The study was withdrawn due to lack of financial support.

This clinical trial aims to investigate the efficacy of Calcipotriol ointment combined with 5-fluorouracil cream as an immunotherapy for actinic keratosis in Organ Transplant Recipients (OTRs) before transplantation and determine whether it can prevent cutaneous squamous cell carcinoma (SCC) in OTRs post-transplant.

The main goal of this investigator-initiated clinical trial is to determine the efficacy of topical calcipotriol combined with 5-flourouracil (5-FU) treatment in organ transplant candidates with precancerous skin lesions called actinic keratoses (AKs) with a history of skin cancer in order to prevent squamous cell carcinoma (SCC) development after transplantation. SCC is the most common cutaneous malignancy seen after transplantation, with a 65-250 fold greater incidence in organ transplant recipients (OTRs) compared to the general population. This increased risk is due to the systemic immunosuppression caused by anti-rejection medications, which are indispensable for protecting against allograft loss. Previously, we have demonstrated the high efficacy of topical calcipotriol plus 5-FU immunotherapy for AKs on the face and scalp in significantly reducing the risk of SCC development within 3 years post-treatment in immunocompetent patients. This SCC risk reduction is accompanied by the induction of robust T cell immunity and TRM cell formation against AKs. Calcipotriol is a low calcemic vitamin D analogue that is FDA-approved for the treatment of psoriasis. Topical 5-FU is a chemotherapy that is the standard treatment for AKs. Our previous research demonstrates the synergistic impact of calcipotriol in combination with 5-FU on a robust T cell immunity against early skin carcinogenesis in immunocompetent patients. Therefore, we aim to determine the efficacy of this immunotherapy before transplantation in reducing the risk of SCC post-transplant despite the immunosuppressive medications.

Inclusion Criteria:

• Solid organ transplant candidates with AKs and a history of non-melanoma skin cancer. The target population includes the patients who are undergoing kidney, lung, liver and heart transplantations.
• Presence of four to fifteen clinically typical, visible, and discrete AKs in 25 cm2 on any of the four anatomical sites: scalp, face, right upper extremity and left upper extremity.
• The period between the first visit and transplantation is minimum 4 weeks and maximum 12 months.
• Age of at least 18 years
• Ability and willingness of the patient to participate in the study (Informed consent will be obtained)

Exclusion Criteria:

• Treatment area is within 5 cm of an incompletely healed wound or a suspected basal cell or squamous cell carcinoma.
• Treatment area contained hypertrophic and hyperkeratotic lesions, cutaneous horns, or lesions that had not responded to repeated cryotherapy.
• Patients with history of hypercalcemia or vitamin D toxicity.
• Female participants must be either of non-reproductive potential (i.e., post-menopausal by history of age > 50 years old and no menses for >1 year without an alternative medical cause; OR history of hysterectomy, history of bilateral tubal ligation, or history of bilateral oophorectomy) OR must have a negative serum pregnancy test within 7 days prior to study registration.
• Patients with DPD (Dihydropyrimidine Dehydrogenase) deficiency (due to their higher risk of 5-FU toxicity).

All participants, care giver and investigators measuring or analyzing the experimental data will be blinded to the interventions. Tissue samples collected will be labeled with 3-digit unique IDs and de-identified before studying in PI's lab. The study investigator will collect AK/skin samples and label them based on the study ID (e.g. "201") without compromising their blinded status. All the study records/photographs will be kept in a locked office or password-protected computer that is only accessible by the members of the research team.