Use of patient-reported outcomes (PRO) data to complement exposure-response analysis in early clinical cancer drug development.

BACKGROUND: This proof-of-concept retrospective case study investigated whether patient-reported outcomes (PRO) instruments, designed to capture symptomatic adverse event data, could identity a known exposure-response (ER) relationship for safety characterized in an original FDA analysis of an approved anti-cancer agent. PRO instruments have been designed to uniquely quantify the tolerability aspects of exposure-associated symptomatic adverse events. We explored whether standard ER analyses of clinician-reported safety data for symptomatic adverse events could be complemented by ER analysis using PRO data that capture and quantify the tolerability aspects of these same symptomatic adverse events. METHODS: Exposure-associated adverse event data for diarrhea were analyzed in parallel in 120 patients enrolled in a clinical trial using physician reported Common Terminology Criteria for Adverse Events (CTCAE) and patient-reported symptomatic adverse event data captured by the National Cancer Institute's (NCI) PRO Common Terminology Criteria for Adverse Events (PRO-CTCAE) instrument. Comparative ER analyses of diarrhea were conducted using the same dataset. Results from the CTCAE and PRO-CTCAE ER analyses were assessed for consistency with the ER relationship for diarrhea established in the original NDA using a 750-patient dataset. The analysis was limited to the 120-patient subset with parallel CTCAE and PRO-CTCAE assessments. RESULTS: Within the same 120-patient dataset, ER analysis using dense, longitudinal PRO-CTCAE-derived data was sensitive to identify the known ER relationship for diarrhea, whereas the standard CTCAE based ER analysis was not. CONCLUSIONS: ER analysis using PRO assessed symptomatic adverse event data may be a sensitive tool to complement traditional ER analysis. Improved identification of relationships for safety, by including quantification of the tolerability aspect of symptomatic adverse events using PRO instruments, may be useful to improve the sensitivity of exposure response analysis to support early clinical trial dosage optimization strategies, where decision making occurs within limited small patient datasets.

FDA Approval Summary: Selpercatinib for the Treatment of Advanced RET Fusion-Positive Solid Tumors.

On September 21, 2022, the FDA granted accelerated approval to selpercatinib (Retevmo, Eli Lilly and Company) for the treatment of adult patients with locally advanced or metastatic solid tumors with a rearranged during transfection (RET) gene fusion that have progressed on or following prior systemic treatment or who have no satisfactory alternative treatment options. The approval was based on data from Study LOXO-RET-17001 (LIBRETTO-001; NCT03157128), an international, non-randomized, multi-cohort clinical trial that included patients with advanced solid tumors harboring RET alterations. The overall response rate in 41 patients with locally advanced or metastatic RET fusion-positive solid tumors other than non-small cell lung cancer (NSCLC) or thyroid cancer was 44% [95% confidence interval (CI), 28%-60%], with median duration of response 24.5 months (95% CI, 9.2-not evaluable). Patients with 10 of 14 tumor types with a variety of fusion partners had objective responses, including patients with the following tumors: pancreatic adenocarcinoma, colorectal, salivary, unknown primary, breast, soft-tissue sarcoma, bronchial carcinoid, ovarian, small intestine, and cholangiocarcinoma. The recommendation for approval was supported by results from LIBRETTO-001 in patients with RET fusion-positive NSCLC and thyroid cancer, which formed the basis of prior approvals in these tumor types. The most common adverse reactions (>25%) were edema, diarrhea, fatigue, dry mouth, hypertension, abdominal pain, constipation, rash, nausea, and headache. This is the first tissue-agnostic approval of a RET-directed targeted therapy.

US Food and Drug Administration Approval Summary: Nivolumab Plus Platinum-Doublet Chemotherapy for the Neoadjuvant Treatment of Patients With Resectable Non-Small-Cell Lung Cancer.

PURPOSE: On March 4, 2022, the US Food and Drug Administration (FDA) approved nivolumab plus platinum-doublet chemotherapy for the neoadjuvant treatment of patients with resectable non-small-cell lung cancer (NSCLC). We discuss the FDA's review of the key data and regulatory considerations supporting this approval. PATIENTS AND METHODS: The approval was based on the results of CheckMate 816, an international, multiregional, active-controlled trial that randomly assigned 358 patients with resectable NSCLC, stage IB (≥4 cm) to IIIA (N2) per the American Joint Committee on Cancer seventh staging edition to receive either nivolumab plus platinum-doublet or platinum-doublet chemotherapy alone for three cycles before planned surgical resection. The major efficacy end point that supported this approval was event-free survival (EFS). RESULTS: At the first planned interim analysis (IA), the hazard ratio (HR) for EFS was 0.63 (95% CI, 0.45 to 0.87; P = .0052; statistical significance boundary = .0262) favoring the nivolumab plus chemotherapy arm; the median EFS was 31.6 months (95% CI, 30.2 to not reached) in the nivolumab plus chemotherapy arm versus 20.8 months (95% CI, 14.0 to 26.7) in the chemotherapy-only arm. At the time of a prespecified IA for overall survival (OS), 26% of patients had died, and the HR for OS was 0.57 (95% CI, 0.38 to 0.87; P = .0079; statistical significance boundary = .0033). Eighty-three percent of patients in the nivolumab-containing arm versus 75% in the chemotherapy-only arm received definitive surgery. CONCLUSION: This approval, the first for any regimen for the neoadjuvant treatment of NSCLC in the United States, was supported by a statistically significant and clinically meaningful improvement in EFS with no evidence of detriment in OS or negative impact on patients' receipt and timing of surgery or surgical outcomes.

FDA Approval Summary: Pemigatinib for Previously Treated, Unresectable Locally Advanced or Metastatic Cholangiocarcinoma with FGFR2 Fusion or Other Rearrangement.

On April 17, 2020, the FDA granted accelerated approval to pemigatinib (PEMAZYRE, Incyte Corporation) for the treatment of adults with previously treated, unresectable locally advanced or metastatic cholangiocarcinoma with an FGFR2 fusion or other rearrangement as detected by an FDA-approved test. Approval was based on FIGHT-202 (NCT02924376), a multicenter open-label single-arm trial. Efficacy was based on 107 patients with locally advanced unresectable or metastatic cholangiocarcinoma whose disease had progressed on or after at least one prior therapy and had an FGFR2 gene fusion or rearrangement. Patients received pemigatinib, 13.5 mg orally, once daily for 14 consecutive days, followed by 7 days off therapy. Safety was based on a total of 466 patients, 146 of whom had cholangiocarcinoma and received the recommended dose. Efficacy endpoints were overall response rate (ORR) and duration of response (DOR) determined by an independent review committee using RECIST 1.1. ORR was 36% (95% confidence interval: 27-45). Median DOR was 9.1 months. The most common adverse reactions were hyperphosphatemia, alopecia, diarrhea, nail toxicity, fatigue, dysgeusia, nausea, constipation, stomatitis, dry eye, dry mouth, decreased appetite, vomiting, arthralgia, abdominal pain, hypophosphatemia, back pain, and dry skin. Ocular toxicity and hyperphosphatemia are important risks of pemigatinib. The recommended dosage is 13.5 mg orally once daily for 14 consecutive days followed by 7 days off therapy in 21-day cycles. FDA also approved the FoundationOne CDX (Foundation Medicine, Inc.) as a companion diagnostic for patient selection.

Improving Dose-Optimization Processes Used in Oncology Drug Development to Minimize Toxicity and Maximize Benefit to Patients.

This review highlights strategies to integrate dose optimization into premarketing drug development and discusses the underlying statistical principles. Poor dose optimization can have negative consequences for patients, most commonly because of toxicity, including poor quality of life, reduced effectiveness because of inability of patients to stay on current therapy or receive subsequent therapy because of toxicities, and difficulty in developing combination regimens. We reviewed US Food and Drug Administration initial approvals (2019-2021) of small molecules and antibody-drug conjugates for oncologic indications to determine the proportion with a recommended dosage at the maximum tolerated dose or the maximal administered dose, to characterize the use of randomized evaluations of multiple dosages in dose selection, to describe the frequency of dose modifications at the recommended dosage, and to identify case examples that highlight key principles for premarket dose optimization during drug development. Herein, we highlight major principles for dose optimization and review examples of recent US Food and Drug Administration approvals that illustrate how investigation of dose- and exposure-response relationships and use of randomized dose trials can support dose optimization. Although there has been some progress, dose optimization through randomized dose evaluation in oncology trials is not routinely conducted. Dose optimization is essential to ensure that patients receive therapies which maximize efficacy while minimizing toxicity.

FDA Approval Summary: Pembrolizumab, Atezolizumab, and Cemiplimab-rwlc as Single Agents for First-Line Treatment of Advanced/Metastatic PD-L1-High NSCLC.

FDA's approval of cemiplimab-rwlc on February 22, 2021, follows prior approvals of pembrolizumab and atezolizumab for similar indications as first-line treatment for patients with programmed death ligand-1 (PD-L1)-high advanced non-small cell lung cancer (NSCLC). Approvals of these anti-PD-L1 agents were supported by statistically significant and clinically meaningful improvements in overall survival (OS) in international, multicenter, active-controlled randomized trials. In KEYNOTE-024, the OS HR was 0.60 [95% confidence interval (CI), 0.41-0.89; P = 0.005] favoring pembrolizumab over platinum-doublet chemotherapy. In IMpower110, the OS HR was 0.59 (95% CI, 0.40-0.89; P = 0.0106) favoring atezolizumab over platinum-doublet chemotherapy. In Study 1624, the OS HR was 0.68 (95% CI, 0.53-0.87; P = 0.0022) favoring cemiplimab-rwlc over platinum-doublet chemotherapy. The progression-free survival (PFS) effect sizes for these anti-PD-L1 antibodies were also comparable across their respective registrational trials, and their safety profiles were consistent with the anti-PD-L1 class adverse event profile. The consistent survival benefits and manageable toxicity profiles of these single-agent anti-PD-L1 antibodies have established them as important treatment options in the PD-L1-high NSCLC treatment landscape. FDA approvals of these anti-PD-L1 antibodies, based on their favorable benefit-risk profiles, present effective chemotherapy-free therapeutic options for patients with advanced PD-L1-high NSCLC in the United States.

FDA Approval Summary: Tivozanib for Relapsed or Refractory Renal Cell Carcinoma.

On March 10, 2021, the FDA granted regular approval to tivozanib for treatment of patients with relapsed or refractory (R/R) advanced renal cell carcinoma (RCC) following two or more prior systemic therapies. Approval was based on the TIVO-3 study, a randomized trial of tivozanib versus sorafenib in patients with R/R advanced RCC. In TIVO-3, patients were randomized to receive either tivozanib 1.34 mg orally once daily for 21 consecutive days of every 28-day cycle or sorafenib 400 mg orally twice daily continuously. The primary endpoint was progression-free survival (PFS) per RECIST v1.1. Tivozanib demonstrated efficacy compared with sorafenib with an improvement in PFS [HR, 0.73; 95% confidence interval (CI), 0.56-0.95; P = 0.016]. The estimated median PFS was 5.6 months and 3.9 months in the tivozanib and sorafenib arms, respectively. There was no evidence of a detrimental effect on overall survival: HR, 0.97 (95% CI, 0.75-1.24). The most common grade 3 to 4 adverse reaction on the tivozanib arm was hypertension (24%). Compared with sorafenib, tivozanib was associated with lower rates of grade 3 to 4 diarrhea, rash, and palmar-plantar erythrodysesthesia. Patients receiving tivozanib in TIVO-3 had lower rates of dose reduction, interruption, or permanent discontinuation than those receiving sorafenib.

FDA Approval of Palbociclib in Combination with Fulvestrant for the Treatment of Hormone Receptor-Positive, HER2-Negative Metastatic Breast Cancer.

On February 19, 2016, the FDA approved palbociclib (Ibrance, Pfizer) for use in combination with fulvestrant (Faslodex, AstraZeneca) for the treatment of women with hormone receptor (HR)-positive, HER2-negative advanced or metastatic breast cancer (MBC) with disease progression following endocrine therapy. The approval was based on the results of a randomized, double-blind, placebo-controlled trial conducted in 521 pre- and postmenopausal women with HR-positive, HER2-negative advanced or MBC. Patients were randomized (2:1) to receive palbociclib plus fulvestrant (n = 347) or placebo plus fulvestrant (n = 174). The primary endpoint was investigator-assessed progression-free survival (PFS). A statistically significant and clinically meaningful improvement in PFS (9.5 months vs. 4.6 months) was observed in patients receiving palbociclib plus fulvestrant [HR 0.46; 95% confidence interval (CI), 0.36-0.59; P < 0.0001]. Safety data confirmed the known adverse reaction profile of palbociclib. The most common adverse reactions (>20%) in patients treated with palbociclib were neutropenia, leukopenia, infections, fatigue, nausea, anemia, stomatitis, headache, diarrhea, and thrombocytopenia. This approval was granted in the context of a prior accelerated approval for palbociclib in combination with letrozole in patients with HR-positive, HER2-negative advanced breast cancer as initial endocrine-based therapy. Clin Cancer Res; 22(20); 4968-72. ©2016 AACR.

Use of partial AUC (PAUC) to evaluate bioequivalence--a case study with complex absorption: methylphenidate.

PURPOSE: Methylphenidate modified-release products produce early and late peak concentrations critical for treatment of morning and afternoon symptoms of attention deficit hyperactivity disorder (ADHD). Standard bioequivalence (BE) criteria cannot be applied to these products. The performance of partial area under the drug concentration-time curve (PAUC), Cmax and AUCINF to assess BE were independently evaluated for two products. METHODS: A two-stage analysis was performed on plasma data for two methylphenidate modified-release products (Product 1 and 2). Simulations using the fitted parameters determined how changes in fast absorption rate constant (K0Fast) and fraction available (F1) affected curve shape and BE determination using Cmax, AUCINF and PAUC. RESULTS: The sensitivity of the mean PAUC(test)/PAUC(reference) ratios to changes in K0Fast(test) are product dependent. Product 1 mean PAUC(test)/PAUC(reference) ratios for PAUC0-4h are more responsive to both decreases and increases in K0Fast(test) than Product 2. Product 2 showed a greater response in the mean PAUC(test)/PAUC(reference) ratio for PAUC0-4h when the K0Fast(test) is decreased and less response as the value is increased. CONCLUSIONS: PAUC estimated curve shape is sensitive to changes in absorption and are product specific, and may require a new PAUC metric for each drug. A non-product specific metric to assess curve shape is warranted.