Biologics maker Paragon Therapeutics has spun out its seventh biotech startup, this time in pursuit of Roche in the fight against Alzheimer’s.
Like Roche with trontinemab, Korsana Biosciences is attempting to deliver an antibody that shuttles across the blood-brain barrier to thwart the advancement of the memory-robbing disease.
Korsana disclosed its lead asset Wednesday along with the news that it raised a $150 million Series A in September to help get to early clinical data. Investors included Fairmount, Venrock Healthcare Capital Partners, Wellington Management, TCGX, JP Morgan Life Sciences Private Capital, Janus Henderson Investors and Foresite Capital. Sanofi’s venture arm, one of the most active biotech investors of late, also took part.
The nine-figure Series A marks at least the 15th megaround that private biotech startups have disclosed so far this year. The Waltham, MA-based startup was seeded with $25 million in 2024.
The biotech’s battle against Alzheimer’s is much further behind than Roche’s
trontinemab
program, which is seen as a leading shot in the next wave of Alzheimer’s treatments and entered a
set
of large
Phase 3
trials last year.
Trontinemab “is not the end of the road — we do not think it’s the best you can do for these patients,” Korsana CEO Jonathan Violin said in an interview with
Endpoints News.
Korsana anticipates entering Phase 1/2 with its candidate KRSA-028 around the end of this year or early next year. It expects Phase 1 healthy volunteer results in mid-2027 and then initial data on KRSA-028’s amyloid plaque-clearing capabilities around the end of that year.
The nimble 17-employee startup is betting one of its advantages will be a delivery route that eliminates the need to go to infusion centers, Violin said. Korsana is cooking up a subcutaneously delivered medicine, whereas Roche is testing an IV-formulated antibody.
Korsana also hopes to tamp down on concerning side effects that have affected the inaugural class of approved amyloid-targeted medicines, namely Eli Lilly’s Kisunla and Biogen and Eisai’s Leqembi.
While those treatments ended a bleak “graveyard” period for Alzheimer’s drug development, they can carry the risk of concerning side effects known as amyloid-related imaging abnormalities, which can signal brain swelling and bleeding. ARIAs are a “challenge for anyone to contemplate,” Violin said.
That’s one way that trontinemab has changed the game so far in clinical testing. “The data that Roche has released is compelling, not only to take less drug, but plaques are cleared much more quickly, much more robustly and the rate of ARIA is substantially diminished,” Violin said.
Other companies want to join Roche in the brain-shuttle arena.
AbbVie acquired Aliada
for $1.4 billion in 2024. Novartis has launched a broad approach through pacts with
SciNeuro
,
Sironax
and
BioArctic
. The latter is also teaming with
Bristol Myers Squibb
and
Eisai
. Roche itself is doubling down on the blood-brain-barrier approach
with Manifold Bio
, among others.
With the competitive pressure dialed up, Korsana is staying relatively quiet on development plans, including which stage of Alzheimer’s progression it intends to attack and what type of treatment course it’s eyeing. Leqembi is meant to be taken chronically, while Lilly’s Kisunla is supposed to be
stopped
after amyloid plaques sink to a certain level.
The best data so far are in mild cognitive impairment, but some analyses suggest that “earlier intervention is better,” Violin said. “We’ll see some data readouts from companies like Lilly before we need to make decisions.”
Kisunla is in a
Phase 3
trial of patients with preclinical Alzheimer’s.
Korsana’s existing funds will get the startup past its early clinical data readouts, Violin said. The company’s runway goes into 2028. With the padded reserves, Korsana can remain “opportunistic” on its next financing steps, Violin said.
Other Paragon spinouts made quick leaps onto public markets.
Spyre Therapeutics
,
Oruka Therapeutics
and
Crescent Biopharma
all announced reverse mergers at the time of their unveilings. (Violin was CEO of Crescent when it decided to jump onto the Nasdaq.) Another Paragon offshoot,
Jade Biosciences
, went the reverse merger route just a few months after disclosing its launch. Apogee Therapeutics took a traditional IPO path.
All of those companies have done private placements or additional financings since going public.
