A topical gel containing patidegib, a cyclopamine-derived inhibitor of the Hedgehog (Hh) pathway, with potential antineoplastic activity. Upon topical application of the patidegib gel, patidegib binds to and inhibits the activity of the G-protein coupled receptor smoothened (SMO), thereby inhibiting Hh pathway signaling. This decreases proliferation and survival in tumor cells in which the Hh pathway is overactivated. Upregulated Hh signaling is associated with uncontrolled tumor cell proliferation. Topical application of patidegib allows for local anti-tumor activity while avoiding systemic exposure and unwanted systemic effects.