The US Food and Drug Administration (FDA) has granted orphan drug designation for Ignyta's lead product candidate entrectinib for the treatment of TrkA-positive, TrkB-positive, TrkC-positive, ROS1-positive and ALK-positive non-small cell lung cancer (NSCLC).

"Entrectinib has the potential to address unmet needs of patients with rare cancers, and we will continue to aggressively pursue our clinical development program for entrectinib in solid tumors for the benefit of these patients," said Jonathan Lim, MD., chairman and chief executive officer, of Ignyta. "We are pleased to receive from FDA this second orphan drug designation for non-small cell lung cancer, in addition to neuroblastoma, which can potentially provide additional avenues for creating value for our stockholders through our entrectinib clinical programme."

Under the FDA's Orphan Drug Designation programme, orphan drug designation is granted by the FDA to novel drugs or biologics that treat rare diseases or conditions affecting fewer than 200,000 patients in the US The designation allows the drug developer to be eligible for a seven-year period of US marketing exclusivity upon approval of the drug, as well as tax credits for clinical research costs, the ability to apply for annual grant funding, clinical trial design assistance, and the waiver of Prescription Drug User Fee Act (PDUFA) filing fees.

Entrectinib is a potent, novel, orally available, selective tyrosine kinase inhibitor of the Trk family of tyrosine kinase receptors (TrkA, TrkB and TrkC), ROS1 and ALK proteins. Entrectinib is designed as a targeted therapeutic candidate to treat patients with cancers that harbor activating alterations to TrkA, TrkB, TrkC, ROS1 or ALK. Entrectinib has demonstrated in vivo antitumor activity against various TrkA, ROS1 and ALK-driven mouse xenograft models of different human cancers.

Entrectinib is currently in two phase I/II clinical trials, the STARTRK-1 trial and the ALKA-372-001 trial. The company presented interim results from the ALKA-372-001 study in September 2014 at the ESMO annual meeting. The interim findings at such date showed no dose-limiting toxicities were observed, and only one Grade 3 or higher possibly drug-related adverse event was observed (Grade 3 fatigue, which subsided with dose reduction);Eight patients remained on active treatment across the three dosing schedules, with four patients having received 9 to 21 cycles of treatment;Entrectinib demonstrated a complete response in a patient with ROS1-positive NSCLC;Entrectinib demonstrated five partial responses, in patients with three different cancer histologies (colorectal cancer, NSCLC and neuroblastoma) and in patients with each of TrkA, ROS1 and ALK alterations; and Entrectinib demonstrated prolonged stable disease in two patients: one with ALK-positive NSCLC and one with ROS1-positive pancreatic cancer.

Ignyta previously announced that the FDA had granted orphan drug designation for entrectinib for the treatment of neuroblastoma.