Rare Disease New Drug Drops 7% Despite Approval... $270 Billion Vanished in a Day for US Bio

Denali Therapeutics Inc. (NASDAQ: DNLI) shares recently closed at $19.20, a 7.05% drop, trimming its market capitalization to about $3.04 billion (roughly KRW 4.1 trillion). The one-day slide wiped out approximately $200 million in value (around KRW 270 billion), while trading volume surged to about 1.35 million shares, signaling heightened investor interest.

After the U.S. FDA granted accelerated approval for its Hunter syndrome treatment AVLAYAH (tavidenofusp alfa), Denali received a $200 million cash payment under its royalty agreement with Royalty Pharma and, following the termination of its collaboration with Takeda, regained full rights to its DNL593 candidate—moves that reshaped its pipeline. Nonetheless, concerns over the limited rare-disease market and commercial viability prompted a “sell the news” reaction: shares fell by roughly 9% post-approval as investors booked quick profits.

Based in South San Francisco, California, Denali is a biotech company developing therapies for neurodegenerative disorders such as Alzheimer’s and Parkinson’s, as well as rare genetic central nervous system diseases, using its blood–brain barrier–crossing Transport Vehicle platform. AVLAYAH—the first brain-penetrant biologic targeting the neurological symptoms of Hunter syndrome—will serve as the initial product to commercially validate the company’s platform technology.