Tyrosine Kinase Inhibitor-Induced Interstitial Lung Disease: Clinical Features, Diagnostic Challenges, and Therapeutic Dilemmas

Repurposing old drugs in oncology: Opportunities with clinical and regulatory challenges ahead

WHAT IS KNOWN AND OBJECTIVE

In order to expedite the availability of drugs to treat cancers in a cost-effective manner, repurposing of old drugs for oncological indications is gathering momentum. Revolutionary advances in pharmacology and genomics have demonstrated many old drugs to have activity at novel antioncogenic pharmacological targets. We decided to investigate whether prospective studies support the promises of nonclinical and retrospective clinical studies on repurposing three old drugs, namely metformin, valproate and astemizole.

METHODS

We conducted an extensive literature search through PubMed to gather representative nonclinical and retrospective clinical studies that investigated the potential repurposing of these three drugs for oncological indications. We then searched for prospective studies aimed at confirming the promises of retrospective data.

RESULTS AND DISCUSSION

While evidence from nonclinical and retrospective clinical studies with these drugs appears highly promising, large scale prospective studies are either lacking or have failed to substantiate this promise. We provide a brief discussion of some of the challenges in repurposing. Principal challenges and obstacles relate to heterogeneity of cancers studied without considering their molecular signatures, trials with small sample size and short duration, failure consider issues of ethnicity of study population and effective antioncogenic doses of the drug studied.

WHAT IS NEW AND CONCLUSION

Well-designed prospective studies demonstrating efficacy are required for repurposing old drugs for oncology indications, just as they are for new chemical entities for any indication. Early and ongoing interactions with regulatory authorities are invaluable. We outline a tentative framework for a structured approach to repurposing old drugs for novel indications in oncology.

Erlotinib versus vinorelbine plus cisplatin as adjuvant therapy in Chinese patients with stage IIIA EGFR mutation-positive non-small-cell lung cancer (EVAN): a randomised, open-label, phase 2 trial

BACKGROUND

Adjuvant chemotherapy after radical resection of stage IIIA non-small-cell lung cancer (NSCLC) has quite poor outcomes. We aimed to investigate whether adjuvant erlotinib therapy improves 2-year disease-free survival compared with chemotherapy in epidermal growth factor receptor (EGFR) mutation-positive stage IIIA NSCLC.

METHODS

In this randomised, open-label, phase 2 trial, eligible patients aged 18-75 years who had undergone complete (R0) resection of histologically or pathologically confirmed stage IIIA EGFR mutation-positive NSCLC and had not received any previous anticancer therapies were enrolled. Patients were randomly assigned (1:1) to receive either adjuvant erlotinib (150 mg once daily administered orally) or vinorelbine and cisplatin chemotherapy (four cycles of vinorelbine [25 mg/m² intravenously on days 1 and 8 of each 21-day cycle] plus cisplatin [75 mg/m² intravenously on day 1 of each 21-day cycle]). Randomisation was done by Simon's minimisation with a random element and was stratified by EGFR activating mutation type (exon 19 vs 21), histology (adenocarcinoma vs non-adenocarcinoma), and smoking status (smoker vs non-smoker). The primary endpoint in the unblinded intention-to-treat analysis was 2-year disease-free survival. This ongoing study is registered with ClinicalTrials.gov, number NCT01683175.

FINDINGS

Between Sept 8, 2012, and May 21, 2015, 102 patients from 16 centres across China were enrolled and randomly assigned to receive erlotinib (n=51) or chemotherapy (n=51). Median follow-up was 33·0 months (IQR 17·8-43·1). 2-year disease-free survival was 81·4% (95% CI 69·6-93·1) in the erlotinib group and 44·6% (26·9-62·4) in the chemotherapy group (relative risk 1·823 [95% CI 1·194-2·784; p=0·0054). The difference in 2-year disease-free survival between the groups was 36·7% (95% CI 15·5-58·0; p=0·0007). Adverse events of any grade occurred in 29 (58%) of 50 patients in the erlotinib group and 28 (65%) of 43 patients in the chemotherapy group. Grade 3 or worse adverse events occurred in six (12%) of 50 patients in the erlotinib group versus 11 (26%) of 43 in the chemotherapy group; the most common of these in the erlotinib group was rash (in two [4%] of 50 patients) and in the chemotherapy group were decreased neutrophil count (in seven [16%] of 43 patients) and myelosuppression (in four [9%]). No treatment-related deaths were reported.

INTERPRETATION

Adjuvant erlotinib improved 2-year disease-free survival in patients with EGFR mutation-positive stage IIIA NSCLC compared with chemotherapy, with a better tolerability profile. This study suggests that tyrosine kinase inhibitors could have a potentially important role as adjuvant therapy in EGFR mutation-positive stage IIIA NSCLC. However, this trial was a phase 2 study. Mature overall survival data are also needed. Ongoing studies will hopefully confirm the role of adjuvant EGFR tyrosine kinase inhibitor therapy in patients with NSCLC.

FUNDING

National Key Research and Development Program of China and Shanghai Roche Pharmaceuticals Ltd.

Precision medicine: does ethnicity information complement genotype-based prescribing decisions?

Inter-ethnic differences in drug response are all too well known. These are underpinned by a number of factors, including pharmacogenetic differences across various ethnic populations. Precision medicine relies on genotype-based prescribing decisions with the aim of maximizing efficacy and mitigating the risks. When there is no access to genotyping tests, ethnicity is frequently regarded as a proxy of the patient's probable genotype on the basis of overall population-based frequency of genetic variations in the ethnic group the patient belongs to, with some variations being ethnicity-specific. However, ever-increasing transcontinental migration of populations and the resulting admixing of populations have undermined the utility of self-identified ethnicity in predicting the genetic ancestry, and therefore the genotype, of the patient. An example of the relevance of genetic ancestry of a patient is the inadequate performance of European-derived pharmacogenetic dosing algorithms of warfarin in African Americans, Brazilians and Caribbean Hispanics. Consequently, genotyping a patient potentially requires testing for all known clinically actionable variants that the patient may harbour, and new variants that are likely to be identified using state-of the art next-generation sequencing-based methods. Furthermore, self-identified ethnicity is associated with a number of ethnicity-related attributes and non-genetic factors that potentially influence the risk of phenoconversion (genotype-phenotype discordance), which may adversely impact the success of genotype-based prescribing decisions. Therefore, while genotype-based prescribing decisions are important in implementing precision medicine, ethnicity should not be disregarded.

Anti-Angiogenic Tyrosine Kinase Inhibitors and Reversible Posterior Leukoencephalopathy Syndrome: Could Hypomagnesaemia Be the Trigger?

Reversible posterior leukoencephalopathy syndrome (RPLS), also known frequently as posterior reversible encephalopathy syndrome (PRES), is a characteristic acute neuro-radiology syndrome with clinical presentation that typically includes acute hypertension, seizures and other neurological symptoms and signs. Many patients with RPLS have (a history of) pre-existing hypertension and in receipt of diuretics. It is being diagnosed more frequently and in association with an increasing number of morbidities and medications. Drugs most frequently implicated are immunosuppressant drugs and anticancer agents, including a number of anti-angiogenic tyrosine kinase inhibitors (TKIs). Hypomagnesaemia is a frequent finding at presentation in RPLS patients, which is known to lead to or aggravate hypertension. Pre-eclampsia, a variant of RPLS, responds effectively to intravenous magnesium. Cyclosporin, tacrolimus and some TKIs that induce RPLS are also known to give rise to both hypertension and hypomagnesaemia. This raises an interesting hypothesis that hypomagnesaemia may play a contributory role in triggering RPLS in some patients by acutely raising the blood pressure further. Additional systematic studies are required to test this hypothesis. If the hypothesis is confirmed, hypomagnesaemia offers an effective target for risk mitigation and prevention of RPLS in patients identified at risk.

Bosutinib induced pleural effusions: Case report and review of tyrosine kinase inhibitors induced pulmonary toxicity

Tyrosine kinase inhibitors are known to cause pulmonary complications. We report a case of bosutinib related bilateral pleural effusions in a patient with chronic myeloid leukemia. Characteristics of the pleural fluid are presented. We also discuss other tyrosine kinase inhibitors induced pulmonary toxicities, including pulmonary hypertension and interstitial lung disease.