Efficacy of oral tetra-arsenic tetra-sulfide maintenance therapy for ovarian cancer: a single-center observational study

Objective To investigate firstly Chinese patent medicine Realgar-Indigo Naturalis Formula (RIF), which mainly contains tetra-arsenic tetra-sulfide formula for the maintenance therapy of ovarian cancer. Methods We recruited all patients with ovarian epithelial cancer who were diagnosed at Peking University People’s Hospital between January 2018 and January 2021. All these patients received standard chemotherapy and achieved complete remission. The patients took RIF (60 mg/kg daily in an oral divided dose) in a 4-week-on and 4-week-off regimen. The main efficacy indicators, including progression-free interval (PFI) and overall survival (OS), were measured and evaluated regularly. Additionally, the safety and side effects were closely monitored. Results A total of 20 patients were included in this study. Regarding the treatment, patients received oral arsenic for 3–18 courses (the longest treatment interval was equivalent to 3 years). The median follow-up time was 43 months. Subsequently, data analysis was conducted, revealing that the median PFI was 23 months. P53 mutations were worse than P53 wild-type PFI, and the median PFI was 19.2 months (p=0.03). Regarding P53 wt status, the HR for disease progression or death was 0.25 (95% CI 0.07 to 0.91). The 3-year OS was 89%, and the 5-year OS was 77%. The common side effects were abdominal pain and diarrhoea. Conclusions RIF compound proved to be an effective Chinese patent medicine maintenance therapy for ovarian cancer, thus prolonging the PFI of patients and controllable side effects, in particular simple and convenient for the method of administration and better potency ratio. These findings need to be validated in multicentre research studies with large sample sizes. Trial registration number ChiCTR2400090349.