Protego Biopharma is advancing a small-molecule drug that helps light chain proteins fold correctly, in turn addressing the underlying biological cause of AL amyloidosis.
Protego Biopharma has closed an oversubscribed series B round, counting $130 million in proceeds to move its light chain amyloidosis program closer to the market.
California-based Protego will use the money to launch a pivotal clinical trial for PROT-001, its investigational small-molecule drug being tested for the rare disorder, according to a Monday release. The biotech did not provide a specific timeline for this registrational study. Protego is backed by big names, with Novartis Venture Fund and Forbion leading the series B funding. New investors include YK Bioventures, Digitalis Ventures and Droia Ventures.
Affecting nine to 14 patients per 1 million people in the U.S., light chain (AL) amyloidosis arises when light chain proteins are misfolded and accumulate in various organs such as the heart and kidneys, in turn compromising their function. Symptoms include carpal tunnel syndrome, numbness in the extremities, shortness of breath and fatigue. In severe cases, it can lead to death.
Protego’s answer to AL amyloidosis is PROT-001, a small molecule drug that acts as a “guide” to help the target protein fold correctly, according to the Monday release. Through this mechanism, PROT-001 stabilizes the light chain proteins and prevents the buildup of toxic, misfolded amyloid, in turn offering a therapeutic option that targets the “root cause” of the disease, Forbion Principal Tim Lohoff said in a statement.
Protego was founded in 2017 by Jeffery Kelly, a protein folding expert at Scripps. Kelly’s research played a crucial role in the formation of FoldRx, which he also co-founded, and contributed to the development of the transthyretin amyloidosis drugs Vyndaqel and Vyndamax. FoldRx was acquired by Pfizer in 2010.
With Protego’s series B, 2025 continues to rack up hefty fundraising rounds. In March, Isomorphic Labs brought home $600 million to further develop its AI-powered drug design engine. A few months earlier, obesity specialist Verdiva Bio drummed up $411 million in its oversubscribed series A round.
The moneymaking has continued into the back half of the year, with Artios Pharma last month bringing in $115 million in series D proceeds for its oncology pipeline. In October, hair loss biotechs Veradermics and Pelage Pharmaceuticals closed back-to-back fundraising rounds, raising $150 million and $120 million, respectively.
