Why Alzheimer’s partnerships with Roche, BMS, and Novo Nordisk still matter for Prothena

In the wake of Prothena Corporation plc’s Phase 3 failure with birtamimab, attention has swiftly shifted to its broader pipeline and the strategic partnerships that underpin it. While the company is discontinuing its late-stage amyloidosis drug, it retains several high-potential collaborations that could significantly influence its future—especially in the Alzheimer’s disease domain. Among these, Prothena’s partnerships with Roche, Bristol Myers Squibb (BMS), and Novo Nordisk are particularly vital.

These collaborations are not only financial lifelines but also scientific validations of Prothena’s core platform in protein misfolding and neurodegeneration. As the biotech sector remains highly capital-intensive and competitive, the role of large pharmaceutical partners is becoming increasingly central to risk-sharing, accelerated development, and global commercialization.

For Prothena, the failure of birtamimab is not a full-stop but a comma—and its next chapter is likely to be written in collaboration with some of the world’s largest drugmakers.

Why Is the Roche Collaboration Pivotal to Prothena’s Neuroscience Ambitions?

Prothena and Roche have a well-established history of co-developing neuroscience programs. Their most notable joint venture was around prasinezumab, a monoclonal antibody targeting alpha-synuclein in Parkinson’s disease. While prasinezumab did not achieve clear success in earlier trials, Roche continues to pursue its development, reflecting a shared long-term vision for disease-modifying treatments in neurodegeneration.

Although PRX012, Prothena’s lead Alzheimer’s program, is not formally partnered with Roche, the two companies remain aligned in therapeutic focus. Roche has signaled continued investment in CNS innovation, particularly in protein aggregation disorders. This increases the likelihood of expanded collaboration if PRX012 yields promising Phase 1 data in August 2025.

Roche’s expertise in large-scale clinical trials and global commercialization could be instrumental in bringing Prothena’s therapies to market. Moreover, the preexisting collaboration infrastructure ensures smoother tech transfer and operational synergy, should future joint development agreements materialize.

What Role Does Bristol Myers Squibb Play in the Alzheimer’s Pipeline?

Prothena’s partnership with Bristol Myers Squibb, originally inked in 2021, is centered on tau-targeting therapies for Alzheimer’s disease and other neurodegenerative conditions. The collaboration includes milestone payments and royalties, and provides BMS with rights to develop and commercialize Prothena’s PRX005.

Tau protein, like beta-amyloid, is a key pathological hallmark in Alzheimer’s, and many in the scientific community view it as a complementary or even superior target in certain disease stages. BMS’s financial backing and clinical development strength ensure that Prothena’s tau program receives robust support as it progresses through preclinical and early clinical phases.

While PRX005 remains in early development, its association with a pharmaceutical heavyweight like BMS serves as both de-risking for Prothena and external validation of its scientific approach. The upcoming updates from BMS in 2026 are expected to provide further clarity on clinical viability and may elevate investor confidence in the non-amyloid component of Prothena’s Alzheimer’s portfolio.

Why Is the Novo Nordisk Relationship Strategically Valuable?

Novo Nordisk’s collaboration with Prothena was announced in July 2021, focusing on developing antibody-based therapies for type 2 diabetes and obesity, with potential CNS applications. While the primary focus of this partnership is metabolic disease, Novo Nordisk has been expanding its interest in neurodegeneration, creating future optionality for CNS crossovers.

The partnership includes discovery-stage research, and Novo Nordisk has exclusive rights to lead candidate development and commercialization, while Prothena retains milestone and royalty rights. Updates are expected in the second half of 2025. The flexibility of this collaboration structure allows both parties to explore novel pathways that might intersect with Alzheimer’s-related mechanisms, particularly given the growing evidence of metabolic dysfunction’s role in cognitive decline.

If Novo Nordisk’s emerging CNS strategy aligns with Prothena’s capabilities in protein dysregulation, the partnership could expand to include direct Alzheimer’s-focused programs. Such developments would further diversify Prothena’s risk exposure and reinforce its scientific brand in CNS innovation.

How Do These Partnerships Impact Investor Confidence?

While the birtamimab failure delivered a short-term blow to Prothena’s valuation, analysts have pointed out that its partnered pipeline may serve as a stabilizing force. The involvement of Roche, BMS, and Novo Nordisk—each with deep R&D infrastructure and commercialization scale—suggests that Prothena is not operating in a vacuum.

These collaborations represent long-term optionality and non-dilutive capital sources. They also mitigate the binary nature of wholly owned clinical assets. From an institutional investment standpoint, the ability to weather late-stage failures while preserving forward momentum is critical—and Prothena’s diversified partnership strategy aligns with this resilience model.

Moreover, the continued commitment of its partners despite setbacks in other programs reflects a vote of confidence in the company’s platform and management. As more updates emerge from these collaborations, investors are likely to reassess Prothena through a broader lens than just birtamimab’s performance.

What Should Stakeholders Expect in 2025 and Beyond?

The next 18 months will be pivotal. The first major milestone is the August 2025 readout of Phase 1 data from PRX012, which, if successful, could act as a trigger for expanded partnership discussions—possibly with Roche or even new entrants. Mid-year updates from Roche and a second-half report from Novo Nordisk will also shed light on progress in Prothena’s extended pipeline.

By 2026, Bristol Myers Squibb is expected to provide data or strategic guidance on the tau-targeting PRX005 program. These staggered catalysts ensure that Prothena will remain in the biotech news cycle, offering several opportunities for narrative reset, revaluation, and potential deal-making.

Even as birtamimab exits the clinical stage, Prothena’s platform remains underpinned by high-quality science and marquee pharmaceutical alliances. Its strategic partnerships with Roche, BMS, and Novo Nordisk are more than business arrangements—they are the scaffolding that could elevate Prothena from a single-asset disappointment to a multifaceted player in the future of Alzheimer’s therapy. If its partnered programs stay on track, Prothena’s post-birtamimab story could be one of rebound and reinvention—with collaboration at its core.