Prasinezumab (, ; developmental code names NEOD002, PRX-002, RG-7935, RO-7046015) is an

anti-α-synuclein drug An anti-α-synuclein drug, or an α-synuclein inhibitor, is a drug which blocks or inhibits α-synuclein. α-Synuclein is a protein which is thought to be involved in the development and progression of α-synucleinopathies including Parkinson's d ...

acting as a

monoclonal antibody A monoclonal antibody (mAb, more rarely called moAb) is an antibody produced from a cell lineage made by cloning a unique white blood cell. All subsequent antibodies derived this way trace back to a unique parent cell. Monoclonal antibodie ...

against

α-synuclein Alpha-synuclein (aSyn) is a protein that in humans is encoded by the ''SNCA'' gene. It is a neuronal protein involved in the regulation of synaptic vesicle trafficking and the release of neurotransmitters. Alpha-synuclein is abundant in the bra ...

which is under development for the treatment of

Parkinson's disease Parkinson's disease (PD), or simply Parkinson's, is a neurodegenerative disease primarily of the central nervous system, affecting both motor system, motor and non-motor systems. Symptoms typically develop gradually and non-motor issues become ...

. No significant effect on disease progression was seen in a 52-week

phase 2 Michael Lawrence Marrow (August 2, 1955 – December 12, 2019), known as PHASE 2 and Lonny Wood, was an American aerosol paint artist based in New York City. Mostly active in the 1970s, Phase 2 is generally credited with originating the "bubble ...

clinical trial Clinical trials are prospective biomedical or behavioral research studies on human subject research, human participants designed to answer specific questions about biomedical or behavioral interventions, including new treatments (such as novel v ...

.There have been concerns about

research misconduct Scientific misconduct is the violation of the standard codes of scholarly conduct and ethical behavior in the publication of professional scientific research. It is the violation of scientific integrity: violation of the scientific method and ...

and

data fabrication In scientific inquiry and academic research, data fabrication is the intentional misrepresentation of research results. As with other forms of scientific misconduct, it is the intent to deceive that marks fabrication as unethical, and thus differ ...

relevant to prasinezumab. As of May 2024, prasinezumab is in phase 3 clinical trials for Parkinson's disease. It is under development by Prothena Biosciences and Roche.

Mechanism of action

Prasinezumab is a humanized IgG1 monoclonal antibody that selectively binds to aggregated forms of alpha-synuclein while sparing the physiological monomeric form. The antibody recognizes the C-terminus of α-synuclein and preferentially targets pathological aggregates that form insoluble fibrils and

Lewy bodies Lewy bodies are the inclusion bodies – abnormal aggregations of protein – that develop inside neurons affected by Parkinson's disease (PD), the Lewy body dementias (Parkinson's disease dementia and dementia with Lewy bodies (DLB)) ...

—hallmark features of Parkinson's disease pathology.

Development history

Prasinezumab was originally developed under the designation PRX002 through a collaboration between

Hoffmann-La Roche F. Hoffmann-La Roche AG, commonly known as Roche (), is a Swiss multinational holding healthcare company that operates worldwide under two divisions: Pharmaceuticals and Diagnostics. Its holding company, Roche Holding AG, has shares listed on ...

and Prothena. The drug entered clinical development as a potential disease-modifying therapy for Parkinson's disease, representing one of the first attempts to target aggregated α-synuclein therapeutically.

Clinical trials

PASADENA Trial

The Phase II PASADENA trial was a randomized, double-blind, placebo-controlled study that evaluated prasinezumab in participants with early-stage Parkinson's disease. Participants were randomly assigned to receive either placebo or prasinezumab at doses of 1500 mg or 4500 mg intravenously every 4 weeks for 52 weeks. While the trial did not meet its primary endpoint (change in Movement Disorder Society Unified Parkinson's Disease Rating Scale DS-UPDRSsum of Parts I + II + III from baseline to week 52), exploratory analyses revealed promising signals: * Prasinezumab-treated participants showed slower progression of motor signs compared to placebo (MDS-UPDRS Part III) * The effect was more pronounced in participants with rapidly progressing disease * Benefits appeared to be sustained over the 4-year open-label extension period

PADOVA Trial

The Phase IIb PADOVA trial further evaluated prasinezumab's efficacy and safety profile. While the primary endpoint of time to confirmed motor progression did not achieve statistical significance (HR=0.84, p=0.0657), the results suggested potential clinical benefit, particularly in pre-specified subgroups.

Recent Developments

Based on encouraging results from Phase II studies, Genentech announced in June 2025 its decision to advance prasinezumab into Phase III clinical development for early-stage Parkinson's disease. This represents a significant milestone in the development of α-synuclein-targeting therapies. As of 2025, prasinezumab development includes: * Phase III development initiated for early-stage Parkinson's disease * Continued evaluation in open-label extension studies

References

External links

Prasinezumab - AlzForum
{{Monoclonals for bone, musculoskeletal, circulatory, and neurologic systems Experimental drugs Experimental monoclonal antibodies Parkinson's disease Monoclonal antibodies Roche Genentech