Secukinumab demonstrates high efficacy and a favourable safety profile in paediatric patients with severe chronic plaque psoriasis: 52-week results from a Phase 3 double-blind randomized, controlled trial.

BACKGROUND: Secukinumab has demonstrated sustained long-term efficacy with a favourable safety profile in various psoriatic disease manifestations in adults. OBJECTIVES: Here, the efficacy and safety of two secukinumab dosing regimens [low dose (LD) and high dose (HD)] in paediatric patients with severe chronic plaque psoriasis over one year are reported. METHODS: In this multicentre, double-blind study (NCT02471144), patients aged 6 to <18 years with severe chronic plaque psoriasis were stratified and randomized by weight (<25 kg, 25 to <50 kg, ≥50 kg) and age (6 to <12 years, 12 to <18 years) to receive low-dose (LD: 75/75/150 mg) or high-dose (HD: 75/150/300 mg) subcutaneous secukinumab or placebo or etanercept 0.8 mg/kg (up to a max of 50 mg). RESULTS: Overall, 162 patients were randomized to receive secukinumab LD (n = 40) or HD (n = 40), etanercept (n = 41) or placebo (n = 41). The co-primary objectives of the study were met with both secukinumab doses (LD and HD) showing superior efficacy compared to placebo (P < 0.0001) with respect to PASI 75 response (80.0%, 77.5% vs. 14.6%) and IGA mod 2011, 0 or 1 response (70%, 60% vs. 4.9%) at Week 12. Both secukinumab doses were superior to placebo (P < 0.0001) with respect to PASI 90 response at Week 12 (72.5%, 67.5% vs. 2.4%). The efficacy of both doses was sustained to Week 52 with secukinumab achieving higher responses vs. etanercept (PASI 75/90/100: LD, 87.5%/75.0%/40.0% and HD, 87.5%/80.0%/47.5.% vs. etanercept, 68.3%/51.2%/22.0% and IGA 0 or 1: LD, 72.5% and HD, 75.0% vs. etanercept, 56.1%). The safety profile of secukinumab was consistent with the adult Phase 3 studies, with no new safety signals identified. CONCLUSIONS: Both doses of secukinumab demonstrated high and sustained efficacy up to Week 52 with a favourable safety profile in paediatric patients with severe chronic plaque psoriasis.

Adiponectin levels in a large pooled plaque psoriasis study population.

Background: Adiponectin is an adipocyte-secreted protein potentially relevant in the context of cardiometabolic comorbidity of psoriasis patients.Objective: This post-hoc analysis aimed to assess the impact of obesity, metabolic syndrome, psoriasis severity and treatment with secukinumab/etanercept on adiponectin.Methods: Three phase III trials in moderate to severe plaque psoriasis were included. Correlations of Psoriasis Area and Severity Index (PASI), body mass index (BMI), and associated comorbidity with adiponectin levels as well as the impact of secukinumab, etanercept, and placebo were analyzed.Results: Data of 3010 patients were included of whom 71.2% had a BMI >25. Adiponectin levels were significantly higher in patients with lower BMI (r = -0.23; p < .0001) and in patients without metabolic syndrome compared to patients with higher BMI and with metabolic syndrome. PASI score was negatively associated with adiponectin levels (r = -0.065; p = .0004). However, the correlation was extremely weak and thus clinically irrelevant. During treatment with secukinumab or etanercept over 52 weeks adiponectin levels remained stable.Conclusion: Metabolic syndrome and BMI are key determinants of adiponectin levels in psoriasis patients. Psoriasis severity and anti-psoriatic treatment had no relevant impact on adiponectin levels.

Effects of secukinumab on metabolic and liver parameters in plaque psoriasis patients.

BACKGROUND: Psoriasis is associated with metabolic, liver and cardiovascular comorbidity. Secukinumab, a fully human monoclonal antibody that selectively neutralizes interleukin-17A, has shown significant and sustained efficacy in the treatment of moderate to severe psoriasis. OBJECTIVES: This was an exploratory post hoc analysis of pooled data from three phase 3 studies in plaque psoriasis patient populations. The objective was to show the course of metabolic and liver parameters under secukinumab, etanercept or placebo treatment over time. A further objective was to assess the impact of selected comorbidities and metabolic characteristics on high-sensitivity C-reactive protein (hs-CRP), as a surrogate marker of systemic inflammation. METHODS: Data from the phase 3 randomized controlled trials [FIXTURE (NCT01358578), ERASURE (NCT01365455) and SCULPTURE (NCT01406938); n = 3010] were included in this analysis. Patients were treated with secukinumab 150 mg or 300 mg, placebo or etanercept 50 mg (FIXTURE only) as active comparator. A set of metabolic and liver parameters was longitudinally assessed over 52 weeks. Multivariate regression analyses assessed the impact of selected comorbidities and metabolic characteristics on hs-CRP levels at baseline and under treatment. RESULTS: Secukinumab treatment reduced hs-CRP levels. Body weight and uric acid levels tended to decrease over 52 weeks with secukinumab. Secukinumab showed a neutral effect on fasting plasma glucose, lipid parameters and liver enzymes. Psoriatic arthritis, metabolic syndrome, obesity, impaired glucose metabolism, and hyperuricemia were each associated with increased hs-CRP levels at baseline. Concomitant obesity attenuated the decline in hs-CRP under treatment. CONCLUSIONS: These analyses suggest neutral to favourable long-term trends in metabolic and liver parameters under secukinumab treatment. Metabolic comorbidities were associated with increased hs-CRP levels, reflecting the role of systemic inflammatory processes in their pathophysiology.

Secukinumab sustains good efficacy and favourable safety in moderate-to-severe psoriasis after up to 3 years of treatment: results from a double-blind extension study.

BACKGROUND: Secukinumab has demonstrated significant efficacy with a good safety profile through 1 year in plaque psoriasis. Given the chronic nature of this disease, long-term follow-up is needed to evaluate psoriasis therapies fully. OBJECTIVES: To determine the long-term (3-year) efficacy and safety of secukinumab in moderate-to-severe psoriasis. METHODS: Patients completing 52 weeks of secukinumab treatment in the SCULPTURE core study entered an extension in which they continued the same double-blind regimens. Dosing regimens included a fixed-interval schedule (FI; every 4 weeks) and retreatment as needed (RAN), in which patients were withdrawn from secukinumab and received placebo until the start of relapse, at which time secukinumab every 4 weeks was reinitiated. The study was registered with number NCT01640951. RESULTS: In total 168 patients receiving secukinumab 300 mg FI and 172 receiving secukinumab 300 mg RAN entered the extension. Secukinumab 300 mg FI sustained high efficacy: at the end of year 3, the proportion of responders achieving ≥ 90% improvement in Psoriasis Area and Severity Index (PASI 90) was 63·8%, and of PASI 100 responders it was 42·6%. The mean absolute PASI remained low (2-4) from week 52 to week 152 with 300 mg FI, with approximately two-thirds of patients reporting no impact of skin disease on their lives (Dermatology Life Quality Index of 0 or 1). Improvements in overall and subscale scores on all quality-of-life instruments were well sustained. As in the core study, FI dosing was consistently more efficacious than RAN. No new safety signals were identified to year 3. CONCLUSIONS: Secukinumab 300 mg FI sustained high responses and improved quality of life with no new safety concerns through 3 years.

Secukinumab administration by autoinjector maintains reduction of plaque psoriasis severity over 52 weeks: results of the randomized controlled JUNCTURE trial.

BACKGROUND: User satisfaction is an important factor associated with treatment adherence in chronic diseases including moderate-to-severe psoriasis. OBJECTIVE: To evaluate the efficacy, safety and patient acceptability of 300 and 150 mg secukinumab - a fully human anti-interleukin-17A monoclonal antibody that has demonstrated efficacy in the treatment of patients with moderate-to-severe plaque psoriasis - self-administered by autoinjection. METHODS: Patients with moderate-to-severe plaque psoriasis were randomized to secukinumab 300 mg, secukinumab 150 mg or placebo self-administered by autoinjection at baseline, Weeks 1, 2 and 3 and then every 4 weeks from Week 4 to Week 48. Efficacy responses [≥75/90/100% improvement in Psoriasis Area and Severity Index (PASI 75/90/100) and clear/almost clear skin by Investigator's Global Assessment 2011 modified version (IGA mod 2011 0/1)] were measured at Week 52. Patient-reported usability of the autoinjector was evaluated by the self-injection assessment questionnaire to Week 48. RESULTS: At Week 52 with secukinumab 300 mg, PASI 75/90/100 and IGA mod 2011 0/1 responses were achieved by 81.4/64.1/38.8% and 69.6% of patients, respectively, by multiple imputation. At Week 52 with secukinumab 150 mg, PASI 75/90/100 and IGA mod 2011 0/1 responses were achieved by 75.2/57.4/33.1% and 60.2% of patients, respectively, by multiple imputation. Patient-assessed acceptability of the autoinjector remained high to Week 48. The proportion of patients experiencing adverse events was greater with secukinumab 300 mg (88.6%) than with secukinumab 150 mg (78.7%). CONCLUSION: Self-administration of secukinumab using an autoinjector was associated with robust and sustained efficacy, a good safety profile and high acceptability.

Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, exhibits minimal immunogenicity in patients with moderate-to-severe plaque psoriasis.

BACKGROUND: The proinflammatory cytokine interleukin (IL)-17A plays a pivotal role in psoriasis pathogenesis. Secukinumab, a fully human monoclonal antibody (mAb) that selectively targets IL-17A, has been demonstrated to be highly efficacious for the treatment of moderate-to-severe psoriasis, starting at early time points, with a sustained effect and a favourable safety profile. mAb therapies may be associated with production of antidrug antibodies (ADAs) that can affect drug pharmacokinetics, diminish response or cause hypersensitivity reactions. OBJECTIVES: To investigate the immunogenicity of secukinumab across six phase III clinical trials in which patients with plaque psoriasis were treated with secukinumab for up to 52 weeks and additionally followed up at week 60. METHODS: Immunogenicity in patients with plaque psoriasis exposed to secukinumab was evaluated at baseline and at weeks 12, 24, 52 and 60. Treatment-emergent (TE)-ADAs were defined as a positive ADA signal detected in post-treatment samples from patients with a negative baseline signal. Confirmed positive samples were further analysed for their drug-neutralizing potential. RESULTS: Among 2842 patients receiving secukinumab and evaluated for ADAs, 11 (0·4%) developed TE-ADAs. Associations between TE-ADAs and secukinumab dose, frequency or mode of administration were not observed. Neutralizing antibodies were detected in three of nine evaluable patients with TE-ADAs. CONCLUSIONS: Secukinumab immunogenicity was low, as shown by TE-ADA detection in only 11 of 2842 (0·4%) patients with moderate-to-severe plaque psoriasis treated with secukinumab. All but one of the patients with TE-ADAs were biologic naive. Neither TE-ADAs nor neutralizing antibodies were associated with loss of secukinumab efficacy or issues of clinical concern.

Secukinumab in psoriasis: randomized, controlled phase 3 trial results assessing the potential to improve treatment response in partial responders (STATURE).

BACKGROUND: Secukinumab, an anti-interleukin-17A monoclonal antibody, has demonstrated rapid and sustained efficacy in phase 3 psoriasis trials. OBJECTIVES: To examine whether partial responders could achieve improved responses with intravenous (IV) secukinumab vs. the same or a higher subcutaneous (SC) dose. METHODS: Forty-three participants with moderate-to-severe psoriasis and partial response [Psoriasis Area and Severity Index (PASI) score improvement of ≥ 50% but < 75%] after 12 weeks of 300 or 150 mg SC secukinumab therapy were randomized 1 : 1 to secukinumab 10 mg kg(-1) IV (baseline, weeks 2 and 4, respectively) or secukinumab 300 mg SC (baseline, week 4). All participants subsequently received secukinumab 300 mg SC every 4 weeks (weeks 8-36). Co-primary end points were PASI 75 and Investigator's Global Assessment [2011 modified version (IGA mod 2011)] 0/1 response rates at week 8 (IV vs. SC). RESULTS: Higher IGA mod 2011 0/1 response rates (66.7% vs. 33.3%; P = 0.03) and a trend towards higher PASI 75 response rates (90.5% vs. 66.7%; P = 0.06) were observed with secukinumab IV vs. SC at week 8. The primary objective was not met, as the difference was not significant for both co-primary end points. Improved responses in both groups were maintained at week 40 in most participants. Safety profiles for IV and SC secukinumab were similar. The trial was underpowered owing to its small sample size. CONCLUSIONS: Improved response may be attained in patients with psoriasis achieving partial response after 12 weeks of SC secukinumab treatment by continued dosing with 300 mg SC or treatment with higher doses.

Efficacy, safety and usability of secukinumab administration by autoinjector/pen in psoriasis: a randomized, controlled trial (JUNCTURE).

BACKGROUND: Secukinumab is a fully human anti-interleukin-17A monoclonal antibody. OBJECTIVE: Determine the efficacy, safety and usability of secukinumab administered via autoinjector/pen. METHODS: This phase III trial randomized subjects with moderate to severe plaque psoriasis to secukinumab 300 mg, 150 mg or placebo self-injection once weekly to Week 4, then every 4 weeks. Co-primary end points at Week 12 were ≥75% improvement in Psoriasis Area and Severity Index (PASI 75) and clear/almost clear skin by investigator's global assessment 2011 modified version (IGA mod 2011 0/1). Secondary end points included autoinjector usability, assessed by successful, hazard-free self-injection and subject-reported acceptability on Self-Injection Assessment Questionnaire. RESULTS: Week 12 PASI 75 and IGA mod 2011 0/1 responses were superior with secukinumab 300 mg (86.7% and 73.3%, respectively) and 150 mg (71.7% and 53.3%, respectively) vs. placebo (3.3% and 0%, respectively) (P < 0.0001 for all). All subjects successfully self-administered treatment at Week 1, without critical use-related hazards. Subject acceptability of autoinjector was high throughout 12 weeks. Adverse events were higher with secukinumab (300 mg, 70.0%; 150 mg, 63.9%) vs. placebo (54.1%), with differences largely driven by mild/moderate nasopharyngitis. CONCLUSION: Secukinumab delivered by autoinjector/pen is efficacious, well-tolerated and associated with high usability in moderate to severe plaque psoriasis.

Secukinumab administration by pre-filled syringe: efficacy, safety and usability results from a randomized controlled trial in psoriasis (FEATURE).

BACKGROUND: Secukinumab, a fully human anti-interleukin-17A monoclonal antibody, demonstrated efficacy and safety in moderate-to-severe plaque psoriasis when administered via subcutaneous injection. Self-administration by pre-filled syringe (PFS) can offer patients clinical benefits of a drug, with increased convenience. OBJECTIVES: To assess efficacy, safety and usability of secukinumab administration via PFS in subjects with moderate-to-severe plaque psoriasis. MATERIALS AND METHODS: Subjects in this phase 3 trial were randomized 1 : 1 : 1 to secukinumab 300 or 150 mg or matching placebo. Results to week 12 are presented here. Each treatment was delivered using a PFS once weekly to week 4, and again at week 8. Co-primary endpoints were secukinumab superiority over placebo for week 12 PASI 75 (≥ 75% reduction in Psoriasis Area and Severity Index) and IGA mod 2011 (2011 modified Investigator's Global Assessment) 0/1 response rates. Secondary endpoints included PFS usability, determined by observer rating of successful, hazard-free self-injection and subject rating of acceptability by the Self-Injection Assessment Questionnaire (SIAQ). RESULTS: Co-primary endpoints were met, with demonstration of superiority for each secukinumab dose vs. placebo at week 12 (PASI 75: 75·9%, 69·5% and 0% for secukinumab 300 mg, 150 mg and placebo; IGA mod 2011 0/1: 69·0%, 52·5% and 0%, respectively; P < 0·0001 for all comparisons vs. placebo). PFS usability was high: 100% of subjects successfully self-administered treatment at week 1, and subjects reported high SIAQ-assessed acceptability of the PFS throughout the trial. No new/unexpected safety signals were observed. CONCLUSIONS: Secukinumab administration by PFS was effective, with an acceptable safety profile and high usability. The PFS provides a reliable, convenient form of secukinumab administration in subjects with moderate-to-severe plaque psoriasis.

Secukinumab improves hand, foot and nail lesions in moderate-to-severe plaque psoriasis: subanalysis of a randomized, double-blind, placebo-controlled, regimen-finding phase 2 trial.

BACKGROUND: Psoriasis affecting sites such as the hands, feet and nails can be particularly difficult to treat. There are limited data on the efficacy of biological agents to treat these specific localizations. OBJECTIVE: This analysis of a phase 2 regimen-finding study evaluated the efficacy of secukinumab in subjects with moderate-to-severe psoriasis and non-pustular involvement of the hands, feet and/or nails. METHODS: Subjects were randomized (1 : 2 : 2 : 1) to one of three subcutaneous secukinumab 150-mg induction regimens [Single (Week 0), Monthly (Weeks 0, 4, 8), Early (Weeks 0, 1, 2, 4)] or placebo. In the subgroup (n = 131) with hand and/or foot psoriasis [baseline 5-point hand/foot Investigator's Global Assessment (IGA) score ≥2], efficacy was assessed as percentage of subjects achieving an IGA response [a score of 0 (clear) or 1 (minimal) and an improvement of ≥2 points on the 5-point hand/foot scale vs. baseline] at Week 12. In the subgroup (n = 304) with fingernail psoriasis (baseline composite score ≥1), efficacy was assessed as mean percentage change from baseline to Week 12 in a composite score. RESULTS: At Week 12, a markedly higher percentage of subjects with hand and/or foot psoriasis achieved an IGA response with the Early regimen vs. placebo (54.3% vs. 19.2%, P = 0.005). The composite fingernail score improved with the Early and Monthly regimens, but worsened with placebo [percentage mean change from baseline (SE): -19.1% (6.12) and -10.6% (7.06) vs. 14.4% (11.92); P = 0.010 vs. placebo for Early, P = 0.027 for Monthly). Secukinumab was well tolerated. CONCLUSION: Secukinumab demonstrated a beneficial effect on psoriasis of the hands/feet/nails in this short-term assessment.

Secukinumab induction and maintenance therapy in moderate-to-severe plaque psoriasis: a randomized, double-blind, placebo-controlled, phase II regimen-finding study.

BACKGROUND: Interleukin (IL)-17A has major proinflammatory activity in psoriatic lesional skin. OBJECTIVES: To assess the efficacy and safety of secukinumab, a fully human IgG1κ monoclonal anti-IL-17A antibody, in moderate-to-severe plaque psoriasis in a phase II regimen-finding study. METHODS: A total of 404 patients were randomized to subcutaneous placebo (n = 67) or one of three secukinumab 150 mg induction regimens: single (week 0; n = 66), early (weeks 0, 1, 2, 4; n = 133) and monthly (weeks 0, 4, 8; n = 138 patients). The primary outcome was ≥ 75% improvement from baseline Psoriasis Area and Severity Index score (PASI 75) at week 12. PASI 75 responders from active treatment arms at week 12 were rerandomized to either a fixed-interval (secukinumab 150 mg at weeks 12 and 24; n = 65) or a treatment-at-start-of-relapse maintenance regimen (secukinumab 150 mg at visits at which a start of relapse was observed; n = 67). RESULTS: At week 12, early and monthly induction regimens resulted in higher PASI 75 response rates vs. placebo (54·5% and 42·0% vs. 1·5%; P < 0·001 for both). Among PASI 75 responders at week 12 entering the maintenance period, PASI 75 and PASI 90 achievement at least once from week 20 to week 28 was superior with the fixed-interval regimen [85% (n = 55) and 58% (n = 38), respectively] vs. the start-of-relapse regimen [67% (n = 45), P = 0·020, and 21% (n = 14), respectively]. Fifteen weeks after last study drug administration, < 10% of patients in the fixed-interval and start-of-relapse groups experienced a start of relapse. No immunogenicity was observed, and no injection-site reactions were reported. Reported cases of neutropenia were mild-to-moderate (≤ grade 2); none was associated with clinically significant adverse events or resulted in study discontinuation. Due to the brief duration of the safety assessment, no firm conclusions can be drawn regarding long-term safety. CONCLUSIONS: Secukinumab shows efficacy for induction and maintenance treatment of moderate-to-severe plaque psoriasis.

Efficacy and safety of secukinumab in the treatment of moderate-to-severe plaque psoriasis: a randomized, double-blind, placebo-controlled phase II dose-ranging study.

BACKGROUND: Conventional systemic therapies for plaque psoriasis have not fully met the needs of patients, and although current biologic treatments are generally well tolerated, concerns exist with respect to long-term safety. Interleukin (IL)-17A is believed to be an important effector cytokine in the pathogenesis of psoriasis and is produced by Th17 cells, a class of helper T cells that act outside the established Th1/Th2 paradigm for regulation of innate and adaptive immunity. OBJECTIVES: To assess the efficacy and safety of different doses of secukinumab, a fully human anti-IL-17A IgG1κ monoclonal antibody, in patients with moderate-to-severe plaque psoriasis. METHODS: Patients (n = 125) were randomized 1 : 1 : 1 : 1 : 1 to receive subcutaneous doses of placebo (n = 22) or secukinumab [1 × 25 mg (n = 29), 3 × 25 mg (n = 26), 3 × 75 mg (n = 21) or 3 × 150 mg (n = 27)] at weeks 0, 4 and 8. After the 12-week treatment period, patients entered a follow-up period of 24 weeks. The primary efficacy outcome was at least 75% improvement from baseline in the Psoriasis Area and Severity Index score (PASI 75); secondary outcomes included the Investigator's Global Assessment (IGA) and PASI 90 and 50 response rates. RESULTS: After 12 weeks of treatment, secukinumab 3 × 150 mg and 3 × 75 mg resulted in significantly higher PASI 75 response rates vs. placebo (82% and 57% vs. 9%; P < 0·001 and P = 0·002, respectively). Higher PASI 75 response rates compared with placebo were maintained throughout the follow-up period with these dosages [week 36, 26% (n = 7) and 19% (n = 4) vs. 4% (n = 1), respectively], with a gradual decline of PASI 75 response over time after the dosing period. IGA response rates were significantly higher in the 3 × 150 mg group vs. placebo at week 12 (48% vs. 9%; P = 0·005) and were consistently higher for the 3 × 150 mg and 3 × 75 mg groups vs. placebo at all time points from week 4 onward. The PASI 90 response rate was significantly higher in the 3 × 150 mg group vs. placebo (52% vs. 5%) at week 12 and remained higher during the follow-up period. Secukinumab was well tolerated. Two cases of neutropenia (≤ grade 2) were reported in the 3 × 150 mg cohort. CONCLUSIONS: Treatment with subcutaneous secukinumab 3 × 75 mg and 3 × 150 mg met the primary outcome of PASI 75 response achievement after 12 weeks, demonstrating efficacy in moderate-to-severe psoriasis.

Medium-chain triglycerides inhibit growth of Malassezia: implications for prevention of systemic infection.

OBJECTIVE: Lipophilic Malassezia species may induce catheter-associated sepsis in newborns and immunocompromised patients receiving parenteral lipids. Therefore, we tested whether M. furfur and six other Malassezia species can use commercially available infusions as a lipid source. DESIGN: Prospective in vitro study. SETTING: Research laboratory in a university hospital. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: With the exception of M. restricta, all Malassezia species grow on lipid infusions. There are no substantial differences among the different brands. The most rapid growth is shown by M. furfur, which grows better on agar containing a 20% rather than a 10% lipid infusion. Growth of M. furdur and M. sympodialis can be reduced by infusions containing medium-chain triglycerides. Incubated in triglycerides, M. furfur is strongly suppressed by 50% medium-chain triglycerides and M. sympodialis by 8% medium-chain triglycerides. When medium-chain free fatty acids are added to triglycerides, both species can be suppressed by about 1% free fatty acids. CONCLUSION: Medium-chain triglycerides and medium-chain free fatty acids are toxic for Malassezia species. Commercially available infusions containing medium-chain triglycerides might be used to prevent systemic Malassezia infections.

Different utilization of neutral lipids by Malassezia furfur and Malassezia sympodialis.

In recent years, the genus Malassezia has been expanded based on molecular data; in addition to M. furfur and M. pachydermatis, five new species (M. sympodialis, M. globosa, M. obtusa, M. restricta, M. slooffiae) have been described. Apart from their lipid dependence, little is known about the metabolism and nutritional requirements of these new species. Defined inocula of Malassezia reference strains were cultured on selective agar for pathogenic fungi which was overlaid with olive oil. Samples of the olive oil overlay were taken at regular intervals and the lipid fractions were analysed by high performance thin layer chromatography. Depending on the time of incubation and the number of cells, M. sympodialis and the other recently described species produced a significant increase in free fatty acids. In addition, a band of an apolar substance was identified as a mixture of fatty acid ethyl esters. While showing growth, strains of M. furfur produced only small amounts of ethyl esters and free fatty acids. The growth kinetics of M. furfur and M. sympodialis were also different: for M. sympodialis, a clear lag phase was observed, possibly indicating the necessity of extracellular hydrolysis of the triglycerides. The significance of the synthesis of ethyl esters could not be clarified. For routine differentiation, this metabolic difference is only of limited usefulness because slight contamination of M. furfur strains with other lipophilic Malassezia species may lead to misinterpretation due to the high metabolic activity. These metabolic differences might be important in the pathogenesis of Malassezia infections.

Growth requirements and nitrogen metabolism of Malassezia furfur.

Investigations on the nutrient requirements of Malassezia yeasts led to the preparation of a new minimal medium consisting of an amino nitrogen and a lipid source, which only allowed the growth of the species M. furfur. Carbohydrates, electrolytes, vitamins and trace elements were not required. Using the basal medium, a nitrogen auxanogram for M. furfur was developed, which allowed investigation of the assimilation of 22 amino acids and 9 further nitrogen sources. With the exception of cysteine, all amino acids were metabolized, as were ammonium salts, urea, creatine, creatinine, uric acid and allantoin. KNO3, however, failed to support growth. Depending on the source used, the yeast cells changed micromorphologically: both oval and round forms were induced. Assimilation of several amino acids resulted in dimorphism, especially in the case of glycine and serine. The cell yield differed significantly depending on the nitrogen source; short-chain unbranched amino acids were utilized most readily. Thus, M. furfur can be characterized as a relatively undemanding yeast species which is optimally adapted to the superficial skin environment. All other lipid-dependent Malassezia species seem to require more complex media.

Differentiation of Malassezia species: selectivity of cremophor EL, castor oil and ricinoleic acid for M. furfur.

In recent years, the genus Malassezia has been reclassified based on molecular data. In addition to M. furfur, M. pachydermatis and M. sympodialis, four new species, M. globosa, M. obtusa, M. restricta and M. slooffiiae, have been described. However, apart from their lipid dependence, little is known about the metabolism and nutritional requirements of all the seven species. Further to recent studies, 10 hydrophilic emulsifiers (HLB > 10) were examined in an agar diffusion test to determine their growth-promoting effect on reference strains of the different Malassezia species. Polyethylene glycol (PEG) 7 glyceryl monoalcanoate (Cetiol HE). PEG-glyceryl stearate (Tagat S2) and macrogol-50 stearate (Myrj 53) were metabolized by all strains, while PEG-35 castor oil (Cremophor EL) was metabolized only by M. furfur. The latter observation is due to a different metabolism of castor oil and its main component, ricinoleic acid (12-hydroxy oleic acid), which may also give an insight into the pathogenesis of diseases that are associated with Malassezia spp. As hydroxy fatty acids are important in maintaining the epidermal structure and function, their metabolism specifically by M. furfur might clarify some clinical aspects of pityriasis versicolor. Apart from this speculation, use of Cremophor EL, with splitting of esculin as an additional key character, improves the distinction of the species M. furfur, M. slooffiae and M. sympodialis.