This is a two-part, double-blind, randomized, placebo-controlled study designed to evaluate safety and efficacy of various doses of STP705 administered as an intralesional injection in subjects with isSCC.~A total of up to 100 eligible subjects will be enrolled. Enrolled subjects will be randomly allocated to receive STP705 or placebo injection once weekly for 6 weeks.~After 6 weeks, the lesion will be excised.~In part 1 (dose ranging study): 40 subjects will be randomized to receive 1 of the 3 STP705 doses or placebo.~An interim analysis will be done after all subjects have completed end of treatment (EOT) visits to determine 2 selected dose levels of STP705 to be used in part of the study.~In part 2: 60 additional subjects will be randomized to receive 1 of the 2 selected doses (from part 1) or placebo.~In both parts at the End of Treatment (EOT), the lesion will be excised.
The purpose of this trial is to evaluate safety, tolerability and efficacy of various doses of STP705 administered as intralesional injection in subjects with cutaneous squamous cell carcinoma (in situ) skin cancer (isSCC).