IGAxBSA composite for assessing disease severity and response in patients with atopic dermatitis.

BACKGROUND: Accurate assessment of atopic dermatitis (AD) severity is critical when initiating and monitoring therapy. Use of existing research tools such as the Eczema Area and Severity Index (EASI) and Scoring Atopic Dermatitis (SCORAD) is complex and time-consuming in clinical practice. A previous analysis found the product of validated Investigator's Global Assessment (vIGA) and affected body surface area (BSA) to be an accurate and practical tool for routine assessment of paediatric AD. OBJECTIVE: To evaluate the IGAxBSA composite as an alternative to EASI or SCORAD for assessment of AD disease severity and disease responsiveness. METHODS: The relationship between IGAxBSA, EASI and SCORAD was assessed in a post hoc analysis of pooled data from the dupilumab clinical trial programme in adult and paediatric patients with moderate-to-severe AD who had received dupilumab or placebo, with or without topical corticosteroids (TCS). The trials are registered at ClinicalTrials.gov and EudraCT: LIBERTY AD SOLO 1 (NCT02277743, 2014-001198-15), LIBERTY AD SOLO 2 (NCT02277769, 2014-002619-40), LIBERTY AD SOLO-CONTINUE (NCT02395133, 2014-003384-38), LIBERTY AD CHRONOS (NCT02260986, 2013-003254-24), LIBERTY AD CAFÉ (NCT02755649, 2015-002653-35), LIBERTY AD ADOL (NCT03054428, 2015-004458-16), LIBERTY AD PEDS (NCT03345914, 2016-004997-16), LIBERTY AD OLE (NCT01949311, 2013-001449-15) and LIBERTY AD PEDS OLE (NCT02612454, 2015-001396-40). RESULTS: Using datapoints from pooled dupilumab randomized controlled trials (n = 3473) and open-label extension trials (n = 3045), we found that IGAxBSA correlated well with EASI and SCORAD, irrespective of treatment group and race (white, Asian, black). IGAxBSA correlated better with objective measures (EASI, SCORAD) than with patient- or caregiver-reported subjective measures. IGAxBSA correlated strongly with EASI and SCORAD in assessing disease change over time (r = 0·90, r = 0·76, respectively; P < 0·0001), and concordance between IGAxBSA-50/75/90 and EASI-50/75/90 was excellent (88-94%). CONCLUSIONS: IGAxBSA is a valid alternative for assessment of AD disease severity and response over time, compared with EASI or SCORAD in patients with AD, irrespective of race.

Laboratory safety of dupilumab in moderate-to-severe atopic dermatitis: results from three phase III trials (LIBERTY AD SOLO 1, LIBERTY AD SOLO 2, LIBERTY AD CHRONOS).

BACKGROUND: Dupilumab [a monoclonal antibody blocking the shared receptor subunit for interleukin (IL)-4 and IL-13] is approved for patients aged ≥ 12 years with inadequately controlled, moderate-to-severe atopic dermatitis (AD). Dupilumab trials of up to 52 weeks demonstrated efficacy and a favourable safety profile in patients with moderate-to-severe AD inadequately controlled with topical medications. OBJECTIVES: To further characterize the safety of dupilumab by evaluating clinical laboratory findings from three randomized, double-blinded, placebo-controlled phase III trials (LIBERTY AD SOLO 1 & 2 and LIBERTY AD CHRONOS). METHODS: Patients were randomized 1 : 1 : 1 (SOLO 1 & 2) or 3 : 1 : 3 (CHRONOS) for 16 and 52 weeks, respectively, to dupilumab weekly, every 2 weeks or placebo. CHRONOS patients received a standardized concomitant topical corticosteroid regimen. Laboratory outcomes were summarized descriptively in 1376 patients from SOLO 1 & 2 and 740 from CHRONOS. RESULTS: Treatment groups had similar results in baseline laboratory parameters. Platelets and neutrophils showed mild decreases from baseline in dupilumab vs. placebo groups. Some dupilumab-treated patients had small transient increases in eosinophils. Grade 3 eosinophilia was reported in < 1% of dupilumab-treated and placebo-treated patients; no adverse events were associated with eosinophilia. Lactate dehydrogenase levels decreased from baseline during dupilumab treatment in all trials. No clinically meaningful changes were observed between treatment groups in other haematology, chemistry or urinalysis parameters. CONCLUSIONS: There were no clinically important changes in routine laboratory parameters that could be attributed to dupilumab. This study supports the use of dupilumab as a systemic treatment for moderate-to-severe AD that does not require laboratory monitoring. What's already known about this topic? Long-term treatment of atopic dermatitis (AD) with conventional immunosuppressive agents is limited by the risk of significant side-effects and a need for repeated tests to monitor haematological and/or organ (e.g. liver, kidney) toxicities. Dupilumab [a monoclonal antibody blocking the shared receptor subunit for interleukin (IL)-4 and IL-13] is approved for the treatment of patients with inadequately controlled, moderate-to-severe AD. In 16-week and 52-week studies, dupilumab demonstrated a positive risk/benefit profile in moderate-to-severe AD. What does this study add? This study is the first comprehensive analysis of dupilumab laboratory safety data of the 16-week SOLO 1 & 2 (pooled N = 1376) and 52-week CHRONOS (N = 740) trials, demonstrating an absence of clinically important changes in haematology, serum chemistry and urinalysis parameters in patients with moderate-to-severe AD treated with dupilumab. Our data support the use of dupilumab as a systemic treatment for the long-term management of moderate-to-severe AD without routine laboratory monitoring in clinical practice.

Assessing the need for routine safety testing for patients being treated with dupilumab for moderate-to-severe atopic dermatitis.

Atopic dermatitis (also known as AD or eczema) is a common skin disease that can cause intense and persistent itching and rashes. Skin creams or ointments are not suitable or effective for some patients with moderate-to-severe AD. In these patients, oral (taken by mouth) or injected medications may be required. Some of those oral or injected treatments could be toxic and often have unwanted side effects, especially when used for a longer period of time, so patients must be regularly tested to see whether those treatments are harming their blood or organs. Dupilumab is a newer injectable drug for treating moderate-to-severe AD. Dupilumab specifically targets key molecules in the body that cause AD. Dupilumab has been tested for up to one year in more than 2000 patients enroled in placebo-controlled clinical trials. During those trials, patients provided blood and urine samples for laboratory testing while they were being treated with dupilumab or placebo (dummy drug). In this paper, the authors from Germany and the U.S.A, analysed how blood cells, blood chemistry, and urine chemistry changed during treatment, to check whether dupilumab is safe to use without the need for regular laboratory tests. After performing many routine laboratory tests on patients' blood and urine, they found that there were no clinically important changes in test results that could be linked to dupilumab. They concluded that patients using dupilumab for moderate-to-severe AD do not need routine laboratory testing. This is a summary of the study: Laboratory safety of dupilumab in moderate-to-severe atopic dermatitis: results from three phase III trials (LIBERTY AD SOLO 1, LIBERTY AD SOLO 2, LIBERTY AD CHRONOS).

Dupilumab provides important clinical benefits to patients with atopic dermatitis who do not achieve clear or almost clear skin according to the Investigator's Global Assessment: a pooled analysis of data from two phase III trials.

BACKGROUND: In the U.S.A., an Investigator's Global Assessment (IGA) score of ≤ 1 (clear or almost clear skin) has been the standard measure in regulatory outcomes for registration clinical trials in atopic dermatitis (AD), including those supporting the recent approval of dupilumab. OBJECTIVES: To evaluate the treatment effect of dupilumab in patients with IGA > 1 at the end of treatment, using other validated outcome measures for AD signs, symptoms and quality of life. METHODS: LIBERTY AD SOLO 1 and 2 were two 16-week, randomized, double-blind trials enrolling adult patients with moderate-to-severe AD (IGA ≥ 3) inadequately controlled with topical treatment. We performed a post hoc analysis in patients receiving dupilumab 300 mg every 2 weeks (q2w) or placebo. Outcome measures in patients with IGA > 1 included Eczema Area and Severity Index (EASI), pruritus numerical rating scale (NRS), affected body surface area (BSA), Patient-Oriented Eczema Measure (POEM) and Dermatology Life Quality Index (DLQI). The trials were registered at ClinicalTrials.gov: NCT02277743 and NCT02277769. RESULTS: At week 16, 278 of 449 dupilumab q2w-treated patients (median age 36·0 years) and 396 of 443 placebo-treated patients had IGA > 1. Among patients with IGA > 1 at week 16, dupilumab significantly improved several outcome measures compared with placebo: EASI (-48·9% vs. -11·3%, P < 0·001), pruritus NRS (-35·2% vs. -9·1%, P < 0·001), affected BSA (-23·1% vs. -4·5%, P < 0·001), POEM score ≥ 4-point improvement (57·4% vs. 21·0%, P < 0·001) and DLQI score ≥ 4-point improvement (59·3% vs. 24·4%, P < 0·001). CONCLUSIONS: In patients with IGA > 1 at week 16, dupilumab induced statistically significant benefits in multiple validated outcome measures compared with placebo. The IGA ≤ 1 end point significantly underestimates clinically relevant dupilumab treatment effects.

Stepwise approach of development of dermo-cosmetic products in healthy and atopic dermatitis paediatric population: safety evaluation, clinical development and postmarket surveillance.

BACKGROUND/OBJECTIVES: Paediatric skin, considered sensitive, and infant skin, more susceptible to percutaneous toxicity, require specially formulated cosmetic products. As recently shown, early use of emollients in infants "at risk" of developing atopic dermatitis has shown controversial results in reducing the incidence of atopic dermatitis. Development of dermo-cosmetic products for this specific population should especially ensure tolerance and safety. In absence of good clinical practice guideline, we propose here a stepwise approach for the development of paediatric cosmetic skincare products. METHODS: Our stepwise methodology for cosmetics aimed at paediatrics, starts with in vitro assessment of product's ingredients safety, followed by preclinical and clinical evaluations of the final product, including sequentially: (1) Repeated Open Application Test (ROAT), (2) Human Repeated Insult Patch Test (HRIPT), (3) In-use dermatological and ophthalmological tolerance studies (sequentially in 3a: healthy adults, 3b: healthy paediatric subjects and finally 3c: paediatric patients). We also describe the integrated cosmetovigilance-toxicological surveillance during the clinical development phase and postmarketing. RESULTS: As illustrated with one dermo-cosmetic product intended to be used as a preventative/maintenance treatment for atopic dermatitis in paediatric population, we show that using this stepwise methodology to test a product reduces potential risks of irritation and contact dermatitis in this sensitive population. CONCLUSION: Standardized ethical stepwise development approach is needed to ensure the commercialization of safe and well-tolerated dermo-cosmetics for paediatrics. The approach described here could potentially serve as guidance for evaluation of new paediatric cosmetic products.

Efficacy of a global supportive skin care programme with hydrotherapy after non-metastatic breast cancer treatment: A randomised, controlled study.

This study investigated the efficacy of post-treatment hydrotherapy as supportive care for management of persistent/long-lasting dermatologic adverse events (dAEs) induced in breast cancer survivors by adjuvant therapy, and its impact on quality of life (QoL). Patients in complete remission after standardised (neo)adjuvant chemotherapy, surgery and radiotherapy combination treatment for infiltrating HR+/HER2-breast carcinoma were enrolled in this randomised, multicentre controlled study 1-5 weeks after completing radiotherapy. The control group (CG, n = 33) received best supportive care and the treatment group (HG, n = 35) received 3-weeks of specific hydrotherapy. The primary criterion was change in QoL (QLQ-BR23) after hydrotherapy. Clinical grading of dAEs, cancer-related QoL (QLQ-C30), dermatologic QoL (DLQI) and general psychological well-being (PGWBI) were assessed. Significant dAEs were found at inclusion in both groups (n = 261). Most items showed significantly greater improvement in the HG versus CG group: QLQ-BR23 (breast [p = .0001] and arm symptoms [p = .0015], systemic therapy side effects [p = .0044], body image [p = .0139]), some dAE grading, DLQI (p = .0002) and PGWBI (p = .0028). Xerosis (88% of patients at inclusion) completely healed in all HG patients. Specific hydrotherapy is an effective supportive care for highly prevalent and long-lasting dAEs occurring after early breast cancer treatment, including chemotherapy, and leads to improved QoL and dermatologic toxicities.

Fragility of epidermis: acne and post-procedure lesional skin.

'Fragile skin', or skin with lower resistance to aggressors, can be broadly classified into four causal categories: constitutional (age-dependent or associated with specific vulnerable locations on the body, e.g. eyelids), pathological (related to disease), circumstantial (related to environmental or internal factors, e.g. stress) and iatrogenic (caused by medical interventions or treatments). In this supplement, we focus on the fourth category, the iatrogenic origin of fragile skin and the role that dermo-cosmetics can have in restoring the natural protective function of the skin following treatments for skin diseases and medical interventions. We present epidemiological data on the prevalence of fragile skin in three different geographical regions, and the results of two randomized controlled studies investigating the efficacy and tolerability of dermo-cosmetics in combination with topical acne treatment and following physical skin damage. Overall, we found that prevalence across the three regions (23% in Germany, 41% in UAE, 56% in Taiwan) reflected previous global estimates (24-53%) across skin types, with significant associations found with environmental and lifestyle factors, such as stress, humidity and pollution. The iatrogenic effects of topical acne treatments can result in poor compliance or use of over-the-counter moisturizers, which may reduce treatment efficacy. Dermo-cosmetics were found to aid in restoration of fragile skin caused by the acne topical retinoid treatment adapalene 0.1% gel, by reducing transepidermal water loss and improving skin hydration, as well as reducing the side-effects such as skin irritation that are frequently associated with topical retinoids. Additionally, dermo-cosmetic products were found to accelerate wound closure following skin damage in a laser ablation model and reduced the duration of post-procedural side-effects such as itching and burning.

Fragility of epidermis in newborns, children and adolescents.

Within their first days of life, newborns' skin undergoes various adaptation processes needed to accommodate the transition from the wet uterine environment to the dry atmosphere. The skin of newborns and infants is considered as a physiological fragile skin, a skin with lower resistance to aggressions. Fragile skin is divided into four categories up to its origin: physiological fragile skin (age, location), pathological fragile skin (acute and chronic), circumstantial fragile skin (due to environmental extrinsic factors or intrinsic factors such as stress) and iatrogenic fragile skin. Extensive research of the past 10 years have proven evidence that at birth albeit showing a nearly perfect appearance, newborn skin is structurally and functionally immature compared to adult skin undergoing a physiological maturation process after birth at least throughout the first year of life. This article is an overview of all known data about fragility of epidermis in 'fragile populations': newborns, children and adolescents. It includes the recent pathological, pathophysiological and clinical data about fragility of epidermis in various dermatological diseases, such as atopic dermatitis, acne, rosacea, contact dermatitis, irritative dermatitis and focus on UV protection.

Dupilumab provides rapid and sustained improvement in SCORAD outcomes in adults with moderate-to-severe atopic dermatitis: combined results of four randomized phase 3 trials.

BACKGROUND: Dupilumab, a first-in-class therapy targeting the two key cytokines involved in the persistent underlying inflammatory pathway in atopic dermatitis (AD), is approved for treatment of moderate-to-severe AD in Europe, USA, Japan and several other countries. OBJECTIVE: To assess dupilumab effects on SCORing Atopic Dermatitis (SCORAD) and component scores (objective and subjective SCORAD) over time in adults with moderate-to-severe AD. METHODS: This post hoc analysis included 2,444 patients in four placebo-controlled, double-blind, randomized, phase 3 trials. SOLO 1 and 2 (NCT02277743; NCT02277769) evaluated 16 weeks of dupilumab monotherapy against placebo. CAFÉ (NCT02755649) and CHRONOS (NCT02260986) evaluated dupilumab with concomitant topical corticosteroids (TCS) against TCS alone for 16 and 52 weeks, respectively. RESULTS: 2,444 patients randomized to treatment in SOLO 1 and 2 (N = 1,379), CAFÉ (N = 325) and CHRONOS (N = 740) were analyzed. Dupilumab treatment significantly improved overall SCORAD and individual components as early as Week 1 or 2, with significant and clinically meaningful differences vs. control through end of treatment (p < .0001). These results occurred irrespective of dupilumab regimen, 300 mg subcutaneously weekly or every 2 weeks. CONCLUSIONS: In four large phase 3 trials in adults with moderate-to-severe AD, dupilumab treatment with or without concomitant TCS resulted in rapid and sustained improvements in all SCORAD outcomes vs. placebo or TCS alone.

Development and validation of a photonumeric grading scale for assessing lip volume and thickness.

BACKGROUND: Currently, there is the need of a validated grading scale for assessing lip volume/thickness. OBJECTIVE: The aim of this study was to assist clinicians in managing individuals seeking lip rejuvenation and to provide an objective method for evaluating the efficacy and longevity of such treatments. METHODS: Using accepted criteria for the development of dermatological grading scales, we have developed and validated a photographic grading scale for assessing lip volume and thickness based on digital parallel-polarized light imaging. RESULTS: The photographic grading scale was shown to be a valid and reliable instrument for assessing lip volume and thickness, with good inter- and intra-grader consistency. The validity of the scale was demonstrated by its correlation with clinical evaluation and 3-dimensional measurements. CONCLUSIONS: This validated lip-volume/thickness grading scale should prove helpful in clinical trial settings to standardize clinical evaluations and to quantify results and measure the longevity of dermal fillers and other procedures for lip rejuvenation.

A pilot methodology study for the photographic assessment of post-inflammatory hyperpigmentation in patients treated with tretinoin.

BACKGROUND: Post-inflammatory hyperpigmentation (PIH) is a common occurrence in patients with acne vulgaris, particularly in those with skin of colour. AIMS: A previous study has demonstrated the benefit of tretinoin (retinoic acid) in the treatment of PIH; however, there is currently no standard protocol to evaluate change in PIH following treatment. Based on these findings, we performed a pilot, exploratory, blinded, intraindividual-controlled methodology study that consisted of a photographic assessment protocol with facial mapping. MATERIALS AND METHODS: The study was based on a secondary analysis of a phase 4, community-based trial of 544 acne patients who were treated with tretinoin gel microsphere 0.04% or 0.1%. Only patients with Fitzpatrick types III-V (skin of colour) were included in the study; subjects with Fitzpatrick skin type VI were excluded because the photographic assessment did not allow for proper evaluation. RESULTS: Despite the small number of subjects evaluated (n=25), the results revealed consistent assessment of improvement in PIH between two independent graders (weighted κ=0.84). CONCLUSION: Further study with a larger population is recommended to validate the accuracy of this method.

Control of atopic eczema with pimecrolimus cream 1% under daily practice conditions: results of a > 2000 patient study.

BACKGROUND: Pimecrolimus cream 1% has been shown to effectively control atopic eczema (AE) when applied twice daily from the first signs or symptoms of AE until clearance. Moreover, pimecrolimus cream 1% has a favourable safety profile, lacking topical corticosteroid-related side-effects such as skin atrophy, making it particularly useful to treat delicate body regions (e.g. the face). OBJECTIVE: The objective of this naturalistic study was to monitor the safety, tolerability and efficacy of pimecrolimus when used in the long-term management of AE in a real-life setting. METHODS: A multicentre, open-label study was conducted in 2034 patients aged >or= 3 months with mild to moderate AE for up to 12 months' duration. Patients applied pimecrolimus cream twice daily, initiating treatment at first signs or symptoms of AE, continuing until clearance. RESULTS: Patients (n= 1847; 91%) completed 3 months of the study. Treatment success (clear or almost clear AE) after 3 months of treatment was observed on the whole body in 59% of patients and on the face in 81% of patients. Disease improvement of whole body and face was seen in 77% and 63% of patients, respectively. Pruritus was absent or mild in 79% of patients. Pimecrolimus cream was well tolerated throughout the study. CONCLUSION: In a daily practice setting, pimecrolimus cream 1% effectively and safely controls AE.

Rab37 is a novel mast cell specific GTPase localized to secretory granules.

GTPases regulate a myriad of cellular functions including signal transduction, cytoskeletal organization and membrane trafficking. Rab GTPases act to coordinate the membrane dynamics of cells by organizing and regulating the activity of effector proteins important in vesicle trafficking. Rab37 is a novel Rab GTPase specifically expressed in the MC-9 mast cell line and bone marrow mast cells. Rab37 is 74% identical to Rab26 and 47% identical to Rab8, a GTPase important in Golgi to plasma membrane vesicle trafficking in mammalian cells. When green fluorescent protein tagged Rab37 is expressed in bone marrow mast cells, the secretory granules are labeled. These data suggest that Rab37 may play an important role in mast cell degranulation making this protein a potentially important target for therapeutic intervention in the treatment of allergy.

Use of autologous fibrin glue in dermatologic surgery: application of skin graft and second intention healing.

OBJECTIVE: To evaluate the efficiency of biological sealant, an autologous fibrin glue, in dermatological surgery. DESIGN: Randomized clinical trial. SETTING: The Dermatology Service of Hospital das Clinicas, Universidade de Campinas (UNICAMP), referral center. PATIENTS: 14 patients with malign epithelial cutaneous tumors participated in the evaluation, each having two tumors, generally facial and symmetrical, in order to perform a comparative evaluation on the same individual. PROCEDURES: The glue was prepared beforehand with a sample of autologous blood. Surgical extirpation of the tumor was followed by grafts or second intention healing. OUTCOMES: The efficiency of the sealant was then evaluated in relation to hemostasis, adhesion, surgical time and evolution of the granulation tissue, clinically and histologically. RESULTS: Immediate hemostasis and graft adhesion, with a significant reduction of surgical time, and in the open wounds there was immediate hemostasis and a clinical increase in granulation tissue, but with no histological differences among the groups on the 7th day. CONCLUSION: It is an adjuvant resource in skin cancer surgery.

Cellulite: a review.

Gynoid lipodystrophy (cellulite) is an extremely controversial topic. A lack of knowledge regarding specific aetiopathogenic factors, as well as the opportunism of some professionals and the media, has fuelled debate regarding the scientific basis of this condition. This article reviews the clinical, epidemiological, histopathological and therapeutic aspects of cellulite.

Expression of functional mouse muscle acetylcholine receptors in Chinese hamster ovary cells.

CHO cells were transfected with cDNAs for all 4 subunits of the mouse muscle acetylcholine receptor (AChR) to obtain a stable cell line (CHO-AR) expressing the AChR on its surface. Immunoprecipitation experiments established that the AChR contained alpha- and beta-subunits assembled with gamma- and/or delta-subunits. In addition, one of the toxin-binding sites of the AChR was blocked by a myasthenic serum that specifically recognizes AChR containing the gamma-subunit. AChR from the CHO-AR cells had the same sedimentation rate, association rate constant for the binding of alpha-bungarotoxin (alpha BTX), and the same metabolic half-life as the AChR in myotubes of the mouse muscle cell line C2C12. Electrophysiological assay of CHO-AR cells by single-channel recording showed the presence of ACh-responsive ion channels with the characteristics of the embryonic AChR (gamma = 40 pS, tau = 5.6 msec). In some patches a smaller conductance channel was also seen that may represent partially assembled receptor. Fluorescence microscopy of fixed, permeabilized cells stained with rhodamine-alpha-BTX demonstrated both perinuclear and diffuse surface staining. The expression of fully assembled, functional mammalian muscle AChR in nonmuscle cells will allow detailed investigation of its properties and interactions with other cellular components.

Optimization of regulated LTR-mediated expression.

Retroviral vectors are ideally suited to the study of gene function, allowing efficient, stable expression. Many biological systems (e.g., cell cycle, apoptosis) require the use of regulated expression systems. We therefore developed a regulated retroviral vector system, TRA99, based on a tetracycline transactivator-dependent LTR, where the MMLV enhancer was replaced with a tetracycline-response element. Using fluorescence-activated flow cytometric analysis of a destabilized green fluorescent protein to monitor expression levels, we optimized the minimal promoter configuration with respect to both activated and repressed transcription. The TRA99 vectors demonstrate regulated expression with activated levels comparable to those of standard retroviral vectors and repressed levels indistinguishable from background. This was achieved without using an internal promoter cassette, thus retaining the cis-packaging elements requisite for helper-mediated transfer.

Human bleomycin hydrolase: molecular cloning, sequencing, functional expression, and enzymatic characterization.

We have cloned the cDNA of human bleomycin hydrolase (hBH), a protease which is thought to be involved in the metabolic inactivation of the antineoplastic drug bleomycin. The open reading frame consists of 1365 base pairs and is predicted to encode a 52 kDa protein. The protein shares 40% identity with yeast bleomycin hydrolase and contains the conserved active site residues (Cys, His, Asn) characteristic for cysteine proteases of the papain superfamily. Human bleomycin hydrolase has been functionally expressed in Spodoptera frugiperda Sf9 cells using the Autographa californica nuclear polyhedrosis virus. The 52 kDa recombinant protein forms a hexamer of 310 kDa and acts strictly as an aminopeptidase with a broad substrate specificity. The lack of a leader sequence and its pH optimum at 7.2 suggest a cytosolic/nuclear localization. Human bleomycin hydrolase was detected at low to moderate expression levels in most of the human organs tested. Significantly higher RNA levels have been observed in a variety of tumor cell lines. The human enzyme effectively degrades both forms of bleomycin (A2 and B2) in vitro and could indeed be responsible for the resistance of various tumors to this widely used anticancer drug.