AC Immune SA dosed the first patients in Cohort AD4 in the ongoing Phase 1b/2 ABATE trial. Treatment of first patient in Cohort AD4 in ABATE trial triggers $12 million milestone payment. ABATE is assessing ACI-24 in subjects with prodromal AD and in adults with Down syndrome (DS).
AD4 includes subjects with prodromal AD. ACI-24 is an anti-Abeta active immunotherapy candidate designed to induce a robust antibody response against the toxic forms of Abeta believed to drive plaque formation and AD progression. By inducing plaque clearance and efficiently inhibiting plaque formation in the brain, ACI-24 has the potential to delay or slow AD progression.
ACI-24 is being investigated in the ongoing ABATE randomized, double-blind, placebo-controlled Phase 1b/2 trial to assess its safety, tolerability, immunogenicity and pharmacodynamic effects. Data so far show that ACI-24 is generally safe and well tolerated, and that it has generated anti-Abeta antibody responses at all tested doses. Cohorts AD1, AD2 and AD3 enrolled a total of 74 patients who received ACI-24 at escalating dose levels.
The 12-month data readouts from Cohorts AD1, AD2 and AD3 are expected later in Second Quarter 2026. Cohort AD4 will include an initial group of 36 patients treated for 12 months, with follow-up of 6 months, significantly expanding the safety and biomarker efficacy data set. A subsequent expansion of the AD4 cohort could potentially see the total number of subjects reach approximately 112 patients.
AC Immune is responsible for conducting the ABATE trial. Following the potential option exercise, Takeda would conduct and fund all further clinical development and be responsible for all global regulatory activities as well as worldwide commercialization. Under the terms of the agreement with Takeda, AC Immune received an upfront payment of $100 million and is eligible to receive an option exercise fee and additional potential development, commercial and sales-based milestones of up to approximately $2,100 million, if all related milestones are achieved over the course of the agreement.
Upon commercialization, AC Immune will be entitled to receive tiered double-digit royalties on worldwide net sales. The ABATE randomized, double-blind, placebo-controlled Phase 1b/2 trial of ACI-24 for treatment of Alzheimer?s disease (AD) continues fully blinded (NCT05462106). Enrolled patients are required to have a diagnosis of prodromal AD: MCI due to AD according to the National Institute on Aging Alzheimer?s Association (NIA-AA) criteria, and a PET scan at screening must be consistent with the presence of amyloid pathology.
Patients will be randomized to one of several doses of ACI-24 or placebo. Following multiple data safety monitoring board (DSMB) reviews, no safety concerns have been raised to date, consistent with previous results. Very encouraging immunogenicity has been shown with clear evidence of anti-Abeta antibody responses against toxic Abeta species observed in the blinded data.
