseline circumferential resection margin (CRM) status showed a 100% three-year DFS rate, compared to 69.5% for those with CRM-positive status. A similar trend was observed for extramural venous invasion (EMVI), with negative EMVI status associated with a 100% three-year DFS rate, compared to 54.5% for those with positive EMVI.

According to Zhenyu Lin, a researcher at the institute of Radiation Oncology at the Union hospital of Tongji Medical College in Wuhan, China, “With over 3 years of follow-up, neoadjuvant SCRT followed by camrelizumab and CAPOX regimen was associated with promising survival outcomes in patients [with LARC].” Lin added that the data suggests this regimen “may be a promising therapeutic option, especially with the potential to address an unmet need for patients with MSS [microsatellite-stable] Tumor.”

In the trial, patients aged 18 to 75 years with previously untreated LARC, an inferior margin of 10 cm or fewer from the anal verge, and an ECOG performance status of 0 or 1 were enrolled at Tongji Medical Hospital.The treatment protocol included five 5 Gy doses of SCRT over five days, followed by intravenous camrelizumab at 200 mg one week after SCRT. The CAPOX regimen consisted of 130 mg/m² of intravenous oxaliplatin and 1000 mg/m² of oral capecitabine administered twice daily for two weeks,repeated every three weeks for two cycles.

TME was performed one week after the completion of neoadjuvant treatment, and adjuvant chemotherapy regimens were administered at the investigator’s discretion three to four weeks after surgery.

the study population included a important proportion of patients with advanced disease characteristics. A total of 26 patients (86.7%) had positive lymph nodes, with 10 (33.3%) having N2 disease. Twenty-one patients (70.0%) had CRM involvement, 12 (40.0%) had EMVI, and half (50.0%) had tumors located less than 5 cm from the anal verge. The majority of patients (93.3%) had microsatellite-stable (MSS) disease, and 20 (66.7%) had a PD-L1 combined positive score of less than 1.

The primary endpoint of the study was the pCR rate,while secondary endpoints included three-year DFS and OS,R0 resection rate,complication rate,and safety.

Of the 27 patients who underwent TME, 21 (77.8%) received subsequent adjuvant CAPOX, with a median of four adjuvant cycles. Dose reductions were required in two patients due to weight loss and hand-and-foot syndrome, while three patients discontinued adjuvant oxaliplatin due to adverse events. No grade 5 adverse effects or emergent toxicities were observed.