Inhaled dry powder cisplatin increases antitumour response to anti-PD1 in a murine lung cancer model.

Despite advances in targeted therapies and immunotherapy in lung cancer, chemotherapy remains the backbone of treatment in most patients at different stages of the disease. Inhaled chemotherapy is a promising strategy to target lung tumours and to limit the induced severe systemic toxicities. Cisplatin dry powder for inhalation (CIS-DPI) was tested as an innovative way to deliver cisplatin locally via the pulmonary route with minimal systemic toxicities. In vivo, CIS-DPI demonstrated a dose-dependent antiproliferative activity in the M109 orthotopic murine lung tumour model and upregulated the immune checkpoint PD-L1 on lung tumour cells. Combination of CIS-DPI with the immune checkpoint inhibitor anti-PD1 showed significantly reduced tumour size, increased the number of responders and prolonged median survival over time in comparison to the anti-PD1 monotherapy. Furthermore, the CIS-DPI and anti-PD1 combination induced an intra-tumour recruitment of conventional dendritic cells and tumour infiltrating lymphocytes, highlighting an anti-tumour immune response. This study demonstrates that combining CIS-DPI with anti-PD1 is a promising strategy to improve lung cancer therapy.

Optimization of Long-Acting Bronchodilator Dose Ratios Using Isolated Guinea Pig Tracheal Rings for Synergistic Combination Therapy in Asthma and COPD.

The co-administration of a long-acting ß2-agonist (LABA), and a long-acting muscarinic antagonist (LAMA), has been shown to be beneficial in the management of non-communicable chronic respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD). The resulting relaxation of the airways can be synergistically enhanced, reducing symptoms and optimizing lung function. This provides an insight into more effective treatments. In this study, the LABAs formoterol fumarate dihydrate (FOR) and indacaterol maleate (IND) were each associated with tiotropium bromide monohydrate (TIO) to assess their synergistic potential. This was done using an appropriate ex vivo model of isolated perfused guinea pig tracheal rings, and pharmacological models of drug interaction. Among the dose ratios studied for both types of combination, a higher synergistic potential was highlighted for FOR/TIO 2:1 (w/w). This was done through three steps by using multiple additions of drugs to the organ baths based on a non-constant dose ratio and then on a constant dose ratio, and by a single addition to the organ baths of specific amounts of drugs. In this way, the synergistic improvement of the relaxant effect on the airways was confirmed, providing a basis for improving therapeutic approaches in asthma and COPD. The synergy found at this dose ratio should now be confirmed on a preclinical model of asthma and COPD by assessing lung function.

Development of Neutralizing Multimeric Nanobody Constructs Directed against IL-13: From Immunization to Lead Optimization.

IL-13 is a pleiotropic cytokine mainly secreted by Th2 cells. It reacts with many different types of cells involved in allergy, inflammation, and fibrosis, e.g., mastocytes, B cells, and fibroblasts. The role of IL-13 in conditions involving one or several of these phenotypes has therefore been extensively investigated. The inhibition of this cytokine in animal models for various pathologies yielded highly promising results. However, most human trials relying on anti-IL-13 conventional mAbs have failed to achieve a significant improvement of the envisaged disorders. Where some studies might have suffered from several weaknesses, the strategies themselves, such as targeting only IL-13 using conventional mAbs or employing a systemic administration, could be questioned. Nanobodies are recombinant Ag-binding fragments derived from the variable part of H chain-only Abs occurring in Camelidae. Thanks to their single-domain structure, small size (≈15 kDa), good stability, and solubility, they can be engineered into multispecific constructs for combined therapies or for use in new strategies such as formulations for local administration, e.g., pulmonary administration. In this study, we describe the generation of 38 nanobodies that can be subdivided into five CDR3 families. Nine nanobodies were found to have a good affinity profile (KD = 1-200 nM), but none were able to strongly inhibit IL-13 biological activity in vitro (IC50 > 50 µM: HEK-Blue IL-13/IL-4 cells). Multimeric constructs were therefore designed from these inhibitors and resulted in an up to 36-fold improvement in affinity and up to 300-fold enhancement of the biological activity while conserving a high specificity toward IL-13.

A Design of Experiment Approach to Optimize Spray-Dried Powders Containing Pseudomonas aeruginosaPodoviridae and Myoviridae Bacteriophages.

In the present study, we evaluated the effect of spray-drying formulations and operating parameters of a laboratory-scale spray-dryer on the characteristics of spray-dried powders containing two Pseudomonas aeruginosa bacteriophages exhibiting different morphotypes: a podovirus (LUZ19) and a myovirus (14-1). We optimized the production process for bacteriophage-loaded powders, with an emphasis on long-term storage under ICH (international conference on harmonization) conditions. D-trehalose-/L-isoleucine-containing bacteriophage mixtures were spray-dried from aqueous solutions using a Büchi Mini Spray-dryer B-290 (Flawil, Switzerland). A response surface methodology was used for the optimization of the spray-drying process, with the following as-evaluated parameters: Inlet temperature, spray gas flow rate, and the D-trehalose/L-isoleucine ratio. The dried powders were characterized in terms of yield, residual moisture content, and bacteriophage lytic activity. L-isoleucine has demonstrated a positive impact on the activity of LUZ19, but a negative impact on 14-1. We observed a negligible impact of the inlet temperature and a positive correlation of the spray gas flow rate with bacteriophage activity. After optimization, we were able to obtain dry powder preparations of both bacteriophages, which were stable for a minimum of one year under different ICH storage conditions (up to and including 40 °C and 75% relative humidity).

The combination of an innovative dry powder for inhalation and a standard cisplatin-based chemotherapy in view of therapeutic intensification against lung tumours.

Cisplatin is one of the most commonly used chemotherapy in lung cancer despite its high nephrotoxicity leading to an administration only every 3-4 weeks. This study is the first report of a preclinical investigation of therapeutic intensification combining a cisplatin dry powder for inhalation (CIS-DPI) with an intravenous (iv) cisplatin-based treatment. CIS-DPI with 50% cisplatin content (CIS-DPI-50) was developed using lipid excipients through scalable processes (high-speed and high-pressure homogenization and spray-drying). CIS-DPI-50 showed good aerodynamic performance (fine particle fraction of ~ 55% and a mass median aerodynamic particle size of ~ 2 µm) and a seven-fold increase and decrease in Cmax in the lungs and in plasma, respectively, in comparison with an iv cisplatin solution (CIS-iv) in healthy mice. Finally, the addition of CIS-DPI-50 to the standard cisplatin/paclitaxel iv doublet increased the response rate (67% vs 50%), decreased the tumour growth and prolonged the median survival (31 vs 21 days), compared to the iv doublet in the M109 lung carcinoma model tending to demonstrate a therapeutic intensification of cisplatin.

Drug-related problems and risk factors related to unplanned hospital readmission among cancer patients in Belgium.

INTRODUCTION: There are about 60,000 diagnoses of cancer per year in Belgium. After hospital care, about 12-13% of cancer patients are readmitted within 30 days after discharge. These readmissions are partly related to drug-related problems (DRP), such as interactions or adverse drug effects (ADE). OBJECTIVES: The aim of this study is to quantify and to classify DRP readmissions within 30 days for cancer patients and to highlight risk factors potentially correlated to readmissions. METHODS: This study is a 6-month observational retrospective study in two care facilities in Brussels: an academic general hospital and an academic oncology center. Patients readmitted within 30 days after their last hospital care for a potential DRP were included. Patient files were evaluated with an intermediate medication review that included interactions analysis (Lexicomp®). The probability of DRP readmission was assessed using the World Health Organization's Uppsala Monitoring Centre (WHO-UMC) system. RESULTS: The final population included 299 patients; among them, 123 (41.1%) were readmitted due to DRP (certain DRP (4.9%), probable DRP (49.6%), and possible DRP (45.5%)). Risks factors linked to these DRP were a low Charlson Comorbidity Index, polypharmacy, the kind of hospital, and some chemotherapies (platinum preparations). Among all readmitted patients, the D-type interactions were the most common (44.8%), which suggest a possible therapy modification. However, around 10% of interactions were X-type (drug combination to avoid). CONCLUSION: Almost 10% of patient readmitted within 30 days were potentially related to a DRP, most of them from adverse drug effects. Four risk factors (low Charlson Comorbidity Index, polypharmacy, the hospital, and some chemotherapies) were highlighted to prevent these readmissions.

Inhaled cytotoxic chemotherapy: clinical challenges, recent developments, and future prospects.

INTRODUCTION: Since 1968, inhaled chemotherapy has been evaluated and has shown promising results up to phase II but has not yet reached the market. This is due to technological and clinical challenges that require to be overcome with the aim of optimizing the efficacy and the tolerance of drug to re-open new developments in this field. Moreover, recent changes in the therapeutic standard of care for treating the patient with lung cancer also open new opportunities to combine inhaled chemotherapy with standard treatments. AREAS COVERED: Clinical and technological concerns are highlighted from the reported clinical trials made with inhaled cytotoxic chemotherapies. This work then focuses on new pharmaceutical developments using dry powder inhalers as inhalation devices and on formulation strategies based on controlled drug release and with sustained lung retention or based on nanomedicine. Finally, new clinical strategies are described in regard to the impact of the immunotherapy on the patient's standard of care. EXPERT OPINION: The choice of the drug, inhalation device, and formulation strategy as well as the position of inhaled chemotherapy in the patient's clinical care are crucial factors in optimizing local tolerance and efficacy as well as in its scalability and applicability in clinical practice.

Deciphering the chemical instability of sphaeropsidin A under physiological conditions - degradation studies and structural elucidation of the major metabolite.

The fungal metabolite sphaeropsidin A (SphA) has been recognised for its promising cytotoxicity, particularly towards apoptosis- and multidrug-resistant cancers. Owing to its intriguing activity, the development of SphA as a potential anticancer agent has been pursued. However, this endeavour is compromised since SphA exhibits poor physicochemical stability under physiological conditions. Herein, SphA's instability in biological media was explored utilizing LC-MS. Notably, the degradation tendency was found to be markedly enhanced in the presence of amino acids in the cell medium utilized. Furthermore, the study investigated the presence of degradation adducts, including the identification, isolation and structural elucidation of a major degradation metabolite, (4R)-4,4',4'-trimethyl-3'-oxo-4-vinyl-4',5',6',7'-tetrahydro-3'H-spiro[cyclohexane-1,1'-isobenzofuran]-2-ene-2-carboxylic acid. Considering the reduced cytotoxic potency of aged SphA solutions, as well as that of the isolated degradation metabolite, the reported antiproliferative activity has been attributed primarily to the parent compound (SphA) and not its degradation species. The fact that SphA continues to exhibit remarkable bioactivity, despite being susceptible to degradation, motivates future research efforts to address the challenges associated with this instability impediment.

Feasibility study into the potential use of fused-deposition modeling to manufacture 3D-printed enteric capsules in compounding pharmacies.

The purpose of this work was to investigate the feasibility to manufacture enteric capsules, which could be used in compounding pharmacies, by fused-deposition modeling. It is well-known that conventional enteric dip coating of capsules in community pharmacies or hospitals is a time-consuming process which is characterized by an erratic efficacy. Fused-deposition modeling was selected as a potential 3D printing method due its ease and low-cost implementation. Before starting to print the capsules, an effective sealing system was designed via a computer-aided design program. Hot melt extrusion was used to make printable enteric filaments. They were made of the enteric polymer, a plasticizer and a thermoplastic polymer, namely Eudragit® L100-55, polyethylene glycol 400 and polylactic acid, respectively. Riboflavine-5'-phosphate was selected as a coloured drug model to compare the efficacy of the 3D printed capsules to that of enteric dip coated capsules as they are currently produced in community pharmacies and hospitals. Different parameters of fabrication which could influence the dissolution profile of the model drug, such as the layer thickness or post-processing step, were studied. It was demonstrated that our 3D printed enteric capsules did not release the drug for 2 h in acid medium (pH 1.2). However, they completely dissolved within 45 min at pH 6.8 which allowed the release of a minimal amount of 85% w/w of drug as it was recommended by the European Pharmacopoeia 9th Edition for enteric products.

Development of PLGA microparticles with high immunoglobulin G-loaded levels and sustained-release properties obtained by spray-drying a water-in-oil emulsion.

In this study, the possibility of producing highly antibody-loaded microparticles with sustained-release properties was evaluated. Polyclonal immunoglobulin G (IgG) was used as a model of antibody and its encapsulation into poly(lactide-co-glycolide) acid (PLGA) microparticles was performed by spray-drying a water-in-oil (w/o) emulsion. It was demonstrated that the use of the Resomer® RG505 PLGA allowed an IgG loading of 20% w/w with an encapsulation efficiency higher than 85%. The produced microparticles were characterized by a mean diameter lower than 10 µm. The burst effect was shown to reach a maximal value of 40%. IgG stability after encapsulation was also assessed. The use of this single PLGA provided a lag time of 3 months which dramatically slowed down the release rate after the initial release of the encapsulated IgG. Using blends of PLGA characterized by different inherent viscosities allowed decreasing the lag time and modulating the dissolution profile of the IgG from the spray-dried microparticles. Therefore, spray-drying a water-in-oil emulsion appeared to be a promising strategy to produce highly antibody-loaded microparticles characterized by sustained-release properties.

Development and evaluation of an omeprazole-based delayed-release liquid oral dosage form.

Modified-release oral dosage forms are commonly used in pharmaceutics to delay or sustain the release of drugs. Nowadays, they are only marketed as solid dosage forms such as capsules or tablets. Therefore, the development of a liquid oral dosage form with modified-release properties has been keenly awaited to increase the compliance of patients with a swallowing impairment, such as paediatric, older or critically ill patients. In this study, a new technology has been developed that consists of multi-layered particles suspended extemporaneously in a syrup, using omeprazole as a model drug. The coating procedure was optimized to obtain a yield of minimum 90% w/w and a mean diameter below 500 µm. Eudragit® E100 and Eudragit® L100-55 were used to prevent the early release of omeprazole in the syrup and in the acidic environment of the stomach, respectively. These polymers allowed the stability of the coated particles to be ensured when dispersed in a liquid and the enteric release of the drug to be targeted. It was demonstrated that our new system presented similar release performances to existing marketed enteric dosage forms. It is able to protect omeprazole for 2 h in acidic medium at pH 1.2, while omeprazole was entirely released at pH 6.8 within 45 min. Once the final suspension is prepared extemporaneously, it presents sufficient stability to guarantee the administration of multiple doses filled into a syrup bottle and kept for a limited storage time at room temperature (e.g. up to 10 doses to be administered within 10 days).

The Position of Inhaled Chemotherapy in the Care of Patients with Lung Tumors: Clinical Feasibility and Indications According to Recent Pharmaceutical Progresses.

Despite new treatment modalities, including targeted therapies and checkpoint inhibitors, cytotoxic chemotherapy remains central in the care of patients with lung tumors. Use of the pulmonary route to deliver chemotherapy has been proved to be feasible and safe in phase I, Ib/IIa and II trials for lung tumors, with the administration of drug doses to the lungs without prior distribution in the organism. The severe systemic toxicities commonly observed with conventional systemic chemotherapy are consequently reduced. However, development has failed in phase II at best. This review first focuses on the causes of failure of inhaled chemotherapy. It then presents new promising technologies able to take up the current challenges. These technologies include the use of a dry powder inhaler or a smart nebulizer with advanced drug formulations such as controlled-release formulations and nanomedicine. Finally, the potential position of inhaled chemotherapy in patient care is discussed and some indications are proposed based on the literature.

How to characterize a nasal product. The state of the art of in vitro and ex vivo specific methods.

Nasal delivery offers many benefits over other conventional routes of delivery (e.g. oral or intravenous administration). Benefits include, among others, a fast onset of action, non-invasiveness and direct access to the central nervous system. The nasal cavity is not only limited to local application (e.g. rhinosinusitis) but can also provide direct access to other sites in the body (e.g. the central nervous system or systemic circulation). However, both the anatomy and the physiology of the nose impose their own limitations, such as a small volume for delivery or rapid mucociliary clearance. To meet nasal-specific criteria, the formulator has to complete a plethora of tests, in vitro and ex vivo, to assess the efficacy and tolerance of a new drug-delivery system. Moreover, depending on the desired therapeutic effect, the delivery of the drug should target a specific pathway that could potentially be achieved through a modified release of this drug. Therefore, this review focuses on specific techniques that should be performed when a nasal formulation is developed. The review covers both the tests recommended by regulatory agencies (e.g. the Food and Drug Administration) and other complementary experiments frequently performed in the field.

Implementation study of an interprofessional medication adherence program for HIV patients in Switzerland: quantitative and qualitative implementation results.

BACKGROUND: An interprofessional medication adherence program (IMAP) for chronic patients was developed and successfully implemented in the community pharmacy of the Department of ambulatory care and community medicine (Lausanne, Switzerland). This study assesses the capacity of a physician and a nurse at the infectious diseases service of a public hospital and of community pharmacists in the Neuchâtel area (Switzerland) to implement the IMAP in their practice. METHODS: Mixed method, prospective, observational study. Quantitative and qualitative analyses of the implementation process were conducted following the RE-AIM model (reach, effectiveness, adoption, implementation and maintenance). RESULTS: Implementation started in November 2014. One physician, one nurse, and five pharmacists agreed to participate. Healthcare professionals perceived the benefits of the program and were motivated to implement it in their practice (adoption). Seventeen patients were included in the program; 13 refused to participate. The inclusion of naïve HIV patients was easier than the inclusion of experienced patients with difficult psychosocial issues (reach). Pharmacists were engaged in reinforcing patient medication adherence in 25% of interviews (effectiveness). Key facilitators expressed by healthcare professionals were patient inclusion by the physician and the nurse instead of the pharmacist and the organisation of regular meetings between all stakeholders. In contrast, the encountered barriers were the lack of time and resources, the lack of team uptake, and the lack of adoption by senior managers (implementation). Interviewed patients were all satisfied with this new program, encouraging healthcare professionals to scale it up. Structural changes allowed the hospital and one pharmacy to enter the maintenance stage (maintenance). CONCLUSION: The research team and collaboration between all professionals involved played an important role in this implementation. However, the dissemination of such a program to a larger scale and for the long term requires financial and structural resources as well as transitional external support.

Impact of capsule type on aerodynamic performance of inhalation products: A case study using a formoterol-lactose binary or ternary blend.

The aerodynamic performance of a dry powder for inhalation depends on the formulation and the dry powder inhaler (DPI). In the case of capsule-based DPIs, the capsule also plays a role in the powder aerosolisation and the dispersion of the micronized drug during the inhalation. This study evaluated the impact of gelatine capsules (Quali-G™ and Hard Gelatine Capsules for DPIs), cold-gelled hypromellose (HPMC) capsules (Quali-V®-I and Vcaps®) and thermal-gelled HPMC capsules (Vcaps®Plus) from Qualicaps® and Capsugel® respectively, on the delivered dose (DD), fine particle dose (FPD), and capsule retention for formoterol-lactose binary and ternary blends. This study used a low resistance Axahaler® DPI based on the RS01 design (Plastiape, Italy). Similar trends were observed with the different capsule types that packaged both dry powder formulations. The highest DD and FPD and the lowest formoterol capsule retention were observed with cold-gelled HPMC capsules such as Quali-V-I® and Vcaps®, without significant differences between these capsules (p > 0.05, one-way ANOVA with Newman-Keuls post-hoc test) for both dry powders. Therefore, the capsule composition and manufacturing process have an influence on aerodynamic performance. In addition, the ternary blend showed higher DDs and FPDs but also higher capsule retention in comparison to the binary blend.

Implementation of an interprofessional medication adherence program for HIV patients: description of the process using the framework for the implementation of services in pharmacy.

BACKGROUND: The community pharmacy center of the Department of Ambulatory Care and Community Medicine of the Policlinique Médicale Universitaire (PMU), Lausanne, Switzerland developed and implemented an interprofessional medication adherence program for chronic patients (IMAP). In 2014, a project was launched to implement the IMAP for HIV patients in a public non-academic hospital with the collaboration of community pharmacists in the Neuchâtel area (Switzerland). This article aims to describe the different implementation stages and strategies of the project. METHODS: A posteriori description of the implementation process, including the conceptualization strategies and stages (exploration, preparation, operation, sustainability) using the Framework for the Implementation of Services in Pharmacy (FISpH). RESULTS: In 2014, an attending infectious disease physician and a nurse at a public hospital (Neuchâtel, Switzerland) contacted the PMU to implement the IMAP in their setting in collaboration with community pharmacies. Five volunteer community pharmacies in Neuchâtel were trained to deliver the program. Three factors were found to be essential to the successful launch and progress of the implementation project: the experience of the community pharmacy center of the PMU with the IMAP, the involvement of the PMU research team, and collaboration with an external start up (SISPha) to train and support pharmacists. During the operation stage, the most important strategy developed was that of regular meetings between all stakeholders. These allowed healthcare professionals to discuss the implementation progress, to address each stakeholder's expectations, and to exchange experiences to facilitate interprofessional collaboration and program delivery. Structural changes allowed the formalization of the activities at the hospital and in a community pharmacy. This formalization was identified as the transition step between the operation and the sustainability stages. CONCLUSIONS: The transfer of the IMAP for HIV patients to a non-academic setting and its implementation are feasible. However, implementation of a new model of pharmacy service such as IMAP implies a deep change in practice. A transitional external support and the allocation of sufficient resources to carry out the IMAP are essential for its long-term sustainability.

Chitosan-coated liposome dry-powder formulations loaded with ghrelin for nose-to-brain delivery.

The nose-to-brain delivery of ghrelin loaded in liposomes is a promising approach for the management of cachexia. It could limit the plasmatic degradation of ghrelin and provide direct access to the brain, where ghrelin's specific receptors are located. Anionic liposomes coated with chitosan in either a liquid or a dry-powder formulation were compared. The powder formulation showed stronger adhesion to mucins (89 ±â€¯4% vs 61 ±â€¯4%), higher ghrelin entrapment efficiency (64 ±â€¯2% vs 55 ±â€¯4%), higher enzymatic protection against trypsin (26 ±â€¯2% vs 20 ±â€¯3%) and lower ghrelin storage degradation at 25 °C (2.67 ±â€¯1.1% vs 95.64 ±â€¯0.85% after 4 weeks). The powder formulation was also placed in unit-dose system devices that were able to generate an appropriate aerosol characterized by a Dv50 of 38 ±â€¯6 µm, a limited percentage of particles smaller than 10 µm of 4 ±â€¯1% and a reproducible mass delivery (CV: 1.49%). In addition, the device was able to deposit a large amount of powder (52.04% w/w) in the olfactory zone of a 3D-printed nasal cast. The evaluated combination of the powder formulation and the device could provide a promising treatment for cachexia.

Evaluation of compliance with isotretinoin PPP recommendations and exploration of reasons for non-compliance: Survey among French-speaking health care professionals and patients in Belgium.

PURPOSE: To evaluate awareness of and compliance in Belgium by French-speaking health care professionals and patients with the isotretinoin safety recommendations regarding its teratogenic risk. METHOD: Survey using online questionnaires, delivered from December 2014 to March 2015 for patients, pharmacists, dermatologists, and GPs and delivered again from September 2015 to October 2015 for GPs. RESULTS: Questionnaires were completed by 24 dermatologists, 24 GPs, 58 pharmacists, and 33 female patients. The pregnancy prevention programme was poorly known by health care professionals (23.6%) and patients (15.2%). Health care professionals informed women of childbearing age in depth about the teratogenic risk (98.3% of pharmacists and 100.0% of GPs and dermatologists) and the importance of an effective contraceptive method (87.9% and 100.0%, respectively). Patients were less informed about the pregnancy test (25.9% and 14.6%) and the need to use a second contraceptive method (29.3% and 27.1%). The low compliance with the last 2 recommendations was due to a lack of adoption by health care professionals regarding the need for these recommendations if female patients have an effective contraceptive method and the pregnancy risk is discussed in detail with them. CONCLUSION: The effectiveness of the pregnancy prevention programme recommendations should be reconsidered by an expert committee. Justifications should be added to effective recommendations to increase their adoption by health care professionals and patients.

Assessment of medication adherence and responsible use of isotretinoin and contraception through Belgian community pharmacies by using pharmacy refill data.

PURPOSE: The aims of the study were to evaluate medication adherence and the influencing factors for isotretinoin and contraception (oral, patches, and rings) and to evaluate the concomitant use of contraception and isotretinoin. METHODS: Reimbursed prescription data from January 2012 to August 2015 of all patients in Belgium were received from Pharmanet-National Institute for Health and Disability Insurance. Medication adherence was measured according to the medication possession ratio. The influence of gender and age was analyzed using the Mann-Whitney test and the Spearman coefficient correlation. The independence between adherence to contraception and adherence to isotretinoin was analyzed using the Pearson chi-square test of independence. Persistence was defined as the number of days between initiation and presumed end of treatment. The Kaplan-Meier method was used to plot the medication persistence curves, and the log-rank test was used to compare the curves. The concomitant use of contraception and isotretinoin was analyzed using descriptive statistics. RESULTS: The medication possession ratio was ≥0.8 for 46.1% of patients receiving isotretinoin and for 74.0% of women using contraception. For isotretinoin, this percentage decreased as the number of attempts increased (29.8% for the second attempt and 19.8% for more than two attempts). Men seemed more adherent than women, and a weak negative correlation between adherence and age was observed. The adherence data of isotretinoin and contraception were independent. The median persistence for isotretinoin treatment was 139 days (interquartile range 71-209) and was higher for men. Among women between 12 and 21 years old taking isotretinoin, 63.8% received at least one contraceptive prescription. However, 15.7% of women taking isotretinoin adhered to the use of contraception 1 month before, during, and 1 month after treatment. CONCLUSION: Medication adherence to isotretinoin and contraception and compliance with the isotretinoin safety recommendation could be improved. Health service interventions, using pharmacy refill data, should be delivered to ensure patient safety and strict adherence to contraception when under isotretinoin treatment.