Early-Phase Trial to Study Novel Drug, With or Without Keytruda, in Solid Cancers

The first patient received treatment in a phase 1b expansion trial evaluating the novel drug PY159 in patients with ovarian cancer, pancreatic ductal adenocarcinoma, non-small cell lung cancer (NSCLC), triple-negative breast cancer (TNBC), HR-positive, HER2-negative breast cancer, head and neck squamous cell carcinomas and colorectal cancer, according to Pionyr Immunotherapeutics, the manufacturer of the drug.

PY159 is a monoclonal antibody that works by targeting TREM1, a protein found on certain cancer cells, thereby igniting the body’s immune system. The drug will be studied as a single agent and in combination with Keytruda (pembrolizumab).

"We developed PY159 to target TREM1 and reprogram myeloid cells within the tumor microenvironment to promote anti-tumor responses – a novel approach to TREM1 biology for anti-tumor drug development," said Dr. Leonard Reyno, Pionyr’s executive vice president and chief medical officer, in a press release.

Reyno explained that PY159 was “well tolerated in doses up to 10 milligrams per kilogram” in a prior phase 1a study. As such, researchers found the optimal dose in the phase 1a trial that will be used in a larger cohort of patients who are expected to participate in phase 1b.

So far, at least one patient with ovarian cancer received treatment with single-agent PY159.

The main goal of the phase 1b trial is to determine the anti-tumor effect of PY159, both alone and when given with Keytruda. Researchers will also analyze safety, tolerability and pharmacokinetics (how the drug moves throughout the body).

To be eligible, patients must be aged 18 years or older, have TREM1 expression, have experienced disease progression on a PD1/PD-L1 inhibitor. Patients who are candidates to receive a Food and Drug Administration-approved molecularly targeted therapy are not eligible to enroll onto the trial.

Investigators plan on enrolling 343 patients in the non-randomized trial. They plan on completing the study in April 2023.

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