Isotretinoin vs. Doxycycline for Acneiform Rash in Patients Receiving Drugs That Target the MAPK Pathway (PNOC039)

A Phase 2 Study of Isotretinoin vs. Doxycycline for Acneiform Rash in Patients Receiving Drugs That Target the MAPK Pathway

A phase 2 study testing the efficacy of isotretinoin versus doxycycline in treating participants who develop a acneiform rash caused by standard of care, tumor-directed therapies targeting the mitogenactivated protein kinase (MAPK) pathway.

Study Overview

• Status: Not yet recruiting
• Conditions: Acneiform Eruptions; Acneiform Drug Eruption
• Intervention / Treatment: Drug: Isotretinoin; Procedure: Blood specimen collection; Other: Photographs of Rash; Behavioral: Questionnaires; Procedure: Stool Specimen collection; Drug: Doxycycline

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Estimated): 50
• Phase: Phase 2

Contacts and Locations

• Study Contact: Name: Jannerfer An; Phone Number: 877-827-3222; Email: PNOC039@ucsf.edu

Study Locations

• United States
  • California
    • San Francisco, California, United States, 94143
      • University of California, San Francisco
      • Principal Investigator: Sabine Mueller, MD, PhD, MAS
      • Contact: PNOC Operations Office; Phone Number: 877-827-3222; Email: PNOC039@ucsf.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Participants must have developed either a grade 2, 3, or 4 rash categorized as acneiform while taking tumor-directed therapy that targets the MAPK pathway.

   • Acneiform rash will be defined according to CTCAE v5.0 as a disorder characterized by an eruption of papules and pustules, typically appearing in face, scalp, upper chest and back.

     1. Grade 2 = Papules and/or pustules covering 10-30% body surface area (BSA), which may or may not be associated with symptoms or of pruritus or tenderness; associated with psychosocial impact; limiting instrumental Activities of Daily Living (ADL); papules and/or pustules covering > 30% BSA with or without mild symptoms.
     2. Grade 3 = Papules and/or pustules covering > 30% BSA with moderate or severe symptoms; limiting self-care ADL; associated with local superinfection with oral antibiotics indicated.
     3. Grade 4 = Life-threatening consequences; papules and/or pustules covering any % BSA, which may or may not be associated with symptoms of pruritus or tenderness and are associated with extensive superinfection with IV antibiotics indicated.
2. Prior Therapy: Participants may have received either doxycycline or isotretinoin in the past for treatment of their targeted therapy induced rash or acne. However, if they took doxycycline or another tetracycline antibiotic for a rash caused by a targeted therapy or for acne, the last dose must have been at least 4 weeks before study registration. If a participant took isotretinoin for any reason, the last dose must be at least 6 months prior to study registration.
3. Age. 12-39 years old.

4. Organ Function Requirements.

   a. Adequate Liver Function Defined as:

   • Total bilirubin ≤ 1.5 x upper limit of normal (ULN) for age; in presence of Gilbert's syndrome, total bilirubin < 3 x ULN or direct bilirubin < 1.5 x ULN
   • alanine aminotransferase (ALT) ≤ 3 x ULN
   • aspartate aminotransferase (AST) ≤ 3 x ULN.
   • Serum triglycerides < 500 mg/dL or < 5.7 mmol/L
5. Due to the harmful effects of isotretinoin and doxycycline on the developing human fetus women of child-bearing potential and men must agree to use adequate contraception (as recommended by the iPLEDGE system if residing in the United States for those who will take isotretinoin) prior to study entry, for the duration of study participation, and one (1) month after completion of isotretinoin and doxycycline administration. If a participant requires contraception, they will require two forms of contraception as outlined by the iPLEDGE system. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. The proper steps in the iPLEDGE system must also be taken.
6. Participants must be able and willing to take a gelatin capsule.
7. Participants must be able to swallow pills.
8. A legal parent/guardian or participant must be able to understand, and willing to sign, a written informed consent and assent document, as appropriate.

Exclusion Criteria:

1. History of allergic reactions attributed to compounds of similar chemical or biologic composition to doxycycline or isotretinoin, or other agents used in study. Participants also must not have a paraben allergy.
2. Participants taking any medications listed must be discussed with study chair(s).
3. Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, other than skin infection in setting of rash.
4. Women of childbearing potential must not be pregnant or breast-feeding.
5. Participants who report active suicidal ideation due to isotretinoin's black box warning.
6. Participants who refuse to be photographed for the centralized dermatology review.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Arm A: Isotretinoin; Participants randomized to the isotretinoin arm will be enrolled in the iPLEDGE program prior to treatment initiation. Female participants of childbearing potential will undergo a urine or serum pregnancy test as required for iPLEDGE registration. Participants will receive oral isotretinoin daily at a dose based on body weight, ranging from 10 mg to 40 mg, for up to 12 weeks. Treatment will consist of three consecutive 28-day cycles. Participants will undergo follow-up at the end of treatment and at 30 days, 3 months, and 6 months after treatment completion for safety monitoring and post-treatment assessments, until withdrawal from the study or death, whichever occurs first.	Drug: Isotretinoin; Given Orally; Other Names: Accutane; Procedure: Blood specimen collection; Perform blood draw; Other Names: Blood sample collection; Other: Photographs of Rash; Undergo photography; Behavioral: Questionnaires; Participants will be asked to complete questionnaires; Other Names: Health-Related Quality of Life Questionnaires; Procedure: Stool Specimen collection; Perform stool sample collection; Other Names: Stool Sample collection
Experimental: Arm B: Doxycycline; Participants randomized to the doxycycline arm will receive oral doxycycline daily at a body weight-based dose of 50 mg or 100 mg for up to 12 weeks. Treatment will consist of three consecutive 28-day cycles. Participants will undergo follow-up at the end of treatment and at 30 days, 3 months, and 6 months after treatment completion for safety monitoring and post-treatment assessments, until withdrawal from the study or death, whichever occurs first.	Procedure: Blood specimen collection; Perform blood draw; Other Names: Blood sample collection; Other: Photographs of Rash; Undergo photography; Behavioral: Questionnaires; Participants will be asked to complete questionnaires; Other Names: Health-Related Quality of Life Questionnaires; Procedure: Stool Specimen collection; Perform stool sample collection; Other Names: Stool Sample collection; Drug: Doxycycline; Given Orally; Other Names: Vibramycin; Doryx

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of Participants who experienced acneiform rash	The proportion of participants who experience a Grade < 2 acneiform rash at week 12 while receiving non-investigational treatment for cancer that targets the mitogen activated protein kinase (MAPK) pathway as classified by the National Cancer Institute Common Terminology Criteria for Adverse Events (CTCAE version 5.0) and 95% confidence interval will be reported.	Up to 12 weeks following treatment

Collaborators and Investigators

• Sponsor: University of California, San Francisco
• Collaborators: Day One Biopharmaceuticals, Inc.
• Investigators: Principal Investigator: Sabine Mueller, MD, PhD, MAS, University of California, San Francisco

Study record dates

Study Major Dates

• Study Start (Estimated): August 30, 2026
• Primary Completion (Estimated): August 30, 2029
• Study Completion (Estimated): March 30, 2030

Study Registration Dates

• First Submitted: June 1, 2026
• First Submitted That Met QC Criteria: June 1, 2026
• First Posted (Actual): June 5, 2026

Study Record Updates

• Last Update Posted (Actual): June 5, 2026
• Last Update Submitted That Met QC Criteria: June 1, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Supportive Care; Mitogen-Activated Protein Kinase (MAPK) Pathway; Cutaneous Adverse Events
• Additional Relevant MeSH Terms: Skin Diseases; Skin and Connective Tissue Diseases; Acneiform Eruptions; Health Care Quality, Access, and Evaluation; Organic Chemicals; Investigative Techniques; Epidemiologic Methods; Specimen Handling; Clinical Laboratory Techniques; Diagnostic Techniques and Procedures; Diagnosis; Punctures; Surgical Procedures, Operative; Retinoids; Carotenoids; Polyenes; Alkenes; Hydrocarbons, Acyclic; Hydrocarbons; Cyclohexenes; Cyclohexanes; Cycloparaffins; Hydrocarbons, Alicyclic; Hydrocarbons, Cyclic; Terpenes; Pigments, Biological; Biological Factors; Data Collection; Health Care Evaluation Mechanisms; Quality of Health Care; Public Health; Environment and Public Health; Polycyclic Aromatic Hydrocarbons; Hydrocarbons, Aromatic; Polycyclic Compounds; Naphthacenes; Tetracyclines; Doxycycline; Isotretinoin; Surveys and Questionnaires; Blood Specimen Collection
• Other Study ID Numbers: 250833; NCI-2026-04129 (Registry Identifier: NCI Clinical Trials Reporting System (CTRP))

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified datasets may be shared with research collaborators during the course of the study.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: Yes