Genta Incorporated has received notice from the FDA that tesetaxel, the latest addition to Genta’s oncology product portfolio, has been granted designation as an “Orphan Drug” for treatment of patients with advanced gastric cancer. Orphan drug status provides for a period of marketing exclusivity, certain tax benefits, and an exemption from certain fees upon submission of a New Drug Application. As a late Phase 2 agent, the Company believes tesetaxel is the leading oral taxane currently in clinical development. In the completed Phase 2 study, 35 patients with advanced gastric cancer were treated with tesetaxel at doses ranging from 27 to 35 mg/m2 once every three weeks. All patients had received extensive prior treatment, having failed a combination regimen that included cisplatin plus 5-fluorouracil or Xeloda(R), and all but 2 patients had received a third chemotherapy drug with this regimen. Final intent-to-treat analysis, including all patients enrolled in the study, showed that 5 patients achieved a partial response, 2 patients achieved a partial response unconfirmed by CT scan, and 14 patients achieved stable disease, for an overall major response rate of 20% and a disease-control rate of 60%. The most serious adverse reaction was Grade 3-4 neutropenia, which occurred in 57% of patients. Six patients failed to complete the first course of treatment. Five patients died on study from differing causes that included intestinal perforation, pneumonia, hepatic failure, hemorrhagic shock, and rapid disease progression. One patient withdrew before receiving the first treatment dose. “These response data for tesetaxel in a critically ill patient population show clinical activity at levels that are at least comparable to studies with other taxanes,” said Dr. Raymond P. Warrell, Jr., Genta’s Chief Executive Officer. “Based on these data, we have consulted extensively with international experts and will be defining a global registration path for tesetaxel as a 2nd-line treatment for patients with advanced gastric cancer. FDA designation as an Orphan Drug provides important assistance in the clinical development process.” Tesetaxel is a novel, orally absorbed, semi-synthetic taxane that is in the same class of drugs as paclitaxel and docetaxel. However, both prototype agents suffer from serious safety issues, particularly hypersensitivity reactions related to intravenous infusions that are occasionally fatal and that require careful premedication and observation. Other prominent side-effects of this drug class include myelosuppression (low blood counts) and peripheral neuropathy (disabling nerve damage). With administration as an oral capsule, tesetaxel was developed to maintain the high antitumor activity of the taxane drug class while eliminating infusion reactions, reducing neuropathy, and increasing patient convenience. The oral route also enables development of novel schedules that may expand dosing options when tesetaxel is used alone or in combination with other anticancer drugs. Preclinically, tesetaxel has demonstrated substantially higher activity against cell lines that were resistant to paclitaxel and docetaxel, since acquired resistance is not mediated by the multidrug-resistant p-glycoprotein. As a late Phase 2 oncology product, tesetaxel has demonstrated anticancer activity in its initial clinical trials, and the drug has not been associated with the severe infusion reactions that are linked with other taxanes. Moreover, unlike other oral taxanes, nerve damage has not been a prominent side effect of tesetaxel. Thus, the drug offers substantial opportunities to improve patient convenience, safety, and anticancer activity. More than 250 patients worldwide have been treated with oral tesetaxel in Phase 1 and Phase 2 clinical trials.
