Treatment Outcome with Fosravuconazole for Onychomycosis

Antifungal Selection for the Treatment of Onychomycosis: Patient Considerations and Outcomes

Onychomycosis, a common fungal nail infection, affects >20% of adults over age 60 and >50% of people over age 70. Onychomycosis may cause pain, psychosocial problems, and secondary infections, therefore meriting treatment. This review describes the range of treatment modalities, including FDA-approved systemic drugs and topical therapies. Additionally, new and emerging oral and topical therapies are discussed. We emphasize the importance of tailoring onychomycosis therapy to individual patient characteristics, comorbidities, preferences, extent of nail involvement, and fungal species, such that physicians may optimize treatment outcomes, patient satisfaction, and safety.

Prodrugs as empowering tools in drug discovery and development: recent strategic applications of drug delivery solutions to mitigate challenges associated with lead compounds and drug candidates

The delivery of a drug to a specific organ or tissue at an efficacious concentration is the pharmacokinetic (PK) hallmark of promoting effective pharmacological action at a target site with an acceptable safety profile. Sub-optimal pharmaceutical or ADME profiles of drug candidates, which can often be a function of inherently poor physicochemical properties, pose significant challenges to drug discovery and development teams and may contribute to high compound attrition rates. Medicinal chemists have exploited prodrugs as an informed strategy to productively enhance the profiles of new chemical entities by optimizing the physicochemical, biopharmaceutical, and pharmacokinetic properties as well as selectively delivering a molecule to the site of action as a means of addressing a range of limitations. While discovery scientists have traditionally employed prodrugs to improve solubility and membrane permeability, the growing sophistication of prodrug technologies has enabled a significant expansion of their scope and applications as an empowering tool to mitigate a broad range of drug delivery challenges. Prodrugs have emerged as successful solutions to resolve non-linear exposure, inadequate exposure to support toxicological studies, pH-dependent absorption, high pill burden, formulation challenges, lack of feasibility of developing solid and liquid dosage forms, first-pass metabolism, high dosing frequency translating to reduced patient compliance and poor site-specific drug delivery. During the period 2012-2022, the US Food and Drug Administration (FDA) approved 50 prodrugs, which amounts to 13% of approved small molecule drugs, reflecting both the importance and success of implementing prodrug approaches in the pursuit of developing safe and effective drugs to address unmet medical needs.

Risk factors for the development of tinea pedis and onychomycosis: Real-world evidence from a single-podiatry center, large-scale database in Japan

Dermatomycosis, including tinea pedis and onychomycosis, is frequently encountered in routine medical care in Japan. Identifying the risk factors for tinea pedis and onychomycosis development is important to encourage hospital visits by patients who may have these diseases but who are not undergoing any treatment. This approach may lead to the prevention of disease progression and the spread of infections to others. Risk factors for onychomycosis development have been reported both in and outside of Japan. However, most of the risk factors were identified based on a multicenter, questionnaire survey study and included evidence obtained from unclear or inconsistent diagnostic criteria for tinea pedis, onychomycosis, and identified risk factors. The current study analyzed the risk factors for developing tinea pedis and onychomycosis in real-world practice in Japan using a single-center, large-scale database that included the data of patients managed with consistent diagnostic criteria at the Podiatry Center of Juntendo University Hospital. A total of 2476 patients (1012 males, 1464 females) with a mean age of 63.4 years were included. Among these patients, 337 (13.6%) had tinea pedis and 346 (14.0%) had onychomycosis. A total of 259 patients (~ 75% of each patient population) had both diseases concomitantly. Multivariate logistic regression analysis adjusted for the possible risk factors of age (per 10 years), sex, diabetes, dialysis, visual impairment, ulcer history, lower-limb ischemia (LLI), and diabetic peripheral neuropathy (DPN) revealed that advanced age, male sex, diabetes, and LLI were independent risk factors for the development of tinea pedis. In addition, DPN was an independent risk factor for developing onychomycosis. We believe that these data are useful for identifying patients who are at high risk of developing tinea pedis and onychomycosis, which may result in disease prevention and suppression in real-world clinical practice in Japan.

Outcome of fosravuconazole treatment for onychomycosis refractory to topical antifungal agents

Fosravuconazole L-lysine ethanolate (F-RVCZ) is an oral antifungal agent approved in Japan for the treatment of onychomycosis. We treated 36 patients (mean age 77.6 years) with onychomycosis that had been refractory to long-term topical treatment. The patients took F-RVCZ (100 mg ravuconazole) once daily for a mean of 11.3 weeks, and were followed up for an average of 48 weeks (mean 48.3 ± 2.1 weeks). The mean rate of improvement of the affected nail area at 48 weeks was 59.4%, and 12 patients achieved complete cure. Patients with total dystrophic onychomycosis (TDO) showed a significantly lower improvement rate than those with distal and lateral subungual onychomycosis (DLSO), and those with an affected nail area of 76%-100% at the first visit showed a significantly lower improvement rate than those with an affected nail area of 0%-75%. Six patients had adverse events necessitating treatment discontinuation, but the symptoms and laboratory data improved without specific treatment in all of them. The data suggest that F-RVCZ would be effective in various age groups, including the elderly, and even in patients with onychomycosis refractory to long-term topical antifungal treatment. It was also suggested that its early use in mild cases might achieve a higher rate of complete cure. Furthermore, the average cost of oral F-RVCZ therapy was lower than that for topical antifungal agents. Therefore, F-RVCZ is considered to be much more cost-effective than topical antifungal agents.

Dermatophytomas: Clinical Overview and Treatment

Dermatophytomas are characterized as a hyperkeratotic fungal mass in the subungual space, showing as dense white or yellow, typically in longitudinal streaks or patches. Masses can be visualized by traditional microscopy or histology. Newer technologies such as dermoscopy and optical coherence tomography also provide visual features for dermatophytoma diagnosis. The density of fungal mass, and lack of adherence to the nail structures, as well as possible biofilm development, may play a role in the reduction in drug penetration and subsequent lack of efficacy with traditional oral therapies such as terbinafine and itraconazole. A combination of drug treatment with mechanical or chemical debridement/avulsion has been recommended to increase efficacy. The topical antifungal solutions such as tavaborole, efinaconazole, and luliconazole may reach the dermatophytoma by both the transungual and subungual routes, due to low affinity for keratin and low surface tension. Current data indicates these topicals may provide efficacy for dermatophytoma treatment without debridement/avulsion. Similarly, fosravuconazole (F-RVCZ) has an improved pharmacological profile versus ravuconazole and may be an improved treatment option versus traditional oral therapies. The availability of improved treatments for dermatophytomas is crucial, as resistance to traditional therapies is on the increase.

Mycetoma: Development of Diagnosis and Treatment

Mycetoma describes a heterogeneous group of cutaneous and subcutaneous infections caused by either fungi (eumycetomas) or bacteria (actinomycetomas). It is characterized by a triad of clinical symptoms: painless subcutaneous tumor-like swelling, multiple sinuses and fistulas, and discharged grains in pus. This predominantly affects the feet in more than 70% of patients. It is endemic in the "mycetoma belt" regions, including Africa, South America, and South Asia. Autochthonous mycetoma is rare in the United States of America (USA). We recently reported a Latin American immigrant with eumycetoma in the State of Maryland, USA. With millions of immigrants from endemic regions, the true number of mycetomas in the USA is most likely higher than currently recognized. With the aim to raise the awareness of clinicians about mycetoma, especially dermatologists and podiatrists, we update the development of the epidemiology, etiology, clinical presentations, pathogenesis, diagnosis, differential diagnosis, and treatment of mycetoma.