First Patients With SCLC to Receive HPN328 Plus Tecentriq in Phase 1/2 Trial

The first patients in a phase 1/2 trial with small cell lung cancer (SCLC) have received a treatment combination of HPN328 and Tecentriq (atezolizumab).

HPN328 is an immunotherapy that is manufactured by Harpoon Therapeutics, a clinical-stage immuno-oncology company. The drug is used to target DLL3, a protein found in abnormally high amounts on cancer cells, according to Memorial Sloan Kettering Cancer Center.

SCLC is a type of lung cancer that is known to be aggressive, meaning it grows quickly. This type of lung cancer also forms in the tissue of the lung and could spread to other areas of the body, as defined by National Cancer Institute.

According to statistics from American Cancer Society, SCLC cases only make up approximately 10% to 15% of all lung cancer cases in the United States, whereas non-small cell lung cancer (NSCLC) — the most common type of lung cancer — makes up 80% to 85% of lung cancer cases.

Lung cancer, including both small cell and non-small cell, is the second most common cancer in the United States, and is considered the leading cause of cancer death, established by American Cancer Society, accounting for approximately one in five cancer deaths each year.

With new and improved treatments, people who received diagnoses for SCLC or NSCLC and received treatment have a better chance of surviving, compared with people who received diagnoses and were treated at least five years ago, the American Cancer Society determined.

The phase 1/2 trial, reported in a press release from Harpoon Therapeutics, is designed to determine safety, tolerability and pharmacokinetics (the activity of drugs, such as absorption and distribution, within the body over a period of time) regarding the treatment combination of HPN328 and Tecentriq in patients with SCLC who have DLL3 expressions.

Regarding patient enrollment for the trial, clinicalTrials.gov reported that approximately 162 patients will be participating. Eligible patients for the study must have confirmed SCLC with the DLL3 expression and have experienced relapsed/refractory SCLC (return of SCLC after previous improvements or SCLC that does not respond to treatment) after one or more lines of systemic therapy that included platinum-based chemotherapy.

“Dosing the first patients in these combination cohorts for HPN328 with (Tecentriq) in patients with SCLC marks a significant milestone for this clinical program,” Dr. Luke Walker, chief medical officer for Harpoon Therapeutics, said in the press release. “Building on the strength of our phase 1 data, we remain committed to realizing the full potential of HPN328 as an important treatment option for patients with SCLC and other neuroendocrine tumors across early and late lines of therapy.”

LEARN MORE: Comparing Small Cell and Non-Small Lung Cancer

In terms of secondary outcome measures, the trial’s researchers aim to identify objective response rate (percentage of patient-participants who partially or completely respond to treatment within a given time), progression-free survival (period during and after treatment when the disease does not worsen), overall survival (period between diagnosis until end of treatment when patients remain alive).

The press release also noted that the researchers will also aim to analyze duration of response (length of time when a tumor responds to treatment without it growing or spreading) and anti-drug antibody formation (when the immune system creates antibodies against the drug).

The company anticipates receiving initial results from the HPN328 and Tecentriq combination cohorts mid-year in 2024.

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