Introduction
As the world of medical research takes on the challenge of Alzheimer’s disease, it is crucial to not only focus on amyloid-beta but also on another key player: tau. Amyloid plaques have traditionally been the primary focus, but recent developments indicate that targeting tau may hold significant promise in the fight against this devastating disease.
The Importance of Tau
Tangles of protein called tau play a critical role in the progression of Alzheimer’s. Recent studies have shown that by eliminating amyloid plaques, the spread of tau can also be reduced. This has prompted drug developers, including Biogen, Eisai, Prothena, and other start-ups, to investigate the direct targeting of tau as a potential treatment strategy.
Prothena: Pioneering Breakthroughs
Prothena, with decades of research under its belt, has emerged as a key player in tau-targeting therapies. The company’s journey began in the 1980s at Athena Neurosciences, a start-up that was later acquired by Elan Pharmaceuticals. When Elan faced challenges, Prothena was born in 2012 with a mission to develop treatments for Alzheimer’s and other neurological disorders.
The recent boost in Prothena’s stock came when Bristol Myers Squibb (BMS) exercised its option to invest $55 million in an experimental antibody designed to halt the spread of tau in the brain. With Prothena shares now valued at $71, the stock has surged by nearly 140% in the past 12 months, outperforming the Nasdaq Composite’s 26% rise. The company’s market valuation currently stands at an impressive $3.7 billion.
A Ray of Hope: Targeting the Spread of Tau
While previous trials focusing on tau have experienced setbacks, companies like Prothena are now testing a new approach. Instead of targeting the entire tau protein, researchers are developing antibodies that attach to the specific region responsible for the spread of tau between brain cells. Initial results from a Phase 1 study on Prothena’s PRX005 antibody were promising, indicating its safety.
This week’s Alzheimer’s conference provided further insights into the study, revealing that the administration of PRX005 to 19 patients resulted in concentrations similar to those observed in lab mice, which effectively prevented the damaging spread of tau tangles. Bristol Myers has agreed to fund a follow-up study that will evaluate the impact of multiple doses of this tau-blocking antibody.
Conclusion
As the world embraces a renewed focus on the tau protein in Alzheimer’s research, Prothena stands at the forefront of groundbreaking advancements. With promising results from their PRX005 antibody and the support of key investors like Bristol Myers, Prothena is paving the way towards a potential breakthrough in the treatment of this debilitating disease.
Analysis of Prothena’s $55 Million Bet on Tau Treatment
Analysts, including Oppenheimer’s Jay Olsen, suspect that Bristol may have made an informed decision on its $55 million investment in the tau treatment after glimpsing the results of the multidose trial. Olsen has a positive outlook on Prothena, giving it a Buy rating with a target price of $120.
Prothena’s Alzheimer’s Program
Apart from its bet on tau treatment, Prothena has other exciting developments in its Alzheimer’s program. It is currently conducting Phase 1 trials for an antibody that targets amyloid-beta plaques – similar to the recently approved Leqembi from Biogen and Eisai, as well as Lilly’s promising donanemab. Initial laboratory tests indicate that Prothena’s PRX012 may be more potent than other anti-amyloid drugs. Additionally, it can be conveniently administered through injections rather than requiring hospital infusions.
Vaccine Development at Prothena
During the Amsterdam conference, Prothena researchers presented compelling data on a vaccine that successfully induced mice to produce their own antibodies against both amyloid and tau. The administration of these vaccine shots effectively cleared amyloid in the mice. Prothena aims to seek permission from U.S. regulators to commence human trials for its double-barreled PRX123 vaccine by the end of this year.
Financial Standing and Competition
With $700 million in cash reserves, Prothena has ample resources to support its ongoing research and development efforts. However, it is also burning through approximately $200 million annually as of Q1 2022. Furthermore, the company faces tough competition from larger players in the field that are also targeting tau.
Alternative Approaches to Targeting Tau
At the recent Alzheimer’s conference, Japan’s Eisai presented an anti-tau antibody – E2814. Like Prothena’s tau antibody, E2814 blocks the spread of tau protein between cells. In a Phase 1 trial involving several dozen patients, Eisai observed a reduction in tau-related measures in some individuals.
Biogen, another significant player in the field, shared information about an antisense drug that it is developing in collaboration with Ionis Pharmaceuticals (IONS). This drug works by blocking the genetic instructions that prompt brain cells to produce tau. Biogen has advanced to Phase 2 trials following positive results from a Phase 1 study, which showed a decrease in tau levels in the brain and blood of Alzheimer’s patients.
