Vismodegib demonstrated 60% response rates in the ERIVANCE trial. Basal cell carcinoma has various histopathologies. Their effect on response is unclear.

The purpose of this study was to determine whether basal cell carcinoma histopathology affected vismodegib response.

This phase 2b, single-center, prospective case series study compared the efficacy of vismodegib in infiltrative, nodular, and superficial basal cell carcinomas treated for 12 or 24 weeks in 27 patients. Patients had 1 target lesion and up to 3 nontarget lesions.

Twenty-seven patients were enrolled, with 65 tumors (27 target lesions/38 nontarget lesions). At 24 weeks, most basal cell carcinomas achieved histologic clearance, with positive biopsy results in 10.5% of target lesions, 30.4% of nontarget lesions, and 21.4% overall. No statistical differences were observed between histopathologic subtypes. One hundred percent of patients experienced an adverse event, 94% grade 1 or 2. The most common adverse events were dysgeusia/loss of taste (86%), muscle spasms (82%), and alopecia (71%). Clinically progressive disease during treatment was low (1.5%). Two patients had recurrence within 1 year of treatment.

Limitations included sample size of basal cell carcinoma histopathologic subtypes, sampling punch biopsies, and short follow-up.

Basal cell histopathologic subtype did not significantly affect response to vismodegib. Each subtype was observed to completely respond at 12 weeks of therapy, 24 weeks, or both.