BioNTech quietly drops Claudin6 work

BioNTech has been one of the leaders in Claudin6, but its interest in this target might be cooling, the group’s second-quarter presentation suggests. A phase 2 testicular cancer trial of its Car-T candidate BNT211 has been withdrawn only a few months after it was first posted.

Meanwhile, two Genmab-partnered programmes were also absent from BioNTech’s update on Monday: the Ox40-targeting BNT315 and the PD-L1 x 4-1BB bispecific antibody, BNT322. The two companies still have other projects on the go; indeed, the EpCAM x 4-1BB bispecific antibody BNT314 (GEN1059) will become the latest asset to be combined with BioNTech and Bristol Myer’s Squibb’s PD-L1 x VEGF project BNT327.

Disappointing data

The Claudin6-targeting Car-T BNT211 has produced decent efficacy data, but toxicity has long been a worry. Nonetheless, BioNTech had been pressing ahead, albeit slowly: the testicular cancer study, once expected to start in 2023, was finally listed on clinicaltrials.gov in April.

However, this progress was short-lived, with the trial being withdrawn in July. The ct.gov entry only states that this was a “sponsor decision”; BioNTech confirmed that it decided not to proceed with phase 2 development in germ cell tumours as part of its portfolio prioritisation. A phase 1 trial in solid tumours continues.

The company had also been developing an mRNA-encoded T-cell engager, BNT142, which doesn't appear in the second-quarter presentation. However, a spokesperson explained the absence by saying: "We do not list completed trials in the pipeline chart." 

Still, the future of BNT142 hangs in the balance after BioNTech reported disappointing data at ASCO in various Claudin6-positive solid tumours. At the time, the company told ApexOnco that the results validated its mRNA-encoding T-cell engager technology, which it plans to keep developing. The group also didn’t rule out persevering with BNT142 itself – but BioNTech’s next steps with this platform may well lie elsewhere.

Other companies developing Claudin6 projects include TORL Biotherapeutics and Daiichi Sankyo.

Meanwhile, the Ox40 asset BNT315 only went into the clinic last year, and was seen as part of a renewed push into this mechanism, being led by Inhibrx’s INBRX-106.

Trials missing from BioNTech’s Q2 2025 presentation

Note: *developed with Genmab. Source: OncologyPipeline & company presentation.

But BioNTech’s focus is increasingly on combinations with its PD-L1 x VEGF project BNT327, and on Monday the group announced that these efforts will now include the Genmab-partnered EpCAM x 4-1BB bispecific BNT314.

A phase 1/2 trial in colorectal cancer is set to start this year – adding to ongoing ADC combinations.

EpCAM-targeting therapies have been dogged by toxicity in the past, stemming from the target’s expression on healthy tissue, although CytomX recently had success with a masked ADC.

However, attempts to activate the co-stimulatory domain 4-1BB have largely not impressed so far.

BioNTech’s ongoing & planned BNT327 combos

Note: PROC=platinum-resistant ovarian cancer. Source: OncologyPipeline & company releases.

This story has been updated.