Alector (ALEC) Corporate presentation summary

Platform overview and strategic value

• ABC platform enables delivery of biologics and siRNA across the blood-brain barrier, targeting neurodegenerative diseases with high unmet need.

• Platform supports multiple assets, including anti-amyloid, anti-tau, anti-alpha-synuclein, and enzyme replacement therapies.

• Reproducing the ABC platform would require 5-7 years, creating a significant strategic moat.

• Comparable BBB platforms have been acquired at a premium, highlighting strategic value.

• Fully owned pipeline offers optionality for partnerships or independent growth.

Lead asset: AL137 (anti-amyloid beta antibody)

• AL137 is engineered for high brain exposure, subcutaneous delivery, and full effector function to maximize efficacy and safety.

• Designed to overcome safety and efficacy trade-offs of previous anti-amyloid antibodies, minimizing ARIA, anemia, and infusion reactions.

• Demonstrates superior brain uptake and plaque clearance in preclinical models compared to competitors.

• Well-tolerated in NHPs at doses up to 30 mg/kg, with only transient reticulocyte reduction and no adverse findings.

• Phase 1 clinical plan targets subcutaneous dosing, aiming for robust amyloid clearance and low adverse event rates.

Pipeline assets: AL064/AL164 (anti-tau siRNA), AL062 (anti-alpha-synuclein siRNA), AL050 (GCase ERT)

• AL064/AL164 siRNA programs target brain-wide tau reduction via systemic delivery, showing up to 81% knockdown in murine models and 60-70% in NHPs.

• AL062 targets intracellular alpha-synuclein, achieving up to 94% knockdown in NHP brain regions.

• AL050 is a brain-penetrant GCase enzyme replacement therapy, increasing brain GCase activity by over 2x and reducing toxic substrate accumulation.

• All programs demonstrate favorable safety and tolerability in preclinical studies.