Greenwich LifeSciences has announced the expansion of its Flamingo-01 Phase III clinical trial of GLSI-100 (GP2 + GM-CSF) into five key European countries following approval.

The immunotherapy, designed to prevent breast cancer recurrences, has received formal approval for the company’s application from regulatory bodies in Spain, France, Germany, Italy, and Poland.

This marks a significant milestone for the trial, which aims to evaluate the safety and efficacy of GLSI-100 in HER2/neu positive breast cancer patients.

In the trial, patients with residual disease or who are at increased risk of pathologic complete response at surgery, and who have received both neoadjuvant and postoperative adjuvant trastuzumab based treatment, will be enrolled.

The academic networks participating in the European expansion are Geicam in Spain, Unicancer in France, GBG in Germany, GIM in Italy, and a network of Polish sites.

With the approval, Greenwich is set to activate 105 new clinical sites across these countries.

Site initiation visits are scheduled to commence as early as the first week of March.

Baylor College of Medicine is leading the Flamingo-01 trial, which presently has US clinical sites primarily from university-based hospitals and cooperative networks.

The trial's expansion into Europe is part of a broader plan to open up to 150 sites across the globe.

In the double-blinded arms of the trial, approximately 500 HLA-A*02 subjects will be enrolled and randomised to receive either GLSI-100 or a placebo.

An additional arm will treat up to 250 patients of other HLA types with GLSI-100.

The trial's design aims to detect a hazard ratio of 0.3 in invasive breast cancer-free survival, requiring 28 events to occur.

Greenwich LifeSciences CEO Snehal Patel said: “We have been planning this expansion for over two years and are thrilled to be making GLSI-100 available to patients in Europe in these major countries, with a total population of approximately 300 million.

“The interest in developing a vaccine to prevent the recurrence of breast cancer is very high in the European clinical and academic community, especially given the promising efficacy and safety profile from the prior GLSI-100 trials.

“We hope to open sites as quickly as possible while applying to open additional sites in the approved countries and potentially adding additional countries in Europe.”