Dose Escalation and Pharmacokinetics Study of Enzastaurin and Sunitinib Versus Placebo and Sunitinib in Patients With Metastatic Renal Cell Carcinoma

FHIT, a Novel Modifier Gene in Pulmonary Arterial Hypertension

RATIONALE

Pulmonary arterial hypertension (PAH) is characterized by progressive narrowing of pulmonary arteries, resulting in right heart failure and death. BMPR2 (bone morphogenetic protein receptor type 2) mutations account for most familial PAH forms whereas reduced BMPR2 is present in many idiopathic PAH forms, suggesting dysfunctional BMPR2 signaling to be a key feature of PAH. Modulating BMPR2 signaling is therapeutically promising, yet how BMPR2 is downregulated in PAH is unclear.

OBJECTIVES

We intended to identify and pharmaceutically target BMPR2 modifier genes to improve PAH.

METHODS

We combined siRNA high-throughput screening of >20,000 genes with a multicohort analysis of publicly available PAH RNA expression data to identify clinically relevant BMPR2 modifiers. After confirming gene dysregulation in tissue from patients with PAH, we determined the functional roles of BMPR2 modifiers in vitro and tested the repurposed drug enzastaurin for its propensity to improve experimental pulmonary hypertension (PH).

MEASUREMENTS AND MAIN RESULTS

We discovered FHIT (fragile histidine triad) as a novel BMPR2 modifier. BMPR2 and FHIT expression were reduced in patients with PAH. FHIT reductions were associated with endothelial and smooth muscle cell dysfunction, rescued by enzastaurin through a dual mechanism: upregulation of FHIT as well as miR17-5 repression. Fhit-/- mice had exaggerated hypoxic PH and failed to recover in normoxia. Enzastaurin reversed PH in the Sugen5416/hypoxia/normoxia rat model, by improving right ventricular systolic pressure, right ventricular hypertrophy, cardiac fibrosis, and vascular remodeling.

CONCLUSIONS

This study highlights the importance of the novel BMPR2 modifier FHIT in PH and the clinical value of the repurposed drug enzastaurin as a potential novel therapeutic strategy to improve PAH.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for nonrhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In people with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity. The rationale for this update is to determine whether any randomized controlled trials (RCTs) have been conducted and to clarify whether HDCT followed by autologous HSCT has a survival advantage.

OBJECTIVES

To assess the efficacy and safety of high-dose chemotherapy (HDCT) followed by autologous hematopoietic stem cell transplantation (HSCT) for all stages of nonrhabdomyosarcoma soft tissue sarcomas (NRSTS) in children and adults.

SEARCH METHODS

For this update, we revised the search strategy to improve the precision and reduce the number of irrelevant hits. We searched the following electronic databases: Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 8), PubMed from 2012 to 6 September 2016, and Embase from 2012 to 26 September 2016. We searched online trial registries and congress proceedings from 2012 to 26 September 2016.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title or abstract. We restricted the study design to RCTs. We included studies if at least 80% of participants had a diagnosis listed in any version of the World Health Organization (WHO) classification and classified as malignant. The search included children and adults with no age limits.

DATA COLLECTION AND ANALYSIS

We used standard methodologic procedures expected by Cochrane. The primary outcomes were overall survival and treatment-related mortality.

MAIN RESULTS

We identified 1549 records; 85 items from electronic databases, 45 from study registries, and 1419 from congress proceedings. The revised search strategy did not identify any additional RCTs. In the previous version of the review, we identified one RCT comparing HDCT followed by autologous HSCT versus standard-dose chemotherapy (SDCT). The trial randomized 87 participants who were considerably heterogeneous with respect to 19 different tumor entities. The data from 83 participants were available for analysis.In the single included trial, overall survival at three years was 32.7% in the HDCT arm versus 49.4% in the SDCT arm and there was no difference between the treatment groups (hazard ratio (HR) 1.26, 95% confidence interval (CI) 0.70 to 2.29, P = 0.44; 1 study, 83 participants; high quality evidence). In a subgroup of participants who had a complete response before HDCT, overall survival was higher in both treatment groups and overall survival at three years was 42.8% in the HDCT arm versus 83.9% in the SDCT arm and favored the SDCT group (HR 2.92, 95% CI 1.1 to 7.6, P = 0.028; 1 study, 39 participants).In the single included trial, the authors reported one treatment-related leukemia death two years after HDCT. They also evaluated severe adverse events WHO grade 3 to 4 in 22 participants in the HDCT arm and in 51 participants in the SDCT arm. The authors reported 11 events concerning digestive-, infection-, pain-, or asthenia-related toxicity in the HDCT arm and one event in the SDCT arm (moderate quality evidence). The development of secondary neoplasia was not addressed. We judged the study to have an overall unclear risk of bias as three of seven items had unclear and four items had low risk of bias. For GRADE, we judged three items as high quality and three items were not reported.

AUTHORS' CONCLUSIONS

The limited data of a single RCT with an unclear risk of bias and moderate to high quality evidence showed no survival advantage for HDCT. If this treatment is offered it should only be given after careful consideration on an individual person basis and possibly only as part of a well-designed RCT.

Sunitinib in kidney cancer: 10 years of experience and development

INTRODUCTION

Sunitinib is a multi-target, anti-angiogenic tyrosine kinase inhibitor and a key molecule in the treatment of metastatic renal cell carcinoma (mRCC). Since it first demonstrated its efficacy ten years ago, overall survival of mRCC has more than doubled, in part due to sunitinib. In most recent years, progress has been made in the comprehension of its mechanism of action and resistance. Areas Covered: In this article, clinical trials involving sunitinib in kidney cancer have been reviewed, defining its different indications in metastatic and localized RCC. The rationale of sunitinib's efficacy, preclinical trials, past-clinical trials and ongoing clinical trials are summarized. Dose and scheme base are discussed, as the recommended dosage is frequently not well tolerated. Combination therapies appear to be toxic. Novel immunotherapies are changing the landscape of mRCC treatment and challenging sunitinib. Special attention has been paid towards cancer cell biology and immunity involved in treatment response. Expert Commentary: Sunitinib's place in the therapeutic arsenal is being redefined with the arrival of major challengers. Dosage and scheduling of sunitinib remains a major challenge.

The Evolution of Nephrectomy and Patient Characteristics in Metastatic Renal Cell Carcinoma Patients Enrolled Into First-Line Tyrosine Kinase Inhibitors Clinical Trials

INTRODUCTION

The objective of this study was to compare rates of nephrectomy (Nx) in, and characteristics of, patients with metastatic renal cell carcinoma (mRCC) enrolled in prospective clinical trials of tyrosine kinase inhibitors (TKIs) that were completed through (Group 1) versus after (Group 2) 2007.

PATIENTS AND METHODS

Searching online databases, we retrospectively identified phase I to III trials with ≥ 15 patients with mRCC treated with first-line TKIs, alone or in combination with other agent(s).

RESULTS

Of 70 trials identified, 42 were included in the analysis (n = 6074 patients). Compared with Group 1, Group 2 patients had significantly less Nx (85.7% vs. 93.7%; P < .001) and prior cytokine therapy (11.1% vs. 46.8%; P < .001). Group 2 also had significantly fewer patients with good prognostic risk (based on Memorial Sloan-Kettering Cancer Center criteria) or performance status (both P < .001). Group 2 patients had a significantly greater objective response rate than Group 1 patients (intent-to-treat analysis: 28.6% vs. 23.1%, respectively; P < .001), whereas Group 1 patients had significantly more stable disease. Clinical benefit was similar in both groups (P = .157), and the means of median progression-free survival were comparable (8.2 and 9.0 months in Groups 1 and 2, respectively; P = .2528).

CONCLUSIONS

Use of Nx in mRCC patients participating in clinical trials has declined in the TKI era. More patients with worse prognostic risk profiles are participating in first-line TKI trials after 2007, but objective response rates are higher. Despite patient characteristics that favor the earlier group, progression-free survival is similar as TKIs have replaced cytokines as first-line therapy.

Benefit, Risk, and Outcomes in Drug Development: A Systematic Review of Sunitinib

BACKGROUND

Little is known about the total patient burden associated with clinical development and where burdens fall most heavily during a drug development program. Our goal was to quantify the total patient burden/benefit in developing a new drug.

METHODS

We measured risk using drug-related adverse events that were grade 3 or higher, benefit by objective response rate, and trial outcomes by whether studies met their primary endpoint with acceptable safety. The differences in risk (death rate) and benefit (overall response rate) between industry and nonindustry trials were analyzed with an inverse-variance weighted fixed effects meta-analysis implemented as a weighted regression analysis. All statistical tests were two-sided.

RESULTS

We identified 103 primary publications of sunitinib monotherapy, representing 9092 patients and 3991 patient-years of involvement over 10 years and 32 different malignancies. In total, 1052 patients receiving sunitinib monotherapy experienced objective tumor response (15.7% of intent-to-treat population, 95% confidence interval [CI] = 15.3% to 16.0%), 98 died from drug-related toxicities (1.08%, 95% CI = 1.02% to 1.14%), and at least 1245 experienced grade 3-4 drug-related toxicities (13.7%, 95% CI = 13.3% to 14.1%). Risk/benefit worsened as the development program matured, with several instances of replicated negative studies and almost no positive trials after the first responding malignancies were discovered.

CONCLUSIONS

Even for a successful drug, the risk/benefit balance of trials was similar to phase I cancer trials in general. Sunitinib monotherapy development showed worsening risk/benefit, and the testing of new indications responded slowly to evidence that sunitinib monotherapy would not extend to new malignancies. Research decision-making should draw on evidence from whole research programs rather than a narrow band of studies in the same indication.

Novel approaches targeting the vascular endothelial growth factor axis in renal cell carcinoma

In recent years, functional characterization of the von Hippel-Lindau tumor suppressor, hypoxia-induced factors, and one of their key downstream effectors, the vascular endothelial growth factor (VEGF), has revolutionized treatment of advanced renal cell carcinoma. Therapeutic strategies targeting the ligand itself (VEGF-A) or its receptor (VEGFR2) have proven successful. However, complete remissions are rare, and with time patients invariably suffer disease progression. It is understood that this is due to incomplete suppression of VEGF signaling and/or adaptive up-regulation of non-VEGF-dependent tumor-promoting stimuli. In this article, we review novel VEGF-directed agents that are being developed to address the shortcomings of current targeted drugs for the treatment of advanced renal cell carcinoma. Building on our current understanding of molecular mechanisms behind resistance, examples include next-generation multitarget tyrosine kinase inhibitors, biologics, and other compounds.