A Phase 1 Study of a CDH6-Targeting Antibody-Drug Conjugate in Patients with Advanced Solid Tumors with Evaluation of Inflammatory and Neurological Adverse Events.

PURPOSE: This first-in-human study (NCT02947152) evaluated the safety, tolerability, pharmacokinetics, and preliminary efficacy of HKT288, a first-in-class CDH6-targeting antibody-drug conjugate (ADC). EXPERIMENTAL DESIGN: HKT288 was administered intravenously (IV) every 3 weeks until patients experienced unacceptable toxicity or progressive disease (PD). The starting dose of 0.3 mg/kg was determined based on the highest nonseverely toxic dose in monkeys, which was 2 mg/kg IV weekly. Based on preclinical toxicology, skin, eyes, bone marrow, and liver were expected targets of toxicity. RESULTS: Nine patients were enrolled: 5 with renal cell carcinoma and 4 with epithelial ovarian cancer. The best overall response on the 0.3 mg/kg cohort in patients with measurable disease was RECIST v1.1 stable disease in 3 patients and PD in 2 patients. The most frequent adverse events (AEs) regardless of causality were pyrexia (44.4%), constipation (44.4%), fatigue (33.3%), and vomiting (33.3%). Three suspected-related neurologic AEs (Grade 2) were reported on the 0.75 mg/kg cohort: seizure in 1 patient and another patient with aphasia and encephalopathy. Further studies were unable to identify the underlying mechanism of the neurologic AEs, and the study was terminated early. CONCLUSIONS: Preclinical toxicology did not predict the neurotoxicity observed with HKT288, and a comprehensive assessment performed post hoc did not identify the mechanism of toxicity. The development of further CDH6-targeting ADCs should be pursued with caution.

Phase Ib Study of Ribociclib plus Fulvestrant and Ribociclib plus Fulvestrant plus PI3K Inhibitor (Alpelisib or Buparlisib) for HR+ Advanced Breast Cancer.

PURPOSE: Resistance to treatment with endocrine therapy in patients with HR+, HER2- advanced breast cancer (ABC) is common and dual inhibition of CDK4/6 and PI3K pathways may delay the development of resistance. This phase Ib trial evaluates the safety and tolerability of triple and double regimens containing the CDK4/6 inhibitor ribociclib. PATIENTS AND METHODS: In this open-label, multicenter, phase Ib study, 70 postmenopausal women with HR+, HER2- ABC were enrolled into one of four treatment combinations: ribociclib (once daily, 3 weeks on, 1 week off) plus fulvestrant; ribociclib (continuous dosing) plus fulvestrant; ribociclib plus alpelisib plus fulvestrant; or ribociclib plus buparlisib plus fulvestrant. RESULTS: The recommended phase II dose (RP2D) of ribociclib was confirmed to be 600 mg (3 weeks on, 1 week off) and 400 mg (continuous dosing) plus fulvestrant 500 mg. For the triple combination with buparlisib, the RP2D was ribociclib 400 mg plus buparlisib 30 mg plus fulvestrant 500 mg. Enrollment for the triple combinations was stopped due to unexpected toxicity. No RP2D was determined for the alpelisib combination. The safety profiles of the ribociclib plus fulvestrant combinations were consistent with those in previous studies. There was no marked difference in ribociclib exposure in the presence of triple-combination partners. The highest overall response rate was seen in the buparlisib triple combination (25.0%; 95% confidence interval, 9.8-46.7). CONCLUSIONS: Ribociclib plus fulvestrant demonstrated safety in the treatment of patients with HR+, HER2- ABC. Triple combinations with alpelisib or buparlisib plus fulvestrant are not recommended for phase II investigation.See related commentary by Clark et al., p. 371.

Real-World Evidence Utilization in Clinical Development Reflected by US Product Labeling: Statistical Review.

The US Food and Drug Administration (FDA) has shown scientific discretion in interpreting the substantial evidence requirement for the approval of new drugs with its considerations on the use of single controlled or uncontrolled trials (Federal Food, Drug, and Cosmetic Act § 505(d), 21 USC 355(d), 1962). With the passage of the 21st Centuries Cures Act (21st Century Cures-patients. House, Energy and Commerce Committee, Washington, DC, 2019 available at: https://energycommerce.house.gov/sites/republicans.energycommerce.house.gov/files/analysis/21stCenturyCures/20140516PatientsWhitePaper.pdf ), the FDA is mandated to expand the role of real-world evidence (RWE) in support of drug approval. This mandate further broadens the scope of scientific discretion to include data collected outside clinical trials. We summarize the agency's past acceptance of real-world data (RWD) sources for supporting drug approval in new indications which have been reflected in US labels. In our summary, we focus on the type of RWD and statistical methodologies presented in these labels. Furthermore, two labels were selected for in-depth assessment of the RWE presented in these labels. Through these examples, we demonstrate the issues that can be raised in data collection that could affect interpretation. In addition, a brief discussion of statistical methods that can be used to incorporate RWE to clinical development is presented.

Treatment Response With Once-Daily Topical Dapsone Gel, 7.5% for Acne Vulgaris: Subgroup Analysis of Pooled Data from Two Randomized, Double-Blind Stu.

BACKGROUND: Acne vulgaris has varying physical and psychological effects in men and women of different ages, races, and ethnicities.

OBJECTIVE: This analysis assessed the relationship of age, sex, and race to treatment response with once-daily topical dapsone gel, 7.5%.

METHODS: We conducted a pooled subgroup analysis of 2 randomized, double-blind, vehicle-controlled clinical trials conducted in the US and Canada. The studies included patients with 20 to 50 inflammatory and 30 to 100 noninflammatory facial lesions, and a Global Acne Assessment Score (GAAS) of 3 (moderate). Pooled data (N=4340) were analyzed by age (12-17 and ≥18 years), sex, and race (Caucasian and non-Caucasian) for GAAS success (score of 0 [none] or 1 [minimal]) and mean percent change from baseline in inflammatory, noninflammatory, and total lesion counts. The impact of age and sex on treatment response was examined using multivariate analysis. Adverse events were analyzed by subgroups.

RESULTS: Treatment responses with dapsone gel, 7.5% were greater overall and for all subgroups versus vehicle. GAAS success rates and mean decrease in all lesion counts with dapsone gel, 7.5% were greater in older (aged ≥18 years) versus younger patients, and for females versus males. Treatment response with dapsone gel, 7.5% in racial subgroups was similar. Multivariate analysis showed statistical significance for age group and sex as predictors of GAAS success (P less than equal to .005) and reduction in lesion counts (P less than equal to .025). Adverse events were similar across subgroups.

CONCLUSIONS: Older age (≥18 years) and female sex were predictors of treatment response. These subgroups tended to have greater acne improvement in subgroup comparisons. Caucasian and non-Caucasian patients had similar responses. The safety profile of dapsone gel, 7.5% was similar across subgroups.

J Drugs Dermatol. 2017;16(6):591-598.

Efficacy and Safety of Once-Daily Dapsone Gel, 7.5% for Treatment of Adolescents and Adults With Acne Vulgaris: Second of Two Identically Designed, Large, Multicenter, Randomized, Vehicle-Controlled Trials.

BACKGROUND: Dapsone gel, 5% is administered twice daily for the treatment of acne vulgaris, and some patients may find adherence challenging.
OBJECTIVE: The study objective was to assess the efficacy and safety, compared with vehicle, of acne treatment with a recently FDA-approved, once-daily formulation of dapsone gel, 7.5%, with a 50% greater concentration of dapsone.
METHODS: This 12-week, randomized, double-blind, vehicle-controlled, multicenter clinical trial enrolled patients aged 12 years and older with 20-50 facial inflammatory lesions, 30-100 facial noninflammatory lesions, and an acne grade of 3 (moderate) on the Global Acne Assessment Score (GAAS). Patients were randomized (1:1 ratio) to topical dapsone gel, 7.5% or vehicle once daily for 12 weeks. Investigators assessed GAAS success rate (proportion of patients with a GAAS of 0 or 1) and percent change from baseline in inflammatory, noninflammatory, and total lesions.
RESULTS: The intent-to-treat population comprised 2238 patients (1118 in the dapsone gel, 7.5% group and 1120 in the vehicle group). The GAAS success rates were 29.8% for the dapsone gel, 7.5% group and 20.9% for the vehicle group (P<0.001) at week 12. At week 12, mean inflammatory lesions decreased from baseline by 53.8% and 47.3%, noninflammatory lesions decreased by 45.9% and 40.4%, and total lesions decreased by 48.9% and 43.2% for the dapsone gel, 7.5% group and the vehicle group, respectively (all, P<0.001). The incidence of treatment-emergent adverse events was similar for dapsone gel, 7.5% (17.6%) and vehicle (17.1%). Most adverse events were mild to moderate in severity. The most frequently reported increase in severity for all of the dermal tolerability scales was from "none" to "mild."
CONCLUSION: Dapsone gel, 7.5% applied topically once daily is an effective, safe, and well-tolerated treatment for acne vulgaris. Improvements in acne severity and lesions were observed over the 12-week course of treatment.

J Drugs Dermatol. 2016;15(8):962-969.

Benefit-Risk Evaluation and Decision Making: Some Practical Insights.

Pharmaceutical drugs and devices are increasingly evaluated by quantitative tools that combine benefit and risk. These tools vary by their limitations and desirable properties, which may confuse the decision-making process. Experts from the Food and Drug Administration (FDA) and industry shared their perspectives at the 2012 American Statistical Association (ASA) Biopharmaceutical Section FDA-Industry Statistics Workshop, and these insights are presented here. First, benefit-risk terminology is given to better understand subtle distinctions. Next, pragmatic considerations in endpoint selection are given that distinguish between benefit-risk assessment and analysis of clinical trials. Then the strengths of weighting methods, including ranking, utilities, and risk tolerance for assessing the trade-off between benefits and risks, are compared. The last topic presented is summarizing information to ease the interpretation, transparency, and ability to support decisions. Benefit-risk methods are moving towards a unified paradigm to make selection of endpoints, weights, and metrics easier and more structured. This will lead to better decision-making based on a transparent assessment and clear interpretability.

A causal model for joint evaluation of placebo and treatment-specific effects in clinical trials.

Evaluation of medical treatments is frequently complicated by the presence of substantial placebo effects, especially on relatively subjective endpoints, and the standard solution to this problem is a randomized, double-blinded, placebo-controlled clinical trial. However, effective blinding does not guarantee that all patients have the same belief or mentality about which treatment they have received (or treatmentality, for brevity), making it difficult to interpret the usual intent-to-treat effect as a causal effect. We discuss the causal relationships among treatment, treatmentality and the clinical outcome of interest, and propose a causal model for joint evaluation of placebo and treatment-specific effects. The model highlights the importance of measuring and incorporating patient treatmentality and suggests that each treatment group should be considered a separate observational study with a patient's treatmentality playing the role of an uncontrolled exposure. This perspective allows us to adapt existing methods for dealing with confounding to joint estimation of placebo and treatment-specific effects using measured treatmentality data, commonly known as blinding assessment data. We first apply this approach to the most common type of blinding assessment data, which is categorical, and illustrate the methods using an example from asthma. We then propose that blinding assessment data can be collected as a continuous variable, specifically when a patient's treatmentality is measured as a subjective probability, and describe analytic methods for that case.

Bayesian approaches in medical device clinical trials: a discussion with examples in the regulatory setting.

Challenging statistical issues often arise in the design and analysis of clinical trials to assess safety and effectiveness of medical devices in the regulatory setting. The use of Bayesian methods in the design and analysis of medical device clinical trials has been increasing significantly in the past decade, not only due to the availability of prior information, but mainly due to the appealing nature of Bayesian clinical trial designs. The Center for Devices and Radiological Health at the Food and Drug Administration (FDA) has gained extensive experience with the use of Bayesian statistical methods and has identified some important issues that need further exploration. In this article, we discuss several topics relating to the use of Bayesian statistical methods in medical device trials, based on our experience and real applications. We illustrate the benefits and challenges of Bayesian approaches when incorporating prior information to evaluate the effectiveness and safety of a medical device. We further present an example of a Bayesian adaptive clinical trial and compare it to a traditional frequentist design. Finally, we discuss the use of Bayesian hierarchical models for multiregional trials and highlight the advantages of the Bayesian approach when specifying clinically relevant study hypotheses.