Pharmacokinetic and clinical comparison of super-bioavailable itraconazole and conventional itraconazole at different dosing in dermatophytosis

SUBA-itraconazole in the treatment of systemic fungal infections

Conventional itraconazole (c-ITZ) can be used for a variety of fungal infections although variable absorption has been a significant limitation. Super-bioavailable itraconazole (SUBA-ITZ) is a novel formulation that overcomes absorption concerns by utilizing a polymer-matrix to disperse active drug and facilitate dissolution. The pH-driven matrix allows concurrent proton pump inhibitor administration without significant effects on drug concentrations. The enhanced bioavailability of SUBA-ITZ allows for lower dosing, while achieving similar serum concentrations as c-ITZ and SUBA-ITZ is now US FDA approved in the treatment of blastomycosis, histoplasmosis and aspergillosis. Common side effects of SUBA-ITZ include gastrointestinal disorders, peripheral edema and drug-induced hypertension. Given the significant differences in pharmacokinetics between the formulations, c-ITZ and SUBA-ITZ capsules are not considered interchangeable. It is important to note that drug errors may occur when transitioning a patient from one formulation to another.

Clinico-mycological and therapeutic updates on cutaneous dermatophytic infections in the era of Trichophyton indotineae

Trichophyton indotineae has emerged as a novel dermatophyte species resulting in treatment recalcitrant skin infections. While the earliest reports came from India, T. indotineae has now spread to many parts of the world and is rapidly becoming a global health concern. Accurate identification of T. indotineae requires elaborate mycological investigations which is beyond the domain of routine microbiology testing. Extensive, non-inflammatory and atypical presentations are commonly seen with this novel species. T. indotineae shows an alarmingly high rate of mutations in the squalene epoxidase gene leading to lowered in vitro susceptibility to terbinafine. This has also translated into a lowered clinical response and requirement of a higher dose and much longer durations of treatment with the drug. Although the species remains largely susceptible to itraconazole, prolonged treatment durations are required to achieve cure with itraconazole. Fluconazole and griseofulvin do not have satisfactory in vitro or clinical activity. Apart from requirement of prolonged treatment durations, relapse postsuccessful treatment is a distressing and yet unexplained consequence of this "species-shift." Use of third generation azoles and combinations of systemic antifungals is unwarranted as both have not demonstrated clear superiority over itraconazole given alone, and the former is an important class of drugs for invasive mycoses.

Comparative Efficacy and Safety of Super-Bioavailable Itraconazole-130 mg Once Daily in Obese and Non-Obese Patients of Glabrous Tinea

Background

Obesity is considered one of the risk factors for dermatophytosis and warrants systemic therapy. Itraconazole is the most commonly used antifungal, but owing to pharmacokinetic challenges, super-bioavailable itraconazole (SITZ) was approved globally, recently. For the management of dermatophytosis in obese patients, there are mixed opinions regarding the dosing of systemic antifungals.

Materials and Methods

This study was conducted to compare the efficacy and safety of SITZ-130 mg once daily in glabrous tinea or dermatophytosis in obese and non-obese patients for a total duration of 10 weeks on 87 eligible patients. Efficacy and safety assessments were done at weeks 3 and 6 with follow-up at week 10 for relapse. The primary objective was to assess the proportion of patients achieving complete cure at week 6 with the assessment of safety, clinical, and mycological cure rates as secondary objectives.

Results

Out of 87 patients, 80 were considered for analysis. At week 6, 22/35 (63%) and 33/45 (73%) patients in obese and non-obese groups were completely cured (P = 0.47). Similarly, there was no statistically significant difference for mycological and clinical cure in both the groups (P = 0.17 and P = 0.61, respectively). Four patients in the obese group (18% of completely cured), while one patient in the non-obese group (3% of completely cured), relapsed within 4 weeks of completion of treatment (P = 0.14). The therapy was well tolerated by both groups, with only one patient in the non-obese group experiencing pruritus.

Conclusion

SITZ-130 mg once daily achieved desired and similar clinical response in obese patients as of non-obese patients suffering from dermatophytosis, and hence, a higher dose may not require in obesity.

Efficacy of Super-Bioavailable Itraconazole and Conventional Itraconazole at Different Dosing Regimens in Glabrous Tinea Infection - A Randomized Clinical Trial

Introduction

Itraconazole follows non-linear pharmacokinetics and hence is recommended once daily, but in real-world practice, is commonly prescribed as twice daily. Hence, this study aimed to evaluate the efficacy and safety of super-bioavailable-itraconazole-130 mg (SB-130) and conventional-itraconazole-200 mg (CITZ-200) once daily compared with conventional-itraconazole-100 mg (CITZ-100) twice daily in glabrous tinea.

Methods

A total of 261 eligible patients were enrolled in this prospective, randomized, clinical study from December-2021 to August-2022 at seven centers in India. Efficacy and safety assessments were done at week-3 and 6, with follow-up at week-10 for relapse. The primary objective was to assess the proportion of patients who achieved complete cure at week-6 following treatment in all itraconazole groups. The secondary outcomes were safety and clinical and mycological cure rates.

Results

Of 261 patients, 240 were included in the analysis. At week-6, 140 patients were completely cured; thus, overall cure rate was 58.33%. Fifty-five patients (69%) in SB-130 while 47/77 (61%) and 38/83 (46%) patients were completely cured in CITZ-200 and CITZ-100 groups respectively (p<0.05; SB-130: CITZ-100, p=0.32; SB-130: CITZ-200, p=0.058; CITZ-200: CITZ-100). There was no statistical difference in the mycological cure rate and area clearance rate between any of the groups (p=0.14); however, a statistically significant difference was noted for OD dosing over BD dosing in achieving clinical cure rates (p<0.05). A total of 13/140 patients (9%) relapsed following complete cure, with no statistically significant difference between any of the groups (p=0.50). All treatments were safe and well-tolerated, with no discontinuation.

Conclusion

In this clinical study, moderate efficacy with all doses of ITZ was reported but was better with OD dosing. Although there was no statistical difference between SB-130 and CITZ-200, SB-130 may be preferred over CITZ-200 owing to the advantage of SB over the conventional ITZ.

Therapeutic Updates on the Management of Tinea Corporis or Cruris in the Era of Trichophyton Indotineae: Separating Evidence from Hype-A Narrative Review

The emergence and spread of Trichophyton indotineae (T. indotineae) has led to a sea change in the prescription practices of clinicians regarding the management of dermatophytic skin infections. An infection easily managed with a few weeks of antifungals, tinea corporis or cruris, is now often chronic and recurrent and requires prolonged treatment. Rising resistance to terbinafine, with documented squalene epoxidase (SQLE) gene mutations, and slow clinical response to itraconazole leave clinicians with limited treatment choices. However, in these testing times, it is essential that the tenets of antifungal stewardship be followed in making therapeutic decisions, and that the existing armamentarium of antifungals be used in rationale ways to counter this extremely common cutaneous infection, while keeping the growing drug resistance among dermatophytes in check. This review provides updated evidence on the use of various systemic antifungals for dermatophytic infection of the glabrous skin, especially with respect to the emerging T. indotineae species, which is gradually becoming a worldwide concern.