HLA-B*5801 testing: Is it time to consider mandatory testing prior to prescribing allopurinol in Singapore?

Stevens-Johnsons Syndrome (SJS) and Toxic Epidermal Necrolysis (TEN) are severe, life- threatening mucocutaneous reactions that most commonly occur as drug-related reactions.1 In recent years, several risk factors for the develop- ment of SJS/TEN, such as genetic factors, have been identified. Notably, carriers of the HLA-B*5801 and HLA-B*1502 alleles have an increased risk of SJS/TEN with the use of allopurinol and carbamazepine, respectively.2 Consequently, much debate has arisen over the utility of pharmacogenomics in preventing SJS/ TEN. We will discuss the evidence surrounding genetic testing in the prevention of allopurinol- induced SJS/TEN, with the aim of highlighting the potential value of pre-testing.

Delabeling, safety, and impact of β-lactam allergy testing: A systematic review

Background

To improve β-lactam delabeling outcomes, we need to understand current practice and the evidence base regarding its outcomes, safety, and impact.

Objectives

We sought to assess the existing published evidence reporting on the effectiveness of penicillin allergy testing and delabeling.

Methods

We conducted a systematic review of studies reporting β-lactam delabeling practices and outcomes after testing, including β-lactam use and patient understanding of the delabeling result. Searches of the PubMed, Scopus, and Embase databases; clinical trial registries; and websites of professional organizations were conducted. Data were extracted from the included studies in duplicate, with a third extraction if discrepancies remained.

Results

We included 284 publications (covering 98,316 participants); 173 were prospective studies, with no randomized controlled trials. The overall study quality was low. In all, 95.6% of individuals who underwent provocation testing were delabeled. Factors associated with successful delabeling could not be determined because of significant heterogeneity between studies. Anaphylaxis due to testing occurred in 0.3% of participants (95 of 31,667). Subjects who did not undergo skin testing (6,980 patients in 31 studies) before challenge had higher rates of provocation test positivity (8.8% vs 4.1% [P < .0001]) and anaphylaxis (15.9% vs 2.7% [P < .0001]) than those subjects who underwent skin testing (51,607 patients in 177 studies). Six studies (2.1%) followed patients after testing to assess their adherence to prescribing recommendations. In all, 136 participants (20.6%) were actively avoiding β-lactams despite delabeling.

Conclusions

The available data suggest that penicillin allergy testing is safe and effective in delabeling most individuals, but the evidence base is incomplete and more work is required to assess the role of skin testing and the impact that delabeling is having on prescribing habits.

Cyclosporine in the Treatment of Drug Reaction With Eosinophilia and Systemic Symptoms Syndrome: Retrospective Cohort Study

BACKGROUND

Drug reaction with eosinophilia and systemic symptoms (DRESS) syndrome is a severe, life-threatening reaction to a culprit drug that frequently involves end-organ damage. Corticosteroids are the first-line treatment for DRESS syndrome; however, corticosteroids may be contraindicated in certain patient populations. There are currently only 54 cases detailing the use of cyclosporine for the treatment of DRESS syndrome reported in the literature.

OBJECTIVE

The aim of this case series was to examine the treatment of DRESS syndrome with cyclosporine in a large patient cohort by aggregating time to symptom resolution, recurrence rate, and treatment dose and duration.

METHODS

This study was a retrospective cohort study. Patients diagnosed with DRESS syndrome by a board-certified dermatologist and treated at the University of Colorado Hospital from 2015 to 2019 were included.

RESULTS

Our inclusion criterion was met by 19 occurrences of DRESS syndrome. With a short course of cyclosporine, 17 of 19 patients in our cohort (89%) had resolution of symptoms (mean treatment length of 5.26 days). DRESS syndrome's relapse after treatment with cyclosporine occurred in 3 of 19 (16%) occurrences of the cohort.

CONCLUSIONS

Our study supports the use of cyclosporine in the treatment of DRESS syndrome, particularly in patients who are unable to sustain prolonged immunosuppression. Further research is necessary to compare the efficacy of cyclosporine to the current standard of care in a larger study population and investigate long-term outcomes.

Clair B. Severe Cutaneous Adverse Reactions Associated With High-Dose Lamotrigine for Mood Disorders: A Case Series

Drug-induced Eosinophilia and Systemic Symptoms (DRESS), Stevens-Johnson Syndrome (SJS), and Toxic Epidermal Necrolysis (TEN) are rare but life-threatening immune-mediated drug reactions known as Severe Cutaneous Adverse Reactions (SCARs). These severe drug reactions have been associated with many commonly prescribed medications, including sulfonamides, allopurinol, carbamazepine, and several antiepileptic drugs including lamotrigine.¹ Although the risk of these adverse events is recognized by many medical providers, the risk may be overlooked when prescribing lamotrigine for mood disorders. Review of the literature and the experience of these cases suggest that the risk of lamotrigine-associated SCARs is increased when starting lamotrigine at high initial doses. Here we present and discuss two cases of SCARs attributed to high-dose lamotrigine prescribed for mood disorders. A third patient also presented with a SCAR related to high-dose lamotrigine prescribed for a mood disorder during this time but was lost to follow-up and was not reachable. All three patients presented to our hospital system from 2019-2020. Due to this clinical experience, we recommend that pharmacists and prescribers alike be alerted of the risk of severe cutaneous drug reactions when lamotrigine is prescribed, particularly at initial doses greater than 25 mg.

Personalized medicine with drugs targeting the underlying protein defect in cystic fibrosis: is monitoring of treatment response necessary?

Cystic fibrosis (CF) is caused by two mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene. In the last years, drugs targeting the underlying protein defect like lumacaftor/ivacaftor (LUM/IVA) or tezacaftor/ivacaftor (TEZ/IVA) and more recently elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) were admitted. Outcome parameters evaluating therapy response like forced expiratory pressure in 1 s (FEV1), body mass index (BMI) or the efficacy of CFTR function in sweat glands showed improvement in several cases. Other, CFTR biomarkers were analysed rarely. This prospective observational study was aimed at evaluating CFTR function in patients treated with different CFTR modulators together with common valid clinical outcome parameters at standardized appointments (day 0, week 2, 4, 16). We followed four patients with the same mutation (F508del-CFTR), sex, age and disease severity. Monitoring focused on lung function, gastrointestinal aspects and CFTR function of sweat glands, nasal and intestinal epithelium. Sweat tests were performed by pilocarpine iontophoresis. Nasal potential difference (NPD) measured transepithelial voltage in vivo and potential increased when CFTR function improved. Rectal biopsies were obtained for intestinal current measurements (ICM) ex vivo. Intestinal CFTR function was assessed by stimulating chloride secretion with different reagents. Response to CFTR modulators regarding clinical outcome parameters was rather variable. A sweat chloride reduction of 35.3 mmol/L, nasal CFTR rescue of 4.4% and fivefold higher CFTR function in the intestine was seen at week 16 post-LUM/IVA. Due to our monitoring, we identified a non-responder to LUM/IVA and TEZ/IVA. In case of ELX/TEZ/IVA, clinical parameters and CFTR bioassays improved and were concordant. Although our cohort is small, results emphasize that non-responders exist and conclusions could not be drawn if patients were not monitored. Data on CFTR function can confirm or disprove ongoing CFTR dysfunction and might be helpful selectively. Non-responders need other alternative therapy options as demonstrated with ELX/TEZ/IVA.

Epidemiology and risk factors for the development of cutaneous toxicities in patients treated with immune-checkpoint inhibitors: A United States population-level analysis

BACKGROUND

A variety of dermatoses have been reported in the growing number of patients treated with immune-checkpoint inhibitors (ICIs), but the current understanding of cutaneous immune-related adverse events (irAEs) is limited.

OBJECTIVE

To determine the cumulative incidence, distribution, and risk factors of cutaneous irAEs after ICI initiation.

METHODS

This was a retrospective cohort study of patients in a national insurance claims database including cancer patients treated with ICIs and matched controls.

RESULTS

The study included 8637 ICI patients and 8637 matched controls. The overall incidence of cutaneous irAEs was 25.1%, with a median onset time of 113 days. The ICI group had a significantly higher incidence of pruritus, mucositis, erythroderma, maculopapular eruption, vitiligo, lichen planus, bullous pemphigoid, Grover disease, rash, other nonspecific eruptions, and drug eruption or other nonspecific drug reaction. Patients with melanoma and renal cell carcinoma and those receiving combination therapy were at a higher risk of cutaneous irAEs.

LIMITATIONS

Retrospective design without access to patient chart data.

CONCLUSIONS

This study identifies cutaneous irAEs in a real-world clinical setting and highlights patient groups that are particularly at risk. The results can aid dermatologists at the bedside in the diagnosis of cutaneous irAEs and in formulating management recommendations to referring oncologists regarding the continuation of ICI therapy.

Application of liquid biopsy-based targeted capture sequencing analysis to improve the precision treatment of non-small cell lung cancer by tyrosine kinase inhibitors

BACKGROUND

Targeted therapy of patients with non-small cell lung cancer (NSCLC) who harbour sensitising mutations by tyrosine kinase inhibitors (TKIs) has been found more effective than traditional chemotherapies. However, target genes status (eg, epidermal growth factor receptor (EGFR) TKIs sensitising and resistant mutations) need to be tested for choosing appropriate TKIs. This study is to investigate the performance of a liquid biopsy-based targeted capture sequencing assay on the molecular analysis of NSCLC.

METHODS

Plasma samples from patients with NSCLC who showed resistance to the first/second-generation EGFR TKIs treatment were collected. The AVENIO ctDNA Expanded Kit is a 77 pan-cancer genes detection assay that was used for detecting EGFR TKIs resistance-associated gene mutations. Through comparison of the EGFR gene testing results from the Cobas EGFR Mutation Test v2, and UltraSEEK Lung Panel, the effectiveness of the targeted capture sequencing assay was verified.

RESULTS

A total of 24 plasma cell-free DNA (cfDNA) samples were tested by the targeted capture sequencing assay. 33.3% (8/24) cfDNA samples were positive for EGFR exon 20 p.T790M which leads to EGFR dependent TKIs resistance. 8.3% (2/24) and 4.2% (1/24) samples were positive for mesenchymal-epithelial transition gene amplification and B-Raf proto-oncogene, serine/threonine kinase exon 15 p.V600E mutations which lead to EGFR independent TKIs resistance. The median value of the p.T790M variant allele fraction and variant copy numbers was 2% and 36.10 copies/mL plasma, respectively. The next-generation sequencing test showed higher than 90% concordance with either MassArray or qPCR-based methods for detecting either EGFR TKIs sensitising or resistance mutations.

CONCLUSION

The targeted capture sequencing test can support comprehensive molecular analysis needed for TKIs treatment, which is promising to be clinically applied for the improved precision treatment of NSCLC.

Secondary erythrocytosis following drugs used in rifampicin/multidrug-resistant tuberculosis: a retrospective cohort study

Background

Multidrug-resistant tuberculosis (MDR-TB) drugs have never been associated with erythrocytosis. In Eritrea, however, several cases of incident erythrocytosis had been observed in the MDR-TB hospital. This study was aimed at exploring the association between MDR-TB drugs and secondary erythrocytosis, characterising the cases, and identifying other possible risk factors.

Methods

A retrospective cohort study was conducted in Merhano National Referral MDR-TB hospital. Data were extracted from physically available clinical cards and laboratory results collected longitudinally between 23 June 2011 and 17 January 2021. Initially, univariate descriptive statistics (frequency, mean (SD), median (IQR) and range) were used as appropriate. Then, χ² or Fisher χ² test, and bivariate and/or multivariate Cox proportional hazard model were used to identify the predictors of incident erythrocytosis. All statistical analyses were conducted using R, and a two-sided alpha 0.05 was used to determine the statistical significance.

Results

A total of 257 patients’ medical cards were screened, and 219 were eligible for further analysis. The median age of the patients was 38 years (range: 13–90 years) and 54.8% were males. During the follow-up time, 31 (14.2%) patients developed secondary erythrocytosis yielding an incidence rate of 7.8 cases per 1000 person-months. On average, the median time to onset of the event was found to be 5-months (range: 1–24 months). Males were more likely to develop the event than females (adjusted HR=7.13, 95% CI=1.66 to 30.53), and as body weight increases by 1 kg, the likelihood of developing secondary erythrocytosis was found to increase by 7% (adjusted HR=1.07, 95% CI=1.03 to 1.10). Moreover, all cases of secondary erythrocytosis were found to be possibly associated with the MDR-TB drugs.

Conclusion

The authors hypothesised that the incident erythrocytosis is possibly be associated with MDR-TB drugs, and further studies are required to substantiate this finding.

Safety, satisfaction, and cost savings of accelerated infusions of standard and intensified-dose infliximab for inflammatory bowel disease

INTRODUCTION

Infliximab remains a mainstay for treatment of inflammatory bowel disease (IBD), but a long infusion duration and subsequent monitoring can be burdensome to patients and health care providers. We assessed the safety of accelerated infusions for standard and dose-intensified infliximab regimens, and the effect on patient satisfaction and potential cost savings.

METHODS

Patients with IBD on a stable maintenance dose of infliximab and in clinical remission received one or more accelerated infusions; over 30 min if receiving standard-dose (5 mg/kg), or over 60 min if receiving dose-intensified infliximab (up to 10 mg/kg). Outcomes included incidence of reactions (acute or delayed), patient satisfaction, and potential cost savings. We also explored infliximab trough levels after one and three accelerated infusions.

RESULTS

52 patients who received 150 infusions were studied. Incidence of reactions to accelerated infusions was 3.3% (3 out of 89) with standard-dose and 0% (out of 61) with dose-intensified infliximab. Reactions were delayed, mild, and self-limiting. None requiring drug cessation. Patient satisfaction was improved with shortened infusion time as compared to the patients' previous experiences (p = 0.00002). Mean plasma trough level of infliximab reduced from 9.3 mg/L (± 4.9) to 7.9 mg/L (± 4.1) (p = 0.02) with accelerated infusions, but none developed anti-infliximab antibodies. Nursing cost savings were estimated as $123.52 and $247.04 per-patient per-year for standard and dose-intensified infliximab, respectively.

CONCLUSION

Accelerated infliximab infusions for standard and dose-intensified regimens seems to be safe and improved patient satisfaction. Potential impact on drug trough levels requires further investigations. This article is protected by copyright. All rights reserved.