GSK has formally ended its partnership with Alector, bringing to a close a neurodegenerative disease collaboration that was originally valued at up to $2.2 billion. The alliance focused on two antibody therapies that were designed to block sortilin and increase levels of progranulin, a protein involved in regulating immune activity in the brain and supporting neurons.
The companies first entered the agreement in July 2021. Under the terms of the deal, GSK paid Alector $700 million upfront and committed up to $1.5 billion in potential research and development, regulatory, and commercialization milestone payments.
The collaboration encountered difficulties after both clinical programs failed to achieve their intended goals. The first setback came in October 2025 when latozinemab failed to significantly slow disease progression in a Phase 3 study involving patients with frontotemporal dementia. According to GSK and Alector, the antibody had a significant effect on progranulin levels, a disease biomarker, but did not meet key secondary endpoints, including magnetic resonance imaging measures.
Following the Phase 3 result, the companies discontinued latozinemab. Alector subsequently carried out a strategic business review that reduced its workforce by approximately 49%, affecting around 116 employees according to an estimate. Analysts also viewed the failure as raising questions about the viability of targeting progranulin.
A second setback followed in April 2026. Nivisnebart, the other antibody included in the collaboration, was being evaluated in a Phase 2 Alzheimer’s disease study. An independent data monitoring board determined that the trial was unlikely to achieve its endpoint of slowing disease progression, leading to the study being halted. The companies discontinued the trial after the board concluded that continuing would be futile.
Although analysts viewed the end of the nivisnebart study as effectively ending the collaboration, GSK formally terminated the agreement on July 6, according to a securities filing submitted by Alector. The termination will take effect on Jan. 2, 2027.
The decision leaves GSK writing off the $700 million upfront payment made when the partnership began. It also means that the remaining milestone payments tied to the agreement will not be received by Alector.
In the same securities disclosure, Alector said it had repaid in full and terminated a 2024 loan and securities agreement with Hercules Capital. The company repaid $10.43 million, including interest, related to an initial $10 million tranche.
“Both assets have since failed to show significant clinical benefit,” the companies said regarding the two antibody programs that formed the basis of the partnership.
The termination comes as GSK has pursued a series of transactions under CEO Luke Miels. These include the acquisition of Rapt Therapeutics, the purchase of 35Pharma, and the $10.6 billion acquisition of Nuvalent. At the same time, GSK has not exited Alzheimer’s disease research. In February, the company launched a five-year collaboration with The Jackson Laboratory–New York Stem Cell Foundation Collaborative to advance human cellular models of neurodegenerative diseases.
Alector is now focusing on a new group of assets that use technology intended to cross the blood-brain barrier. The company plans to test an anti-amyloid beta antibody that uses the technology in humans in the first quarter of next year. As of March 31, Alector reported $354.6 million in cash, cash equivalents, and investments, which it said would support operations into the second half of 2027.
Impact on Alector
For Alector, the termination may create short-term financial and operational challenges, including the loss of milestone payments and development support from GSK. However, the company retains ownership of its research assets and has the flexibility to pursue alternative commercialization or licensing opportunities.
The company’s management has emphasized its commitment to advancing innovative therapies targeting immune system pathways involved in neurodegenerative diseases. Alector is expected to prioritize key clinical programs while seeking collaborations that align with its long-term strategy.
What This Means for the Industry
The conclusion of the GSK-Alector partnership highlights the risks associated with neurological drug development. Pharmaceutical companies continue to invest heavily in this field despite frequent clinical failures because of the significant unmet medical need and growing global prevalence of neurodegenerative disorders.
