Benzinga | Jun 4, 2021 09:09AM EDT

Athenex Highlights Data For 2 Poster Presentations At American Society Of Clinical Oncology

* Data from oral docetaxel phase I pharmacokinetic study shows oral administration can achieve exposure comparable to IV docetaxel

* Post-hoc subgroup efficacy analysis based on updated tumor subtypes in the oral paclitaxel phase III study demonstrated an improved response rate with oral paclitaxel plus encequidar across tumor subgroups

BUFFALO, N.Y., June 04, 2021 (GLOBE NEWSWIRE) -- Athenex, Inc., (NASDAQ:ATNX), a global biopharmaceutical company dedicated to the discovery, development, and commercialization of novel therapies for the treatment of cancer and related conditions, announced today that the Company presented data from a phase I pharmacokinetic study of oral docetaxel plus encequidar ("oral docetaxel") and updated data from the phase III study of oral paclitaxel plus encequidar ("oral paclitaxel") illustrating tumor responses by molecular subtype. The data are being presented in two posters at the American Society for Clinical Oncology 2021 (ASCO2021) Virtual Scientific Program, being held from June 4th to June 8th, 2021.

An open label, pharmacokinetic study to determine the bioavailability, safety and tolerability of single dose oral docetaxel (Oradoxel) in metastatic prostate cancer mPC patients treated with IV docetaxel

Abstract 5050; Poster session: Genitourinary Cancer -- Prostate, Testicular, and Penile

Data were presented from the open-label, two-way crossover phase I pharmacokinetic study of oral docetaxel vs IV docetaxel, which demonstrated the drug was well tolerated with no dose limiting toxicities, or drug-related serious adverse events. The mean absolute bioavailability was 15.9% (range 8% to 25%) with PK exposure becoming non-linear at 300 mg/m2. Based on these results and the results of other related studies, oral docetaxel 300 mg/m2 as divided doses is being further evaluated.

Confirmed Tumor Response by Molecular Subtype in Patients with Metastatic Breast Cancer (MBC): Sub analysis From a Phase 3 Clinical Study Comparing Oral Paclitaxel and Encequidar to IV Paclitaxel

Abstract 1073; Poster session: Breast Cancer -- Metastatic

Updated data were presented from the phase III trial of oral paclitaxel, specifically tumor response rates by receptor subtype. Athenex presented the results of a post-hoc subgroup efficacy analysis based on additional tumor subtype data. Overall response rate in the intent-to-treat (ITT) population demonstrated that oral paclitaxel was superior to IV paclitaxel with confirmed responserates of 35.8% versus 23.4%, respectively (p=0.0107). Response based on tumor subtypes is listed in the table below.

N (%) Oral Paclitaxel plus Encequidar IV Paclitaxel Response Rate ORR (n=265) ORR (N=137) DifferenceTotal (ITT) 402 35.8% (95/265) 23.4% (32/137) 12.4%HR+/HER2- 244 28.0% (47/168) 19.7% (15/76) 8.3%HR-/HER2- 57 44.8% (13/29) 21.4% (6/28) 23.4%HER2+ 70 49.0% (25/51) 47.4% (9/19) 1.6%HER2 Unknown 31 58.8% (10/17) 14.3% (2/14) 44.5%