PyL Prostate Cancer Imaging Agent Submitted to FDA for Approval

Lantheus Holdings has submitted an application to the U.S. Food and Drug Administration (FDA) seeking approval of PyL, an investigational imaging agent used to locate prostate cancer lesions. The new drug application (NDA) sent to the FDA includes a request for priority review, which if granted may shorten PyL’s regulatory review process from the usual 10 months to six. Lantheus expects the FDA’s decision on this filing in early December.

PyL, also known as 18F-DCFPyl, is a tracing agent used in positron emission tomography or PET scans to visualize prostate cancer lesions in different types of tissues. It does this by targeting the prostate-specific membrane antigen (PSMA), a protein commonly found on the surface of prostate cancer cells. Once bound to these cells, PyL emits a radioactive signal that can be seen in PET scans, signaling where these lesions are located.

The company’s NDA submission was supported by data from two clinical trials — OSPREY (NCT02981368) and CONDOR (NCT03739684) — that showed PyL can detect local and distant prostate cancer lesions that conventional imaging methods sometimes miss. Such detection makes tracking disease recurrence and spread more accurate, enabling doctors to adjust treatment plans appropriately.

In the Phase 2/3 OSPREY trial, PyL showed good sensitivity and specificity at identifying cancer lesions among 385 men, split into two groups. Group A included men with high-risk locally advanced prostate cancer, while group B involved men with metastatic or recurrent disease. Of note, in this context, sensitivity refers to PyL’s ability to identify true cancer sites, and specificity to its ability to distinguish cancer sites from non-cancer (healthy) sites.

Among men from group A, PyL had a specificity of 96-99%, a sensitivity of 31-42%, and a positive predictive value (PPV) of 78-91% at identifying cancer lesions in pelvic lymph nodes. The PPV is the proportion of patients with positive results who truly have the disease. In the group B participants, PyL had a sensitivity of 93-99% and a PPV of 81-88% at detecting metastatic cancer lesions, meaning those found farther away from the prostate. Metastatic cancer is disease that has spread to other parts of the body.

The participants tolerated PyL well and reported no serious undesirable side effects. The most frequent side effects observed included altered or unpleasant taste sensations and headaches.

The Phase 3, open-label CONDOR study evaluated PyL’s ability to safely and accurately detect prostate cancer lesions in 208 men with suspected disease relapse. All of the patients enrolled in the study had high levels of prostate-specific antigen (PSA), a biomarker of prostate cancer, but had negative or ambiguous imaging results. The study met its main goal, with PyL correctly locating cancer lesions in 85-87% of the patients. As a result of these findings, nearly 64% of participants saw changes in their treatment management plans.

Dr. Istvan Molnar, MD, chief medical officer of Lantheus, stated “we believe that the demonstrated strong diagnostic performance of PyL, will assist in treatment decisions and, ultimately, may improve patient outcomes,”

Much of the above appeared in the Oct. 6th, 2020 Prostate Cancer News Today, by Forest Ray.

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