Inadequate response to imatinib treatment in chronic myeloid leukemia due to a drug interaction with phenytoin.

Imatinib mesylate and the newer BCR-ABL tyrosine kinase inhibitors are the standard therapy for chronic myeloid leukemia. Although these are remarkably effective drugs, some mechanisms of resistance have been identified including drug-to-drug interactions. Here we present the case of a chronic myeloid leukemia patient with an inadequate response to imatinib due to concurrent phenytoin administration. Conspicuously low imatinib plasma trough levels were documented. Imatinib dose was increased from 400 to 800 mg with good response. In conclusion, drug-to-drug interactions should be ruled out in cases of resistance to tyrosine kinase inhibitor treatment. Potent inducers of cytochrome P450 isoenzyme CYP3A4, as phenytoin, could induce inadequate responses due to increased imatinib clearance and low imatinib trough plasma levels. Thus, this interaction should be avoided. When this is not possible, dose escalation of imatinib and measurement of plasma levels, if available, is recommended.

Eosinophilia secondary to lenalidomide therapy.

WHAT IS KNOWN AND OBJECTIVE: Limited data are available on eosinophilia as a drug adverse event. We describe a case of eosinophilia from lenalidomide therapy. CASE DESCRIPTION: A 50-year-old woman received lenalidomide, dexamethasone and cyclophosphamide as POEMS syndrome treatment. Eosinophil count rose during lenalidomide treatment and decreased in the periods off treatment. Naranjo nomogram suggested a probable association between the use of lenalidomide and eosinophilia. WHAT IS NEW AND CONCLUSION: Eosinophilia has rarely been described with lenalidomide. This case shows a clear temporal relationship between lenalidomide and eosinophilia.

Pharmacotherapy follow-up of key points in the safety of oral antineoplastic agents.

We assessed the impact of a pharmacotherapy follow-up programme on key safety points [adverse events (AE) and drug administration] in outpatients treated with oral antineoplastic agents (OAA). We performed a comparative, interventional, quasi-experimental study of outpatients treated with OAA in a Spanish hospital to compare pre-intervention group patients (not monitored by pharmacists during 2011) with intervention group patients (prospectively monitored by pharmacists during 2013). AE data were collected from medical records. Follow-up was 6 months, and 249 patients were included (pre-intervention, 115; intervention, 134). After the first month, AE were detected in 86.5% of patients in the pre-intervention group and 80.6% of patients in the intervention group, P = 0.096. During the remaining months, 79.0% patients had at least one AE in the pre-intervention group compared with 78.0% in the intervention group, P = 0.431. AE were more prevalent with sorafenib and sunitinib. In total, 173 drug interactions were recorded (pre-intervention, 80; intervention, 93; P = 0.045). Drug interactions were more frequent with erlotinib and gefitinib; food interactions were more common with sorafenib and pazopanib. Our follow-up of cancer outpatients revealed a reduction in severe AE and major drug interactions, thus helping health professionals to monitor the safety of OAA.

Impact of medication adherence on the effectiveness of deferasirox for the treatment of transfusional iron overload in myelodysplastic syndrome.

WHAT IS KNOWN AND OBJECTIVE: Regular blood transfusions in the management of myelodysplastic syndrome (MDS) often lead to iron overload. The main objective of this study was to evaluate the impact of medication adherence on the effectiveness of deferasirox for the treatment of transfusional iron overload in patients with MDS. Secondary objectives were to describe treatment effectiveness and safety in daily clinical practice. METHODS: A longitudinal, retrospective, observational study was carried out in a university hospital. The inclusion criteria were age over 18 years, MDS diagnosis and treatment with deferasirox for transfusion-dependent iron overload during the period of study (from January 2011 to April 2015). Treatment effectiveness was estimated by serum ferritin (SF), and adherence was measured by medication possession ratio (MPR). Clinically relevant analytical alterations during the treatment and reasons for treatment discontinuation were also assessed. RESULTS: Thirty-five patients were included in the study. Median SF at baseline was 1636 µg/L, and it decreased to 1399 µg/L during follow-up. The median adherence rate was 92%, although only 54·8% of the patients maintained deferasirox adherence ≥90% during the whole duration of treatment. Adherence rate was inversely correlated to SF (r = -0·288, P = 0·004). The median (p25, p75) duration of treatment was 11 (3·0, 37·8) months. The most common reasons for treatment discontinuation were renal toxicity (35%) and patient's death (25%). WHAT IS NEW AND CONCLUSION: Deferasirox's effectiveness, measured by the decrease in SF, was significantly better in adherent patients. The most frequent reason for treatment discontinuation was renal toxicity. Developing strategies to improve deferasirox treatment adherence and monitoring renal function in those patients should be key points in pharmaceutical care.

Increased INR after gefitinib and acenocoumarol co-administration.

INTRODUCTION: Drug interactions can cause many clinical problems, particularly when the drugs are administered in combination with anticancer agents. CASE REPORT: A patient required two hospitalizations due to risk of bleeding with altered INR probably due to an interaction between gefitinib and acenocoumarol, which resulted in the potentiation of the effect of the latter and acenocoumarol dose adjustment was needed. A causality assessment between the drug-drug interaction and the augmented INR was conducted according to Naranjo algorithm and was classified as a definite adverse drug reaction. CONCLUSIONS: Patient's management recommended is to closely monitor for changes in the effects of coumarin derivatives, if administered concomitantly with antineoplasic agents.

The treatment for primary immune thrombocytopenia with romiplostim in adult and paediatric patients: use experience at a Spanish university hospital.

WHAT IS KNOWN AND OBJECTIVE: Primary immune thrombocytopenia (ITP) is characterized by accelerated platelet destruction, as well as suboptimal platelet production. Thrombopoietin (TPO) receptor agonists bind to and activate human TPO receptor, and have been shown to increase platelet counts. In this study, we assessed the effectiveness and safety of long-term administration of TPO agonist romiplostim in adult and paediatric patients. METHODS: This is a retrospective observational study that included every ITP patient (adults and children) who received romiplostim since its inclusion in our institutional formulary. Data on patients' demographics, romiplostim doses, platelet counts, use of rescue medication and concurrent therapies were collected. Outcomes for effectiveness evaluation were proportion of patients who achieved a platelet response (platelet count >50 × 10(9) per litre and double the platelet count at baseline on any scheduled visit, excluding counts obtained within 8 weeks after receipt of rescue medications), proportion of patients who achieved a durable response (platelet responses during 6 or more weeks of the last 8 weeks of treatment), proportion of patients needing rescue medication, proportion of patients able to stop or reduce concurrent treatment and mean number of weekly platelet responses. Safety was assessed on the basis of the incidence of adverse events documented on the patients' medical records. RESULTS AND DISCUSSION: This study enrolled ten adults and four paediatric patients. None of the paediatric patients and one adult patient had been splenectomized (contraindicated in the other adults). In the adult population, eight achieved a response at least once during treatment, and 1 achieved a durable response. Four patients needed rescue medication (mostly intravenous immunoglobulins). Three patients were able to stop concurrent ITP therapies, and the mean number of weekly platelet responses was 6. All four paediatric patients achieved a response at least once during treatment, and three achieved durable responses. Three patients needed rescue medication. The only patient who was receiving concurrent ITP medication was able to stop it, and the mean number of weekly platelet responses was 25. No serious adverse events were registered during treatment in either population. WHAT IS NEW AND CONCLUSION: The effectiveness of romiplostim was variable with few adult patients achieving a durable response. Our paediatric patients responded better with most achieving a durable response. The treatment was safe for both groups of patients. Studies should be conducted to identify patients more likely to benefit from this treatment.

[Permanence of last generation antiretroviral in daily clinical practice]. / Permanencia del tratamiento antirretroviral de última generación en la práctica clínica diaria.

INTRODUCTION: Time of permanence is a useful measure of success in last generation antiretroviral (LGA) therapy: raltegravir, darunavir, etravirine and maraviroc. The aim of our study was to analyze the permanence of antiretroviral therapy (ART) containing at least one LGA, and to compare it with other ART used in experienced patients. METHODS: Observational case-control study. It included adult outpatients whose ART was switched between 01/05/2008 and 01/09/2009. Cases (patients with at least one LGA) were matched (1:1) with pretreated patients who switched to an ART without any LGA (controls). The primary endpoint was the permanence of ART. The follow-up was conducted from the modification of ART to a year after the closure of the inclusion period. Results were adjusted for confounding variables: CD4 and viral load (VL) at baseline, MDR HIV infection and time from the first ART. RESULTS: 112 patients were included in each group. The permanence of ART was 16.7 months (cases) vs 16.8 months (controls), although statistically significant differences were not found after adjusting for confounding variables. Toxicity was the main reason of discontinuation (53.3% in cases vs 45.2% in controls, p = 0.70). The mean decrease in the logarithm of the VL was 0.89 in cases and 0.58 in controls (p = 0.223). The increase of CD4/microL was 77 and 73 respectively (p = 0.480). CONCLUSION: The permanence of ART in patients whose treatment contains a LGA is similar to those without any LGA.

Introducción: La permanencia es una medida útil del éxito de los tratamientos antirretrovirales de última generación (AUG): raltegravir, darunavir, etravirina y maraviroc. El objetivo de nuestro estudio fue analizar la permanencia de los tratamientos antirretrovirales (TAR) que contenían al menos un AUG, y compararla con otros TAR utilizados en pacientes experimentados. Métodos: Estudio observacional, de casos y controles, de pacientes adultos externos cuyo TAR fue modificado entre 01/05/2008 y 01/09/2009. Los casos (pacientes con al menos un AUG) fueron emparejados (relación 1:1) con pacientes pretratados que cambiaron a un TAR sin AUG (controles). La variable principal fue la permanencia del TAR. El seguimiento se realizó desde la modificación del TAR hasta un año después del cierre del período de inclusión. Los resultados se ajustaron por las variables de confusión: CD4 y carga viral (CV) basales, infección VIH multirresistente y tiempo desde el primer TAR. Resultados: Se incluyeron 112 pacientes en cada grupo. El tiempo de permanencia del TAR fue 16,7 meses (casos) vs 16,8 meses (controles), sin encontrarse diferencias estadísticamente significativas ajustando por las variables de confusión. La toxicidad fue el principal motivo de discontinuación (53,3% en casos vs 45,2% en controles, p = 0,70). La media en la disminución del logaritmo de la CV fue 0,89 en los casos y 0,58 en los controles (p = 0,223). El incremento de CD4/microL fue 77 y 73 respectivamente (p = 0,480). Conclusión: La permanencia del TAR en los pacientes cuyo tratamiento contiene algún AUG es similar a la de los pacientes que no lo contienen.

Permanencia del tratamiento antirretroviral de última generación en la práctica clínica diaria / Permanence of last generation antiretroviral in daily clinical practica

Introducción: La permanencia es una medida útil del éxito de los tratamientos antirretrovirales de última generación (AUG): raltegravir, darunavir, etravirina y maraviroc. El objetivo de nuestro estudio fue analizar la permanencia de los tratamientos antirretrovirales (TAR) que contenían al menos un AUG, y compararla con otros TAR utilizados en pacientes experimentados. Métodos: Estudio observacional, de casos y controles, de pacientes adultos externos cuyo TAR fue modificado entre 01/05/2008 y 01/09/2009. Los casos (pacientes con al menos un AUG) fueron emparejados (relación 1:1) con pacientes pretratados que cambiaron a un TAR sin AUG (controles). La variable principal fue la permanencia del TAR. El seguimiento se realizó desde la modificación del TAR hasta un año después del cierre del período de inclusión. Los resultados se ajustaron por las variables de confusión: CD4 y carga viral (CV) basales, infección VIH multirresistente y tiempo desde el primer TAR. Resultados: Se incluyeron 112 pacientes en cada grupo. El tiempo de permanencia del TAR fue 16,7 meses (casos) vs 16,8 meses (controles), sin encontrarse diferencias estadísticamente significativas ajustando por las variables de confusión. La toxicidad fue el principal motivo de discontinuación (53,3% en casos vs 45,2% en controles, p =0,70). La media en la disminución del logaritmo de la CV fue 0,89 en los casos y 0,58 en los controles (p =0,223). El incremento de CD4/microL fue 77 y 73 respectivamente (p =0,480). Conclusión: La permanencia del TAR en los pacientes cuyo tratamiento contiene algún AUG es similar a la de los pacientes que no lo contienen (AU)

Introduction: Time of permanence is a useful measure of success in last generation antiretroviral (LGA) therapy: raltegravir, darunavir, etravirine and maraviroc. The aim of our study was to analyze the permanence of antiretroviral therapy (ART) containing at least one LGA, and to compare it with other ART used in experienced patients. Methods: Observational case-control study. It included adult outpatients whose ART was switched between 01/05/2008 and 01/09/2009. Cases (patients with at least one LGA) were matched (1:1) with pretreated patients who switched to an ART without any LGA (controls). The primary endpoint was the permanence of ART. The follow-up was conducted from the modification of ART to a year after the closure of the inclusion period. Results were adjusted for confounding variables: CD4 and viral load (VL) at baseline, MDR HIV infection and time from the first ART. Results: 112 patients were included in each group. The permanence of ART was 16.7 months (cases) vs 16.8 months (controls), although statistically significant differences were not found after adjusting for confounding variables. Toxicity was the main reason of discontinuation (53.3% in cases vs 45.2% in controls, p = 0.70). The mean decrease in the logarithm of the VL was 0.89 in cases and 0.58 in controls (p = 0.223). The increase of CD4/microL was 77 and 73 respectively (p = 0.480). Conclusion: The permanence of ART in patients whose treatment contains a LGA is similar to those without any LGA (AU)