Safety, pharmacokinetics and pharmacodynamics of selgantolimod, an oral Toll-like receptor 8 agonist: a Phase Ia study in healthy subjects.

BACKGROUND: Selgantolimod is a novel oral, selective Toll-like receptor 8 (TLR8) agonist in development for the treatment of chronic hepatitis B (CHB). TLR8 is an endosomal innate immune receptor and a target for treatment of viral infections. This first-in-human study investigated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of selgantolimod in healthy volunteers. METHODS: Of 71 subjects enrolled, 59 received a single dose of selgantolimod (0.5, 1.5, 3 or 5 mg) or placebo, and 12 were evaluated for food effect. Safety, PK and PD activity by induction of cytokines, chemokines and acute phase proteins were assessed. PK/PD analyses were conducted. RESULTS: Single doses of 0.5-5 mg were generally safe. No serious adverse events (AEs) or AEs leading to discontinuation were reported, and most were Grade 1 in severity. Selgantolimod displayed rapid absorption and dose-proportional PK and PD activity. Food had minimal effect on PK but resulted in diminished PD activity. In PK/PD analyses, near-saturation of induction for most evaluated biomarkers occurred at the 5-mg dose. CONCLUSIONS: Single doses of up to 5 mg selgantolimod were safe and induced dose-dependent PD responses. These data support evaluation of selgantolimod in combination with other agents in future clinical studies of CHB. Australian New Zealand Clinical Trials Registration: ACTRN12616001646437.

Combined GS-4774 and Tenofovir Therapy Can Improve HBV-Specific T-Cell Responses in Patients With Chronic Hepatitis.

BACKGROUND & AIMS: One strategy to treat chronic hepatitis B virus (HBV) infection could be to increase the functions of virus-specific T cells. We performed a multicenter phase 2 study to evaluate the safety and efficacy of GS-4774, a yeast-based therapeutic vaccine engineered to express HBV antigens, given with tenofovir disoproxil fumarate (TDF) to untreated patients with chronic HBV infection. METHODS: We performed an open-label study at 34 sites in Canada, Italy, New Zealand, Romania, South Korea, and United States from July 2014 to August 2016. Adults who were positive for HB surface antigen (HBsAg) > 6 months and levels of HBV DNA ≥2000 IU/mL who had not received antiviral treatment for HBV within 3 months of screening were randomly assigned (1:2:2:2) to groups given oral TDF 300 mg daily alone (n = 27; controls) or with 2, 10, or 40 yeast units GS-4774 (n = 168), administered subcutaneously every 4 weeks until week 20 for a total of 6 doses. Blood samples were collected and analyzed and patients received regular physical examinations. Efficacy was measured by decrease in HBsAg from baseline to week 24. Specific responses to HBV (production of interferon gamma [IFNG], tumor necrosis factor [TNF], interleukin 2 [IL2], and degranulation) were measured in T cells derived from 12 HBeAg-negative patients with genotype D infections, after overnight or 10 days of stimulation of peripheral blood mononuclear cells with peptides from the entire HBV proteome. T-regulatory cells were analyzed for frequency and phenotype. Data from studies of immune cells were compared with data on reductions in HBsAg, HBV DNA, and alanine aminotransferase in blood samples from patients. RESULTS: GS-4774 was safe and well tolerated but did not produce significant decreases in levels of HBsAg. Production of IFNG, TNF, and IL2 increased significantly at weeks 24 and 48, compared with baseline, in HBV-specific CD8+ T cells from patients given GS-4774 but not from controls. GS-4774 had greater effects on CD8+ than CD4+ T cells, which were not affected at all or very weakly by TDF with or without GS-4774. GS-4774 did not affect responses of T cells to other viruses tested. HBV core peptides induced the greatest production of IFNG by T cells following overnight stimulation, whereas HBV envelope antigens did not induce a response. Following 10 days of stimulation, production of IFNG and TNF increased with time of exposure to GS-4774; the greatest levels of responses were to HBV envelope antigens followed by core and polymerase peptides. We observed a correlation in patients given GS-4774 between increased T-cell functions and reductions in numbers of T-regulatory cells. CONCLUSIONS: In a phase 2 study of patients with chronic HBV infection given TDF with or without GS-4774, we found that vaccination can increase production of IFNG, TNF, and IL2 by CD8+ T cells exposed to antigenic peptides, with little effect on CD4+ T cells. Although GS-4774 did not reduce levels of HBsAg in patients, its strong immune stimulatory effect on CD8+ T cells might be used in combination with other antiviral agents to boost the antivirus immune response. Clinicaltrials.gov no: NCT02174276.

Safety, efficacy and pharmacodynamics of vesatolimod (GS-9620) in virally suppressed patients with chronic hepatitis B.

BACKGROUND & AIMS: Vesatolimod (GS-9620) is an oral agonist of toll-like receptor 7, an activator of innate and adaptive immune responses. Herein the safety and efficacy of vesatolimod is assessed after once-weekly treatment in patients with chronic hepatitis B (CHB) infection suppressed on oral antiviral treatment. METHODS: In a phase II, double-blind, randomized, placebo (PBO)-controlled study, 162 patients stratified by hepatitis B surface antigen (HBsAg) levels and serum hepatitis B e antigen (HBeAg) status were randomized 1:3:3:3 to once-weekly oral PBO or vesatolimod (1-, 2-, or 4-mg doses) for 4, 8 or 12 weeks per cohort. Efficacy was assessed by change in baseline HBsAg (log10 IU/ml) at the primary endpoint (Week 24). Safety assessments included adverse events (AE) and laboratory abnormality monitoring. Pharmacodynamic assessments included peripheral cytokine level quantification and interferon-stimulated gene (ISG) mRNA expression evaluation. RESULTS: The majority of patients were male (76%) and HBeAg-negative (79%) at baseline. Most (41-80%) experienced ≥1 AE during the study with the majority of AEs mild or moderate in severity. No significant declines in HBsAg were observed at the primary (Week 24) or secondary endpoints (Weeks 4, 8, 12, and 48). ISG15 induction was dose-dependent and consistent after repeat dosing, returning closer to baseline by one week after treatment at all dose levels; no patient demonstrated significant serum interferon alpha (IFNα) expression at any timepoint evaluated. Multivariate analyses showed that ≥2-fold ISG15 induction is associated with 2- or 4-mg vesatolimod dose and female sex. CONCLUSIONS: Vesatolimod was safe and well-tolerated in patients with CHB, demonstrating consistent dose-dependent pharmacodynamic induction of ISG15 without significant systemic induction of IFNα expression or related symptoms. However, no significant HBsAg declines were observed. LAY SUMMARY: In a phase II study, vesatolimod, an oral, once-weekly, experimental immune-activating drug for the treatment of hepatitis B virus (HBV), is safe and well-tolerated in chronic HBV patients who are virally suppressed on oral antiviral treatment. Despite demonstrating on-target biomarker responses in patients, no significant declines in hepatitis B surface antigen were observed. Clinical Trial Number: GS-US-283-1059; NCT 02166047.

Statistical design for a confirmatory trial with a continuous predictive biomarker: A case study.

With targeted therapies, it is often hypothesized that their effect may be specific to the subpopulation in which the target pathway is activated. We consider the problem of designing a confirmatory trial when the biological hypothesis of the experimental therapy is strongly supported by the pre-clinical data but limited clinical data is available to pre-define a subpopulation based on a biomarker with continuous values. The study design is further complicated if interim evaluations of the biomarker-based subpopulations are also being considered. We compared several strategies, including a naïve threshold nomination approach, a modification of the "explore and confirm" strategy proposed by Friedlin et al. (2005), and a novel biomarker sequential testing approach, motivated by the "general bivariate normal method" discussed by Wang el al. (2007), and further discussions in Spiessens and Debois (2010) and Holmgren (2017), in a setting where all-comers and biomarker subpopulation evaluations can be performed at interim analyses as well as the end of study. Based on extensive simulations, we concluded that the novel biomarker sequential testing approach out-performed other strategies when there was limited prior information for biomarker threshold determination. This design was implemented in a recently completed clinical trial of simtuzumab (RAINIER study) and provides a useful case study for designing future confirmatory clinical trials of novel targeted therapies.

Phase 2 study of idelalisib and entospletinib: pneumonitis limits combination therapy in relapsed refractory CLL and NHL.

Although agents targeting B-cell receptor signaling have provided practice-changing results in relapsed chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL), they require prolonged administration and provide incomplete responses. Given synergistic preclinical activity with phosphatidylinositol 3-kinase δ and spleen tyrosine kinase inhibition, this phase 2 study evaluated the safety and efficacy of the combination of idelalisib and entospletinib. Eligible patients with relapsed or refractory CLL or NHL underwent intrapatient dose escalation with each agent. With a median treatment exposure of 10 weeks, 60% and 36% of patients with CLL or follicular lymphoma, respectively, achieved objective responses. However, the study was terminated early because of treatment-emergent pneumonitis in 18% of patients (severe in 11 of 12 cases). Although most patients recovered with supportive measures and systemic steroids, 2 fatalities occurred and were attributed to treatment-emergent pneumonitis. Increases of interferon-γ and interleukins 6, 7, and 8 occurred over time in patients who developed pneumonitis. Future studies of novel combinations should employ conservative designs that incorporate pharmacodynamics/biomarker monitoring. These investigations should also prospectively evaluate plasma cytokine/chemokine levels in an attempt to validate biomarkers predictive of response and toxicity. This trial was registered at www.clinicaltrials.gov as #NCT01796470.

A randomised non-comparative phase II trial of cixutumumab (IMC-A12) or ramucirumab (IMC-1121B) plus mitoxantrone and prednisone in men with metastatic docetaxel-pretreated castration-resistant prostate cancer.

BACKGROUND: Cixutumumab, a human monoclonal antibody (HuMAb), targets the insulin-like growth factor receptor. Ramucirumab is a recombinant HuMAb that binds to vascular endothelial growth factor receptor-2. A non-comparative randomised phase II study evaluated cixutumumab or ramucirumab plus mitoxantrone and prednisone (MP) in metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: Men with progressive mCRPC during or after docetaxel therapy received mitoxantrone 12 mg/m(2) on day 1 and prednisone 5mg twice daily and were randomised 1:1 to receive either cixutumumab or ramucirumab 6 mg/kg intravenously weekly in a 21-day cycle. Primary end-point was composite progression-free survival (cPFS). Secondary end-points included safety, response, radiographic progression-free survival (PFS) and overall survival (OS). Sample size was based on a 50% increase in median cPFS from 2.6 (MP) to 3.9 months (either combination). RESULTS: 132 men were treated (66 per arm). Median cPFS was 4.1 months (95% confidence interval (CI), 2.2-5.6) for cixutumumab and 6.7 months (95% CI, 4.5-8.3) for ramucirumab. Median time to radiographic progression was 7.5 months for cixutumumab and 10.2 months for ramucirumab, with a median OS of 10.8 and 13.0 months, respectively. Fatigue was the most frequent adverse event (AE). Incidence of most non-haematologic grade 3-4 AEs was <10% on both arms. Grade 3 cardiac dysfunction occurred in 7.6% of patients on ramucirumab. CONCLUSION: Combinations of cixutumumab or ramucirumab plus MP were feasible and associated with moderate toxicities in docetaxel-pretreated men with mCRPC. Of the two regimens, the ramucirumab regimen is worthy of further testing based on the observed cPFS relative to the historical control.

A phase II, open-label study of ramucirumab in combination with paclitaxel and carboplatin as first-line therapy in patients with stage IIIB/IV non-small-cell lung cancer.

INTRODUCTION: The objective of this study was to determine whether the addition of ramucirumab to first-line paclitaxel-carboplatin chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) resulted in a 6-month progression-free survival (PFS) rate that compares favorably with the historic rate for bevacizumab combined with paclitaxel-carboplatin in this patient population. METHODS: In this phase II, single-arm, open-label, multicenter study, 40 patients with advanced NSCLC received ramucirumab (10 mg/kg intravenous [IV]) followed by paclitaxel (200 mg/m IV) and carboplatin area under the curve = 6 on day 1 every 21 days as first-line therapy. Therapy continued for up to six cycles. Patients not experiencing withdrawal criteria may have continued ramucirumab monotherapy every 3 weeks. The primary endpoint was PFS at 6 months, with 80% power to detect a 6-month PFS rate of at least 55%. RESULTS: The 6-month PFS rate was 59.0% and the objective response rate was 55.0%. The most common treatment-related adverse events were fatigue, peripheral neuropathy, nausea, epistaxis, and myalgia. Single-nucleotide polymorphism (SNP) rs2981582 on the FGFR-2gene had significant associations with improved overall survival, PFS, and best overall response (p values without multiplicity adjustment were 0.0059, 0.0429, and 0.0392, respectively). CONCLUSION: Ramucirumab in combination with paclitaxel-carboplatin resulted in a 6-month PFS rate and safety profile that compared favorably with the historical control. In addition, no deaths were associated with this treatment. Furthermore, we describe an association of SNP on FGFR-2 gene with survival and response. These findings warrant further clinical investigation in patients with NSCLC.

A phase II study of ramucirumab (IMC-1121B) in the treatment of persistent or recurrent epithelial ovarian, fallopian tube or primary peritoneal carcinoma.

OBJECTIVE: Vascular endothelial growth factor (VEGF) receptor-mediated signaling contributes to ovarian cancer pathogenesis. Elevated VEGF expression is associated with poor clinical outcomes. We investigated ramucirumab, a fully human anti-VEGFR-2 antibody, in patients with persistent or recurrent epithelial ovarian, fallopian tube, or primary peritoneal carcinoma. Primary endpoints were progression-free survival at 6 months (PFS-6) and confirmed objective response rate (ORR). METHODS: Women who received ≥ 1 platinum-based chemotherapeutic regimen and had a platinum-free interval of <12 months with measurable disease were eligible. Patients received 8 mg/kg ramucirumab intravenously every 2 weeks. RESULTS: Sixty patients were treated; one patient remained on study as of September 2013. The median age was 62 years (range: 27-80), and median number of prior regimens was 3. Forty-five (75%) patients had platinum refractory/resistant disease. Thirty-nine patients (65.0%) had serous tumors. PFS-6 was 25.0% (n=15/60, 95% CI: 14.7-37.9%). Best overall response was: partial response 5.0% (n=3/60), stable disease 56.7% (n=34/60), and progressive disease 33.3% (n=20/60). The most common treatment-emergent adverse events possibly related to study drug were headache (65.0%; 10.0% Grade ≥ 3), fatigue (56.7%; 3.3% Grade ≥ 3), diarrhea (28.3%; 1.7% Grade ≥ 3), hypertension (25.0%; 3.3% Grade ≥ 3), and nausea (20.0%; no Grade ≥ 3). Two patients experienced intestinal perforations (3.3% Grade ≥ 3). Pharmacodynamic analyses revealed changes in several circulating VEGF proteins following initial ramucirumab infusion, including increased VEGF-A, PlGF and decreased sVEGFR-2. CONCLUSIONS: Although antitumor activity was observed, the predetermined efficacy endpoints were not met.

A phase 2, single-arm study of ramucirumab in patients with metastatic renal cell carcinoma with disease progression on or intolerance to tyrosine kinase inhibitor therapy.

BACKGROUND: Multitargeted tyrosine kinase inhibitors (TKIs) have antitumor activity in metastatic renal cell carcinoma (mRCC). Resistance to these agents develops frequently, and their use is often limited by intolerance. Ramucirumab is a recombinant human monoclonal antibody directed against human vascular endothelial growth factor receptor-2. For this study, the authors investigated the clinical efficacy and safety of ramucirumab in patients with TKI-resistant/intolerant mRCC. METHODS: In this single-arm phase 2 trial, patients received ramucirumab 8 mg/kg every 2 weeks until they developed disease progression or intolerable toxicity. The primary endpoint was the best objective response rate (ORR); additional endpoints included the disease control rate (DCR), progression-free survival (PFS), the median duration of overall response, and safety. RESULTS: Thirty-nine patients with RCC received ramucirumab monotherapy. Prior TKI therapy included sunitinib (59% of patients), sunitinib and sorafenib (30.8% of patients), and sorafenib (10.3% of patients). The ORR was 5.1% (95% confidence interval [CI], 0.6%-17.3%). The 12-week DCR was 64.1% (95% CI, 47.2%-78.8%). The median PFS was 7.1 months (95% CI, 4.1-9.7 months), and the median overall survival was 24.8 months (95% CI, 18.9-32.6 months). Grade 3 or higher adverse events that occurred in ≥5% of patients included grade 3 hypertension (7.7%) and proteinuria (5.1%). There was 1 on-study death from multiorgan failure. CONCLUSIONS: Although the study did not meet its primary endpoint of ≥15% ORR, ramucirumab was associated with evidence of antitumor activity in patients with TKI-resistant/intolerant mRCC. Ramucirumab was safe and well tolerated.

Tumor cell expression of vascular endothelial growth factor receptor 2 is an adverse prognostic factor in patients with squamous cell carcinoma of the lung.

A robust immunohistochemical (IHC) assay for VEGFR2 was developed to investigate its utility for patient tailoring in clinical trials. The sensitivity, specificity, and selectivity of the IHC assay were established by siRNA knockdown, immunoblotting, mass spectrometry, and pre-absorption experiments. Characterization of the assay included screening a panel of multiple human cancer tissues and an independent cohort of non-small cell lung carcinoma (NSCLC, n = 118) characterized by TTF-1, p63, CK5/6, and CK7 IHC. VEGFR2 immunoreactivity was interpreted qualitatively (VEGFR2 positive/negative) in blood vessels and by semi-quantitative evaluation using H-scores in tumor cells (0-300). Associations were determined among combinations of VEGFR2 expression in blood vessels and tumor cells, and clinico-pathologic characteristics (age, sex, race, histologic subtype, disease stage) and overall survival using Kaplan-Meier analyses and appropriate statistical models. VEGFR2 expression both in blood vessels and in tumor cells in carcinomas of the lung, cervix, larynx, breast, and others was demonstrated. In the validation cohort, 99/118 (83.9%) NSCLC tissues expressed VEGFR2 in the blood vessels and 46/118 (39.0%) showed high tumor cell positivity (H-score ≥10). Vascular and tumor cell expression were inversely correlated (p = 0.0175). High tumor cell expression of VEGFR2 was associated with a 3.7-fold reduction in median overall survival in lung squamous-cell carcinoma (SCC, n = 25, p = 0.0134). The inverse correlation between vascular and tumor cell expression of VEGFR2 and the adverse prognosis associated with high VEGFR2 expression in immunohistochemically characterized pulmonary SCC are new findings with potential therapeutic implications. The robustness of this novel IHC assay will support further evaluation of its utility for patient tailoring in clinical trials of antiangiogenic agents.

A phase II and biomarker study of ramucirumab, a human monoclonal antibody targeting the VEGF receptor-2, as first-line monotherapy in patients with advanced hepatocellular cancer.

PURPOSE: To assess the efficacy and safety of the anti-VEGF receptor-2 (VEGFR-2) antibody ramucirumab as first-line therapy in patients with advanced hepatocellular carcinoma and explore potential circulating biomarkers. EXPERIMENTAL DESIGN: Adults with advanced hepatocellular carcinoma and no prior systemic treatment received ramucirumab 8 mg/kg every two weeks until disease progression or limiting toxicity. The primary endpoint was progression-free survival (PFS); secondary endpoints included objective response rate (ORR) and overall survival (OS). Circulating biomarkers were evaluated before and after ramucirumab treatment in a subset of patients. RESULTS: Forty-two patients received ramucirumab. Median PFS was 4.0 months [95% confidence interval (CI), 2.6-5.7], ORR was 9.5% (95% CI, 2.7-22.6; 4/42 patients had a partial response), and median OS was 12.0 months (95% CI, 6.1-19.7). For patients with Barcelona Clinic Liver Cancer (BCLC) stage C disease, median OS was 4.4 months (95% CI, 0.5-9.0) for patients with Child-Pugh B cirrhosis versus 18.0 months (95% CI, 6.1-23.5) for patients with Child-Pugh A cirrhosis. Treatment-related grade ≥ 3 toxicities included hypertension (14%), gastrointestinal hemorrhage and infusion-related reactions (7% each), and fatigue (5%). There was one treatment-related death (gastrointestinal hemorrhage). After treatment with ramucirumab, there was an increase in serum VEGF and placental growth factor (PlGF) and a transient decrease in soluble VEGFR-2. CONCLUSION: Ramucirumab monotherapy may confer anticancer activity in advanced hepatocellular carcinoma with an acceptable safety profile. Exploratory biomarker studies showed changes in circulating VEGF, PlGF, and sVEGFR-2 that are consistent with those seen with other anti-VEGF agents.

Log-Linear Models for Gene Association.

We describe a class of log-linear models for the detection of interactions in high-dimensional genomic data. This class of models leads to a Bayesian model selection algorithm that can be applied to data that have been reduced to contingency tables using ranks of observations within subjects, and discretization of these ranks within gene/network components. Many normalization issues associated with the analysis of genomic data are thereby avoided. A prior density based on Ewens' sampling distribution is used to restrict the number of interacting components assigned high posterior probability, and the calculation of posterior model probabilities is expedited by approximations based on the likelihood ratio statistic. Simulation studies are used to evaluate the efficiency of the resulting algorithm for known interaction structures. Finally, the algorithm is validated in a microarray study for which it was possible to obtain biological confirmation of detected interactions.