The alpha-synuclein protein that Affitope PD01A targets is found in brain cells. Its normal function is not fully understood, but in Parkinson’s disease, it clumps and accumulates in nerve cells. This accumulation leads to the formation of Lewy bodies, spherical masses that replace other cell components, which is a hallmark of Parkinson’s disease.
How does Affitope PD01A work?
Affitope PD01A prompts the immune system to produce antibodies against 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 PD01A that reduce alpha-synuclein levels or prevent it from clumping may someday prevent the development or slow or stop the progression of Parkinson’s disease.
Affitope PD01A in clinical trials
A Phase 1a clinical trial (NCT01568099) evaluated the safety and tolerability of four injections of two doses of Affitope PD01A in people with early-stage Parkinson’s disease. The doses were 15 and 75 micrograms. A total of 32 patients were enrolled in the study with 24 receiving subcutaneous (under-the-skin) injections of Affitope PD01A and eight patients serving as controls.
The treatment was safe and well tolerated, according to the trial results. Patient blood samples showed it triggered the alpha-synuclein antibodies Affiris had designed it to generate.
The patients from that study were enrolled in an extension study (NCT01885494), where they were followed for an additional year with no further study treatment.
The company then conducted a Phase 1b follow-up study (NCT02216188) to assess the safety and effectiveness of booster vaccinations in patients who participated in the Phase 1a trial. Affitope PD01A achieved the study’s primary objective of being safe and well-tolerated.
Researchers detected vaccine-triggered antibodies not only in patients’ blood but in their cerebrospinal fluid (the fluid found in the brain and spinal cord). A total of 19 of 22 patients who were treated in this study (86%) generated an immune response that lasted the entire 24-week trial period. This was higher than the percentage the initial injection triggered, indicating that the booster concept worked. Of these 19 participants, 12 generated the alpha-synuclein-reactive antibodies that the vaccine was supposed to trigger.
One year after the immune “boost” from the Phase 1b study, participants who received treatments were given a second 75 microgram booster shot of Affitope PD01A as part of another Phase 1 trial (NCT02618941).
A total of 26 patients (21 treated and five control) completed all four trials. In all four trials, Affitope PD01A was well tolerated, and the desired antibodies were detected in the cerebrospinal fluid. Data also showed a trend toward lower levels of alpha-synuclein in the blood and cerebrospinal fluid of treated participants, but the studies were not set up or powered to detect changes in Parkinson’s disease symptoms.
After receiving feedback from the U.S. Food and Drug Administration, Affiris intends to investigate the efficacy of Affitope PD01A in Parkinson’s patients in a Phase 2 trial in the second half of 2020.
Last updated: Jan. 30, 2020
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