Progenics Pharmaceuticals Inc. said its imaging agent 18F-DCFPyL could reliably detect the absence of prostate cancer in patients planning to undergo surgery.

Prostate cancer is the second most common form of cancer affecting men in the U.S. The American Cancer Society estimates that each year approximately 161,360 new cases of prostate cancer will be diagnosed and about 26,730 men will die of the disease.

The New York-based biotechnology company was studying the agent, also known as PyL, in a phase 2/3 trial known as Osprey 2301 which enrolled 385 patients. Of these, 268 individuals were believed to have high-risk locally advanced prostate cancer while the other 117 patients were suspected to have prostate cancer that had either returned or spread to other parts of the body.

In the first cohort, which included the 268 individuals scheduled to undergo surgery, the imaging agent showed a specificity of 96% to 99%, a measure of the agent's ability to correctly classify truly non-diseased people.

However, the agent had a sensitivity of 19% to 30%, a measure of how accurately the screening test could identify disease in the patient population. The company was targeting a sensitivity rating of 31% to 42%.

The positive predictive value of the test, a probability that subjects with a positive screening test truly have the disease, was 78% to 91%. Meanwhile, the negative predictive value of pelvic lymph node detection, a probability that subjects with a negative screening test truly do not have the disease, was 81% to 84%.

Meanwhile, in the second cohort of 117 patients, PyL exhibited a sensitivity of 93% to 99% and a positive predictive value of 81% to 88%. Specificity and negative predictive value were not measured since the patients were already suspected to have the disease.

"While specificity and sensitivity are often used to describe diagnostic performance, [positive predictive value] and [negative predictive value] are increasingly considered more relevant indicators of actual clinical utility. Following our discussions with [the U.S. Food and Drug Administration], our phase 3 trial design will use a primary endpoint based on positive predictive value parameters in the biochemical recurrence setting," Vivien Wong, executive vice president of Development at Progenics, said in a statement.

The company plans to launch a phase 3 trial of the agent by the end of 2018.