Results of a phase II, open-label, non-comparative study of intralesional PV-10 followed by radiotherapy for the treatment of in-transit or metastatic melanoma

BACKGROUNDIn-transit and recurrent dermal or subcutaneous melanoma metastases represent a significant burden of advanced disease. Intralesional Rose Bengal can elicit tumor selective ablation and a T-cell mediated abscopal effect in untreated lesions. A subset of patients in a phase II trial setting received external beam radiotherapy to their recurrent lesions with complete or partial response and no significant acute radiation reaction. METHODSAn open-label, single-arm phase II study was performed to assess the efficacy and safety of PV-10 followed by hypofractionated radiotherapy. Patients had in-transit melanoma metastases suitable for IL therapy and radiotherapy. RESULTSFifteen patients were enrolled and thirteen completed both treatment components. The overall response rate was 86.6% and the clinical benefit was 93.3% on an intention to treat analysis (CR 33.3%, PR 53.3%, SD 6.7%). The median follow up duration was 19.25 months. Size of metastases (<10mm) predicted lesion complete response (74.6%). Treatment was well tolerated with no associated grade 4 or 5 adverse events. CONCLUSIONSThe combination of PV-10 and radiotherapy resulted in lesion-specific, normal tissue-sparing, ablation of disease with minimal local or systemic adverse effects.