June 2, 2020

Impact: High

During the virtual AAN 2020 conference, Biogen presented the baseline characteristics of participants in its phase 2 SPARK study of cinpanemab in PD. On May 20th, a month after the virtual conference, AAN opened its presentations to be viewed by the public without need for AAN registration, allowing us to view the slides on the SPARK study.

The study design for SPARK includes 3 treatment arms with cinpanemab doses of 250mg, 1250mg, and 3500mg. 357 patients are enrolled, split into two cohorts, the first consisting of 29 patients undergoing an intensive PK evaluation:

Demographics

  • Enrollment is complete, with most of the 357 participants from North America and Europe.
  • Average age was 60.1 and 70% of participants were male.
  • The median time since disease onset at enrollment was 1.5 years, and median time since diagnosis was 6 months.

Baseline Characteristics

  • Mean MDS-UPDRS score: 32.4
  • Mean H&Y staging:
    • 24% were stage 1
    • 6% were stage 1.5
    • 65% were stage 2
    • Only 5% were higher than 2
  • Mean SE-ADL: 92.2
  • Mean PDQ-39: 9.8

Biogen states that the demographics at baseline are similar to those of the PPMI trial, and that recruitment was completed ahead of projected timelines. Data will be presented at a future scientific meeting.

inThought Analysis

The baseline characteristics are remarkably similar to the population recruited for Roche’s PASADENA study. The mean age and gender ratio are nearly identical. Biogen’s SPARK trial has a slightly higher mean overall MDS-UPDRS (32.4 vs. 31.4), but a lower percentage of participants with an H&Y score of 2 (65% vs. 75%).

Both trials are similar populations as that observed in the PPMI trial, which is meant to represent a real-world scenario. 

There are two key differences between the trials:

  1. SPARK uses 3 treatment arms compared to PASADENA’s 2 arms.
  2. And perhaps more significant, the primary endpoint for Biogen’s SPARK trial is safety/tolerability, where as Roche’s PASADENA uses an efficacy endpoint. 

Therefore Biogen’s trial is highly likely to achieve its primary endpoint, where Roche’s trial did not. Roche did describe a positive trend in its secondary endpoint, which may have gotten lost in the headline of the missed primary endpoint. On the other hand, if Biogen sees similar trends in its secondary endpoints, the perception may be much more positive, simply because of a (likely) positive primary endpoint. 

If we see the same positive trends in the SPARK study secondary efficacy endpoints that were seen in PASADENA, the trend would suggest an overall positive effect of targeting alpha-synuclein through a monoclonal antibody, and may help determine which endpoints to emphasize for future trials.

Source: AAN 2020 Science Highlights