- Bristol Myers Squibb has agreed to pay $80 million for exclusive rights to an experimental drug for Alzheimer's disease developed by Prothena, a biotechnology company whose research focuses on dysfunctional proteins.
- Prothena's drug, known as PRX005, is designed to target a specific part of tau, a protein that scientists have long considered a driver of Alzheimer's disease. Normally, tau serves an important function by providing structure to brain cells and supporting growth. But when these proteins misfold, they can stick together and, it's believed, impair neural signaling, which can then lead to neurodegeneration.
- In 2018, Prothena's work caught the attention of Celgene, which paid $100 million up front for the option to later license up to three of the biotech's programs. Bristol Myers, which acquired Celgene in 2019, has since taken charge of the collaboration. By licensing PRX005, Bristol Myers is re-entering Alzheimer's research, a field it stepped back from more than a decade ago.
Prothena's announcement comes during an extremely eventful period in Alzheimer's drug development.
In early June, the Food and Drug Administration approved, for the first time, a medicine meant to slow the mental decline that Alzheimer's causes. Though the agency's decision provides a highly desirable option to patients, it has been met with intense criticism. Whether the medicine, called Aduhelm, works as intended remains unclear.
Meanwhile, Eli Lilly on Thursday said it's planning to submit one of its experimental Alzheimer's drugs for accelerated approval.
The choice is a reversal for Lilly, which said in April that the evidence supporting its drug, known as donanemab, likely wasn't enough to ask for accelerated approval. However, Lilly's drug works in a similar way to Aduhelm, proving very effective at clearing from the brain a kind of misfolded protein called amyloid, which is believed by many to be the root cause of Alzheimer's.
The FDA, when it approved Aduhelm, claimed that the drug's effect on amyloid beta was "reasonably likely to predict a clinical benefit." Some expect that rationale will lead more companies to seek approval for Alzheimer's drugs that show a big effect on amyloid clearance, but are not yet proven to improve cognitive function.
Bristol Myers, through the Prothena deal, is investing in another closely watched protein, with PRX005 going after tau. PRX005 is the first of program from the collaboration to move into human testing, Prothena said, and is now being studied in an early-stage trial.
While tau has drawn attention, Biogen earlier this month said one of its experimental drugs targeting the protein failed to slow patients' decline. As a result, the biotech company shut down further research.
Like many large pharmaceutical companies, Bristol Myers pulled back from the brain over the last decade, devoting resources instead to burgeoning areas of research like oncology and immunology. It currently lists just two neuroscience programs in its pipeline, both of which are in the earlier stages of human testing.
Given the immense need for new Alzheimer's treatments, the payoff could be significant for Bristol Myers and others. Analysts have forecasted, for example, billions of dollars in annual sales for Aduhelm.
Including the new $80 million payment, Prothena has received $230 million from its collaboration with Celgene and Bristol Myers. Additionally, the biotech said it could take home up to $160 million for U.S. rights, up to $165 million for global rights, and up to $1.7 billion for milestone payments — for a total consideration of $2.2 billion, plus tiered royalties on potential product sales.
Prothena shares were trading at just over $52 late Thursday morning, an increase of close to 9%.