GSK has terminated its five-year neuroscience collaboration with Alector after both experimental antibody drugs at the centre of the deal failed in clinical testing.
The collaboration covered latozinemab, aimed at a rare inherited form of frontotemporal dementia, and nivisnebart, aimed at early Alzheimer’s disease. With both programmes now discontinued, GSK has opted to end the partnership.
Alector disclosed the termination in a filing with the US Securities and Exchange Commission on 8 July. GSK gave written notice on 6 July and, under the terms of the original agreement, the termination will take effect after a 180-day notice period on 2 January 2027.
Why latozinemab and nivisnebart failed
Both antibodies were designed to raise progranulin, a protein linked to neurodegeneration.
Latozinemab advanced furthest, reaching phase 3. Results reported in October 2025 showed the drug successfully increased progranulin levels but failed to slow cognitive and functional decline in patients. Following the readout, Alector cut roughly half of its workforce and its share price fell by more than 50%.
Nivisnebart never reached a full data readout. An independent monitoring committee halted its phase 2 trial in April 2026 after an interim futility analysis concluded it was unlikely to meet its primary endpoint. At the time, Alector CEO Arnon Rosenthal described the outcome as “disappointing for patients and families affected by Alzheimer’s disease”.
Partnership terms and previous exits
When GSK and Alector signed the collaboration in July 2021, GSK paid the US biotech $700m upfront and committed up to $1.5bn in additional development and royalty milestones for rights to latozinemab and nivisnebart. Most of those future payments will now go unpaid.
The GSK withdrawal is Alector’s second major pharma partnership loss in 18 months. AbbVie terminated its collaboration covering AL002, an antibody targeting the TREM2 pathway in Alzheimer’s disease, in January 2025 after the drug missed its primary endpoint in a phase 2 trial. The decision cost Alector a potential $250m milestone payment, and rights to AL002 subsequently reverted to the company.
GSK’s other biotech partnerships
The Alector termination does not reflect a broader retreat from external innovation by GSK, which has continued to expand its partnering strategy through 2026.
In June, GSK agreed to acquire US oncology biotech Nuvalent for $10.6bn, its largest acquisition in more than a decade. The deal adds zidesamtinib and neladalkib, two lung cancer drugs that have both received FDA breakthrough therapy designation.
The company has also expanded its collaboration with Wave Life Sciences. The pair are developing RNA medicines under a deal worth up to $2.8bn, with GSK selecting a fourth development programme in January 2026. GSK did, however, return full rights to an alpha-1 antitrypsin deficiency (AATD) candidate in February 2026, concluding that Wave was better placed to advance the rare disease programme.
Separately, GSK has partnered with Flagship Pioneering on a vaccines and pharmaceuticals alliance covering up to ten new products, initially focused on respiratory disease and immunology.
Similar exits across the sector
Large pharmaceutical companies ending partnerships after clinical disappointments is common across the industry.
Eli Lilly, for example, notified Rigel Pharmaceuticals in April 2026 that it would terminate their collaboration agreement, effective 15 June 2026, following an earlier decision to discontinue a central nervous system programme under the same deal. Rigel no longer expects milestone or royalty payments from the partnership.
Ionis Pharmaceuticals has also experienced several partner exits in recent years. Novartis returned a follow-on programme to pelacarsen in 2025, while Pfizer and Bayer discontinued development of vupanorsen and fesomersen respectively.
Together, these examples underline the risks inherent in pharma-biotech partnerships and show that Alector’s loss of two major pharmaceutical collaborators within 18 months is unusual but not unprecedented.
Outlook for Alector
Despite the latest setback, Alector still has three wholly owned clinical candidates in development that are unrelated to the GSK collaboration. All are based on the company’s proprietary Alector Brain Carrier blood-brain barrier delivery platform and target Alzheimer’s or Parkinson’s disease.
The most advanced programme, an anti-amyloid antibody, remains on track for an IND submission to the FDA in early 2027, suggesting the San Francisco-based biotech retains longer-term pipeline potential despite the recent partnership losses.