AC Immune has received FDA Fast Track designation and IND clearance for ACI-7104, an active immunotherapy being studied in early Parkinson’s disease.

FDA clears US expansion

AC Immune has received FDA Fast Track designation and Investigational New Drug clearance for ACI-7104, an active immunotherapy being developed for early-stage Parkinson’s disease.

The regulatory decisions will allow the company to expand its ongoing VacSYn Phase 2 trial to sites in the US.

ACI-7104 is designed to stimulate antibodies that selectively recognise aggregated forms of alpha-synuclein, a protein associated with Parkinson’s disease and other neurodegenerative conditions.

The candidate is being evaluated in an adaptive, biomarker-based Phase 2 study involving patients with early-stage Parkinson’s disease.

Fast Track designation is intended to facilitate the development and regulatory review of medicines addressing serious conditions with unmet medical needs. It does not constitute FDA approval or establish that a treatment is effective.

AC Immune said the designation followed interim Phase 2 findings showing safety, tolerability and immunogenicity, alongside early signals of activity.

Phase 2 Parkinson’s study

The VacSYn study is evaluating ACI-7104 in patients with early Parkinson’s disease, with Part 1 designed to assess safety, immunogenicity and potential activity over an extended follow-up period.

Interim results from Part 1 at 76 weeks showed no clinically relevant safety issues, according to AC Immune. The company also reported a 100% responder rate for the predefined immunogenicity target.

The results remain interim, with full week-100 results from Part 1 expected in the second half of 2026.

Martin Zügel, interim CEO of AC Immune, said the regulatory milestones would support further development of the programme.

“Fast Track designation and IND clearance from the FDA are important achievements for ACI-7104, one of our wholly-owned programs, given its potential to address the significant unmet need in Parkinson’s,” Zügel said.

The company has also received a $4 million research grant from the Vijay and Marie Goradia Charitable Foundation to support an extension of Part 1 of the VacSYn study.

The extension is intended to provide an additional two years of follow-up for long-term safety and efficacy.

Targeting alpha-synuclein

ACI-7104 is an optimised formulation of an earlier active immunotherapy developed by AC Immune.

The approach is designed to generate antibodies against pathological alpha-synuclein, particularly aggregated forms of the protein. The company is investigating whether targeting these forms could limit their spread and downstream effects on neurons.

Alpha-synuclein accumulation is associated with neuronal dysfunction and degeneration in Parkinson’s disease. Developing treatments that target the underlying biology of the disease, rather than focusing solely on symptoms, remains an area of active research.

Günther Staffler, executive vice president of development at AC Immune, said the company was continuing to evaluate ACI-7104 in prodromal and early Parkinson’s disease.

“ACI-7104 represents a promising active immunotherapy designed to target pathological a-syn for the treatment of prodromal and early PD,” Staffler said.

The full week-100 Part 1 results from VacSYn are expected in the second half of 2026 and will provide additional information on the candidate’s safety, immunogenicity and clinical activity.