Complete response of a large basosquamous carcinoma following treatment with cemiplimab and vismodegib

Abstract

The anti-PD-1 antibody cemiplimab has demonstrated effectiveness in the setting of locally advanced basal cell carcinoma (BCC) and squamous cell carcinoma. We describe a case of a large, locally invasive basosquamous carcinoma, an aggressive type of BCC, invading the left sternocleidomastoid muscle with near compression of the left internal jugular vein producing a severe anaemia secondary to ulceration and chronic blood loss. The patient was initially started on vismodegib monotherapy but failed to respond. He was then started on cemiplimab in addition to vismodegib. Improvement was noted after one cycle. After 21 cycles of cemiplimab, the left shoulder ulcerated lesion was completely re-epithelialised. He remains in complete remission after 31 cycles of cemiplimab in addition to vismodegib.

Basosquamous Carcinoma: Comprehensive Clinical and Histopathological Aspects, Novel Imaging Tools, and Therapeutic Approaches

“…On the other hand, the largest published cohort study of 1675 patients suggests that vismodegib is not associated with an increased risk of developing SCC, while a systematic and a narrative review of the literature concluded that the available evidence does not justify an association between vismodegib and the development of SCC [68,69]. In addition, there are very recent case reports involving a total of five patients that provide preliminary evidence that vismodegib may be effective in difficult-to-treat BSC (Table 1) [69][70][71]. In all cases, the lesions did not "transform" into pure squamous cell tumors but, on the contrary, regressed completely, and in two cases remission was maintained over a very long period [69][70][71].…”

“…In addition, there are very recent case reports involving a total of five patients that provide preliminary evidence that vismodegib may be effective in difficult-to-treat BSC (Table 1) [69][70][71]. In all cases, the lesions did not "transform" into pure squamous cell tumors but, on the contrary, regressed completely, and in two cases remission was maintained over a very long period [69][70][71]. Despite these positive data, in one case of basosquamous carcinoma treated with vismodegib, the drug had to be discontinued due to adverse effects before its efficacy could be evaluated [72].…”

“…This is applicable to patients who have experienced progression on hedgehog pathway inhibitors (HHIs), are intolerant to HHI therapy, or have not objectively responded after months of HHI therapy. Studies on cemiplimab have demonstrated a favorable effectiveness and tolerability profile, albeit with a shorter average length of response compared to SCC [71,[79][80][81]. In a Phase II study led by Stratigos in 2021, which involved 84 patients experiencing progression on hedgehog inhibitors (HHI), 31% of patients achieved an objective response rate, with 6% of those responses being complete [81].…”