EUS-guided paclitaxel injection as an adjunctive therapy to systemic chemotherapy and concurrent external beam radiation before surgery for localized or locoregional esophageal cancer: a multicenter prospective randomized trial.

BACKGROUND AND AIMS: OncoGel (Protherics Salt Lake City, Inc, Salt Lake City, UT) is paclitaxel (PTX) formulated in a thermosensitive, biodegradable copolymer for focused cytotoxicity and radiosensitization. A phase 2a study suggested that EUS-guided PTX injection into esophageal tumors subsequently receiving radiotherapy was safe. METHODS: In an international multicenter, prospective, randomized phase 2b study, patients with local or locoregional adenocarcinoma or squamous cell carcinoma (SCC) of the esophagus/gastroesophageal junction and eligible for neoadjuvant chemoradiotherapy (CRT) before surgery were randomized to standard of care (SOC) plus EUS-guided PTX injection or SOC alone. PTX was injected in 0.5 to 1.0 mL aliquots throughout the tumor. Planned CRT as SOC was intravenous 5-fluorouracil for the first 4 days (weeks 1 and 5), intravenous cisplatin on the first day of each 5-fluorouracil course, and radiotherapy over 5.5 weeks. Patients were evaluated weekly during CRT and re-evaluated at 12 weeks for surgical eligibility and CT for change in overall tumor volume. RESULTS: The analysis included 137 patients (97 males; mean age, 58 ± 9.1 years) randomized to PTX + SOC (n = 72) and SOC (n = 65) by using a modified intention-to-treat approach. Overall response by tumor volume between the PTX (12.5%) and the SOC group (20.0%; P = .24; odds ratio, 0.57; 95% confidence interval, 0.23-1.44) was similar. Pathologic complete response was higher in the SOC group (26.2% vs 12.5%; P = .046); however, 12-month survival (P = .412) and the overall frequency of 1 or more adverse events (P = .17) were similar between the 2 groups. CONCLUSIONS: SOC + PTX is safe but does not improve overall survival or overall tumor response at the primary tumor site for patients with local or locoregional cancer of the esophagus/gastroesophageal junction. (Clinical trial registration number: NCT00573131.).

Phase 2: a dose-escalation study of OncoGel (ReGel/paclitaxel), a controlled-release formulation of paclitaxel, as adjunctive local therapy to external-beam radiation in patients with inoperable esophageal cancer.

OncoGel, a novel injectable formulation of paclitaxel in a biocompatible biodegradable gel (ReGel), provides controlled release of paclitaxel at the injection site, resulting in high intralesional paclitaxel concentrations and continuous radiosensitization without attendant systemic toxicities. This dose-escalation study evaluated the toxicity, pharmacokinetics, and preliminary antitumor activity of OncoGel injected intralesionally in patients with inoperable esophageal cancer who were candidates for palliative external-beam radiotherapy (RT). Eleven patients with inoperable advanced esophageal cancer received a single administration of OncoGel into the primary tumor using conventional endoscopic techniques. Three cohorts received approximately one-third of the tumor volume with increasing paclitaxel concentrations to achieve 0.48, 1.0, and 2.0 mg paclitaxel/cm tumor volume. Subsequent to injection, RT was initiated (50.4 Gy in 1.8 Gy fractions). Pharmacokinetic sampling was performed. All patients completed the study. No dose-limiting toxicities were reported. Dysphagia improved and tumor size decreased in most patients. Biopsies were negative for carcinoma in 4 of 11 patients. Peak paclitaxel plasma concentrations were low (0.53-2.73 ng/ml) and directly related to the absolute amount of paclitaxel administered. Paclitaxel was detectable in plasma for 24 h in all patients and for 3 weeks in six patients. OncoGel given as an adjunct to RT was well tolerated in patients with inoperable esophageal cancer and provided prolonged paclitaxel release with minimal systemic exposure. OncoGel plus RT seemed to reduce tumor burden as evidenced by dysphagia improvement, tumor size reduction, and negative esophageal biopsies. The addition of OncoGel to combined modality therapy merits continued clinical development.