FDA Expedites Review of Petosemtamab in Head and Neck Cancer

A novel treatment for patients with head and neck cancers has received a breakthrough therapy designation from the FDA.

The Food and Drug Administration (FDA) granted a breakthrough therapy designation for petosemtamab, a novel treatment for patients with recurrent or metastatic head and neck cancers, a news release stated.

Specifically, the petosemtamab designation is for patients with head and neck cancers who experienced disease progression after platinum-based chemotherapy and a PD-1 or PD-L1 antibody. PD-1 and PD-L1 are proteins targeted by certain immunotherapy drugs. They play a role in helping cancer hide from the immune system, as defined by the National Cancer Institute.

According to the news release from Merus, the manufacturing company of petosemtamab, the FDA’s decision to grant a breakthrough therapy came after a fast track designation in August 2023.

A breakthrough therapy designation is “designed to expedite the development and review of drugs” used to treat serious conditions, as the FDA defines. A fast track designation facilitates the development and expedites the review of drugs, the FDA explains, to treat serious conditions with unmet needs.

Petosemtamab, the manufacturer defines, is a monoclonal antibody drug that binds to the epidermal growth factor receptor (EGFR) to help the immune system kill cancer cells.

“We are excited and encouraged to receive BTD for petosemtamab which further validates its potential to become a new standard of care for patients with previously treated [head and neck cancers],” Ashley Pereira, SVP of regulatory affairs at Merus, said in the news release.

The breakthrough therapy designation of petosemtamab is based on an ongoing phase 1/2 trial, the release stated.

About the Phase 1/2 Trial

Approximately 360 patients were assigned into two treatment arms to receive either petosemtamab alone or petosemtamab plus Keytruda (pembrolizumab), the ClinicalTrials.gov listing noted. Cancer types included advanced or metastatic solid tumors, such as colorectal cancer, gastric cancer, gastroesophageal-junction cancer, non-small cell lung cancer and head and neck cancers.

During the second half of 2024, the manufacturing company plans to update information about efficacy (how well the drug works), durability (ability to delay disease worsening) and safety, the release reported.

Particularly, researchers on the trial are aiming to identify several primary outcomes, according to the listing. Of note, they are evaluating the number of patients who have dose-limiting toxicities, meaning the number of patients who experience side effects from treatment during dose escalation. An observation of side effect severity from treatment will also be evaluated, the listing stated.

Other primary outcomes that will be measured include safety and tolerability based on the respective treatments, the listing noted. Instances of abnormal readings and results, severity of side effects from treatments and treatment discontinuations based on side effects. The time frame of these safety evaluations is six to 12 months, ClinicalTrials.gov noted.

“We look forward to continue constructive conversations with the FDA as we move forward in our plan to initiate a phase 3 trial in previously treated [head and neck squamous cell carcinoma] mid-2024 and prepare for a potential phase 3 trial evaluating the combination of petosemtamab and [Keytruda] in previously untreated patients,” Pereira said.

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