Alentis doubles down on Claudin1

The private Swiss biotech Alentis Therapeutics, one of the few companies targeting Claudin1, is upping its game with this target, having just started a phase 1 study of the anti-Claudin1 ADC ALE.P03. The move, revealed in recent clinicaltrials.gov listings, comes eight months after Alentis took another anti-Claudin1 ADC into its first-in-human study.

Elsewhere, at least one degrader is starting its first phase 1 trial, with China's Chia Tai attempting to emulate the success of Bristol Myers Squibb's gridegalutamide with its own take on this mechanism. And the CD73 target has seen another clinical entrant, again as part of a bispecific approach, this time from South Korea's GI Innovation.

Alentis is prominent for having tapped venture capitalists a year ago for an impressive $181m in a series D fund raising led by OrbiMed. This was aimed specifically at developing anti-Claudin1 ADCs, and followed a $105m series C in April 2023, and a $67m series B in June 2021.

It was a separate asset, ALE.P02, that was Alentis's first ADC against Claudin1, entering phase 1 last December. However, that project uses a tubulin inhibitor payload, whereas ALE.P03, the subject of the just revealed phase 1 study in Claudin1-positive solid tumours, employs a more in-vogue topoisomerase 1 inhibitor.

Neither asset marks Alentis's first effort at targeting Claudin1; that honour belongs to the naked antibody ALE.C04, which started clinical development two years ago, but whose study was subsequently terminated. While Claudin18.2, and to an extent Claudin6, remain popular targets, OncologyPipeline reveals just one other Claudin1 player, Mabwell's MW-C01/C02, a preclinical-stage ADC.

Degrader success

In targeted protein degradation biopharma has had little cause for celebration, but one undoubted success has come from Bristol's AR “degrader and antagonist” gridegalutamide, which based on phase 1 data alone went straight into phase 3 in March.

Now Chia Tai is attempting to repeat the trick with an AR degrader of its own, TQB3201, which starts phase 1 this month. Another key player here is Novartis, which licensed the AR degrader luxdegalutamide from Arvinas last year, but which has moved this asset into phase 2 rather than a previously hoped for phase 3 study.

Recently disclosed first-in-human studies*

Note: *projects newly listed on the clinicaltrials.gov database between 11 and 15 Sep 2025.

Another phase 1 entrant, Qilu's QLC1401, might be a degrader not of AR but of ER. However, this is still unclear, as its clinicaltrials.gov entry reveals this only to be an ER-targeting therapy, so it might be a straight inhibitor.

Similar secrecy surrounds Qilu's QLS2309, which appears to be a biological that hits CD70, but whose precise modality remains undisclosed. 

Not so GI Innovation's GI-108, which is known to be an anti-CD73 x IL-2 fusion protein. Another anti-CD73 project, AP Biosciences' AP601, also started phase 1 this month, though that molecule is an antibody, and uses 4-1BB co-stimulation as the second part of its bispecific approach.

Also notable among the first-in-human entrants is another bispecific, from the private biotech Eureka Therapeutics. This comprises autologous T cells engineered to express anti-CD19 x CD22 gammadelta (γδ) T-cell receptors, plus a separate co-stimulatory molecule. Eureka reckons that this gives less cytokine release and a less exhausted T-cell phenotype, and it's already in the clinic with an anti-GPC3 asset.