Abata Therapeutics' ABA-101, an autologous regulatory T-cell (Treg) therapy, has received Fast Track designation from the FDA for the treatment of patients with progressive multiple sclerosis (MS). This designation aims to expedite the development and review of ABA-101, addressing a significant unmet need in progressive MS treatment.
Preclinical Evidence and Mechanism of Action
Preclinical studies have demonstrated that ABA-101 exhibits a tolerable safety profile in animal models. The therapy leverages antigen-dependent Treg functionality, promoting anti-inflammatory cytokine production and suppressing the production of inflammatory cytokines. Tregs are believed to have potential in treating MS because they suppress autoreactive T-cells. These cells also possess reparative properties, such as remyelination, mediated by growth-regulatory protein cellular communication network factor 3, and neural stem cell proliferation.
Target Patient Population
ABA-101 is being developed for patients with progressive MS who have imaging evidence of ongoing inflammatory tissue injury and who are HLA-DRB1*15:01 positive. This specific patient population is estimated to be around 45,000 people in the United States.
Management Perspective
"There are no effective treatments for progressive MS, and rapidly advancing new therapies is critical for patients and their families," said Samantha Singer, MS, MBA, the president and chief executive officer of Abata, in a statement. "We are very pleased that the FDA granted us Fast Track designation as it will enable us to expedite our efforts to bring ABA-101 to patients. We are focused on initiating our phase 1 study this year in patients and evaluating the potential impact of this important new therapy."
Current Treatment Landscape and Unmet Needs
Currently, ocrelizumab (Ocrevus; Genentech) is the only FDA-approved disease-modifying therapy for primary progressive MS, and siponimod (Mayzent; Novartis) is approved for secondary progressive MS. The Fast Track designation for ABA-101 highlights the urgent need for more effective treatments, as existing options provide limited benefit for many patients with progressive forms of the disease.
Prior Clinical Experience with Treg Therapy in MS
One prior clinical trial has explored Treg-based therapy in MS. A phase 1b/2a open-label trial published in 2021 included 145 patients with relapsing-remitting MS. Patients received either expanded ex vivo Treg cells intravenously (IV group, n = 11; dose 40 × 106 Treg cells/kg of body weight) or freshly isolated Treg cells intrathecally (IT group, n = 3; dose 1.0×106 Treg cells). The study reported no adverse events and no significant changes in self-assessed quality of life. Notably, disease progression halted in patients receiving Tregs intrathecally, with no relapses or deterioration of more than 1 point on the Expanded Disability Status Scale (EDSS).
