Case 4: Options Beyond HHI for Basal Cell Carcinoma

EXPERT PERSPECTIVE VIRTUAL TUMOR BOARD

Ahmad Tarhini, MD, PhD:Dr McKean, if this patient fails hedgehog inhibitors, what are the options in terms of systemic therapy? Do we have data?

Meredith McKean, MD:For a patient with a basal cell carcinoma that has failed a hedgehog inhibitor, I think your first thought should probably be using anti—PD-1 [programmed cell death protein 1] or an immune checkpoint inhibitor. We know that these patients have high tumor mutational burden, and we’ve seen some data showing that there are high response rates in some durable responses to anti–PD-1. Although not approved, I think trying to look for a clinical trial for a patient to be able to have an immune checkpoint inhibitor would be a great next step.

Ahmad Tarhini, MD, PhD:I agree. I would also pursue a clinical trial for these patients also with anti—PD-1 antibodies, understanding the data. It’s interesting that for superficial basal cell carcinoma, a TLR7 agonist, imiquimod, is an option. It works well and speaks for the potential immunogenicity of these tumors. We know that they have a high mutational burden, which also again has been associated with a likelihood of response to immunotherapy, specifically immune checkpoint inhibitors. There are exciting ongoing studies with anti–PD-1 antibodies. I would do the same.

Unfortunately, because we have limited data otherwise, and it is related to the fact that this is a rare tumor, most of the data we have—in terms of chemotherapy, for example—are based on case reports and case series. Limited guidance is available to us in the community in terms of other options. Hedgehog inhibitors are the first line of treatment for inoperable disease, followed by radiation obviously is an option. In patients who cannot tolerate, a clinical trial with anti—PD-1 antibodies appears to be the next-best option as well.

Thank you to Dr McKean, Dr Wong, and Dr Emerick for your thoughtful case presentations and lively informative discussion. To our viewing audience, thank you for joining us for theTargeted Oncology™Virtual Tumor Board® presentation on skin cancer. We hope today’s discussion was a valuable use of your time and that you acquired some practical knowledge that you can take back to your clinic.

Transcript edited for clarity.