CHICAGO – Justin J. Leitenberger, MD, declared at the annual meeting of the American College of Mohs Surgery.
The oral antifungal inhibits the hedgehog signaling pathway, a key driver of BCC. And while itraconazole is not as potent an inhibitor of hedgehog pathway expression as, say vismodegib (Erivedge), the antifungal acts at a separate site on the pathway, making it an attractive candidate for combination therapy, explained Dr. Leitenberger of Oregon Health & Science University, Portland.
Dermatologists at Stanford University have led the way in exploring oral itraconazole as a treatment for BCC. Among a series of 29 patients with one or more large but nonadvanced BCCs, 19 were treated using oral itraconazole at 200 mg b.i.d. for 1 month or 100 mg b.i.d. for an average of 2.3 months. Hedgehog pathway expression was reduced by 65% in the itraconazole-treated patients, as compared with the 90% reduction which is achieved with vismodegib.
Of more direct clinical relevance, however, itraconazole also reduced tumor area by 24%. Four of eight patients with 57 tumors achieved a partial response, and the other four had stable disease ().
The Stanford group has also shown that combination therapy with oral itraconazole and intravenous arsenic trioxide reduces hedgehog pathway expression by 75%, up by an absolute 10% from itraconazole alone. The two agents inhibit the pathway at different sites.
Five patients with metastatic BCC who relapsed after treatment with vismodegib received intravenous arsenic trioxide for the first 5 days of every month, followed by oral itraconazole at 200 mg b.i.d. on days 6-28. Three patients completed three such cycles, while two discontinued early because of progressive disease or adverse events including a grade 3 infection and grade 2 transaminitis. All three patients who completed three treatment cycles achieved stable disease. The Stanford investigators speculated that concurrent continuous dosing might be required to obtain tumor shrinkage ( ).
Lots more work remains to be done in order to optimize combination therapy utilizing oral itraconazole for advanced BCC. Different dosing regimens and combinations of hedgehog pathway inhibitors need to be studied. Another important question is how effective itraconazole-based combinations will be in vismodegib-naive as compared with vismodegib-resistant patients, Dr. Leitenberger observed.
He reported having no financial conflicts regarding his presentation.