Protego Biopharma Raises $130M to Advance Novel Protein Stabilization Approach for AL Amyloidosis
Key Insights
Protego Biopharma (search) secured $130 million in Series B funding led by Novartis Venture Fund (search) and Forbion (search) to advance PROT-001 (search) into late-stage clinical testing for AL amyloidosis (search).
The experimental drug PROT-001 (search) takes a novel approach by binding to and stabilizing misfolded proteins before they accumulate, rather than clearing existing toxic deposits like previous failed therapies.
An early-stage study began in Q2 2024 with results expected next year, while a Phase 2/3 trial is planned for the second half of 2026.
San Diego-based Protego Biopharma (search) announced Monday it has raised $130 million in Series B funding to advance its experimental drug PROT-001 (search) for amyloid light-chain (AL) amyloidosis into late-stage clinical testing. The round was led by Novartis Venture Fund (search) and Forbion (search), with additional backing from Omega Funds, Vida Ventures and MPM BioImpact.
Novel Protein Stabilization Strategy
PROT-001 (search) represents a fundamentally different approach to treating AL amyloidosis (search) compared to existing therapies. The drug is designed to bind to and stabilize proteins that misfold and toxically accumulate in patients with AL amyloidosis. This mechanism is believed to impact disease progression rather than merely addressing symptoms, though this hasn't yet been proven in clinical testing.
In AL amyloidosis (search), plasma cells (search) errantly produce abnormal antibody fragments called "light chains (search)," which then misfold, clump together in tissues, and damage organs. Current treatment options include stem cell transplants or combinations of cancer chemotherapies with the drug Darzalex, but each approach has significant limitations.
Differentiation from Failed Competitors
Protego's approach stands in contrast to recent failures in the field. In May, disappointing study results led Prothena to abandon a therapy it had been developing for years. Two months later, AstraZeneca reported that a drug acquired in a 2021 buyout failed to meet endpoints in a late-stage study.
Both of those failed drugs were designed to clear existing toxic amyloid deposits from the body. Protego believes its strategy of intervening earlier to prevent accumulation will prove more successful. "Those failures give us a lot of conviction on our approach," said CEO Brent Warner. "There is very clear data that toxic light chain is really what's driving a lot of the mortality in this disease."
Clinical Development Timeline
An early-stage study of PROT-001 (search) began in the second quarter of 2024, with results expected next year. The company plans to initiate a Phase 2/3 trial in the second half of 2026.
Warner explained that the goal of commonly used Darzalex regimens is to eliminate the plasma cells (search) producing misfolded proteins. However, patients typically relapse because some cells return. Adding a protein stabilizer could potentially prompt a "very drastic, fast and deeper response," according to Warner. "In a disease like this, you may not necessarily need a sledgehammer, you just may need a sharper knife to cut it."
Scientific Foundation and Broader Applications
Protego's work builds on research from Jeffery Kelly, one of the company's co-founders and a professor at Scripps Research. Kelly is an expert in protein misfolding and previously co-founded FoldRx (search), which discovered the protein stabilizing drug now known as Vyndamax. That treatment became the first medicine approved in the U.S. for transthyretin amyloidosis (search) affecting the heart and is now owned by Pfizer, generating billions of dollars in annual sales.
Protego claims its approach may also be applicable to other diseases characterized by protein misfolding, potentially expanding the therapeutic utility of its platform beyond AL amyloidosis (search).