Roche Reports Promising Early Data on Alzheimer’s Drug Trontinemab

Roche has disclosed preliminary findings regarding its investigational Alzheimer’s therapy, trontinemab. Early-stage data from the phase 1b/2a study indicate that amyloid levels in 81% of patients fell below the disease-related threshold following 28 weeks of treatment.
The Swiss pharmaceutical company has emphasized the significance of rapid amyloid reduction and achieving sub-threshold levels at an early stage as crucial factors for meaningful clinical outcomes. This perspective is informed by findings from previously successful anti-amyloid-beta antibody treatments. Roche aims to enhance these existing therapies by integrating its antibody with a technology designed to improve penetration across the blood-brain barrier—one of the fundamental obstacles in the development of such medications.
Roche presented its preliminary trontinemab data at the AD/PD 2025 International Conference on Alzheimer’s and Parkinson’s Diseases. The update included findings from 114 individuals who were administered either 1.8 mg/kg or 3.6 mg/kg of the antibody during the double-blind portion of the trial. In its official statement, Roche highlighted results from a subgroup of 26 patients who received the higher 3.6 mg/kg dose. Within this group, 21 participants demonstrated amyloid levels below the established 24-centiloid threshold after receiving trontinemab once every four weeks for a 28-week duration.

Experts in dementia research generally consider amyloid centiloid levels ranging from 24 to 30 as the benchmark for initiating anti-amyloid therapies. Drug developers often assess the efficacy of novel treatments based on the lower end of this range. A comparative phase 2 investigation of Eli Lilly’s donanemab, now marketed as Kisunla, found that 40% of participants exhibited centiloid levels below 24.1 after 24 weeks of treatment. However, given that Eli Lilly enrolled a larger number of participants than Roche, differences in trial design may influence the validity of direct comparisons. Nevertheless, based on the available data, trontinemab appears to demonstrate competitive efficacy in reducing amyloid levels within a relatively short timeframe.
Roche has also reported additional biomarker data that support the observed amyloid reduction. The company cited “early and significant reductions” in markers such as total tau, phosphorylated Tau (pTau)181, pTau217, and neurogranin, which were measured in both cerebrospinal fluid and plasma samples.
Regarding safety, the study identified three cases of amyloid-related imaging abnormalities with edema or effusion (ARIA-E), with one instance accompanied by mild symptoms. Roche also previously reported a patient fatality in the trial, although specific details on the cause of death have not been disclosed.

The investigation into trontinemab remains ongoing as part of the phase 1b/2a study. Concurrently, several pharmaceutical companies are exploring alternative methods to enhance drug delivery across the blood-brain barrier. Industry leaders such as AbbVie, Bristol Myers Squibb, and Eli Lilly have all engaged in partnerships to develop novel strategies for improving drug accessibility to the brain.