The alpha-synuclein protein that Affitope targets is found in brain cells. Its normal function is not fully understood, but in Parkinson’s it clumps and accumulates in nerve cells. The accumulation leads to the formation of Lewy bodies, spherical masses that replace other cell components. Lewy bodies are a hallmark of Parkinson’s.
How Affitope works
The vaccine prompts immune-system antibodies to bind to alpha-synuclein. It is based on the Affitome technology that Affiris developed. This technology involves using short synthetic peptides of altered amino acid sequences to prompt the immune system to generate specific antibodies.
Therapies like Affitope that reduce alpha-synuclein expression or that prevent it from clumping may some day prevent, slow, or stop the progression of Parkinson’s. Expression is the process by which information from a gene is used to create a functional product like a protein.
A Phase 1a clinical trial (NCT01568099) evaluated the safety and tolerability of four injections of two doses of Affitope in people with early-stage Parkinson’s. The doses were 15 and 75 micrograms.
The treatment was safe and participants tolerated it well, according to the trial results. Patient blood samples showed it triggered the alpha-synuclein antibodies that Affiris had designed it to generate.
The company conducted a Phase 1b follow-up study (NCT02216188) to assess the safety and effectiveness of booster vaccinations in Parkinson’s patients who participated in the Phase 1a trial. Affitope achieved the study’s primary objective by proving safe and well-tolerated.
Researchers detected vaccine-triggered antibodies not only in patients’ blood but in cerebrospinal fluid.
Eighty-six percent of the participants — 19 out of 22 — generated an immune response that lasted the entire 24-week trial period. That was higher than the percentage that the initial injection triggered, indicating that the booster concept worked.
Twelve of the 19 participants who had an immune response generated the alpha-synuclein-reactive antibodies that the vaccine was supposed to trigger.
Next steps for Affitope
Researchers looked at the initial injection’s safety and ability to trigger an immune response for up to 48 months. They also checked the booster’s ability to generate an immune response.
Affiris said it would release the results in the last quarter of 2017.
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