Benzos work. That’s the problem. They work so well for anxiety that millions of people can’t stop taking them — and the sedation, cognitive fog, and dependency that come along for the ride have made them one of medicine’s most complicated success stories. So when someone says they’ve got a better mousetrap, you’re right to be skeptical.
But Newleos Therapeutics just dosed the first participant in a UK-based Phase 1b trial of NTX-1955 for generalized anxiety disorder, and the science behind this one is worth a closer look. NTX-1955 is a GABAA-γ1 selective positive allosteric modulator — the first of its kind in the clinic. Instead of hitting GABA receptors across the entire brain like benzodiazepines do, it selectively targets the γ1 subunit, which is concentrated in the amygdala — the brain’s anxiety processing center.
The idea: anxiolytic effect without the sedation, cognitive impairment, or addiction liability. In preclinical models, NTX-1955 matched benzo-level anxiety reduction without the side effect baggage. That’s exactly the profile pharma has been chasing for decades.
Newleos Therapeutics pipeline (licensed from Roche)
Phase 1
Phase 1b
Phase 2
Approved
All four assets completed Phase 1 safety studies under Roche before licensing to Newleos
And here’s the backstory that makes this even more interesting. Newleos didn’t build these molecules from scratch. They licensed four clinical-stage assets from Roche in 2025 — all with Phase 1 safety data already in hand. The company launched in February 2025 with a $93.5 million oversubscribed Series A led by Goldman Sachs Alternatives and Novo Holdings. That’s a significant check for a company that was literally weeks old.
Board member Stephen Brannan previously led clinical strategy for KarXT at Karuna Therapeutics — which Bristol Myers Squibb acquired for $14 billion. The Newleos team knows what a successful CNS exit looks like.
The Phase 1b program spans multiple trials across the UK and EU, with results designed to inform dose selection for a Phase 2 study. Meanwhile, their second asset NTX-1472 — a vasopressin V1a antagonist for social anxiety — already dosed its first Phase 2 patient in January. Four programs, all moving. Phase 2 data expected across the board by fall 2027.
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