Safety and efficacy of oral terbinafine in the treatment of onychomycosis: Analysis of the elderly subgroup in improving results in ONychomycosis-concomitant lamisil® and debridement (IRON-CLAD), an open-label, randomized trial

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.

Updated Perspectives on the Diagnosis and Management of Onychomycosis

Onychomycosis is the most common nail disease encountered in clinical practice and can cause pain, difficulty with ambulation, and psycho-social problems. A thorough history and physical examination, including dermoscopy, should be performed for each patient presenting with nail findings suggestive of onychomycosis. Several approaches are available for definitive diagnostic testing, including potassium hydroxide and microscopy, fungal culture, histopathology, polymerase chain reaction, or a combination of techniques. Confirmatory testing should be performed for each patient prior to initiating any antifungal therapies. There are several different therapeutic options available, including oral and topical medications as well as device-based treatments. Oral antifungals are generally recommended for moderate to severe onychomycosis and have higher cure rates, while topical antifungals are recommended for mild to moderate disease and have more favorable safety profiles. Oral terbinafine, itraconazole, and griseofulvin and topical ciclopirox 8% nail lacquer, efinaconazole 10% solution, and tavaborole 5% solution are approved by the Food and Drug Administration for treatment of onychomycosis in the United States and amorolfine 5% nail lacquer is approved in Europe. Laser treatment is approved in the United States for temporary increases in clear nail, but clinical results are suboptimal. Oral fluconazole is not approved in the United States for onychomycosis treatment, but is frequently used off-label with good efficacy. Several novel oral, topical, and over-the-counter therapies are currently under investigation. Physicians should consider the disease severity, infecting pathogen, medication safety, efficacy and cost, and patient age, comorbidities, medication history, and likelihood of compliance when determining management plans. Onychomycosis is a chronic disease with high recurrence rates and patients should be counseled on an appropriate plan to minimize recurrence risk following effective antifungal therapy.

Combination Therapy Should Be Reserved as Second-Line Treatment of Onychomycosis: A Systematic Review of Onychomycosis Clinical Trials

Onychomycosis is the most common nail disease encountered in clinical practice. Its importance extends well beyond aesthetics, often causing pain, difficulty with ambulation and performing daily activities, and impairing quality of life. Many patients fail to achieve cure with antifungal monotherapy and recurrences are common. Combination therapy has therefore gained considerable interest, given the potential for drug synergy and prevention of antifungal resistance, but it has not been well studied. A systematic review of onychomycosis medication only, as well as medication and procedural (laser, debridement, photodynamic therapy), clinical or randomized controlled trials evaluating combination vs. monotherapies was performed. After exclusions, 30 studies were included in the final analysis. There were conflicting results for medication-only trials, with some showing significant benefit of combination therapy over monotherapy, however, trials were not robustly designed and lacked sufficient follow-up. Procedural studies also lacked long-term follow-up, and failed to demonstrate efficacy in some severe onychomycosis cases. Considering the high cure rates demonstrated in pivotal antifungal monotherapy trials, and conflicting results, costs, and safety concerns associated with combination therapy, we recommend that combination therapy be reserved as second-line treatment options in patients with poor prognostic factors or for those who failed monotherapy for onychomycosis.

Onychomycosis in older adults: The age and associated factors affecting the complete cure rate

BACKGROUND

Limited studies exist on the factors associated with a complete cure of onychomycosis in older adults.

OBJECTIVES

To determine the age and factors associated with a complete cure among older adults diagnosed with toenail onychomycosis.

METHODS

A retrospective cohort study was conducted of 95 older adult patients (aged ≥ 60 years) diagnosed with toenail onychomycosis between January 2016 and December 2017. Demographic data, mycological findings, treatments and durations to a complete cure were reviewed.

RESULTS

The complete cure rates of the patients aged < 70 years and ≥70 years were 67.4% and 44.9%, respectively (P = 0.027). Patients aged ≥ 70 years were significantly higher in male gender, had higher history of smoking, peripheral arterial disease, impaired renal function, antihypertensive drug and amorolfine nail lacquer usage, and polypharmacy. A multivariate analysis revealed that being aged ≥70 years and having a nail thickness >2 mm were associated with failure to achieve a complete cure. The median times to a complete cure for older adults aged <70 years and ≥70 years were 20 months and 47 months, respectively (P = 0.007).

CONCLUSIONS

An age ≥ 70 years was related to a lower cure rate and delays in achieving a complete cure. A nail thickness > 2 mm was a poor prognostic factor for a complete cure. Moreover, very old adults were more likely to suffer side effects arising from the use of systemic antifungal medications.

Efficacy and safety of topical terbinafine 10% solution (MOB-015) in the treatment of mild to moderate distal subungual onychomycosis: A randomized, multicenter, double-blind, vehicle-controlled phase 3 study

BACKGROUND

Onychomycosis is a recalcitrant fungal nail infection. Topical antifungal agents may be preferred over systemic agents due to lack of systemic adverse effects.

OBJECTIVE

To investigate the efficacy and safety of topical terbinafine 10% solution (MOB-015) for the treatment of distal and lateral subungual onychomycosis.

METHODS

In a multicenter, double-blind, phase III, North American study, patients with mild to moderate distal and lateral subungual onychomycosis involving 20% to 60% of at least 1 great toenail were randomized to once daily application of MOB-015 or matching vehicle for 48 weeks. The primary efficacy variable was complete cure, while the secondary efficacy variables were mycological cure and treatment success. Safety evaluations were also performed.

RESULTS

At week 52, the mycological cure (negative culture and potassium hydroxide microscopy) rate in the MOB-015 and vehicle groups was 69.9% and 27.7%, respectively (P < .001), and complete cure (0% clinical disease involvement and mycological cure) was achieved in 4.5% and 0% of patients, respectively (P = .0195). At least 1 adverse event leading to discontinuation of treatment occurred in 2.8% of patients in the MOB-015 group and in 4.2% in the vehicle group.

LIMITATION

The follow-up period after end of treatment may not be sufficient to accurately reflect cure in distal and lateral subungual onychomycosis.

CONCLUSIONS

MOB-015 is a treatment option for onychomycosis with an adverse event profile similar to vehicle.

A Practical Guide to Curing Onychomycosis: How to Maximize Cure at the Patient, Organism, Treatment, and Environmental Level

Onychomycosis is a fungal nail infection caused by dermatophytes, non-dermatophyte molds, and yeasts. Treatment of this infection can be difficult, with relapse likely to occur within 2.5 years of cure. The objective of this article is to review factors that can impact cure and to suggest practical techniques that physicians can use to maximize cure rates. Co-morbidities, as well as disease severity and duration, are among the many patient factors that could influence the efficacy of antifungal therapies. Furthermore, organism, treatment, and environmental factors that may hinder cure include point mutations, biofilms, affinity for non-target enzymes, and exposure to fungal reservoirs. To address patient-related factors, physicians are encouraged to conduct confirmatory testing and treat co-morbidities such as tinea pedis early and completely. To combat organism-focused factors, it is recommended that disruption of biofilms is considered, and drugs with multiple routes of delivery and unique mechanisms of action are prescribed when traditional agents are not effective. Extending follow-up periods, using combination treatments, and considering pulse regimens may also be of benefit. Through these practical techniques, physicians can maximize cure and limit the risk of relapse and re-infection.

Confirmatory Testing Prior to Initiating Onychomycosis Therapy Is Cost-Effective

Background:

Onychomycosis can be investigated by sampling. Information gleaned includes nail bed involvement, nail plate penetration, fungal viability, and species identification. Testing samples can confirm a diagnosis. While diagnostic testing is considered useful in directing therapy, a substantial number of clinicians do not confirm diagnosis prior to treatment.

Objectives:

The aim of this study is to quantify the benefit of confirmatory testing prior to treating toenail onychomycosis.

Methods:

The cost of mycological cure (negative potassium hydroxide and negative culture) and the cost-effectiveness of confirmatory testing were determined using the average cost of potassium hydroxide (KOH), culture, periodic acid–Schiff (PAS), efinaconazole, ciclopirox, terbinafine, and itraconazole. Costs were obtained through literature searches, public domain websites, and telephone surveys to local pharmacies and laboratories. To represent the potential risks of prescribing onychomycosis treatment, the costs associated with liver monitoring, potential life-threatening adverse events, and drug-drug interactions were obtained through public domain websites, published studies, and product inserts.

Results:

PAS was determined to be the most sensitive confirmatory test and KOH the least expensive. The overall cost of an incorrect diagnosis (no confirmatory test used) ranged between $350 and $1175 CAD per patient for treatment of 3 infected toenails. Comparatively, performing confirmatory testing prior to treatment decreases the overall cost to $320 to $930, depending on the therapy, physician, and test.

Conclusions:

It is preferred to diagnose onychomycosis prior to treatment. Furthermore, there are cost savings when confirmatory testing is performed before initiating treatment with both topical and oral antifungals in Canada.

Management of Onychomycosis in Canada in 2014

Background

Onychomycosis has several clinical presentations and is caused by various infectious organisms.

Objective

To provide guidance for selection of appropriate treatment.

Methods

The literature on onychomycosis management was reviewed to generate an evidence-based decision tree.

Results and Conclusion

Several options are available: terbinafine, itraconazole, fluconazole, ciclopirox 8% nail lacquer, efinaconazole 10% nail solution, and laser therapy. Further studies on lasers are needed before use can be recommended. Nondermatophyte molds or mixed infection can be managed with terbinafine or itraconazole with or without topicals. Itraconazole, fluconazole, and efinaconazole can be used for Candida infection. For dermatophytes, topicals can be considered for mild to moderate onychomycosis. For moderate to severe cases, any oral monotherapy can be used; however, we suggest terbinafine if there is a possibility of a drug interaction. These recommendations can be applied for all ages, immune function, or metabolic status, but proper monitoring and contraindications should be taken into consideration.

Oral therapy for onychomycosis: an evidence-based review

INTRODUCTION

Onychomycosis is a very common fungal infection of the nail apparatus; however, it is very hard to treat, even when the causative agent is identified, and usually requires prolonged systemic antifungal therapy. Until the 1990s, oral treatment options included only griseofulvin and ketoconazole, and the cure rate was very low. New generations of antimycotics, such as fluconazole, itraconazole and terbinafine have improved treatment success.

METHODS

Literature was identified by performing a PubMed Ovid MEDLINE, Ovid EMBASE, EBSCO CINAHL, and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS) search. Prospective and randomized clinical trials were chosen to be included in this review. Forty-six trials were included.

RESULTS

Fluconazole, itraconazole and terbinafine are effective in the treatment of onychomycosis and have a good safety profile. When a dermatophyte is the pathogen, terbinafine produces the best results. For Candida and nondermatophyte infections, the azoles, mainly itraconazole, are the recommended therapy.

CONCLUSION

In the majority of the studies, terbinafine treatment showed a higher cure ratio than the other drugs for dermatophyte onychomycosis.

Terbinafine inhibits oral squamous cell carcinoma growth through anti-cancer cell proliferation and anti-angiogenesis

Terbinafine (TB), an oral antifungal agent used in the treatment of superficial mycosis, has been reported to exert an anti-tumor effect in various cancer cells. However, the effect of TB on oral cancer has not been evaluated. Herein we demonstrate that TB (0-60 µM) concentration-dependently decreased cell number in cultured human oral squamous cell carcinoma (OSCC), KB cells. The anti-proliferation effect of TB was also observed in two other OSCC cell lines, SAS and SCC 15. TB (60 µM) was not cytotoxic and its inhibition on KB cell growth was reversible. [(3) H]thymidine incorporation and flow cytometric analyses revealed that TB-inhibited DNA synthesis and induced the G0/G1 cell-cycle arrest. The TB-induced cell-cycle arrest occurred when the cyclin-dependent kinase 2 activity was inhibited just as the protein levels of p21(cip1) and p27(kip1) were increased. The TB-induced G0/G1 cell-cycle arrest was completely blocked when the expressions of p21(cip1) and p27(kip1) were knocked-down together. Taken together, these results suggest that the p21(cip1) - and p27(kip1) -associated signaling pathways might be involved in the TB-induced anti-proliferation in KB cells. In vivo, TB (50 mg/kg, i.p.) significantly inhibited the KB tumor size. In these TB-treated tumors, increases in the levels of p21(cip1) and p27(kip1) protein and decreases in the number of proliferating cell nuclear antigen-positive cells and the microvessel density were observed. These findings demonstrate for the first time that TB might have potential to serve as a therapeutic tool in the treatment of oral cancer.

The impact of aggressive debridement used as an adjunct therapy with terbinafine on perceptions of patients undergoing treatment for toenail onychomycosis

OBJECTIVE

To determine whether adding aggressive debridement to oral terbinafine for treating toenail onychomycosis impacts patient-reported outcomes (PROs).

MATERIALS AND METHODS

A total of 504 patients were randomized to receive 12 weeks of terbinafine 250 mg/day with or without debridement, with an additional 36-week follow-up. The OnyCOE-t, a validated disease-specific PRO questionnaire, was completed at baseline and weeks 6, 12, 24, and 48. It included six multi-item scales (symptom frequency, appearance problems, physical activities problems, stigma, and treatment satisfaction), and one single-item scale: overall problem. Longitudinal analysis of change was conducted to assess treatment effect. Repeated-measures models adjusted for visit, age, sex, baseline scores, severity and duration of infection; treatment interactions were also tested.

RESULTS

Symptom frequency and treatment satisfaction significantly improved in the terbinafine + debridement group compared with terbinafine alone (p = 0.0395 and p = 0.0077, respectively). Age and sex were often significant explanatory variables, and further analysis of change scores at 12 weeks revealed that females treated with terbinafine + debridement reported significantly less improvement in the physical activities problems (p = 0.0021) and overall problem (p = 0.0112) scores.

CONCLUSIONS

Aggressive debridement, when used as an adjunct therapy with oral terbinafine, improved treatment satisfaction and reduced symptom frequency. The observed sex differences warrant further investigation.

Current management of onychomycosis

Onychomycosis is the most common single cause of nail dystrophy and has a marked impact on quality of life. The availability of newer topical and systemic antifungal agents has improved our ability to effectively treat this condition. This article will review the most commonly used therapies and discuss the relative advantages and disadvantages of different treatment strategies.