---
title: "Cinpanemab: Parkinson's Drug Pipeline"
description: An anti–alpha-synuclein antibody that failed its Phase 2 trial in 2021 and was discontinued. Included for an honest picture of the field.
canonical_url: "https://parkinsonspathways.com/pipeline/cinpanemab"
development_stage: Recently stopped or failed
last_updated: 2026-06-01
source: "Parkinson's Pathways"
---
# Cinpanemab

**Stage:** Phase 2 failed (2021)  ·  **Type:** Disease-modifying

**Developer:** Biogen

**How it works:** An antibody infusion that aimed to clear alpha-synuclein, the protein that clumps in Parkinson's.

**Target:** Alpha-synuclein

**Who it's for:** People with early Parkinson's.

**Why it stopped:** Its Phase 2 SPARK trial (2021) missed both its primary and secondary endpoints, and Biogen ended the program.

**Key trials:** NCT03318523

**Last reviewed:** 2026-06-01


## What it is

Cinpanemab was an antibody infusion targeting alpha-synuclein, conceptually similar to prasinezumab, an attempt to slow Parkinson's by clearing the misfolded protein.

## Where it stands

Its Phase 2 SPARK trial failed, and Biogen discontinued the program. It is not in development.

## What the data shows so far

SPARK enrolled around 357 people with early Parkinson's and showed no difference from placebo on either its primary or secondary endpoints over the trial period: a comprehensive negative result.

## What families should know

Cinpanemab's failure, alongside the mixed prasinezumab results, is why experts remain cautious about anti–alpha-synuclein antibodies despite the strong theory behind them. Knowing what has failed helps families judge bold claims.

## Caveats

Discontinued after a clearly negative Phase 2. Not available and not being studied. Listed only for transparency.

## Timeline

_Most recent first._

- **2021**, SPARK Phase 2 fails; program discontinued.

## Sources

- [SPARK on ClinicalTrials.gov](https://clinicaltrials.gov/study/NCT03318523)

_Last reviewed: 2026-06-01._

## More

- [Back to the Parkinson's drug pipeline](https://parkinsonspathways.com/pipeline)
- [Browse all recruiting trials](https://parkinsonspathways.com/trials)