Thursday turned out to be a nightmare for shareholders of Threshold Pharmaceuticals, Inc. (NASDAQ:THLD), after the company announced disappointing interim data from its two Phase 2 proof-of-concept clinical trials of tarloxotinib in patients with advanced non-small cell lung cancer and patients with metastatic squamous cell carcinoma of the head and neck and skin.

Threshold shares reacted to the news, crashing nearly 64% in after-hours trading.

“While the response observed in our squamous cell carcinoma of the skin study with tarloxotinib was encouraging, the overall results from the two studies didn’t meet the activity thresholds required to move forward the molecule forward despite the promising results seen in preclinical translational studies,” said Barry Selick, Ph.D., Chief Executive Officer of Threshold. “As a result, we are making no further investment in this program. Instead, we plan to build on the efforts of our collaborator, Dr. Michael Curran of The University of Texas MD Anderson Cancer Center, to demonstrate the potential therapeutic value of adding evofosfamide to immune checkpoint inhibition, to continue to pursue discussions with Japanese regulatory authorities regarding potential registration pathways for evofosfamide, and to advance TH-3424 through IND-enabling toxicology studies with the goal of reaching the clinic in 2017. We plan to provide additional operational guidance in the fourth quarter of 2016.” (Original Source)

Threshold Pharmaceuticals engages in the development of therapeutics for treating tumors. It develops its product candidates based on hypoxia-activated prodrug technology: evofosfamide and tarloxotinib bromide. It also seeks to optimize patient selectivity for its hypoxia-targeted therapeutics through the development of its [18F]-HX4 investigational hypoxia Positron Emission Tomography (PET) tracer.