Patient enrollment starts in clinical trial of brain imaging agent

18-OF-801 aims to visualize inflammation in Parkinson's, other diseases

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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Patient enrollment has started in a Phase 1/2 clinical trial evaluating 18F-OP-801, Ashvattha Therapeutics’ investigational imaging agent to visualize brain inflammation in people with Parkinson’s disease and other neurodegenerative conditions, the company said in a press release.

The ongoing trial (NCT05395624), which had previously recruited healthy volunteers for an earlier part, now is recruiting up to 20 patients with Parkinson’s, Alzheimer’s, multiple sclerosis, and amyotrophic lateral sclerosis. The testing sites are in California and Florida.

The study will evaluate the safety and tolerability of 18F-OP-801, which is administered intravenously, or into the vein, and is used with imaging scans. It also will assess the compound’s pharmacokinetics — the way it moves into, through, and out of the body — and its ability to identify regions of brain inflammation, or neuroinflammation, via positron emission tomography (PET) imaging.

Preliminary data are expected in the first half of 2024.

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The trial also will determine how the signal obtained from the PET imaging correlates with disease activity biomarkers and clinical disease parameters. A subset of participants will be re-infused with 18F-OP-801 to assess its uptake by brain cells after repeated dosing.

Researchers will use the findings to evaluate 18F-OP-801’s potential as a tool to assess the progression of neuroinflammation.

18F-OP-801 is a radiolabeled — meaning it’s tracked via a radioactive substance — tracer molecule that belongs to a family of chemical agents called hydroxyl dendrimers (HDs). These tiny molecules can cross the blood-brain barrier and target inflammatory immune cells while leaving healthy cells unharmed.

Ashvattha is developing HDs as a new way to deliver therapies to targeted cells. Confirming the uptake of 18F-OP-801 by activated immune cells in the brain would support its potential as an agent to reflect the efficacy of the company’s HDs-based therapies, according to the company.

In preclinical studies with multiple disease models, 18F-OP-801 was able to cross the blood-brain barrier — the semi-permeable membrane that shields the brain and spinal cord from the blood circulating in the rest of the body — and selectively target regions of neuroinflammation. It specifically identified activated microglia, the brain’s resident immune cells, and macrophages, immune cells known to fuel neuroinflammation once activated.

The study builds on those data, and the first part of the clinical trial showed “that there is no appreciable uptake in the brains of healthy volunteers, as expected,” said Jeffrey Cleland, PhD, Ashvattha’s chairman, president, and CEO.

“Our focus now turns to enrolling subjects with neurodegenerative conditions to determine the uptake of 18F-OP0801 in regions of neuroinflammation to support the use of this agent as a companion biomarker for one of our HD therapeutics,” Cleland said.