Press Release

--76-week trial is evaluating the safety and efficacy of a progranulin-elevating candidate in slowing disease progression--

--Enrollment completed ahead of schedule--

SOUTH SAN FRANCISCO, Calif., April 17, 2025 (GLOBE NEWSWIRE) -- Alector, Inc. (Nasdaq: ALEC), a late-stage clinical biotechnology company focused on developing therapies to counteract the devastating progression of neurodegeneration, today announced the completion of enrollment in PROGRESS-AD, a 76-week Phase 2 clinical trial evaluating the safety and efficacy of AL101/GSK4527226 in slowing disease progression in individuals with early Alzheimer’s disease (AD).

Alector and GSK are co-developing AL101, an investigational human monoclonal antibody designed to block and downregulate the sortilin receptor to elevate progranulin (PGRN) levels in the brain. Modest reductions in PGRN levels due to GRN gene mutations have been shown to be associated with an increased risk of developing AD.^{1, 2, 3} Conversely, an elevation of PGRN levels has been shown to be protective in animal models of AD.⁴

“In partnership with GSK, we are pleased to announce the completion of enrollment ahead of schedule in the PROGRESS-AD Phase 2 clinical trial of AL101, marking an important milestone in our pursuit of developing first-in-class therapies for Alzheimer’s disease,” said Arnon Rosenthal, Ph.D., Chief Executive Officer of Alector. “This achievement brings us one step closer to assessing the potential of AL101 in slowing disease progression and to furthering our understanding of AL101’s effects on individuals living with this devastating condition. We remain committed to advancing our progranulin-elevating candidate and evaluating its impact in the ongoing trial.”

PROGRESS-AD is a randomized, double-blind, placebo-controlled Phase 2 clinical trial of AL101, which GSK is conducting at multiple sites globally. Two dose levels of AL101 are being evaluated in the trial, with participants randomized to receive either AL101 or placebo intravenously. The primary endpoint of the study is disease progression as measured by the Clinical Dementia Rating Sum of Boxes (CDR^®-SB). The CDR-SB is a validated instrument that tracks the progression of cognitive impairments in various categories. The trial also measures other clinical and functional outcome assessments.

Additional information about PROGRESS-AD (NCT06079190) may be found at ClinicalTrials.gov.

About AL101/ GSK4527226
AL101/GSK4527226 is an investigational human monoclonal antibody designed to block and downregulate the sortilin receptor to elevate progranulin (PGRN) levels in the brain. PGRN, a protein encoded by the GRN gene, regulates lysosomal function, neuronal survival, and inflammation. The protein is genetically linked to multiple neurodegenerative disorders. Alector and GSK are co-developing AL101 for the potential treatment of early Alzheimer’s disease (AD), and it may also be evaluated for other indications, including Parkinson’s disease (PD). Given PGRN's genetic association with neurodegeneration, elevating PGRN levels may provide a potential therapeutic approach that offers broad neuroprotection in both AD and PD.

Collaboration with GSK
In July 2021, Alector entered into a collaboration and license agreement with GSK (LSE/NYSE: GSK) to collaborate on the global development and commercialization of progranulin-elevating monoclonal antibodies, including latozinemab and AL101/GSK4527226. Under the terms of the GSK agreement, Alector received $700 million in upfront payments. In addition, Alector may be eligible to receive up to an additional $1.5 billion in clinical development, regulatory, and commercial launch-related milestone payments. In the United States, the companies will equally share profits and losses from commercialization of latozinemab and AL101. Outside of the United States, Alector will be eligible for double-digit tiered royalties.

About Alector
Alector is a late-stage clinical biotechnology company focused on developing therapies to counteract the devastating progression of neurodegenerative diseases. Leveraging the principles of genetics, immunology, and neuroscience, the company is advancing a portfolio of genetically validated programs that aim to remove toxic proteins, replace deficient proteins, and restore immune and nerve cell function. Supported by biomarkers, Alector’s product candidates seek to treat a range of indications, such as frontotemporal dementia, Alzheimer’s disease, and Parkinson's disease. The company is also developing Alector Brain Carrier (ABC), a proprietary blood-brain barrier platform, which is being selectively applied to its next-generation product candidates and research pipeline. ABC aims to enhance the delivery of therapeutics, achieve deeper brain penetration and efficacy at lower doses, and ultimately improve patient outcomes while reducing costs. Alector is headquartered in South San Francisco, California. For more information, please visit www.alector.com.

Forward-Looking Statements
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements in this press release include, but are not limited to, statements regarding our business plans, business strategy, product candidates, blood-brain barrier technology platform, research and preclinical pipeline, planned and ongoing preclinical studies and clinical trials, anticipated timing of PROGRESS-AD, expected milestones, expectations of our collaboration with GSK, expectations of our interactions with regulatory authorities, and financial and cash guidance. Such statements are subject to numerous risks and uncertainties, including but not limited to risks and uncertainties as set forth in Alector’s Annual Report on Form 10-K filed for 2024, with the Securities and Exchange Commission (“SEC”), as well as the other documents Alector files from time to time with the SEC. These documents contain and identify important factors that could cause the actual results for Alector to differ materially from those contained in Alector’s forward-looking statements. Any forward-looking statements contained in this press release speak only as of the date hereof, and Alector specifically disclaims any obligation to update any forward-looking statement, except as required by law.

REFERENCES

1. Bellenguez, C., et al. New insights into the genetic etiology of Alzheimer’s disease and related dementias. Nat. Genet. 2022, 54, 412–436.
2. Brouwers, N, et al. Genetic variability in progranulin contributes to risk for clinically diagnosed Alzheimer disease. Neurology. 2008, 71, 656–664.
3. Fenoglio, C, et al. Rs5848 variant influences GRN mRNA levels in brain and peripheral mononuclear cells in patients with Alzheimer’s disease. J. Alzheimer’s Dis. 2009, 18, 603–612
4. Minami, S.S; et al. Progranulin protects against amyloid beta deposition and toxicity in Alzheimer’s disease mouse models. Nat. Med. 2014, 20, 1157–1164.

Alector Contacts:

Alector 
Katie Hogan 
202-549-0557
katie.hogan@alector.com

Argot Partners (media)
David Rosen
646-461-6387
alector@argotpartners.com

Argot Partners (investors)
Laura Perry
212-600-1902
alector@argotpartners.com

Source: Alector, Inc.