The efficacy and safety of oncolytic viruses in the treatment of intermediate to advanced solid tumors: a systematic review and meta-analysis

Background: Cancer treatment remains one of the most formidable challenges worldwide. Some novel treatment strategies, including molecularly targeted therapy, gene therapy, and cellular immunotherapy, have also been investigated to improve therapeutic effects for cancer patients and have demonstrated unexpected positive effects. This systematic review and meta-analysis evaluated the efficacy and safety of oncolytic virus (OV) monotherapy or combination therapy for intermediate to advanced solid tumors. Methods: We retrieved articles from PubMed, Embase, Web of Science, CNKI, Wanfang and VIP. The quality of the included studies was assessed by Review Manager Software version 5.3. STATA software was used to perform meta-analyses of efficacy, overall survival (OS) and adverse reactions. Results: A total of 22 studies involving 3,996 patients were included in this analysis, including 13 H101 studies, 5 T-VEC studies, 2 Pexa-Vec studies, 1 HF10 study and 1 Reolysin study. Regarding oncolytic adenovirus H101, meta-analysis showed that patients treated with H101 monotherapy or H101 combined with chemotherapy had a significantly higher objective response rate (ORR) than those treated with chemotherapy. Patients in the H101 and T-VEC groups had significantly longer effect size (ES) than the control group patients. The odds ratio (OR) and ES of patients with hepatocellular carcinoma, lung cancer and melanoma treated with OV were analyzed. For the safety profile, the total incidence of adverse reactions was similar in both groups. In terms of the other OVs, according to a systematic review, we found that after Reolysin treatment, the ORR was 26.9% in patients with head and neck cancer. The phase I study of HF10 exhibited some therapeutic potential. The adverse events (AEs) associated with the other OVs mainly included fever, nausea and vomiting, leukopenia, and hypotension. Discussion: OVs are effective and well tolerated for the treatment of intermediate to advanced solid cancer and represent a promising therapeutic approach for solid cancers.