Athenex, Inc. announced the presentation of data from a Phase 1 study to assess the safety, tolerability, and activity of oral paclitaxel and encequidar (Oral Paclitaxel) in combination with pembrolizumab in patients with advanced solid malignancies. The data are being presented in a poster presentation at the European Society for Medical Oncology (ESMO) Virtual Congress 2021, being held from September 16th to September 21st. Phase 1 Study with Expansion Cohorts to Assess the Safety, Tolerability, and Activity of Oraxol (Oral Paclitaxel + Encequidar) in Combination with Pembrolizumab in Subjects with Advanced Solid Malignancies. The primary objective for the dose escalation phase of the study was to determine the maximum tolerated dose (MTD) and identify the recommended Phase 2 dose (RP2D) of Oral Paclitaxel in combination with pembrolizumab in patients with advanced solid tumors. The dose escalation phase of the study enrolled 21 patients. Activity data were presented on 17 patients who were evaluable for a response, including eight NSCLC patients as well as patients with head and neck cancer, uveal melanoma, oesophageal cancer, colon cancer and bladder cancer. Four patients had partial response, 10 patients had stable disease, and three patients had progressive disease. The duration on treatment ranged from 9 to 676+ days. There were a total of 10 NSCLC patients enrolled, of which eight were evaluable for response. Four patients achieved partial response and four patients achieved stable disease. All had discontinued previous checkpoint inhibitor therapy due to progressive disease. MTD of the combination was not reached. The RP2D in combination with pembrolizumab was selected as Oral Paclitaxel 270 mg QD Days 1-3 for 2 weeks of a 3-week cycle. The study is proceeding to expansion cohorts and will enroll additional patients with NSCLC to further evaluate the safety and clinical activity of Oral Paclitaxel with pembrolizumab. Phase 1 Study of Oral Paclitaxel and Encequidar in Combination with Pembrolizumab: The Phase 1 study is an open-label dose-escalation design study, to be followed by a 2-arm expansion cohort. The dose escalation utilized the “3+3” design and eligible patients had metastatic or unresectable solid tumors for which pembrolizumab is an FDA approved therapy. The Oral Paclitaxel dose range explored was 270-330mg administered for 2 days up to a maximum of 5 days per week x 2 weeks of a 3-week cycle. Pembrolizumab 200mg IV was administered every three weeks. The primary objective for Part A of the study was to determine the maximum tolerated dose (MTD) and identify the recommended Phase 2 dose of Oral Paclitaxel in combination with pembrolizumab in subjects with advanced solid tumors. Secondary objectives included safety and tolerability, the pharmacokinetics of paclitaxel, and preliminary anti-tumor activity. MTD and dose limiting toxicities were determined based on toxicities observed during the first 3-week cycle of treatment. Response was determined by CT scan evaluated by RECIST 1.1 every 9 weeks. The Part B dose expansion phase will enroll subjects with NSCLC to further evaluate the activity, safety and tolerability of the study treatment.