A single arm phase 2 clinical trial of YIV-906 with neoadjuvant concurrent chemo-radiation therapy in patients with locally advanced rectal cancer

Background: Pre-operative chemoradiation for rectal cancer is often associated with severe gastrointestinal (GI) toxicity which can interrupt, delay, and/or lead to termination of treatment. In this study, we evaluated whether the addition of YIV-906, a novel herbal medicine proven to reduce GI toxicity associated with chemotherapy could also reduce GI side effects during standard pre-operative capecitabine and pelvic radiation therapy (RT) in the neoadjuvant setting for the treatment of locally advanced rectal cancer.

Methods: This single arm clinical study enrolled 24 patients between Dec 23, 2014-Sep 17, 2018 at Smilow Cancer Hospital, a comprehensive cancer center at Yale New Haven Hospital. All patients were age ≥18 years, Eastern Cooperative Oncology Group 0-1 and with histologically confirmed T3-T4 and N0-N2, M0 adenocarcinoma of the rectum. Median follow-up was 61.9 months. All patients received concurrent pelvic external beam RT (50.4 Gy in 28 fractions), YIV-906 (taken orally 800 mg twice daily on days 1-4 of RT each week), and oral capecitabine delivered in a neo-adjuvant fashion, followed by definitive surgery. Toxicity was assessed weekly during radiation and until acute symptoms resolved and then at 28 days, 4 months, 7 months and 10 months. Toxicities were graded in accordance with Common Terminology Criteria for Adverse Events (CTCAE) version 4.0.

Results: At the time of surgery, 4 patients (16.7%) had a complete or near-complete response. At a median follow-up of 61.9 months, the mean overall survival (OS) of our patient cohort was 74.9 months [95% confidence interval (CI): 67.3-82.5]. The estimated 5-year OS was 82.0%. We observed 0% acute grade 4 toxicities, and only two cases of acute grade 3 diarrhea (8.3%).

Conclusions: The addition of YIV-906 to capecitabine based chemoradiation for locally advanced rectal cancer led to reduced rates of GI toxicity compared to historical controls, in particular grade 3 or greater diarrhea. These findings suggest YIV-906 should be evaluated in a randomized clinical trial to further assess potential reductions in the toxicity profile of chemoradiation for GI cancers.