Drug interaction between erlotinib and phenytoin for brain metastases in a patient with nonsmall cell lung cancer

Acute Neurological Complications of Brain Tumors and Immune Therapies, a Guideline for the Neuro-hospitalist

PURPOSE OF REVIEW

Patients with brain tumors presenting to the emergency room with acute neurologic complications may warrant urgent investigations and emergent management. As the neuro-hospitalist will likely encounter this complex patient population, an understanding of the acute neurologic issues will have value.

RECENT FINDINGS

We discuss updated information and management regarding various acute neurologic complications among neuro-oncology patients and neurologic complications of immunotherapy. Understanding of the acute neurologic complications associated with central nervous system tumors and with common contemporary cancer treatments will facilitate the neuro-hospitalist management of these patient populations. While there are aspects analogous to the diagnosis and management in the non-oncologic population, a number of unique features discussed in this review should be considered.

Epileptogenesis and oncogenesis: An antineoplastic role for antiepileptic drugs in brain tumours?

The first description of epileptic seizures due to brain tumours occurred in 19th century. Nevertheless, after over one hundred years, scientific literature is still lacking on how epilepsy and its treatment can affect tumour burden, progression and clinical outcomes. In patients with brain tumours, epilepsy dramatically impacts their quality of life (QoL). Even antiepileptic therapy seems to affect tumor lesion development. Numerous studies suggest that certain actors involved in epileptogenesis (inflammatory changes, glutamate and its ionotropic and metabotropic receptors, GABA-A and its GABA-AR receptor, as well as certain ligand- and voltage-gated ion channel) may also contribute to tumorigenesis. Although some antiepileptic drugs (AEDs) are known operating on such mechanisms underlying epilepsy and tumor development, few preclinical and clinical studies have tried to investigate them as targets of pharmacological tools acting to control both phenomena. The primary aim of this review is to summarize known determinants and pathophysiological mechanisms of seizures, as well as of cell growth and spread, in patients with brain tumors. Therefore, a special focus will be provided on the anticancer effects of commonly prescribed AEDs (including levetiracetam, valproic acid, oxcarbazepine and others), with an overview of both preclinical and clinical data. Potential clinical applications of this finding are discussed.

Epilepsy in brain metastasis: an emerging entity

PURPOSE OF REVIEW

The purpose of this review is to highlight advances in the management of seizures in brain metastases from solid tumors.

RECENT FINDINGS

The highest risk for seizures is in patients with melanoma and lung cancer. There is lack of data on the efficacy of antiepileptic drugs (AEDs), but interactions between enzyme-inducing AEDs and anticancer agents must be avoided. Levetiracetam and valproic acid are the most appropriate drugs. Prophylaxis with AEDs for patients with brain metastases without a history of seizures is not recommended. Total resection of a brain metastasis allows complete seizure control. Seizures may represent an adverse effect of stereotactic radiosurgery or of high-dose chemotherapy. New preclinical and clinical studies should define the risk of brain metastasis in light of the new treatment options in the different tumor types. New clinical trials should be designed in patients with brain metastases in terms of treatment or prophylaxis of seizures.

Efficacy and safety of erlotinib combined with bevacizumab in the treatment of non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

Non-small cell lung cancer (NSCLC) has a poor prognosis despite conventional treatments of surgery, radiotherapy, and chemotherapy. Small-molecule tyrosine kinase inhibitors acting on epidermal growth factor receptor (EGFR) have shown high efficacy and low toxicity for NSCLC. In particular, combining erlotinib with the VEGF antibody bevacizumab has therapeutic value in NSCLC, but the drugs' separate effects as monotherapy and any adverse outcomes of combination therapy remain unclear.

OBJECTIVES

To determine the efficacy and safety of erlotinib and bevacizumab for NSCLC, we conducted a meta-analysis and systematic review of randomized controlled trials.

DATA SOURCES

PubMed, Embase, Web of Science, and Cochrane databases were searched using keywords and manual review.

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We reviewed randomized controlled trials on the use of erlotinib combined with bevacizumab in adult patients with NSCLC, including data on outcome measures of overall survival (OS), progression-free survival (PFS), objective response rate (ORR), and adverse events.

STUDY APPRAISAL AND SYNTHESIS METHODS

After quality assessment, datasets were evaluated for heterogeneity. In the event of significant heterogeneity, a random-effects model was used to assess the overall outcome measures as a result of treatments. Subgroup analysis was conducted to evaluate the source of heterogeneity on PFS.

RESULTS

Compared with erlotinib or bevacizumab alone, the combined treatment did not significantly prolong OS (95% confidence interval [CI] = 0.84-1.11; P = .62) or increase the ORR (95% CI = 0.91-1.20; P = .52), but significantly improved PFS (95% CI = 0.58-0.73; P < .001). This improvement was especially notable in patients with the following characteristics: Eastern Cooperative Oncology Group Performance Status score of 0 or 1, female, no smoking history, adenocarcinoma, and EGFR Exon19 deletion or Exon21 Leu858Arg mutation. Combination therapy significantly increased incidence of grade 1-2 hypertension (20.3% vs 6.3%, 95% CI 1.73-5.88; P < .01) and severe diarrhea (10% vs 3.2%, 95% CI 1.36-6.60; P = .01).

LIMITATIONS

The low number of available randomized controlled trials could influence interpretation.

CONCLUSIONS

Compared with erlotinib or bevacizumab monotherapy, their combination effectively prolongs PFS but increases incidence of adverse events in NSCLC patients.

Clinically Significant Drug-Drug Interactions Involving Medications Used for Symptom Control in Patients With Advanced Malignant Disease: A Systematic Review

CONTEXT

Most patients with advanced malignant disease need to take several drugs to control symptoms. This treatment raises risks of serious adverse effects and drug-drug interactions (DDIs).

OBJECTIVES

To identify studies reporting clinically significant DDIs involving medications used for symptom control, other than opioids used for pain management, in adult patients with advanced malignant disease.

METHODS

Systematic review with searches in Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials, from the start of the databases (Embase from 1980) through June 21, 2018. In addition, reference lists of relevant full-text articles were hand-searched.

RESULTS

Of 9699 retrieved citations, 462 were considered potentially eligible. After full-text reading, 29 were included in the final analysis, together with 13 articles from reference lists. The 42 included publications were case reports, letters to the Editor, and one retrospective study. Drugs most often involved were antiepileptics, antidepressants, corticosteroids, and nonopioid analgesics. Clinical manifestations of identified DDIs included sedation, respiratory depression, serotonin syndrome, neuroleptic malignant syndrome, delirium, seizures, ataxia, liver and kidney failure, bleeding, cardiac arrhythmias, rhabdomyolysis, and others. The most common mechanisms eliciting DDIs were alteration of CYP450-dependent metabolism and overstimulation of serotonin receptors in the central nervous system.

CONCLUSION

Drugs used for symptom control in patients with advanced cancer may cause serious DDIs. Although there is limited evidence for the risk of clinically significant DDIs, physicians treating patients with cancer should try to limit polypharmacy, avoid drug combinations with a high risk of DDIs, and closely monitor patients for adverse drug reactions.

Probable drug-drug interaction between erlotinib and amiodarone causes severe neurotoxicity in a patient with advanced lung cancer

Drug-drug interactions (DDIs) are of great concern in the treatment of cancer, especially when target therapies, such as tyrosine kinase inhibitors, are being used. Here, we report a case of probable DDI between erlotinib and amiodarone leading to severe neurotoxicity. Amiodarone inhibits P-glycoprotein (P-gp), for which erlotinib is a substrate. P-gp is an important drug transporter that is involved in limiting the blood-brain barrier penetration of erlotinib. Clinicians should be aware of emerging data characterizing the effect of the P-gp transport system on drug exposure and its potential for DDI.

Meta-analysis of efficacy and adverse events of erlotinib-based targeted therapies for advanced/metastatic non-small cell lung cancer

A network meta-analysis evaluating efficacy and adverse events of eight erlotinib-based therapies (erlotinib+placebo, erlotinib+tivantinib, erlotinib+celecoxib, erlotinib+onartuzumab, erlotinib+sunitinib, erlotinib+entinostat, erlotinib+sorafenib, and erlotinib+bevacizumab) for advanced/metastatic non-small-cell lung cancer (NSCLC) was performed. PubMed and Cochrane Library were reviewed, and ten randomized controlled trials were identified in which patients receiving at least one erlotinib-based therapy. Efficacy outcomes, including progression-free survival (PFS), overall survival (OS), overall response rate (ORR), disease control rate (DCR), and adverse outcomes were evaluated. Patients treated with erlotinib+tivantinib, or erlotinib+celecoxib had longer PFS than patients on erlotinib+placebo; patients on erlotinib+tivantinib had longer OS compared to erlotinib+placebo. For PFS, erlotinib+celecoxib had the highest value of surface under the cumulative ranking curve (SUCRA). For OS, erlotinib+tivantinib had the highest SUCRA. For ORR, erlotinib+bevacizumab had the highest SUCRA, while erlotinib+entinostat ranked the lowest. For DCR, erlotinib+sorafenib had the highest SUCRA. Erlotinib+onartuzumab had the highest SUCRA for diarrhea, nausea, vomiting, decreased appetite, and dyspnea. Erlotinib+sunitinib had the lowest SUCRA for diarrhea, nausea, vomiting, and decreased appetite. Erlotinib + entinostat had the lowest SUCRA for fatigue, asthenia, and dyspnea. Our study suggests erlotinib+tivantinib and erlotinib+celecoxib regimens have the best long-term efficacy, while erlotinib+sunitinib and erlotinib+entinostat have the fewest adverse effects in patients with advanced/metastatic NSCLC.