Combination vismodegib and photodynamic therapy for multiple basal cell carcinomas.

Background: Oral vismodegib therapy and photodynamic therapy (PDT) are non-invasive treatments for basal cell carcinoma (BCC) with overlapping utility in widespread BCCs and patients who are poor surgical candidates. There is no published study to date investigating the combination use of PDT with vismodegib to optimize individual response rates.

Objective: To evaluate the combination of red light PDT and vismodegib therapy in patients with multiple nodular BCCs. The primary objective was to determine the safety of this combination therapy. Secondary outcomes included evaluation of the overall response rate, treatment-related pain, and cosmesis.

Methods: An open label pilot study of immunocompetent patients with multiple BCCs treated with 3 months of continuous vismodegib therapy (150 mg daily) and 3 consecutive ALA PDT sessions. Outcomes were assessed following each PDT session and 30 days post-treatment.

Results: Four patients with multiple nodular BCC (median=5) were enrolled in the trial between January and August of 2016. Three patients completed the full intervention phase trial and a total of 19 lesions were treated. One patient completed 2 months of vismodegib and 2 PDT sessions. One PDT session was sufficient for small lesions, whereas larger lesions required all 3 sessions. The fifteen evaluable lesions at the end of the 3 PDT sessions showed complete responses. At 30-day follow-up, one of the treated lesions was noted to have clinical evidence of disease. Overall response rate showed 90% complete response and 10% partial response for the study. Combination therapy was well tolerated and yielded a similar or superior side effect profile to that of individual therapies with excellent cosmesis.

Conclusion: Combination PDT-vismodegib is a potential safe & effective therapy for the treatment of multiple BCCs that may enhance efficacy of individual therapies.