Dose-Ranging Safety and Efficacy Study of Topical Creams Containing API 31510 for the Treatment of in Situ Cutaneous Squamous Cell Carcinoma

Inclusion Criteria:

• Male or female adults ≥ 18 years of age
• Primary, histologically confirmed SCCIS with a minimum area of 0.5 cm2 and with a maximum diameter of 2.0 cm target SCCIS lesion suitable for excision
• Histological diagnosis made no more than 4 weeks prior to the screening visit
• Histological biopsy removed 25% or less of the target lesion
• No other dermatological disease in the SCCIS target site or surrounding area
• Willing to refrain from using non-approved lotions or creams on the target site and surrounding area during the treatment period. Willing to refrain from washing the treated area for at least 8 hours following the application of study medication
• Willing to refrain from exposure to direct sunlight or ultraviolet light and to avoid the use of tanning parlors for the duration of the study
• Laboratory values for the tests listed in the Study Schedule on page 2 within the reference ranges as defined by the central laboratory, or "out of range" test results that are clinically acceptable to the investigator.
• Ability to follow study instructions and likely to complete all study requirements
• Written informed consent obtained, including consent for tissue to be examined and stored by the central dermatopathologist
• Written consent to allow photographs of the target SCCIS lesion to be used as part of the study data
• For females of childbearing potential, a negative pregnancy test at screening and using an acceptable form of birth control (oral/implant/injectable/transdermal contraceptives, intrauterine device, condom, diaphragm, abstinence, or a monogamous relationship with a partner who has had a vasectomy)

Exclusion Criteria:

• Pregnant or lactating
• Presence of known or suspected systemic cancer
• Histological evidence of nBCC, sBCC, or any other tumor in the biopsy specimen
• Histological evidence of severe squamous metaplasia, infiltrative, desomoplastic or micronodular growth patterns in the biopsy specimen
• History of recurrence of the target SCCIS lesion
• Evidence of dermatological disease or confounding skin condition in the treatment area, e.g., BCC, actinic keratosis, rosacea, psoriasis, atopic dermatitis, eczema, xeroderma pigmentosa
• Concurrent disease or treatment that suppresses the immune system
• Chronic medical condition that in the judgment of the investigator(s) would interfere with the performance of the study or would place the patient at undue risk
• Known sensitivity to any of the ingredients in the study medication
• Use of a tanning parlor or other excessive or prolonged exposure to ultraviolet light or direct sunlight during the course of the study
• Treatment with systemic chemotherapeutic agents within the 6 months prior to the screening visit
• Use of systemic retinoids within the 6 months prior to the screening period
• Treatment with systemic immunomodulators or immunosuppressants within the 6 months prior to the screening period
• Use of topical immunomodulators within 2 cm of the target SCCIS lesion within the 4 weeks prior to the screening period
• Treatment with the following topical agents within the 4 weeks prior to the screening visit: levulanic acid, 5-fluorouracil, corticosteroids, retinoids, diclofenac, hyaluronic acid, imiquimod
• Undergone a facial resurfacing procedure, i.e., chemical peel, laser resurfacing, dermabrasion, within the 6 months prior to the screening visit, if the target SCCIS lesion is on the face
• Treatment with liquid nitrogen, surgical excision or curettage within 2 cm of the target SCCIS lesion during the 4 weeks prior to the screening visit
• Elective surgery within 4 weeks prior to the screening visit, during the study, or 4 weeks after the treatment period
• Evidence of current chronic alcohol or drug abuse
• Current enrollment in an investigational drug or device study or participation in such a study within 4 weeks of the screening visit
• In the investigator's opinion, evidence of unwillingness, or inability to follow the restrictions of the protocol and complete the study