Novel HER3-Directed Therapy Granted Priority Review for Previously Treated NSCLC

The Food and Drug Administration (FDA) has accepted and granted priority review for the biologics license application for patritumab deruxtecan to treat adults with locally advanced or metastatic EGFR-mutated non-small cell lung cancer (NSCLC) previously treated with two or more systemic therapies.

Patritumab deruxtecan is a HER3-directed deruxtecan antibody drug conjugate, according to a press release from Merck, one of the drug’s manufacturers.

With a biologics license application, a pharmaceutical company is requesting permission to introduce a biologic product — in this case, patritumab deruxtecan — into interstate commerce, according to the FDA’s website. When granting a priority review of the application, the FDA selects agents that, if approved, would offer significant efficacy and safety improvement compared with the currently available options for the given disease.

“The acceptance of the (biologics license application) submission of patritumab deruxtecan marks an important step in potentially bringing this new medicine to previously treated patients with EGFR-mutated non-small cell lung cancer who often experience recurrence and have few remaining options,” Dr. Marjorie Green, senior vice president and head of late-stage oncology in global clinical development at Merck Research Laboratories, said in the release.

This biologics license application is based on findings from the phase 2 HERTHENA-Lung01 trial, which included 225 patients with EGFR-mutated locally advanced or metastatic NSCLC after disease progression with an EGFR tyrosine kinase inhibitor and platinum-based therapy, according to the release. Treatment with patritumab deruxtecan conferred an objective response rate (the percentage of patients who achieved a response from treatment) of 29.8%, which included one complete response (the disappearance of all signs of cancer from treatment) and 66 partial responses (a decrease in tumor size or the extent of cancer in the body) to therapy. In addition, the median duration of response (the time from a response to treatment until disease progression or death) was 6.4 months.

“The FDA’s prioritization of the (biologics license application) submission reflects the strength of the data from HERTHENA-Lung01 and emphasizes the need to provide new options to patients with locally advanced or metastatic EGFR-mutated non-small cell lung cancer previously treated with two or more systemic therapies,” Dr. Ken Takeshita, global head of research and development at Daiichi Sankyo, the other manufacturer of patritumab deruxtecan, said in Merck’s release. “If approved, patritumab deruxtecan could become the first HER3-directed medicine approved in the U.S.”

Researchers also reported on the safety profile of patritumab deruxtecan in the HERTHENA-Lung01 trial and found that it was consistent with previous clinical trials in NSCLC. The discontinuation rate related to treatment-emergent side effects was 7.1%. Treatment-emergent side effects considered severe or worse occurred in 64.9% of patients in the trial. The most common severe or worse treatment-emergent side effects, occurring in at least 5% of patients, included neutropenia (lower than normal number of white blood cells called neutrophils in the blood), thrombocytopenia (lower than normal number of platelets in the blood), leukopenia (lower than normal number of a white blood cell called leukocytes), anemia (low red blood cells), hypokalemia (low blood potassium levels), fatigue (tiredness) and asthenia (weakness).

Confirmed interstitial lung disease (a disorder that causes progressive scarring of lung tissue) related to the treatment occurred in 12 patients (5.3%) in the study, of which one instance resulted in death.

According to the release, the FDA has until June 26, 2024, to make their decision on patritumab deruxtecan.

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