Role of cytochrome P450 polymorphisms in the development of pulmonary drug toxicity: a case-control study in the Netherlands

Cancer therapy-related interstitial lung disease

ABSTRACT

With the increasing utilization of cancer therapy, the incidence of lung injury associated with these treatments continues to rise. The recognition of pulmonary toxicity related to cancer therapy has become increasingly critical, for which interstitial lung disease (ILD) is a common cause of mortality. Cancer therapy-related ILD (CT-ILD) can result from a variety of treatments including chemotherapy, targeted therapy, immune checkpoint inhibitors, antibody-drug conjugates, and radiotherapy. CT-ILD may progress rapidly and even be life-threatening; therefore, prompt diagnosis and timely treatment are crucial for effective management. This review aims to provide valuable information on the risk factors associated with CT-ILD; elucidate its underlying mechanisms; discuss its clinical features, imaging, and histological manifestations; and emphasize the clinical-related views of its diagnosis. In addition, this review provides an overview of grading, typing, and staging treatment strategies used for the management of CT-ILD.

Drug-Gene Risk Stratification in Patients with Suspected Drug-Induced Interstitial Lung Disease

BACKGROUND

Pulmonary toxicity has been associated with drug use. This is often not recognized in clinical practice, and underestimated.

OBJECTIVE

We aimed to establish whether polymorphisms in certain genes corresponding with a metabolic pathway of drug(s) used are associated with pulmonary toxicity in patients with suspected drug-induced interstitial lung disease (DI-ILD).

METHODS

This retrospective observational study explored genetic variations in three clinically relevant cytochrome P450 (CYP) iso-enzymes (i.e., CYP2D6, CYP2C9, and CYP2C19) in a group of patients with a fibroticinterstitial lung disease, either non-specific interstitial pneumonia (n = 211) or idiopathic pulmonary fibrosis (n = 256), with a suspected drug-induced origin.

RESULTS

Of the 467 patients, 79.0% showed one or more polymorphisms in the tested genes accompanied by the use of drug(s) metabolized by a corresponding affected metabolic pathway (60.0% poor metabolizers and/or using two or more drugs [likely DI-ILD], 37.5% using three or more [highly likely DI-ILD]). Most commonly used drugs were statins (63.1%) with a predominance among men (69.4 vs 47.1%, p < 0.0001). Nitrofurantoin, not metabolized by the tested pathways, was prescribed more frequently among women (51.9 vs 4.5%, p < 0.00001).

CONCLUSIONS

In our cohort with suspected DI-ILD, 79% carried one or more genetic variants accompanied by the use of drugs metabolized by a corresponding affected pathway. In 60%, the diagnosis of DI-ILD was likely, whereas in 37.5%, it was highly likely, based on CYP analyses. This study underlines the importance of considering both drug use and genetic make-up as a possible cause, or at least a contributing factor, in the development and/or progression of fibrotic lung diseases.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT00267800, registered in 2005.

Drug-induced interstitial lung disease: a narrative review of a clinical conundrum

INTRODUCTION

Drug-induced interstitial lung disease (DI-ILD) is increasing in incidence, due to the use of many new drugs across a broad range of cancers and chronic inflammatory diseases. The presentation and onset of DI-ILD are variable even for the same drug across different individuals. Clinical suspicion is essential for identifying these conditions, with timely drug cessation an important determinant of outcomes.

AREAS COVERED

This review provides a comprehensive and up-to-date summary of epidemiology, risk factors, pathogenesis, diagnosis, treatment, and prognosis of DI-ILD. Relevant research articles from PubMed and Medline searches up to September 2023 were screened and summarized. Specific drugs including immune checkpoint inhibitors, CAR-T cell therapy, methotrexate, and amiodarone are discussed in detail. The potential role of pharmacogenomic profiling for lung toxicity risk is considered.

EXPERT OPINION

DI-ILD is likely to be an increasingly important contributor to respiratory disability in the community. These conditions can negatively impact quality of life and patient longevity, due to associated respiratory compromise as well as cessation of evidence-based therapy for the underlying disease. This clinical conundrum is relevant to all areas of medicine, necessitating increased understanding and greater vigilance for drug-related lung toxicity.

Skin disorders and interstitial lung disease: Part I-Screening, diagnosis, and therapeutic principles

Numerous inflammatory, neoplastic, and genetic skin disorders are associated with interstitial lung disease (ILD), the fibrosing inflammation of lung parenchyma that has significant morbidity and mortality. Therefore, the dermatologist plays a major role in the early detection and appropriate referral of patients at risk for ILD. Part 1 of this 2-part CME outlines the pathophysiology of ILD and focuses on clinical screening and therapeutic principles applicable to dermatological patients who are at risk for ILD. Patients with clinical symptoms of ILD should be screened with pulmonary function tests and high-resolution chest computed tomography. Screening for pulmonary hypertension should be considered in high-risk patients. Early identification and elimination of pulmonary risk factors, including smoking and gastroesophageal reflux disease, are essential in improving respiratory outcomes. First-line treatment interventions for ILD in a dermatological setting include mycophenolate mofetil, but the choice of therapeutic agents depends on the nature of the primary disease, the severity of ILD, and comorbidities and should be the result of a multidisciplinary assessment. Better awareness of ILD among medical dermatologists and close interdisciplinary collaborations are likely to prevent treatment delays improving long-term outcomes.

Drug-induced comorbidities in patients with sarcoidosis

PURPOSE OF REVIEW

Sarcoidosis is a chronic multisystemic inflammatory disease of unknown aetiology with a wide range of highly variable clinical manifestations and unpredictable disease course. Sarcoidosis patients may present with specific organ-related symptoms involving functional impairments, and less specific symptoms. The decision whether and when to treat a sarcoidosis patient with pharmacotherapy depends on two major factors: risk of organ failure and/or death and impairment of quality of life. This decision is complex and not standardized.

RECENT FINDINGS

Glucocorticoids (GCs) are recommended as initial treatment, when needed. Subsequent GC-sparing alternatives frequently follow. Comorbidities or adverse drug reactions (ADRs) from drugs used in sarcoidosis treatment are sometimes very hard to differentiate from symptoms associated with the disease itself, which may cause diagnostic dilemmas. An ideal approach to minimalize ADRs would involve genetic screening prior to prescribing certain 'high-risk drugs' and therapeutic drug monitoring during treatment. Pharmacogenomic testing aims to guide appropriate selection of medicines, with the potential of reducing unnecessary polypharmacy while improving clinical outcomes.

SUMMARY

A multidisciplinary approach to the management of sarcoidosis may avoid unnecessary ADRs. It is important to consider the possibility of drug-induced damage in sarcoidosis, especially if the clinical situation deteriorates after the introduction of a particular drug.

Role of Drug-Gene Interactions and Pharmacogenetics in Simvastatin-Associated Pulmonary Toxicity

Introduction

Simvastatin has previously been associated with drug-induced interstitial lung disease. In this retrospective observational study, cases with non-specific interstitial pneumonia (NSIP) or idiopathic pulmonary fibrosis (IPF) with simvastatin-associated pulmonary toxicity (n = 34) were evaluated.

Objective

To identify whether variations in genes encoding cytochrome P450 (CYP) enzymes or in the SLCO1B1 gene (Solute Carrier Organic anion transporting polypeptide 1B1 gene, encoding the organic anion transporting polypeptide 1B1 [OATP1B1] drug transporter enzyme), and/or characteristics of concomitantly used drugs, predispose patients to simvastatin-associated pulmonary toxicity.

Methods

Characteristics of concomitantly used drugs and/or variations in the CYP or SLCO1B1 genes and drug–gene interactions were assessed. The outcome after withdrawal of simvastatin and/or switch to another statin was assessed after 6 months.

Results

Multiple drug use involving either substrates and/or inhibitors of CYP3A4 and/or three or more drugs with the potential to cause acidosis explained the simvastatin-associated toxicity in 70.5% (n = 24) of cases. Cases did not differ significantly from controls regarding CYP3A4, CYP2C9, or OATP1B1 phenotypes, and genetic variation explained only 20.6% (n = 7) of cases. Withdrawal of simvastatin without switching to another statin or with a switch to a hydrophilic statin led to improvement or stabilization in all NSIP cases, whereas all cases who were switched to the lipophilic atorvastatin progressed.

Conclusion

Simvastatin-associated pulmonary toxicity is multifactorial. For patients with this drug-induced pulmonary toxicity who need to continue taking a statin, switching to a hydrophilic statin should be considered.

ClinicalTrials.gov identifier

NCT00267800, registered in 2005.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40264-021-01105-8.

Vitamin E acetate as linactant in the pathophysiology of EVALI

The recent identification of Vitamin E acetate as one of the causal agents for the e-cigarette, or vaping, product use associated lung injury (EVALI) is a major milestone. In membrane biophysics, Vitamin E is a linactant and a potent modulator of lateral phase separation that effectively reduces the line tension at the two-dimensional phase boundaries and thereby exponentially increases the surface viscosity of the pulmonary surfactant. Disrupted dynamics of respiratory compression-expansion cycling may result in an extensive hypoxemia, leading to an acute respiratory distress entailing the formation of intraalveolar lipid-laden macrophages. Supplementation of pulmonary surfactants which retain moderate level of cholesterol and controlled hypothermia for patients are recommended when the hypothesis that the line-active property of the vitamin derivative drives the pathogenesis of EVALI holds.

Epidemiology and Risk Factors for Severe Delayed Drug Hypersensitivity Reactions

Severe delayed drug hypersensitivity reactions comprise different clinical entities and can involve different immune-mediated mechanisms. Common examples are severe cutaneous adverse reactions and druginduced internal organ injuries. The incidence of such reactions is overall low but seems to be on the rise reaching numbers as high as 9 per million individuals-years in the case of SJS/TEN and DRESS. Such conditions carry an important associated morbidity, and mortality can attain 40% in SJS/TEN patients, making these hypersensitivity reactions important targets when implementing preventive measures. Several risk factors have been identified for reaction severity; some are transverse, such as older age and underlying chronic diseases. The recent advances in pharmacogenetics allowed the identification of specific populations with higher risk and permitted strategic avoidance of certain drugs being HLA-B*57:01 screening in patients initiating abacavir the best successful example. In this work, we reviewed the epidemiology of SCARs and liver/kidney/lung drug-induced immune-mediated reactions. We focus on particular aspects such as prevalence and incidence, drugs involved, mortality and risk factors.

Analysis of drug-induced interstitial lung disease using the Japanese Adverse Drug Event Report database

Objectives:

Drug-induced interstitial lung disease occurs when exposure to a drug causes inflammation and, eventually, fibrosis of the lung interstitium. Drug-induced interstitial lung disease is associated with substantial morbidity and mortality. The aim of this retrospective study was to obtain new information on the time-to-onset profiles of drug-induced interstitial lung disease by consideration of other associated clinical factors using the Japanese Adverse Drug Event Report database.

Methods:

We identified and analyzed reports of drug-induced interstitial lung disease between 2004 and 2018 from the Japanese Adverse Drug Event Report database. The reporting odds ratio and 95% confidence interval was used to detect the signal for each drug-induced interstitial lung disease incidence. We evaluated the time-to-onset profile of drug-induced interstitial lung disease and used the applied association rule mining technique to uncover undetected relationships, such as possible risk factors.

Results:

The reporting odds ratios (95% confidence intervals) of drug-induced interstitial lung disease due to temsirolimus, gefitinib, sho-saiko-to, sai-rei-to, osimertinib, amiodarone, alectinib, erlotinib, everolimus, and bicalutamide were 18.3 (15.6–21.3), 17.8 (16.5–19.2), 16.3 (11.8–22.4), 14.5 (11.7–18.2), 12.5 (10.7–14.7), 10.9 (9.9–11.9), 10.6 (8.1–13.9), 9.6 (8.8–10.4), 9.4 (8.7–10.0), and 9.2 (7.9–10.6), respectively. The median durations (day (interquartile range)) for drug-induced interstitial lung disease were as follows: amiodarone (123.0 (27.0–400.5)), methotrexate (145.5 (67.8–475.8)), fluorouracil (86.0 (35.5–181.3)), gemcitabine (53.0 (20.0–83.0)), paclitaxel (52.0 (28.5–77.5)), docetaxel (47.0 (18.8–78.3)), bleomycin (92.0 (38.0–130.5)), oxaliplatin (45.0 (11.0–180.0)), nivolumab (56.0 (21.0–135.0)), gefitinib (24.0 (11.0–55.0)), erlotinib (21.0 (9.0–49.0)), temsirolimus (38.0 (14.0–68.5)), everolimus (56.0 (35.0–90.0)), osimertinib (51.5 (21.0–84.8)), alectinib (78.5 (44.3–145.8)), bicalutamide (50.0 (28.0–147.0)), pegylated interferon-2α (140.0 (75.8–233.0)), sai-rei-to (35.0 (20.0–54.5)), and sho-saiko-to (33.0 (13.5–74.0)) days. Association rule mining suggested that the risk of drug-induced interstitial lung disease was increased by a combination of amiodarone or sho-saiko-to and aging.

Conclusion:

Our results showed that patients who receive gefitinib or erlotinib should be closely monitored for the development of drug-induced interstitial lung disease within a short duration (4 weeks). In addition, elderly people who receive amiodarone or sho-saiko-to should be carefully monitored for the development of drug-induced interstitial lung disease.

HRCT Patterns of Drug-Induced Interstitial Lung Diseases: A Review

Interstitial Lung Diseases (ILDs) represent a heterogeneous group of pathologies, which may be related to different causes. A low percentage of these lung diseases may be secondary to the administration of drugs or substances. Through the PubMed database, an extensive search was performed in the fields of drug toxicity and interstitial lung disease. We have evaluated the different classes of drugs associated with pulmonary toxicity. Several different high resolution computed tomography (HRCT) patterns related to pulmonary drug toxicity have been reported in literature, and the most frequent ILDs patterns reported include Nonspecific Interstitial Pneumonia (NSIP), Usual Interstitial Pneumonia (UIP), Hypersensitivity Pneumonitis (HP), Organizing Pneumonia (OP), Acute Respiratory Distress Syndrome (ARDS), and Diffuse Alveolar Damage (DAD). Finally, from the electronic database of our Institute we have selected and commented on some cases of drug-induced lung diseases related to the administration of common drugs. As the imaging patterns are rarely specific, an accurate evaluation of the clinical history is required and a multidisciplinary approach-involving pneumologists, cardiologists, radiologists, pathologists, and rheumatologists-is recommended.

Tamsulosin Associated with Interstitial Lung Damage in CYP2D6 Variant Alleles Carriers

Drugs are serious but underestimated causative agents of interstitial lung disease (ILD). Both cytotoxic and immune mechanisms may be involved in drug-induced ILD (DI-ILD). We aimed to investigate whether polymorphisms of relevant CYP enzymes involved in the metabolization of tamsulosin might explain the pathologic mechanism of the DI-ILD in the cases with suspected tamsulosin DI-ILD. We collected 22 tamsulosin-associated DI-ILD cases at two ILD Expertise Centers in the Netherlands between 2009 and 2020. CYP2D6, CYP2C9, CYP2C19, CYP3A4, and CYP3A5 single nucleotide polymorphisms were genotyped and compared with a control group of 78 healthy Caucasian male volunteers. Nine cases were phenotyped as CYP2D6 poor metabolizers and 13 as CYP2D6 intermediate metabolizers. The phenotypes of the cases differed significantly from those of the healthy controls, with more poor metabolizers. After withdrawal of tamsulosin, the pulmonary condition of three cases had improved, six patients had stabilized, and one patient stabilized after reducing the tamsulosin dose. The described 22 cases suggest that an association between the presence of CYP2D6 allelic variants and tamsulosin-associated ILD is highly likely. These cases highlight the importance of both clinical and genetic risk stratification aimed to achieve a more accurate prevention of DI-ILD in the future and enhance the quality of life of patients.

Drug-induced interstitial lung disease: role of pharmacogenetics in predicting cytotoxic mechanisms and risks of side effects

PURPOSE OF REVIEW

The diagnosis of drug-induced interstitial lung disease (DI-ILD) is challenging and mainly made by exclusion of other possible causes. Toxicity can occur as a cause of drug(s) or drug-drug interactions. In this review, we summarize the possible role of pharmacogenetics of metabolizing enzymes in DI-ILD.

RECENT FINDINGS

Knowledge of the genetic predispositions of enzymes involved in drug metabolization and their relation with proposed cytotoxic mechanisms of DI-ILD, in particular direct cell toxicity and free oxygen radical production is increasing. The cytochrome P450 enzyme family and other enzymes play an important role in the metabolism of all sorts of ingested, injected, or inhaled xenobiotic substances. The liver is the major site for metabolism. Metabolic cytotoxic mechanisms have however also been detected in lung tissue. Polymorphisms in genes coding for enzymes that influence metabolic activity may lead to localized (toxic) reactions and tissue damage. This knowledge may be helpful in preventing the risk of DI-ILD.

SUMMARY

Drug toxicity can be the consequence of absence or very poor enzyme activity, especially if no other metabolic route is available. In the case of reduced enzyme activity, it is recommended to reduce the dose or to prescribe an alternative drug, which is metabolized by a different, unaffected enzyme system to prevent toxic side effects. However, enhanced enzyme activity may lead to excessive formation of toxic and sometimes reactive metabolites. Therefore, knowing a patient's drug-metabolizing profile before drug prescription is a promising way to prevent or explain DI-ILD.

Drug-Induced Interstitial Lung Disease: A Systematic Review

BACKGROUND

Drug-induced interstitial lung disease (DIILD) occurs as a result of numerous agents, but the risk often only becomes apparent after the marketing authorisation of such agents.

METHODS

In this PRISMA-compliant systematic review, we aimed to evaluate and synthesise the current literature on DIILD.

RESULTS

Following a quality assessment, 156 full-text papers describing more than 6000 DIILD cases were included in the review. However, the majority of the papers were of low or very low quality in relation to the review question (78%). Thus, it was not possible to perform a meta-analysis, and descriptive review was undertaken instead. DIILD incidence rates varied between 4.1 and 12.4 cases/million/year. DIILD accounted for 3⁻5% of prevalent ILD cases. Cancer drugs, followed by rheumatology drugs, amiodarone and antibiotics, were the most common causes of DIILD. The radiopathological phenotype of DIILD varied between and within agents, and no typical radiological pattern specific to DIILD was identified. Mortality rates of over 50% were reported in some studies. Severity at presentation was the most reliable predictor of mortality. Glucocorticoids (GCs) were commonly used to treat DIILD, but no prospective studies examined their effect on outcome.

CONCLUSIONS

Overall high-quality evidence in DIILD is lacking, and the current review will inform larger prospective studies to investigate the diagnosis and management of DIILD.

Simultaneous interstitial pneumonitis and cardiomyopathy induced by venlafaxine

Venlafaxine is a serotonin-norepinephrine reuptake inhibitor used as an antidepressant. Interindividual variability and herb-drug interactions can lead to drug-induced toxicity. We report the case of a 35-year-old female patient diagnosed with synchronous pneumonitis and acute cardiomyopathy attributed to venlafaxine. The patient sought medical attention due to dyspnea and dry cough that started three months after initiating treatment with venlafaxine for depression. The patient was concomitantly taking Centella asiatica and Fucus vesiculosus as phytotherapeutic agents. Chest CT angiography and chest X-ray revealed parenchymal lung disease (diffuse micronodules and focal ground-glass opacities) and simultaneous dilated cardiomyopathy. Ecocardiography revealed a left ventricular ejection fraction (LVEF) of 21%. A thorough investigation was carried out, including BAL, imaging studies, autoimmune testing, right heart catheterization, and myocardial biopsy. After excluding other etiologies and applying the Naranjo Adverse Drug Reaction Probability Scale, a diagnosis of synchronous pneumonitis/cardiomyopathy associated with venlafaxine was assumed. The herbal supplements taken by the patient have a known potential to inhibit cytochrome P450 enzyme complex, which is responsible for the metabolization of venlafaxine. After venlafaxine discontinuation, there was rapid improvement, with regression of the radiological abnormalities and normalization of the LVEF. This was an important case of drug-induced cardiopulmonary toxicity. The circumstantial intake of inhibitors of the CYP2D6 isoenzyme and the presence of a CYP2D6 slow metabolism phenotype might have resulted in the toxic accumulation of venlafaxine and the subsequent clinical manifestations. Here, we also discuss why macrophage-dominant phospholipidosis was the most likely mechanism of toxicity in this case.

[Drug induced interstitial lung disease in systemic diseases]

Immunosuppressants and immunomodulators are designed to regulate excessive immune response responsible for inflammatory lesions and are prescribed more and more in internal medicine. These drugs are known for their efficiency but with a significant toxicity including interstitial lung disease (ILD). Some factors liable to pulmonary toxicity include advanced age, genetic polymorphism and the existence of prior pulmonary disease. Cytotoxicity and hypersensitivity are the main mechanisms of pulmonary toxicity. There is no universal classification of drug induced-lung disease. Theoretically, drugs may be responsible for all histological aspects of ILD. Methotrexate is the most well-known drug as a provider of ILD with a prevalence of 0.3 to 11.6%. Some cases of ILD have also been reported with the new biologics used in systemic diseases. The diagnostic approach to the suspicion of drug ILD is to eliminate non-medicinal causes of pneumonia including infections and tumors before exploring the clinical symptomatology and the results of imaging and bronchoalveolar lavage cell profile. The analysis of the clinical symptomatology check the compatibility of the chronology of clinical and/or radiological pneumonia with the medication suspected. Subsequently, data from the clinical case are compared with those of the literature. Treatment involves stopping the suspected drug. The use of corticosteroids may be required in case of signs of severity or a lingering evolution.

Drug induced interstitial lung disease

With an increasing number of therapeutic drugs, the list of drugs that is responsible for severe pulmonary disease also grows. Many drugs have been associated with pulmonary complications of various types, including interstitial inflammation and fibrosis, bronchospasm, pulmonary edema, and pleural effusions. Drug-induced interstitial lung disease (DILD) can be caused by chemotherapeutic agents, antibiotics, antiarrhythmic drugs, and immunosuppressive agents. There are no distinct physiologic, radiographic or pathologic patterns of DILD, and the diagnosis is usually made when a patient with interstitial lung disease (ILD) is exposed to a medication known to result in lung disease. Other causes of ILD must be excluded. Treatment is avoidance of further exposure and systemic corticosteroids in patients with progressive or disabling disease.

Drug-induced interstitial lung disease: mechanisms and best diagnostic approaches

Drug-induced interstitial lung disease (DILD) is not uncommon and has many clinical patterns, ranging from benign infiltrates to life-threatening acute respiratory distress syndrome. There are two mechanisms involved in DILD, which are probably interdependent: one is direct, dose-dependent toxicity and the other is immune-mediated. Cytotoxic lung injury may result from direct injury to pneumocytes or the alveolar capillary endothelium. Drugs can induce all types of immunological reactions described by Gell and Coombs; however, most reactions in immune-mediated DILD may be T cell-mediated.

DILD can be difficult to diagnose; diagnosis is often possible by exclusion alone. Identifying the causative drug that induces an allergy or cytotoxicity is essential for preventing secondary reactions.

One method to confirm the diagnosis of a drug-induced disease is re-exposure or re-test of the drug. However, clinicians are reluctant to place patients at further risk of illness, particularly in cases with severe drug-induced diseases. Assessment of cell-mediated immunity has recently increased, because verifying the presence or absence of drug-sensitized lymphocytes can aid in confirmation of drug-induced disease. Using peripheral blood samples from drug-allergic patients, the drug-induced lymphocyte stimulation test (DLST) and the leukocyte migration test (LMT) can detect the presence of drug-sensitized T cells. However, these tests do not have a definite role in the diagnosis of DILD. This study explores the potential of these new tests and other similar tests in the diagnosis of DILD and provides a review of the relevant literature on this topic.

Development of cocaine-induced interstitial lung damage in two CYP2C and VKORC1 variant allele carriers

BACKGROUND

Often, the connection between drug use and the development of related inflammatory damage or idiosyncratic toxicities is hard to recognize and objectify. The presence of cytochrome P450 (CYP) variant genotypes appears to be a substantial susceptibility risk factor in the development of drug-induced pulmonary adverse events. We hypothesized that the presence of variant alleles may be associated with serious complications of illicit drug use.

CASE REPORT

We report the cases of two cocaine users who developed a 'flu-like' syndrome with diffuse interstitial infiltrates after cocaine abuse. Genotyping for CYP (CYP2C9, CYP2C19) and vitamin K epoxide reductase complex 1 (VKORC1) allelic variants (-1639G/A and 1173C/T) was performed in these two patients. Both cases were heterozygous for VKORC1 variant alleles, and both possessed a CYP2C polymorphism (case 1: CYP2C19*1/*2; case 2: CYP2C9*1/*3).

CONCLUSIONS

The described drug abuse cases suggest that an association between the presence of CYP2C and VKORC1 allelic variants and cocaine-induced interstitial lung damage is highly likely. It is assumed that these polymorphisms contribute to intra-individual variability in drug response and toxicity, including cocaine response and toxicity. Moreover, the importance of including pharmacogenomics in the work-up of patients with suspected drug-induced (lung) toxicity, such as alveolar hemorrhage, is highlighted by these cases.

Interstitial lung disease in gefitinib-treated Japanese patients with non-small-cell lung cancer: genome-wide analysis of genetic data

Aim: To investigate potential relationships between SNPs and acute interstitial lung disease (ILD) events in Japanese non-small-cell lung cancer patients receiving gefitinib. Materials & methods: Japanese non-small-cell lung cancer patients treated with gefitinib from a prospective pharmacoepidemiological cohort with a nested case–control study component (‘CCS’; 52 ILD cases, 139 controls) and a retrospective study (28 ILD cases, 55 controls) were genotyped for nearly 500,000 SNPs. Associations between genotype and ILD were evaluated using Fisher’s exact test and logistic regression modeling, and false discovery rate analysis was used to adjust for the large number of statistical tests. Results: The CCS data provided some false discovery rate evidence that the significance of top-ranking SNPs exceeded levels expected by chance, suggesting some genuine associations. However, replication analyses using retrospective study data were not supportive and there was little evidence of strong genetic associations from a combined analysis. Adjustment of CCS analyses for clinical variables provided little additional convincing evidence. Significant gene–gene interactions between SNP pairs using CCS data were not confirmed in retrospective study replication analyses. Conclusion: Although it is not possible to exclude genetic influences in ILD etiology, common sequence variation is unlikely to explain a major component of ILD risk. Our top results may provide a useful hypothesis-generating starting point for further research.

Presented, in part, at the 26th ICPE: International Conference on Pharmacoepidemiology & Therapeutic Risk Management, Brighton, UK, 19–22 August 2010.

Original submitted 1 December 2010; Revision submitted 22 February 2011

Role of microorganisms in interstitial lung disease

PURPOSE OF REVIEW

To review the role of microorganisms in interstitial lung disease (ILD) and to emphasize their importance in initiation and course of ILD.

RECENT FINDINGS

ILD can be idiopathic but often causality such as drugs or connective tissue disease can be found. Multiple microorganisms have been associated with ILD. On the one hand, pulmonary infection can cause extensive pulmonary damage with patterns of an ILD. On the other hand, microorganisms can trigger the immune system and provoke an abnormal response- not directed against the causative pathogen- that may result in ILD. Moreover, patients with ILD often are susceptible to infection, and infections can importantly influence the course of ILD. Furthermore, not only an infection but also its treatment can result in a drug-induced pneumonitis, eventually resulting in long-term lung damage.

SUMMARY

Microorganisms can initiate and/or influence the course of ILD. Early recognition, adequate diagnostic evaluation and therapy are essential to prevent permanent damage. Prevention of infection in patients with established ILD is strongly recommended.

Relationship between drug-induced interstitial lung diseases and cytochrome P450 polymorphisms

PURPOSE OF REVIEW

Interstitial lung disease and especially drug-induced interstitial lung disease can occur as a cause of drug(s) or drug-drug interactions. In this review we summarize the possible role of cytochrome P450 (CYP) enzymes in drug-induced interstitial lung disease.

RECENT FINDINGS

The CYP enzyme family plays an important role in the metabolism of all sorts of ingested, injected or inhaled xenobiotic substances. Although the liver is considered to be the major metabolism site of CYP enzymes, in recent years more CYP isoforms have been detected in lung tissue. Polymorphisms in these CYP genes can influence the metabolic activity of the subsequent enzymes, which in turn may lead to localized (toxic) reactions and tissue damage.

SUMMARY

Drug toxicity can be the consequence of no or very poor enzyme activity, especially if no other metabolic route is available. In the case of reduced enzyme activity, dose reduction or prescribing an alternative drug metabolized by a different, unaffected CYP enzyme is recommended to prevent toxic side effects. Therefore, knowing a patient's CYP profile before drug prescription could be a way to prevent drug-induced interstitial lung disease. Moreover, it might be helpful in explaining serious adverse effects from inhaled, injected or ingested xenobiotic substances.

A multicenter phase II study of erlotinib and sorafenib in chemotherapy-naive patients with advanced non-small cell lung cancer

PURPOSE

This multicenter, phase II study evaluates the efficacy and safety of erlotinib, an epidermal growth factor receptor (EGFR) inhibitor, plus sorafenib, a multityrosine kinase inhibitor against vascular endothelial growth factor receptors, in patients with previously untreated advanced non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Chemotherapy-naïve patients with stage IIIB/IV NSCLC received erlotinib (150 mg once a day) and sorafenib (400 mg twice a day) until disease progression or unacceptable toxicity. The primary end point was the rate of nonprogression at 6 weeks. Secondary end points included objective response rate (ORR), time to progression, overall survival, and adverse events. Exploratory end points included pretreatment EGFR and KRAS mutation status, pharmacokinetics, and cytochrome P450 polymorphisms.

RESULTS

Fifty patients initiated therapy. The nonprogression rate at 6 weeks was 74%: 12 (24%) partial response and 25 (50%) stable disease. Ultimately, the ORR was 28%. Median time to progression was 5.0 months [95% confidence interval (95% CI), 3.2-6.8 months]. Median overall survival was 10.9 months (95% CI, 3.8-18.1 months). Grade 3/4 adverse events included fatigue (16%), hand-foot skin reaction (16%), rash (16%), diarrhea (14%), and hypophosphatemia (42%). There was one treatment-related fatal pulmonary hemorrhage. Patients with wild-type EGFR had a higher ORR (19%) than previously reported for single-agent erlotinib/sorafenib. Erlotinib levels were lowered. This was associated with CYP3A4 polymorphism and was possibly due to sorafenib.

CONCLUSION

Despite a possible drug interaction, sorafenib plus erlotinib has promising clinical activity in patients with stage IIIB/IV NSCLC and has an acceptable safety profile. Further evaluation of this combination as potential salvage therapy in EGFR mutation-negative patients and the possible drug interaction is warranted.

Depressive effect of an antidepressant: therapeutic failure of venlafaxine in a case lacking CYP2D6 activity

Understanding the mechanisms of drug metabolism and interactions can help to prevent side-effects. Not only drug interactions, environmental factors, disease processes and ageing are factors in the inter-individual metabolic capacity variance but also genetic factors probably play an important role, as is illustrated in the case presented. Besides therapeutic drug monitoring, genotyping some important cytochrome P450 (CYP450) enzymes was of additional value in explaining why the patient developed severe adverse effects and, moreover, did not experience any therapeutical effect of venlafaxine. Results indicated that the patient was a poor metabolizer for CYP2D6, the most important phase I enzyme to metabolize venlafaxine. This corroborates that polymorphisms in the CYP450 gene influence the metabolic activity of the corresponding enzymes, thus affecting the subsequent serum drug levels and their metabolites. This case highlights the potential benefit of both clinical and genetic risk stratification (pharmacogenetics) prior to treatment, either for setting the individual dose or for making a decision about using a particular drug.

Pharmacogenetic testing after a simple DNA isolation method on buccal swab samples

AIM

To evaluate whether the quality and quantity of DNA isolated from noninvasively obtained buccal swab (BS) samples, using the previously described isolation method for dried blood spot (DBS) samples was satisfactory.

MATERIALS & METHODS

From 25 healthy volunteers, DBS samples were obtained by the capillary finger prick method and BS samples were obtained by rubbing a sterile, dry cotton swab against the inside of their cheek. Thereafter, DNA was isolated. In addition, the quantity of the obtained DNA was measured and melting curve analyses for both sampling methods were performed to establish the quality of the obtained DNA from both the DBS and BS samples.

RESULTS

The derivative melting curves of the DNA samples obtained from the capillary blood and BS were comparable and highly reproducible. The mean DNA concentrations measured were 16.0 ng/microl (12.6-19.4 ng/microl) and 70.2 ng/microl (57.3-83.1 ng/microl), respectively, for the DBS and BS samples (p < 0.001).

CONCLUSION

The DBS DNA isolation method appeared to be extremely useful to discriminate between genotypes. This expands the possibilities of this quick and easy DNA isolation procedure. In particular, the noninvasive BS sampling method appeared to be a good alternative to invasive sampling methods.