The efficacy and safety of standardized allergen-removed Rhus verniciflua extract as maintenance therapy after first-line chemotherapy in patients with advanced non-small cell lung cancer

Chemotherapy improves the survival of patients with advanced non-small cell lung cancer (NSCLC), but tumor progression is often inevitable. Strategies are needed to improve the therapeutic efficacy of chemotherapy. Over recent years, there has been increasing interest in the role of maintenance therapy after first-line chemotherapy. We investigated the efficacy and safety of standardized allergen-removed Rhus verniciflua Stokes extract (aRVS) as maintenance therapy in patients with non-progressive disease following first-line chemotherapy. We reviewed the medical records of 33 patients with advanced NSCLC, who started treatment with aRVS in a state of tumor regression or stable disease after completion of four or six cycles of induction chemotherapy at the Integrative Cancer Center, Kyung Hee University Hospital at Gangdong from June 2006 to April 2012. The primary objective of this study was progression-free survival (PFS) of aRVS as maintenance therapy. Secondary objectives included assessments of disease control rate (DCR), overall survival (OS), and the safety of aRVS treatment. The median PFS was 5.2 months with a 6- and 12-month PFS rate of 40.6% and 12.9%, respectively. The DCR was 93.9% and the median OS was 34.8 months. The overall survival rates at 12, 24, and 36 months were 84.2%, 76.7% and 49.9%, respectively. We observed no hematologic toxicity, nephrotoxicity, or hepatotoxicity during aRVS treatment. In conclusion, maintenance therapy with aRVS for patients with advanced NSCLC is well-tolerated and offers encouraging improved PFS and OS compared with historical controls. Our data provide further evidence that aRVS may be used beyond disease progression in this clinical setting.