Athersys provides update on ischaemic stroke and haemorrhagic trauma trials of stem cell treatment


Athersys, the company developing MultiStem (invimestrocel)—an off-the-shelf stem cell treatment intended for critical care indications, including acute ischaemic stroke, trauma and other inflammatory conditions—has provided an update regarding two ongoing clinical trials with this product.

The MASTERS-2 trial is attempting to elucidate MultiStem’s utility in the treatment of ischaemic stroke, while the MATRICS-1 trial is assessing the use of MultiStem in the treatment of patients following haemorrhagic trauma.

“Cell therapy is among the most promising treatment paradigms for neurological and other disorders,” said World Stroke Organization (WSO) director Sean Savitz and Frank Yatsu (both UTHealth, Houston, USA). “MultiStem’s unique mechanism may shift the treatment of stroke by expressing a range of therapeutically relevant proteins and other factors to deliver multiple clinical benefits, including reducing inflammation, protecting damaged or injured tissue, and enhancing the formation of new blood vessels in regions of ischaemic injury. By considering the effects of secondary immune modulation, therapeutic benefit may be better observed over longer periods of time versus current commercial treatments like tPA [tissue plasminogen activator].”

MASTERS-2 is a company-sponsored, Phase 3, multicentre, randomised, double-blind, placebo-controlled trial evaluating MultiStem for the treatment of acute ischaemic stroke. Athersys has announced that more than half of the 300 expected patients have now been enrolled in this multinational study. The rate of patient enrolment “significantly increased” during 2022 due in part to the opening of new sites across more geographies, and more sites are expected to be activated throughout 2023, according to the company.

MATRICS-1 is an investigator-initiated, Phase 1/2, randomised, double-blind, placebo-controlled trial evaluating MultiStem in patients following resuscitation from haemorrhagic trauma that is underway at the University of Texas and the Memorial Hermann Hospital in Houston, USA. Athersys has announced that complete enrolment has been reached in the second cohort in which patients were dosed with MultiStem cells manufactured under the company’s new 3D manufacturing process. This will provide Athersys with safety data for 3D-treated patients and comparability against 2D-treated patients in the first cohort, as per a company press release. MATRICS-1 aims to enrol 156 patients in total, and enrolment in the third and final cohort is expected to begin later in 2023.

“Clinical results to date—including those from TREASURE and MASTERS-1—demonstrate success that meets or even exceeds the efficacy that tPA delivers to stroke patients after 90 days when administered within approximately 30 minutes of the ischaemic event,” said David Chiu (Houston Methodist Hospital, Houston, USA). “I believe that MultiStem holds potential to be a significant advancement in the treatment of stroke, with longer-term patient benefits, by providing a solution as impactful as tPA while significantly extending the treatment window. In fact, I see strong parallels between tPA treatment results in the 1990s and MultiStem today.”

As per Athersys’ recent announcement, MultiStem cells deliver benefit through distinct mechanisms, including reducing inflammatory damage, protecting at-risk tissue at the site of injury, and upregulating reparative aspects of the local and systemic immune system in a more timely way. Data in multiple animal models of acute neurological injury led to the development of this hypothesis regarding the cell-mediated mechanism of action and is supported by two human clinical trials evaluating the MultiStem cell product following acute ischaemic stroke that led to increased recovery benefit over time.

“We are pleased to report these enrolment updates as they demonstrate both increasing interest in MultiStem, and improved execution by our team and our partners,” stated Athersys CEO Dan Camardo. “We have been able to significantly accelerate patient enrolment in MASTERS-2 due to more effective site management, enhanced clinician confidence based on TREASURE results and the opening of more sites. Athersys’ enthusiasm about MultiStem for the treatment of ischaemic stroke has been bolstered by results from completed clinical trials, and we look forward to providing updates on MASTERS-2 after we engage with regulatory authorities during the first quarter of 2023.”


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