Isotretinoin vs. Doxycycline for Acneiform Rash in Patients Receiving Drugs That Target the MAPK Pathway

PRIMARY OBJECTIVES:

1\. To compare the efficacy of the isotretinoin and doxycycline after 12 weeks of therapy in patients who develop an acneiform rash caused by a MAPK pathway-inhibitor, measured by the NCI Common Terminology Criteria for Adverse Events (CTCAE) v5.0.

EXPLORATORY OBJECTIVES:

1. To assess feasibility of a centralized dermatology review to confirm rash grading and response to treatment. 2. The participants' Multinational Association of Supportive Care in Cancer (MASCC) Epidermal Growth Factor Receptor Inhibitors (EGFRI) Skin Toxicity Tool (MESST) scores will be compared to CTCAE grading. 3. To measure time to rash response by comparing CTCAE rash grading. 4. To measure the change in quality-of-life scores from baseline to after 12 weeks of doxycycline or isotretinoin therapy using the Children's Dermatology Life Quality Index (CDLQI) and Dermatology Life Quality Index (DLQI). 5. To record adverse events caused by doxycycline or isotretinoin and any cutaneous adverse events thought to be caused by the targeted agent per CTCAE v5.0. 6. To characterize cutaneous toxicities across participants with different skin colors and tones. 7. To measure the frequency of dose alterations in the MAPK inhibitor and then compare between the two study arms. 8. To evaluate the number of participants who require retreatment for a rash 3 months after stopping study treatment. 9. To describe the microbiome profile in participants receiving doxycycline and isotretinoin.

OUTLINE:

Participants will be randomized to receive 12 weeks of isotretinoin or doxycycline. Participants are followed at the end of treatment, day 30, 3 months and 6 months after treatment.