AC Immune is looking ahead to the second part of its Phase II Parkinson’s disease (PD) vaccine trial.

The Swiss biotech presented at the AP/PD Conference 2024 on 6 March 2024, discussing several approaches that the company is taking in tackling early-stage PD.

This included a presentation on the status of the company's Phase II trial of ACI-7104.056, an anti-alpha-synuclein (a-syn) active immunotherapy, designed to induce a-syn specific antibodies.

In 2023, the first patient was dosed in the first part of the Phase II VacSYn trial (NCT06015841). Part one of the trial is evaluating the safety and pharmacodynamics (PD) of the candidate, while the second part will be a proof-of-concept study.

At the conference, AC Immune's chief medical officer Dr Nuno Mendonça said that the first part of the trial is nearly fully enrolled and will include 32 patients who will be separated into two cohorts, a placebo group and a treatment group. Patients will undergo eight weeks of screening; 18 months of treatment and a six-month follow-up.

Up to the February data point, 26 patients had been enrolled into the trial from Spain, Germany, and the UK with randomisation for part one expected to be completed by the end of this month.

The data reported from part one will help to finish determining the primary endpoint for the second part of the trial said Mendonça.

Part two of the trial will enrol 150 patients, including patients from part one, who will undergo the same treatment period. Investigators will use the same dose as the first part.

Mendonça said that the trial will enrol patients who are early-stage PD, both treatment naïve and on low-level levodopa, current PD standard of care (SoC).

Up until the February data cut-off, there had been no deaths, no other serious treatment-emergent adverse events (TEAEs) and no TEAEs leading to discontinuation. The most common TEAEs reported have been injection site reactions with all events being mild or moderate in severity.

The trial is due to end in January 2028, according the ClinicalTrials.gov.

A-syn has been identified as a key contribution to PD. A-syn’s aberrant soluble oligomeric conformations, called protofibrils, are a toxic species which mediate disruption of cellular homeostasis and neuronal death. It is also thought that a-syn exerts deleterious effects on neighbouring cells, including seeding or aggregation.

Other AD/PD discussions by AC Immune

AC Immune also discussed other research it is conducting during the presentation including its a-syn positron emission tomography (PET) programme, a PET tracer capable of detecting a-syn pathology in a living human brain.

Another discussion explored the company’s development in immunotherapies.

AC Immune's PET programme has first been investigated in patients with multiple system atrophy, an atypical parkinsonism disorder.