Immutep updates on AIPAC breast cancer study and announces new trial

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Immunotherapy company Immutep (ASX:IMM) has announced what it describes as promising overall survival data from a breast cancer trial of its eftilagimod alpha (efti) and that its Chinese partner, EOC Pharma, will commence a new phase two clinical trial in up to 152 patients.

The promising results are from a ongoing phase two trial (AIPAC) that is evaluating efti in combination with paclitaxel chemotherapy compared to a combination of placebo and paclitaxel chemotherapy in patients with HER2-negative/HR positive metastatic breast cancer (HR+ MBC).

The company said the early results show an improving overall trend in overall survival (OS) with a median of +2.7 months from efti plus chemotherapy compared to chemotherapy plus placebo.

It said there was a statistically significant OS benefit in the efti combination in pre-defined patient groups.

It was +7.1 months survival benefit from efti with chemotherapy for patients under 65 years of age. It was +9.4 months survival benefit from efti with chemotherapy for patients with a low starting monocyte count.

According to Immutep CEO, Marc Voigt, “AIPAC marks an important milestone for Immutep and builds our confidence that efti is beneficial for many cancer patients, including those with metastatic breast cancer. Notably, we have seen a more material OS benefit than PFS benefit in this study; however, we note that this is not unusual for some immunotherapies where it can take time for the body’s immune system to be boosted and provide a therapeutic benefit.

"We are very encouraged by these first OS results which, subject to ongoing data collection, warrant a registrational perspective and regulatory interactions towards what we hope will be an important new class of medicines.”

EOC Pharma is the exclusive licensee of efti from Immutep for the Chinese market. Under its agreement with Immutep, it will make further milestone payments to the company if efti achieves specific development milestones as well as undisclosed royalties on sales and is also required to fund the Chinese development of efti.

The new study is similar to AIPAC study. The EOC Pharma trial will be a randomised, double-blind, placebo-controlled phase two clinical study with the study endpoints including progression-free survival, overall survival and overall response rate.

It is expected to take place across 20 clinical trial sites in China over 24 months and will evaluate efti in combination with paclitaxel in HER2-negative/HR positive metastatic breast cancer patients who have progression after endocrine therapy.

EOC Pharma CEO, Xiaoming Zou, said, “Breast cancer is now the most common cancer in Chinese women, with more than 1.6 million people being diagnosed and 1.2 million people dying of the disease each year. It is very important that we find new ways to enhance paclitaxel chemotherapy which continues to be a standard of care for HER2-negative/HR positive metastatic breast cancer patients. Immutep’s recent encouraging interim AIPAC results give us hope we can boost the body’s immune system to deliver better outcomes to patients.”

Marc Voigt added, “EOC Pharma shares our growing excitement about the potential for the combination of efti with paclitaxel chemotherapy in metastatic breast cancer. Our ongoing AIPAC study evaluating the same combination is already reporting very encouraging data, including a statistically significant survival benefit of 7.1 months in patients under 65 years of age and 9.4 months for patients with a low starting monocyte count. EOC Pharma’s new trial in China brings this innovative new treatment much closer to market for metastatic breast cancer patients.”