Effects of additional oral fosravuconazole l-lysine ethanolate therapy following inadequate response to initial treatment for onychomycosis: A multicenter, randomized controlled trial.

Onychomycosis, a superficial fungal infection, develops when dermatophytes infect nail plate and beds. Fosravuconazole l-lysine ethanolate (F-RVCZ), a fourth-generation azole antifungal agent with potent antifungal activity and few drug interactions, was highly effective in a clinical trial, with a complete cure rate of 59.4% at 48 weeks after treatment initiation. However, some patients were not completely cured. To achieve a higher complete cure rate, additional therapy needs to be examined. We aimed to examine (i) the criteria for additional F-RVCZ therapy in patients with an inadequate response to initial F-RVCZ treatment for onychomycosis; (ii) the timing of additional therapy; and (iii) the effects of additional treatment. This was a multicenter, open-label, three-arm randomized clinical trial. Patients with onychomycosis were orally administered an approved dose of F-RVCZ for 12 weeks, and its efficacy was assessed at week 24. Patients who demonstrated ≥55% reduction in nail involvement ratio at week 24 were included in Group X and followed up. Patients with <55% reduction were randomly assigned to follow-up (Group A) or additional treatment (Group B) groups. The complete cure rate at week 72 in Group X was 73.3%. In Groups A and B, the complete cure rates were 29.6% and 46.7%, respectively, and were significantly different (P = 0.0414, odds ratio 2.08). During the study, 63 adverse drug reactions were recorded in 59 of the 318 patients (18.6%), for which a causal relationship with F-RVCZ could not be ruled out. In Group B, three of 75 patients (4.0%) experienced three adverse drug reactions, all observed during additional treatment; none were serious. A high complete cure rate is possible without additional F-RVCZ treatment when nail involvement decreases by ≥55% at week 24; however, when the reduction is <55% at week 24, additional F-RVCZ treatment should be considered to improve the cure rate.
(© 2024 Japanese Dermatological Association.)