EFFICACY AND SAFETY OF ITRACONAZOLE PULSE THERAPY: BRAZILIAN MULTICENTRIC STUDY ON TOENAIL ONYCHOMYCOSIS
CAUSED BY DERMATOPHYTES - Journal of the European Academy of Dermatology and Venereology 1998;11:109-116

Marcia Ramos-e-Silva, MD, PhD 1
Silvio Alencar Marques, MD, PhD 2
Bernardo Gontijo, MD, PhD 3
Clarisse Zaitz, MD, PhD 4
Iphis Campbell, MD 5
Simone Tavares Veloso, MD 6

Research developed at the Hospitals of Universidade Federal do Rio de Janeiro1, Universidade Estadual Paulista2, Universidade Federal de Minas Gerais3, Santa Casa da Misericórdia de São Paulo4, Universidade de Brasília5 and Universidade do Rio de Janeiro6
Supported by Janssen Pharmaceuticals

ABSTRACT

Background: Itraconazole is a large spectrum triazole, with known efficacy in both continuous and pulse therapy for various mycosis.
Objectives: Evaluate the efficacy and tolerability of itraconazole pulse therapy for onychomycosis of the toenails due to dermatophytes, in a prospective, open, non-comparative and multicentric investigation.
Patients and Methods: The research was completed by 72 patients, of an initial total of 89. Treatment consisted of four cycles of itraconazole, 200 mg twice a day, for seven consecutive days each month. Patients were evaluated clinically, mycologically and biochemically before, during and at the end of the investigation, and were divided into two groups according to the measure of normal portion of the most affected nail (target nail), as follows: Group 1: 0 to 5,9 mm; and Group 2: more than 6 mm.
Results: Improvement was satisfactory and progressive. Results were statistically significant, when comparing the three moments of the study: pre-treatment, end of the therapy (fourth month) and follow-up (nineth month) in both groups.
Conclusions: Itraconazole pulse therapy was efficient and safe for the treatment of onychomycosis caused by dermatophytes, although a much higher daily dosage than the known continuous administration was used. Group 1, with nails initially more extensively affected, had a more evident improvement, by the mean variation in millimeters of normal portion of the target nail. This group showed a very satisfactory response, although not reaching total cure, thus demonstrating the great importance of the precocious treatment of this disease. A residual therapeutical effect is maintained even after the suspension of the drug. Group 2 obtained better total cure rates, and four pulses were, in general, sufficient, although more cycles would be beneficial for patients of Group 1 with more extensive involvement.

Key words: dermatophyte; itraconazole; onychomycosis; pulse therapy; therapy.

INTRODUCTION
Onychomycosis are frequent fungal affections, responsible for more than 40% of the onychomycopathies.1 Its crescent prevalence can be explained based upon factors such as: increase of the old-aged and the immunodepressed population, higher medical vigilance and patient's and physician's consciousness.

In 80 to 90% of the cases, the etiologic agents are dermatophyte fungi 2 of one of the three known genera: Trichophyton, Microsporum e Epidermophyton,3 and among them T. rubrum is the most frequent causative species. Yeasts of the genus Candida and molds (non-dermatophyte fungi of genera Aspergillus, Fusarium, Scopulariopsis, Acremonium, Scytalidium, and others) can also be implied in onychomycosis pathogenesis.4 Among those caused by dermatophytes, approximately 80% occurs in toenails, especially the first toenail.1

These world-wide affections are recalcitrant and, in 1992, they were still considered incurable by some authors.5 Frequently regarded merely an esthetic problem, neglected in its importance, with prolonged treatment and, in general, disappointing results for both physician and patient, onychomycosis must have its real meaning established in a categorical way: they are associated to physical and psychological discomfort and can in a significant way interfere with the patients' well-being. In comparison with antifungal drugs employed until this decade (griseofulvin and ketoconazole), the therapeutical evolution of the last few years has provided much higher cure rates, shorter time of treatment and more safety for the patients.

Itraconazole is a large spectrum, lipo- and keratinophylic, triazolic derivative,6,7 that acts through inhibition of 14-alpha demethylase,7 enzyme responsible for the conversion of lanostherol into ergostherol, an essential component of the fungal cell membrane.8 In vitro studies with Saccharomyces cerevisae show interaction with the fungal citochrome P-450.9 The consequent reduction in ergostherol synthesis results in an altered production of fungal cell membrane, changing its permeability, and hence, its function.7

This drug has been utilized with very good results, both for superficial and deep mycosis,10 and its pharmacokinetical properties make itraconazole extremely adequate for the treatment of onychomycosis. Its highest concentrations are obtained in adipose tissue, omentum, endometrium, vaginal and cervical mucus, skin and nails.8 Capable to incorporate itself to the matrix and impregnate the lamina by diffusion from the ungueal bed, the drug can already be detected inside the nails, in therapeutical concentrations, 7 days after the start of therapy, remaining there for up to six months after its suspension. This phenomenon happens with doses of 100 to 200mg daily during three months.11 On the other side, a week after its interruption, the plasmatic level is so small that the drug can no longer be detected in the blood.6

Itraconazole pulse therapy, i.e., 400 mg-a-day, for 7 days a month, repeating the monthly cycles three to four times, represents an alternative to the conventional therapeutical regimen of 200 mg-a-day, for 3 to 4 months. Its main advantages are lesser cost (28 capsules/month for pulse therapy in comparison with 60 capsules/month for traditional scheme) and higher patient compliance due to a more convenient schedule (three weeks a month without taking the drug), with equivalent results and tolerance.12

The present study was designed to evaluate the efficacy and tolerance of itraconazole pulse therapy in a four month treatment in toenail onychomycosis caused by dermatophytes.

PATIENTS AND METHODS
Eighty-nine patients, male and female, with the diagnosis of toenail dermatophytosis, confirmed by direct mycological exam with presence of septated hypha, with or without arthroconidia, were evaluated through a prospective, open, non-comparative and multicentric study.

Inclusion criteria were: minimum age 14-year-old; written permission of the patient or a parent when the patient was under 21; no previous antifungal drug (systemic: more than 3 months / topic: more than 2 weeks); no history of hepatopathy; no concomitant use of ciclosporin, anti-H2 inhibitors, rifampicin, phenytoin or antacids; and, in cases of fertile-age women, the use of a reliable contraceptive method.

The therapeutical scheme used was itraconazole, 400 mg/day, subdivided in two intakes, for seven consecutive days a month, which means, monthly cycles of one week treatment, for four months. The study ended nine months after the start of the therapy, that is, five months after the interruption of the drug.

Evaluation criteria
1. Clinical: At the first consultation, patients were classified into one of the two groups, according to the measurement of the normal portion of the target nail, the most clinically involved.
Group 1 - 0 to 5,9 mm of healthy ungueal lamina and
Group 2 - more than 6 mm of healthy ungueal lamina.

Measurement was longitudinally made, from the proximal ungueal edge, on the center of the target-nail, up to a straight transversal line tangent to the beginning of the involvement, as preconized by Zaias & Drachman. 13 The measurements of the normal part of the nails were registered before the start of the treatment (Pre); at the end of pulse therapy (End), that is, four months after the start of therapy; and five months after the suspension of medication (Follow up), that is, nine months after the start of the therapy.

The 'cutting point' for the division in these two groups was considered 6mm of normal nail, after the establishment of the mean of size, at the start of the investigation, in twenty women and twenty healthy men volunteers. The mean size of the first toe nail of these 40 normal individuals without ungueal affections was 12mm.

Monthly clinic revisions, for a total of nine months, were carried out to verify improvement, adverse effects and drug distribution.

2. Mycological: Direct mycological exam and culture in Sabouraud dextrose agar were realized in pre treatment (Pre) and at the end of the fourth month, that is, at the end of the treatment with four pulse therapy cycles. (End).

3. Laboratorial: In order to establishing the treatment safety profile, all the patients were submitted, at Pre and at End, to the following blood exams: complete hemogram; transaminases; alkaline phosphatase; direct, indirect and total billirubins; total cholesterol; and creatinine. Those who presented laboratorial alteration at the End were submitted to a new biochemical evaluation at the next consultation.

4. Results: Results were evaluated at the following moments: End and Follow-up, by the measurement in millimeters of normal portion of the target nail, and at the End, by mycological exam.

For statistical evaluation the following non-parametrical methods were used:

1. The Friedman variance analysis was done to compare the mean levels of the measurement of normal portion of the target nail in the three observed moments (Pre, End and Follow-up). At this time, the test of multiple comparisons, based on Friedman statistics,14 was applied to determine which moments had statistical differences between themselves.

2. The influence of the initial size of the normal portion of the target nail on the mean variation of the improvement of the measurements was analyzed in two ways: Mann-Whitney test14 was applied to compare the mean variation of nail measurement between the two groups: Group 1 (Pre < 5.9 mm) and Group 2 (Pre ³ 6 mm); and Spearman correlation coefficient (rs)14 was used to measure the degree of association between the sizes, comparing the moments Pre with End and Pre with Follow-up (two intervalar variables).

3. The Kruskal-Wallis variance analysis 14,15 was applied to compare the mean measurement variation among the three culture groups (T. rubrum, T. mentagrophytes and negative).
The adopted significance level was 5 %.

RESULTS
From the eighty-nine patients included at the start of the investigation, seventy-two completed all the stages of the protocol, forty female, and thirty-two male; their ages varied from 22 to 74 years (48.2 ± 13.95 years).

Among the patients that did not end the study, sixteen were withdrawn because they did not attend all the scheduled evaluations. Only one had to interrupt the drug due to edema and purpura of lower limbs, adverse effect caused by the interaction of itraconazole with amlodipine. This patient was reported in a separate publication, since it was the first case of adverse reaction due to this interaction.16

Two patients reported nausea, one of them accompanied by abdominal discomfort; one, headache; and another, abdominal pain. These four patients presented the adverse effect(s) during the week of drug administration, and it was not necessary, however, to suspend it.

Concerning the laboratorial evaluation, one patient presented discrete elevation of glutamate-piruvic transaminase and one, of alkaline phosphatase, at the End. These were transitory alterations because they were already normal at the next month evaluation.

All the seventy-two patients that completed the research presented positive direct mycological exam for dermatophyte as a inclusion criterion at the Pre. From these, twenty-seven were still positive at the End. This exam, however, was not repeated at Follow-up, five months after the end of the therapy, for the verification of a possible negative result, at this time.

From the seventy-two patients, fifty-nine presented positive culture for fungus in Pre (81.94%). The most prevalent fungus was Trichophyton rubrum, in 47.22% of the cases, followed by T. mentagrophytes, in 23.61%; in 6.94% the species of Trichophyton was not reported; in 1.38% Microsporum sp. grew; and, in 2.77%, growth of Candida sp. occurred, despite the positive direct exam for dermatophyte. In 18.05%, the culture was negative. (Table 1)

Table 1. Result of the cultures of 72 patients in Pre

At the End, fifty-six cultures were negative, and twelve, positive. In eight of the positive cultures T. mentagrophytes grew, in three T. rubrum, and in one the species of Trichophyton was not mentioned. Four patients that completed all other evaluations were not submitted to culture at this stage.

Group 1, initially more involved, presented a mean measurement of the normal portion of the target nail of 0.93 ± 1.46 mm at Pre, 6.59 ± 3.22 mm at End, and 7.99 ± 3.81 mm at Follow-up, which represents, in average, an improvement of 88.36%, when one calculates the difference between Pre, 0.93mm, and Follow-up, 7.99mm (mean difference of improvement between Pre and Follow-up = 7.06 mm); whereas, those of Group 2, initially less involved, with 8.28 ± 1.73 mm at Pre, 11.86 ± 1.91 mm at End and 13.07 ± 2.61 mm at Follow-up, represent an improvement of 36.64% (mean difference of improvement between Pre and Follow up = 4.79 mm) in average. The percentages of improvement were calculated by dividing the Follow-up mean measure by the mean difference between Follow-up and Pre, multiplied by 100 (Group 1 = 7.06 : 7.99 x 100, and Group 2 = 4.79 : 13.07 x 100).

From the analysis of each one of the two groups separately, as well as the two groups together, the evolution of the measurement of the normal portion of the nail in millimeters had a statistically significant increase (p<0,001) between Pre and End, improvement which continued even after the interruption of the drug, that is, between the End and the Follow-up (p<0,001). This phenomenon can be better visualized on Graphic 1. This significant difference occurred on the comparisons between all the investigation moments, that is, Pre with End, Pre with Follow- up and even End with Follow-up in the two separated groups as well as in both together.

When comparing, by Mann-Whitney test, the mean variation of the measurement in millimeters of healthy portion of the target nail, between Pre and End, and between Pre and Follow-up, in both groups, it can be verified that there was a statistically significant difference (p<0.01 and p<0.04 respectively), as showed on Table 2, that is, patients more involved, Group 1, presented a higher mean variation of improvement between Pre and End (5.66 ± 3.13 mm) than the less involved group (3.57 ± 1.91 mm). (Table 2)

Table 2. Mean variation of measurement (mm of healthy portion of target nail)

The anterior results were also verified by Spearman's correlation coefficient, which showed that the mean variations between Pre and End and between Pre and Follow-up are significantly associated (r8=-0.32, p=0.007 e r8=-0.39, p<0.001, respectively) with the initial measurement, that is, the smaller the initial measurement of healthy portion of the nail, the higher is its improvement in millimeters at End and at Follow-up. Noteworthy, however, despite its significance, this coefficient magnitude (0.32 and 0.39) expresses a relatively feeble degree of association.

When the two more cultivated dermatophyte (T. rubrum and T. mentagrophytes) are correlated with the obtained improvement, by the variation in millimeters of normal portion of the nail between Pre and End and also between Pre and Follow-up, there is not significant difference (Table 3), that is, at the present study, the species of the fungus cultured had no influence on the treatment evolution. In this analysis those of Trichophyton sp., were not considered, due to the small number, and the group of negatives included Candida sp., bacteria, saprophytes, contaminants and those that did not showed any growth. Graphic 2 illustrates this phenomenon by the mean measurements on Pre, End and Follow-up, according to the fungus cultivated.

DISCUSSION
Although onychomycosis is a very frequent fungal feet infection, researches concerning its treatment with pulse therapy, with large patient series, are uncommon in the literature. For this first Brazilian multicentric study on this new therapeutical method with itraconazole, eighty-nine patients with confirmed toenail onychomycosis by direct mycological exam, were studied. Of theses, seven-two carried out all the stages of investigation.

Analysis of our results was in accordance to most of the data found in the international literature. All patients were adult, mostly females, perhaps due to their greater esthetic concern. Positive direct mycological exam for dermatophytes was an inclusion criteria, and showed its great importance, since it confirmed the diagnosis of dermatophytosis more often than the culture. With Sabouraud dextrose agar, Trichophyton rubrum was the most found fungus, followed by T. mentagrophytes, as observed in other countries.3,11,12,17 It is important to comment that the mycological exams were realized in six investigation centers, that have different rates of recuperation of fungi in culture, and that in four of these centers, patients were only included in the protocol if a dermatophyte was isolated, consequently there was this apparent high positivity index (81.94%), whereas in laboratories such as of the St. John's Institute of Dermatology in London, the recuperation rate is 62%.3

The measurement of the normal portion of target nail used on the present study for the observation of the improvement of onychopathies, and the consequent possibility of separation of the patients in two groups (Group 1: with less than 5,9 mm and Group 2: more than 6 mm), was based on the Zaias & Drachman method,13 described in 1983. This clinical method permits the monitorization and evaluation of the evolution (regression or progression) of the ungueal infectious process. Six millimeters was adopted as the half size of a normal of a first toenail, aiming the division in two groups, since that we considered 12mm as the mean size of a normal first toenail, as explained in Patients and Methods. Graphic 1 shows that the nails with more extensive involvement, did not reach this measurement of normal nail, despite the residual effect of itraconazole, even after the Follow-up (nine months) improving, however, in its measurements, of 0.93 ± 1.46 to 7.99 ± 3.81, and by average, 88.36% of improvement. In counterpart, patients of Group 2 evolved from 8.28 ± 1.73 to 13.07 ± 2.61 mm, in average showing 38.49% of improvement, and reaching levels of normality of the measurement of normal portion of the nail. Thus, four cycles of pulse therapy with itraconazole for toenail onychomycosis were enough for involvements smaller than 6 mm, as in Group 2 (Figure 1 and 2), corroborating its efficacy on onychomycosis caused by dermatophytes. One could, however, foresee by the obtained results, that additional cycles of pulse therapy would be of benefit for patients of Group 1 (Figure 3 and 4). Graphic 1 also permits the observation of the residual therapeutical effect of itraconazole by the measurement of normal portion of the target nail, that remained increasing even after treatment suspension. Itraconazole, in this pulse therapy regimen, does not need to be administered until total nail recovery. Nevertheless, as the first toenail presents a mean growth of less than 1 mm a month,18 it would be necessary twelve months to observe the complete evolution (with or without cure) of the patients more involved, considering 12 mm the normal size of a first toenail.

Patients of Group 1, initially more involved, presented a mean variation of the normal nail measurement significantly superior than those of Group 2, and we concluded, by this study, that the evolution in sense of improvement is dependent on the initial measurement, that is, most involved nails present a more exuberant improvement. (Table 2)
Graphic 2 shows that, on the present investigation, the fungi species (between the two more frequent) is not important on the measurement variation between Pre and End, behaving both T. rubrum and T. mentagrophytes onychomycosis the same way.

Biochemical evaluation performed at Pre and at End, as the few adverse reactions reported, permit to conclude that pulse therapy regimen is very safe and well-tolerated for onychomycosis treatment. All seven patients with blood biochemistry alteration on End showed normal values, one month after the drug suspension. There were four cases of mild adverse reactions (nausea, abdominal pain and headache), during the drug administration period, without needing drug suspension. These four patients preferred to maintain the therapy, because they soon observed the beneficial effects of itraconazole on their nails. As the adverse reaction occurred only during the drug ingestion period, one week a month, it was well-tolerated. This would probably not occur with the continuous administration. The only patient that presented lower limbs edema and purpura was in concomitant use of amlodipine and had already presented the same clinical signs with these same drugs before. This case was reason for publication,16 and there were already reports of interaction of itraconazole with others calcium channel blockers or antagonists of calcium,19,20 also causing edema of legs. The investigator responsible for this patient opted to suspend both drugs, in this case.

CONCLUSIONS

1. Itraconazole pulse therapy is safe and efficient for onychomycosis caused by dermatophytes.

2. There is a residual therapeutical effect that is maintained even after the drug suspension.

3. The only adverse reaction that provoked treatment interruption, was caused by its interaction with amlodipine.

4. Other adverse effects, in four patients (headache, nausea and abdominal pain), did not need drug suspension.

5. Blood alterations, at the end of the treatment in seven patients, were discrete and transitory, showing the safety of the use of itraconazole.

6. Fungi species did not interfere in the nail improvement velocity on this study.

7. Mean variation in millimeters of normal portion of the involved nail depends on the extension of involvement, that is, the lesser is the initial measurement of the normal portion, the most exuberant is the improvement.

8. Despite this exuberant improvement of Group 1, with less than 6 mm of normal nail at pre-treatment, the less involved patients obtained the best measurements at follow up, showing the great advantage of the precocious treatment for this affection.

9. As the first toenail presents a mean growth of a little more than 1mm a month, it would be necessary 12 months to observe the complete improvement of the most involved patients, considering 12mm its normal size.

10. Four itraconazole cycles are, in general, enough to treat toenail onychomycosis with more than 6mm of normal nail at the start, nevertheless, an increased number of pulses would be necessary for more extensive involvements.

We acknowledge and thank the collaboration of:
Dr. Marisa Capelozzi, Medical Manager of Janssen Pharmaceuticals, in all phases of execution and writing, and
Mrs. Rosangela Noé, Statistician of HUCFF/UFRJ, in the elaboration of the statistics of this investigation.

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Figure 1: Patient of group 2 (> 6 mm of healthy nail) - Pre treatment
Figure 2: Patient of group 2 (> 6 mm of healthy nail) - Nine month Follow up
Figure 3: Patient of group 1 (< than 5,9 mm of healthy nail) - Pre treatment
Figure 4: Patient of group 1 (< 5,9 mm of healthy nail) - Nine month Follow up