Michael L. Maitland

Inflammation, Growth Factors, and Pulmonary Vascular Remodeling

Inflammatory processes are prominent in various types of human and experimental pulmonary hypertension (PH) and are increasingly recognized as major pathogenic components of pulmonary vascular remodeling. Macrophages, T and B lymphocytes, and dendritic cells are present in the vascular lesions of PH, whether in idiopathic pulmonary arterial hypertension (PAH) or PAH related to more classical forms of inflammatory syndromes such as connective tissue diseases, human immunodeficiency virus (HIV), or other viral etiologies. Similarly, the presence of circulating chemokines and cytokines, viral protein components (e.g., HIV-1 Nef), and increased expression of growth (such as vascular endothelial growth factor and platelet-derived growth factor) and transcriptional (e.g., nuclear factor of activated T cells or NFAT) factors in these patients are thought to contribute directly to further recruitment of inflammatory cells and proliferation of smooth muscle and endothelial cells. Other processes, such as mitochondrial and ion channel dysregulation, seem to convey a state of cellular resistance to apoptosis; this has recently emerged as a necessary event in the pathogenesis of pulmonary vascular remodeling. Thus, the recognition of complex inflammatory disturbances in the vascular remodeling process offers potential specific targets for therapy and has recently led to clinical trials investigating, for example, the use of tyrosine kinase inhibitors. This paper provides an overview of specific inflammatory pathways involving cells, chemokines and cytokines, cellular dysfunctions, growth factors, and viral proteins, highlighting their potential role in pulmonary vascular remodeling and the possibility of future targeted therapy.

Carboplatin and Paclitaxel in Combination With Either Vorinostat or Placebo for First-Line Therapy of Advanced Non–Small-Cell Lung Cancer

PURPOSE Vorinostat, a histone deacetylase inhibitor, exerts anticancer effects by both histone and nonhistone-mediated mechanisms. It also enhances the anticancer effects of platinum compounds and taxanes in non-small-cell lung cancer (NSCLC) cell lines. This phase II randomized, double-blinded, placebo-controlled study evaluated the efficacy of vorinostat in combination with carboplatin and paclitaxel in patients with advanced-stage NSCLC. PATIENTS AND METHODS Patients with previously untreated stage IIIB (ie, wet) or IV NSCLC were randomly assigned (2:1) to carboplatin (area under the curve, 6 mg/mL x min) and paclitaxel (200 mg/m(2) day 3) with either vorinostat (400 mg by mouth daily) or placebo. Vorinostat or placebo was given on days 1 through 14 of each 3-week cycle to a maximum of six cycles. The primary end point was comparison of the response rate. Results Ninety-four patients initiated protocol therapy. Baseline patient characteristics were similar between the two arms. The median number of cycles was four for both treatment arms. The confirmed response rate was 34% with vorinostat versus 12.5% with placebo (P = .02). There was a trend toward improvement in median progression-free survival (6.0 months v 4.1 months; P = .48) and overall survival (13.0 months v 9.7 months; P = .17) in the vorinostat arm. Grade 4 platelet toxicity was more common with vorinostat (18% v 3%; P < .05). Nausea, emesis, fatigue, dehydration, and hyponatremia also were more frequent with vorinostat. CONCLUSION Vorinostat enhances the efficacy of carboplatin and paclitaxel in patients with advanced NSCLC. HDAC inhibition is a promising therapeutic strategy for treatment of NSCLC.

Ambulatory Monitoring Detects Sorafenib-Induced Blood Pressure Elevations on the First Day of Treatment

Purpose: Hypertension is a mechanism-based toxicity of sorafenib and other cancer therapeutics that inhibit the vascular endothelial growth factor (VEGF) signaling pathway. This prospective, single-center, cohort study characterized ambulatory blood pressure monitoring as an early pharmacodynamic biomarker of VEGF signaling pathway inhibition by sorafenib. Experimental Design: Fifty-four normotensive advanced cancer patients underwent 24-hour ambulatory blood pressure monitoring before and between days 6 and 10 of sorafenib therapy. After blood pressure changes were detected among the first cohort within 10 days, ambulatory blood pressure monitoring was done during the first 24 hours of treatment for the second cohort. Results: For the entire patient population, the blood pressure increase [mean systolic, +10.8 mm Hg; 95% confidence interval (95% CI), 8.6-13.0; range, −5.2 to +28.7 mm Hg; mean diastolic, +8.0 mm Hg; 95% CI, 6.3-9.7; range, −4.4 to +27.1 mm Hg] was detected between days 6 and 10 (P < 0.0001 for both) and plateaued thereafter. Variability in blood pressure change did not associate with: age, body size, sex, self-reported race, baseline blood pressure, or steady-state sorafenib plasma concentrations. In the second cohort, the blood pressure elevation was detected during the first 24 hours (mean systolic, +8.2 mm Hg; 95% CI, 5.0-11.3; mean diastolic, +6.5 mm Hg; 95% CI, 4.7-8.3; P < 0.0001 for both). Conclusions: Ambulatory blood pressure monitoring detects the blood pressure response to VEGF signaling pathway inhibition by sorafenib during the first 24 hours of treatment. The magnitude of blood pressure elevation is highly variable and unpredictable but could be important in optimizing the therapeutic index of VEGF signaling pathway inhibitor therapy. (Clin Cancer Res 2009;15(19):6250–7)

A proposed EGFR inhibitor dermatologic adverse event-specific grading scale from the MASCC skin toxicity study group

BackgroundAccurate grading of dermatologic adverse events (AE) due to epidermal growth factor receptor (EGFR) inhibitors (EGFRIs) is necessary for drug toxicity determinations, interagent comparisons, and supportive care trials. The most widely used severity grading scale, the National Cancer Institute’s Common Terminology Criteria for Adverse Events version 4.0 (NCI-CTCAE v4.0), was not designed specifically for this class of agents and may result in underreporting and poor grading of distinctive adverse events. We believe a class-specific grading scale is needed to help standardize assessment and improve reporting of EGFRI-associated dermatologic AEs.MethodsThe Multinational Association of Supportive Care in Cancer (MASCC) Skin Toxicity Study Group conducted an international multidisciplinary meeting that included 20 clinicians and researchers from academic centers and government agencies. Experts from different disciplines presented current information specific to EGFRI-induced dermatologic toxicities: grading scale development, pharmacovigilance safety reporting, health-related quality of life, patient reporting, and pharmacology. Group discussions, literature reviews, and professional expertise established the theoretical foundation for the proposed grading scale.ResultsA new grading system is proposed for the most common events associated with EGFRI-induced dermatologic AEs: papulopustular reaction or acneiform rash, nail changes, erythema, pruritus, xerosis, hair changes, telangiectasias, hyperpigmentation, mucositis, flushing, radiation dermatitis, hyposalivation, and taste changes. The proposed scale maintains consistency with the grading principles and language of the existing CTCAE version 4.0 and MedDRA terminology and includes relevant patient-reported health-related quality of life factors.ConclusionsA grading scale specific to EGFR inhibitor dermatologic AEs is presented for formal integration into future versions of CTCAE and for validation in clinical trial settings. The study group designed this scale to detect and report EGFRI-related toxicities with greater sensitivity, specificity, and range than the scales currently used. This scale should serve as a foundation for efforts to perform objective interdrug comparisons and assessments of supportive care treatment strategies more effectively than with current methods.

Cancer pharmacogenomics: strategies and challenges

Genetic variation influences the response of an individual to drug treatments. Understanding this variation has the potential to make therapy safer and more effective by determining selection and dosing of drugs for an individual patient. In the context of cancer, tumours may have specific disease-defining mutations, but a patients germline genetic variation will also affect drug response (both efficacy and toxicity), and here we focus on how to study this variation. Advances in sequencing technologies, statistical genetics analysis methods and clinical trial designs have shown promise for the discovery of variants associated with drug response. We discuss the application of germline genetics analysis methods to cancer pharmacogenomics with a focus on the special considerations for study design.

Genomic assessment of a multikinase inhibitor, sorafenib, in a rodent model of pulmonary hypertension

Pulmonary hypertension (PH) and cancer pathology share growth factor- and MAPK stress-mediated signaling pathways resulting in endothelial and smooth muscle cell dysfunction and angioproliferative vasculopathy. In this study, we assessed sorafenib, an antineoplastic agent and inhibitor of multiple kinases important in angiogenesis [VEGF receptor (VEGFR)-1-3, PDGF receptor (PDGFR)-beta, Raf-1 kinase] as a potential PH therapy. Two PH rat models were used: a conventional hypoxia-induced PH model and an augmented PH model combining dual VEGFR-1 and -2 inhibition (SU-5416, single 20 mg/kg injection) with hypoxia. In addition to normoxia-exposed control animals, four groups were maintained at 10% inspired O(2) fraction for 3.5 wk (hypoxia/vehicle, hypoxia/SU-5416, hypoxia/sorafenib, and hypoxia/SU-5416/sorafenib). Compared with normoxic control animals, rats exposed to hypoxia/SU-5416 developed hemodynamic and histological evidence of severe PH while rats exposed to hypoxia alone displayed only mild elevations in hemodynamic values (pulmonary vascular and right ventricular pressures). Sorafenib treatment (daily gavage, 2.5 mg/kg) prevented hemodynamic changes and demonstrated dramatic attenuation of PH-associated vascular remodeling. Compared with normoxic control rats, expression profiling (Affymetrix platform) of lung RNA obtained from hypoxia [false discovery rate (FDR) 6.5%]- and hypoxia/SU-5416 (FDR 1.6%)-challenged rats yielded 1,019 and 465 differentially regulated genes (fold change >1.4), respectively. A novel molecular signature consisting of 38 differentially expressed genes between hypoxia/SU-5416 and hypoxia/SU-5416/sorafenib (FDR 6.7%) was validated by either real-time RT-PCR or immunoblotting. Finally, immunoblotting studies confirmed the upregulation of the MAPK cascade in both PH models, which was abolished by sorafenib. In summary, sorafenib represents a novel potential treatment for severe PH with the MAPK cascade a potential canonical target.

Management of cardiac toxicity in patients receiving vascular endothelial growth factor signaling pathway inhibitors

BACKGROUND Interfering with angiogenesis is an effective, widely used approach to cancer therapy, but antiangiogenic therapies have been associated with important systemic cardiovascular toxicities such as hypertension, left ventricular dysfunction, heart failure, and myocardial ischemia and infarction. As the use of vascular endothelial growth factor signaling pathway (VSP) inhibitors broadens to include older patients and those with existing cardiovascular disease, the adverse effects are likely to be more frequent, and cardiologists will increasingly be enlisted to help oncologists manage patients who develop adverse cardiovascular effects. METHODS The Cardiovascular Toxicities Panel of the National Cancer Institute reviewed the published literature and abstracts from major meetings, shared experience gained during clinical development of VSP inhibitors, and contributed extensive clinical experience in evaluating and treating patients with cancer with cardiovascular disease. This report was edited and approved by the National Cancer Institute Investigational Drug Steering Committee. It presents the panels expert opinion on the current clinical use and future investigation for safer, more expansive use of these drugs. RESULTS AND CONCLUSIONS The panel recommends that physicians (1) conduct and document a formal risk assessment for existing cardiovascular disease and potential cardiovascular complications before VSP inhibitor treatment recognizing that preexisting hypertension and cardiovascular disease are common in patients with cancer, (2) actively monitor for blood pressure elevations and cardiac toxicity with more frequent assessments during the first treatment cycle, and (3) aggressively manage blood pressure elevations and early symptoms and signs of cardiac toxicity to prevent clinically limiting complications of VSP inhibitor therapy.

A Dosing/Cross‐Development Study of the Multikinase Inhibitor Sorafenib in Patients With Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) and cancer share elements of pathophysiology. This provides an opportunity for the cross‐development of anticancer agents that can be used in improving PAH care. The adaptation of new drugs across these disease populations warrants a structured approach. This study was a 16‐week, phase Ib, single‐center, open‐label trial of the multikinase/angiogenesis inhibitor sorafenib. In order to assess the safety of sorafenib in PAH, patients with advanced but stable disease on parenteral prostanoids (with or without oral sildenafil) were initiated on treatment at the lowest active dosage administered to cancer patients: 200 mg daily. Patients underwent weekly clinical evaluations and monthly functional testing and dose escalations to a final dosage of 400 mg twice daily. Among 12 patients (10 of them women), sorafenib was well tolerated at 200 mg twice daily. The most common adverse events were moderate skin reactions on the hands and feet and alopecia. Our conclusion was therefore that this is a tolerable dosing regimen for testing the therapeutic activity of sorafenib in PAH patients.

Dose-Finding and Pharmacokinetic Study to Optimize the Dosing of Irinotecan According to the UGT1A1 Genotype of Patients With Cancer

PURPOSE The risk of severe neutropenia from treatment with irinotecan is related in part to UGT1A1*28, a variant that reduces the elimination of SN-38, the active metabolite of irinotecan. We aimed to identify the maximum-tolerated dose (MTD) and dose-limiting toxicity (DLT) of irinotecan in patients with advanced solid tumors stratified by the *1/*1, *1/*28, and *28/*28 genotypes. PATIENTS AND METHODS Sixty-eight patients received an intravenous flat dose of irinotecan every 3 weeks. Forty-six percent of the patients had the *1/*1 genotype, 41% had the *1/*28 genotype, and 13% had the *28/*28 genotype. The starting dose of irinotecan was 700 mg in patients with the *1/*1 and *1/*28 genotypes and 500 mg in patients with the *28/*28 genotype. Pharmacokinetic evaluation was performed at cycle 1. RESULTS In patients with the *1/*1 genotype, the MTD was 850 mg (four DLTs per 16 patients), and 1,000 mg was not tolerated (two DLTs per six patients). In patients with the *1/*28 genotype, the MTD was 700 mg (five DLTs per 22 patients), and 850 mg was not tolerated (four DLTs per six patients). In patients with the *28/*28 genotype, the MTD was 400 mg (one DLT per six patients), and 500 mg was not tolerated (three DLTs per three patients). The DLTs were mainly myelosuppression and diarrhea. Irinotecan clearance followed linear kinetics. At the MTD for each genotype, dosing by genotype resulted in similar SN-38 areas under the curve (AUCs; r(2) = 0.0003; P = .97), but the irinotecan AUC was correlated with the actual dose (r(2) = 0.39; P < .001). Four of 48 patients with disease known to be responsive to irinotecan achieved partial response. CONCLUSION The UGT1A1*28 genotype can be used to individualize dosing of irinotecan. Additional studies should evaluate the effect of genotype-guided dosing on efficacy in patients receiving irinotecan.

Clinical Trials in the Era of Personalized Oncology

The rapid pace of discoveries in tumor biology, imaging technology, and human genetics hold promise for an era of personalized oncology care. The successful development of a handful of new targeted agents has generated much hope and hype about the delivery of safer and more effective new treatments for cancer. The design and conduct of clinical trials has not yet adjusted to a new era of personalized oncology and so we are more in transition to that era than in it. With the development of treatments for breast cancer as a model, we review the approaches to clinical trials and the development of novel therapeutics in the prior era of population oncology, the current transitional era, and the future era of personalized oncology. CA Cancer J Clin 2011.