Comorbidities and pharmacotherapies in patients with Gaucher disease type 1: The potential for drug-drug interactions

Changing clinical manifestations of Gaucher disease in Taiwan

BACKGROUND

Gaucher disease (GD) is a lysosomal storage disorder characterized by deficient glucocerebrosidase activity that results from biallelic mutations in the GBA1 gene. Its phenotypic variability allows GD to be classified into 3 subtypes based on the presence and extent of neurological manifestations. Enzyme replacement therapy (ERT) has been available for all patients with GD in Taiwan since 1998. Newborn screening (NBS) for GD has been available since 2015. This study attempted to unveil the clinical features of patients diagnosed with GD during different eras in Taiwan.

MATERIALS AND METHODS

Data from the health records of two tertiary hospitals responsible for two-thirds of the patients with GD in Taiwan were used. The study population included all patients identified as having GD between 1998, and April 2022, in these two hospitals for review. A total of 42 individuals were included, six of whom were diagnosed by NBS.

RESULTS

Our cohort presented a higher proportion of GD3 individuals, both by clinical suspicion and by NBS diagnosis, than that reported worldwide. The major subtypes that were recognized following NBS diagnosis were GD2 and GD3. The majority of GD patients carry at least one p.Leu483Pro variant. The 5-year survival rates were 0% for GD2 patients and 100% for patients with other subtypes. Patients diagnosed during the post-NBS era were free of symptoms on initial presentation, except for those with the GD2 subtype. For those diagnosed earlier, ERT was shown to be effective in terms of improved hemograms and prevented bone crises. However, the neurological symptoms in GD3 patients progressed despite ERT intervention.

CONCLUSION

ERT is essential in reversing the hematological presentations and preventing the skeletal complications of GD. Timely diagnosis of GD with NBS allows for early intervention with ERT to prevent disease progression and complications. However, the need for effective intervention for neurological dysfunction remains unmet.

Recommendations on the follow-up of patients with Gaucher disease in Spain: Results from a Delphi survey

Management of Gaucher disease (GD) is challenging due to its wide genotypic and phenotypic variability and changing clinical manifestations due to effective treatment. Sixteen face-to-face meetings with experts were held in order to discuss daily clinical practice and identify controversies regarding the management of GD. With this information, a questionnaire with 93 recommendations for different clinical scenarios was designed, and a Delphi survey among 86 physicians with experience in GD was conducted. Consensus was reached on 73 out of the 93 items. Recommendations on follow-up of adult and pediatric patients were in line with current guidelines, and underscored the importance of a patient-tailored approach. For the follow-up of stable patients receiving long-term treatment, consensus was reached on the importance of multidisciplinary care that involves pediatricians, internal medicine, and primary care, specialized radiologists, orthopedic surgeons, and hematologists when required. Degree of pain, use of painkillers and antidepressants, and quality of life should be evaluated at every follow-up visit or at least once per year. In general, a closer follow-up was recommended for untreated patients or patients who underwent a treatment change (every 3 months during the first year) and during pregnancy. For pregnant patients, hemostasis and risk of hemorrhage should be assessed, but no consensus was reached for initiation of treatment in asymptomatic pregnant patients. Lastly, recommendations on how to adapt GD management during a COVID-19 pandemic were collected. This expert consensus may help decision-making during the management of GD in specific clinical scenarios.

Physiologically-Based Pharmacokinetic Model Development, Validation, and Application for Prediction of Eliglustat Drug-Drug Interactions

Eliglustat is a glucosylceramide synthase inhibitor indicated as a long-term substrate reduction therapy for adults with type 1 Gaucher disease, a lysosomal rare disease. It is primarily metabolized by cytochrome P450 2D6 (CYP2D6), and variants in the gene encoding this enzyme are important determinants of eliglustat pharmacokinetics (PK) and drug-drug interactions (DDIs). The existing drug label addresses the DDIs to some extent but has omitted scenarios where both metabolizing CYPs (2D6 and 3A4) are mildly or moderately inhibited. The objectives of this study were (i) to develop and validate an eliglustat physiologically-based pharmacokinetic (PBPK) model with and without drug interactions, (ii) to simulate untested DDI scenarios, and (iii) to explore potential dosing flexibility using lower dose strength of eliglustat (commercially not available). PK data from healthy adults receiving eliglustat with or without interacting drugs were obtained from literature and used for the PBPK model development and validation. The model-predicted single-dose and steady-state maximum concentration (C_max ) and area under the concentration-time curve (AUC) of eliglustat were within 50-150% of the observed values when eliglustat was administered alone or coadministered with ketoconazole or paroxetine. Then as model-based simulations, we illustrated eliglustat exposure as a victim of interaction when coadministered with fluvoxamine following the US Food and Drug Administration (FDA) dosing recommendations. Second, we showed that with lower eliglustat doses (21 mg, 42 mg once daily) the exposure in participants of intermediate and poor metabolizer phenotypes was within the outlined safety margin (C_max <250 ng/mL) when eliglustat was administered with ketoconazole, where the current recommendation is a contraindication of coadministration (84 mg). The present study demonstrated that patients with CYP2D6 deficiency may benefit from lower doses of eliglustat.

Metabolizing profile of the cytochrome pathway CYP2D6, CYP3A4 and the ABCB 1 transporter in Spanish patients affected by Gaucher disease

Several therapeutic options are available for type 1 Gaucher disease (GD1), including enzymatic replacement therapy (ERT) and substrate reduction therapy (SRT). Eliglustat is a selective inhibitor of glucosylceramide synthase that is extensively metabolized by CYP2D6 and, to a lesser extent by CYP3A4; it is also an inhibitor of the P-gp transporter. The aim of this study is to evaluate the metabolizer profile of these cytochrome isoforms in 61 GD1 patients, and to analyze interferences with concomitant therapies. Patients were selected from the Spanish Gaucher Disease Registry considering clinical data, GBA genotype, severity score index, comorbidities, concomitant drugs, type and response to therapy and adverse effects. The polymorphisms of CYP2D6, CYP3A4 and three ABCB1 transporter variants were analyzed by Polymerase Chain Reaction (PCR). The most frequent metabolizer profile was extensive or intermediate for CYP2D6, extensive for CYP3A4*1B and CYP3A4*22 and normal activity for ABCB1. Correlations between metabolizer profile and other variables were analyzed by multiple regression study. Twenty-eight patients received ERT, 17 eliglustat and seven miglustat. Forty-two patients (68.8%) had associated diseases and 54.5% were taking daily concomitant medication. Nine patients under eliglustat therapy received concomitant drugs that interact with the CYPs and/or ABCB1, five of these did not reach therapeutic goals and three presented mild or moderate adverse effects (headache and gastrointestinal disorders). Detailed analysis in four patients with TTT haplotype, corresponding to lack of activity of the transporter, was performed. In order to apply personalized medicine and avoid interferences and adverse effects, the individual CYP metabolizer profile and transporter must be considered when choosing the concomitant medication and/or making dose adjustments.

Potential drug-drug interactions in ICU patients: a retrospective study

Objectives A "potential drug-drug interaction" (pDDI) is the possibility one drug has to alter the effects of another when both are administered simultaneously. Intensive care unit (ICU) patients are especially prone to these pDDIs. This study aimed to determine the frequency and severity of pDDIs during the hospitalization of patients in the ICU. Methods This study was conducted retrospectively in three hospitals, including both governmental and non-governmental hospitals in Nablus, Palestine, over the course of six months; starting in January 2018 and ending in June 2018. The sample size included 232 ICU patients, and medications prescribed during the hospitalization of these patients were evaluated for pDDIs using the drugs.com application. Results A total of 167 patients (72%) were found to have at least one pDDI, while the total number of pDDIs in the study was 422, resulting in an average of 1.82 pDDIs per patient. Out of the total identified pDDIs, 41 interactions (9.7%) were major interactions, 281 (66.6%) were moderate interactions and 100 (23.7%) were minor interactions. The past medical history of these patients showed that many had hypertension (29%), diabetes mellitus (25%) and ischemic heart disease (10%). A serious combination, enoxaparin and aspirin, was found in six patients. Furthermore, as the number of administered drugs increased, the number of interactions increased as well. Conclusions The pDDIs are common in ICU patients. The most common and clinically most important pDDIs require special attention. Polypharmacy significantly increases the number and level of pDDIs, especially in patients with multiple chronic illnesses. Adequate knowledge regarding the most common pDDIs is necessary to enable healthcare professionals to implement ICU strategies that ensure patient safety.