Study to Investigate the Efficacy, Safety, and Tolerability of Topical HT-001 for the Treatment of Skin Toxicities Associated With Epidermal Growth Factor Receptor Inhibitors

The goal of this clinical trial is to learn about HT-001 Topical Gel for treatment of EGFR inhibitor-induced skin toxicities. The main questions it aims to answer are: * Determine the therapeutic effect of HT-001 for treatment of patients who develop acneiform rash undergoing Epidermal Growth Factor inhibitor (EGFRI) therapy using the acneiform rash investigator's global assessment scale \[ARIGA\] * Evaluate the safety of HT-001 during treatment Participants will apply HT-001 Gel once per day for 6 weeks, during which the effect on treating acneiform rash or other skin disorders induced by EGFRI therapy will be evaluated using different assessment tools to measure severity of rash, pain, and itching (pruritus), as well as the change in quality of life. The study will be completed in 2 periods: the first period is open-label (unblinded) and all patients will receive HT-001 topical gel with the active ingredient; the second period is blinded and patients will be randomized to receive one of three concentrations of HT-001 or placebo. Researchers will compare HT-001 to the placebo in the second period to see if HT-001 provides a significant treatment effect.

This is a randomized, double-blind, placebo-controlled, multi-center Phase 2a dose-ranging study to evaluate the efficacy, safety, and tolerability of HT-001 for treatment of EGFRI-induced skin toxicity. The study will include adult patients (≥ 18 years of age) scheduled to receive initial or repeat EGFRI therapy. The study will be conducted in 2 periods: Part 1, an open-label cohort consisting of 12 patients to measure pharmacokinetics of HT 001 gel followed by Part 2, a randomized, parallel arm study comparing 3 dose strengths of HT-001 gel to placebo (HT 001 vehicle). Patients in the randomized cohorts will be randomly assigned to 1 of the 4 treatment arms in a 2:2:2:1 ratio (active groups = 2: placebo = 1). All patients in both open-label and blinded cohorts will apply the study drug once a day to each area affected with cutaneous toxicity up to 30% body surface area (BSA) involvement, inclusive of skin, scalp, and nails. The goal of the study is to determine the minimum efficacious dose strength(s) for further investigation. The dose effect, together with the application site safety assessments, and therapeutic effects based on the primary and secondary endpoints will be evaluated.