In a large cohort study, researchers found that higher cumulative dosages of isotretinoin were associated with reduced rates of acne relapse and treatment retrial, while daily dosing had no significant impact on outcomes for patients receiving conventional or high cumulative doses.

The study of 19,907 patients revealed that 22.5% experienced acne relapse requiring systemic treatment, and 8.2% needed isotretinoin retrial. Female patients were significantly more likely to experience relapse but less likely to undergo retrial treatment.

"These findings suggest that daily dosing can be individualized to patient goals and preferences, balancing course duration and adverse effects," wrote Jenny Lai, PhD, and John S. Barbieri, MD, MBA, both of Harvard Medical School and Brigham and Women's Hospital, in JAMA Dermatology.

Using MarketScan commercial claims data from 2017 to 2020, researchers analyzed outcomes for patients aged 12 years or older who completed at least 4 months of isotretinoin treatment. The mean age was 20.6 years, and 52.8% of participants were female.

Higher cumulative dosage was associated with decreased rates of relapse and retrial. However, when stratified by cumulative dosage groups, these protective effects were primarily observed in patients receiving low (<120 mg/kg) and conventional (120-220 mg/kg) doses, with no significant benefit seen beyond 220 mg/kg.

Among patients experiencing relapse, the median time to relapse was 7.5 months. The most common subsequent treatments were oral antibiotics (44.6%), isotretinoin retrial (32.9%), and spironolactone (22.4%).

The study found that having a dermatologist practitioner was associated with increased rates of both relapse and retrial, possibly reflecting greater disease severity or more frequent follow-up among these patients.

"An important limitation of this study was the absence of data on patient weight in the MarketScan database," the authors noted. Weight-based calculations relied on national average data matched by age and sex.

The findings suggest that optimizing cumulative dosage may be more critical than daily dose for preventing relapse, potentially allowing clinicians to tailor daily dosing schedules to individual patient preferences and tolerability while maintaining efficacy through appropriate total exposure.

For second courses of isotretinoin, researchers found these tended to be partial courses, with a mean duration of 2.3 months compared to 5.6 months for initial treatment. The median time to second course was 2.8 months, with only 26.7% of retrials occurring after 6 months from the initial course completion.

The study identified factors associated with relapse risk, with the authors noting the need for further research to determine effective prevention strategies for high-risk patients.

One investigator reported consulting fees from Dexcel Pharma and Honeydew Care outside the submitted work. No other disclosures were reported.