Negative Phase 2 Trial Data Ends Development of PSP Drug

Negative Phase 2 Trial Data Ends Development of PSP Drug

Topline results from the phase two PASSPORT trial show the experimental drug gosuranemab (BIIB092, Biogen) did not meet its primary or key secondary endpoints in patients with the atypical parkinsonian disorder of progressive supranuclear palsy (PSP), the manufacturer has announced.

The company noted in a statement released earlier today that the primary outcome measure of improved score on the PSP rating scale (PSPRS) at week 52 was not significantly different. Nor were key clinical secondary outcomes.

On the basis of these findings, “Biogen will discontinue development of gosuranemab for PSP and other primary tauopathies,” the manufacturer reported.

“We are disappointed with the efficacy results,” Alfred Sandrock Jr, MD, PhD, executive vice president of research and development and chief medical officer at Biogen, said in the press release.

However, “we remain unwavering in our commitment to advancing therapies that have the potential to address the significant unmet medical needs of people with neurodegenerative diseases who are faced with limited to no treatment options,” Sandrock added.

Currently No Effective Treatment

PSP is a neurodegenerative disease that affects cognition, eye movements, gait, posture, and swallowing.  According to the National Institute of Neurological Disorders and Stroke (NINDS), only 3 to 6 in 100,000 individuals worldwide have PSP. In comparison, an estimated 50,000 Americans are diagnosed with Parkinson’s disease each year, whereas only a total of 20,000 Americans are afflicted with PSP.

“Currently there is no effective treatment for PSP, but some symptoms can be managed with medication or other interventions,” NINDS notes on its website.

Gosuranemab, which was known previously as BIIB092, is a humanized monoclonal antibody that targets N-terminal-tau and is administered intravenously.

According to information about PASSPORT posted on, the trial’s primary objective was to assess the drug’s efficacy vs placebo by measuring change from baseline on the PSPRS at Week 52.

Secondary outcomes included gosuranemab vs placebo in change from baseline to Week 52 on the Unified Parkinson’s Disease Rating Scale Part II, the Clinical Global Impression of Change, the Repeatable Battery for the Assessment of Neuropsychological Disease Severity, and the PSP Quality of Life scale.

The study’s start date was April 24, 2017 and enrollment was estimated to include 490 participants.

Safety results from PASSPORT “were generally consistent with previous studies of gosuranemab. Detailed results of this study will be made available in a future scientific forum,” Biogen noted in their release. The company licensed the drug from Bristol-Myers Squibb.

Interestingly, the ongoing phase 2 TANGO trial will continue. In that study, the drug is being assessed for mild cognitive impairment from Alzheimer’s disease or for mild AD itself. This trial is moving forward “given differences in disease pathology” from PSP, the company reports.

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