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 (CLEER)

Inclusion Criteria: Adult patient (ie, ≥ 18 years of age at Screening [V1]) prescribed an approved EGFRI to treat cancer (indication within the approved labeling for the EGFRI) and is expected to begin EGFRI treatment within < 4 weeks of Screening (V1). Patient has developed a rash or symptoms of a rash (papular and/or pustular eruptions) or symptoms of a rash (cutaneous burning), at Baseline (V2), as assessed by both the Common Terminology Criteria for Adverse Events (CTCAE) grading and Acneiform rash IGA scales (ARIGA) (severity ≤ 3) with overall involvement ≤ 30% BSA. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2. Predicted life expectancy ≥ 3 months. Patient is able and willing to comply with contraceptive requirements. Patient must have the ability and willingness to attend the necessary visits (telehealth and in person). Patient must be willing and able to provide written informed consent after the nature of the study has been explained and prior to the commencement of any study procedures. Exclusion Criteria: Patient has severe cutaneous toxicity (severity = 4 on the CTCAE grading and Acneiform rash IGA scales) or cutaneous toxicity involvement that is > 30% BSA, or other severe systemic toxicity (severity > 3 on the CTCAE v5.0 scale ) as a result of EGFRI therapy. Subject has a presence of any underlying physical or psychological medical condition that, in the opinion of the Investigator, would make it unlikely that the patient will comply with the protocol or complete the study per protocol. Patient has a history of other skin disorders (eg, atopic dermatitis, psoriasis, recurrent skin infections) and presence of active dermatological symptoms at the time of screening (prior to initiation of EGFRI therapy), or history of illness that, in the opinion of the Investigator, would confound results of the study or pose unwarranted risk in administering study drug to the patient. Patient has abnormal laboratory values at Screening (V1): Absolute neutrophil count < 1000/mm3 and white blood cell (WBC) count < 3000/mm3 Platelet count < 50,000/mm3 Aspartate transaminase (AST) > 2.5 × upper limit of normal (ULN) Alanine transaminase (ALT) > 2.5 × ULN Bilirubin > 1.5 × ULN Creatinine > 1.5 × ULN Patient has a prescribed EGFRI therapy treatment plan that is less than 8 weeks total duration. Patient has a prescribed cancer treatment plan that requires radiation treatment to the head, neck, or upper trunk concurrent with EGFRI therapy or has previously received radiation therapy within 4 weeks prior to Screening (V1). Patient has received neurokinin-1 receptor antagonist within 4 weeks prior to Screening (V1). Patient has had prior treatment with an investigational drug within 4 weeks prior to Screening (V1), or at least 8 half-lives of the drug, whichever is longer. Subject has an active infection (eg, pneumonia) or any uncontrolled disease except for the malignancy that, in the opinion of the Investigator, might confound the result or the study or pose unwarranted risk in administering the study drug to the patient. Patient has received topical antibiotics, topical steroids, or other topical treatments (non-medicated emollients are allowed up until 1 day prior to V2) within 14 days to Baseline (V2). Patient has used systemic steroids within 14 days prior to Screening (V1) except for low dose systemic corticosteroids as part of standard of care for prevention or treatment of chemotherapy-induced nausea and vomiting; acceptability of the steroid and dose is determined by the study Investigator. Use of steroid inhalers and nasal corticosteroids is allowed. Patient has received treatment with a systemic antibiotic within 7 days prior to Screening (V1) (unless minocycline/doxycycline administered for CTCAE grade 3 acneiform rash). Patient has received concomitant treatment with pimozide, moderate to strong CYP3A4 inhibitors (diltiazem, ketoconazole, itraconazole, nefazodone, troleandomycin, clarithromycin, ritonavir, nelfinavir), or strong CYP3A4 inducers (rifampin, carbamazepine, phenytoin) with 30 days of Day 1 of treatment (V2). Patient has a history of hypersensitivity to any component of HT-001 (to be confirmed at Screening [V1] with patch testing). Patient is pregnant or lactating at Screening (V1) or planning to become pregnant (self or partner) at any time during the study, including the follow-up period.