Biohaven’s Troriluzole Joins Long List of Failed Alzheimer’s Drugs

The chances of getting a cure for Alzheimer’s disease took one more hit as another Alzheimer’s trial bit the dust. On January 18th, Biohaven Pharmaceuticals announced that its drug troriluzole, a symptomatic treatment of mild-to-moderate Alzheimer’s disease has missed its co-primary endpoints in a Phase 2/3 clinical trial.

Unlike other AD drugs that target amyloid plaques, Troriluzole modulates glutamate, the most abundant excitatory neurotransmitter in the human body. Excessive glutamate release has been linked to many neurodegenerative diseases, including AD.

Troriluzole addresses this problem by augmenting the expression and function of an excitatory amino acid transporter located on glial cells that play a key role in clearing glutamate from the synapse.

The Failed Trial

The 48 weeks study with 350 patients experiencing mild to moderate Alzheimer’s symptoms revealed that the drug did not bring any positive change on the study’s prespecified co-primary endpoint of the Alzheimer’s Disease Assessment Scale-Cognitive Subscale 11 (ADAS-cog) and the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB). Additionally, it failed to beat placebo on the key secondary endpoint of hippocampal volume assessed by MRI.

However, all is not lost for the company that observed “a nonsignificant numerical difference of a potential benefit at week 48” in the subgroup analysis of AD patients in which the symptoms had just started to set. The data suggestive of “a potential benefit” is the -1.1% change in hippocampal volume from baseline in drug-treated mild AD patients compared to -1.6% for placebo-treated.

However, full study results, including biomarker analysis and additional secondary outcomes are warranted before making any conclusion about the benefits in early AD. The company is planning to gather additional data from the trial and present it at an upcoming scientific conference.

Vlad Coric, M.D., Chief Executive Officer of Biohaven commented “Alzheimer’s is a devastating disease and we must continue to advance the science to improve treatment outcomes for the many patients who are in need.

Conclusions

This study was well conducted but unfortunately it is clear from this preliminary analysis that troriluzole is not efficacious as a symptomatic treatment in a mixed population of patients with mild and moderate AD. We are awaiting additional biomarker data and other secondary analyses that will help inform whether troriluzole may provide benefit in early AD as a disease-modifying agent.

Alzheimer’s research is one of the hot topics of the decade. There are dozens of drugs in development for the disease and billions invested. Despite this, the rate of failure of the drugs is huge. In the past decade, the majority of the drugs were developed to target one protein, amyloid-beta plaque.

However, the trials for most of them have failed either due to the drug’s inability to target the plaques or its usage on the wrong population (advanced in the disease). Some of the drugs showed benefits in early AD patients such as in the case of troriluzole, however, it failed later in subsequent trials.

It is difficult to predict anything about Biohaven’s AD drug target with the current data. Nevertheless, when the new analysis comes out, it will become much clearer if the drug has the potential to move the needle.

Related Article: Lilly’s Donanemab Aces Phase 2 Trial, Slows Clinical Decline in Alzheimer’s Patients

References

1. https://www.biohavenpharma.com/investors/news-events/press-releases/01-18-2021

Author

Ruchi Jhonsa