Daiichi Sankyo, Merck withdraw FDA BLA for lung cancer drug in US

USA—Daiichi Sankyo and Merck & Co. (MSD) have withdrawn their US biologics license application (BLA) for ifinatamab deruxtecan in adults with extensive-stage small cell lung cancer (ES-SCLC) after progression on platinum-based chemotherapy.

The companies had sought accelerated approval from the US Food and Drug Administration (FDA) for the B7-H3 directed antibody drug conjugate (ADC).

They said the decision followed discussions with the FDA, which indicated that the available evidence, including data from the Phase II IDeate-Lung01 trial, did not support approval under the pathway.

FDA discussions prompt withdrawal

The accelerated approval pathway can allow the FDA to authorize medicines for serious diseases based on surrogate endpoints that are considered reasonably likely to predict clinical benefit.

The pathway is intended to provide earlier access to treatments while confirmatory evidence is generated.

Following the FDA discussions, Daiichi Sankyo and MSD chose to withdraw the application rather than proceed with the current data package.

The companies have not indicated that the development of ifinatamab deruxtecan in ES-SCLC will stop.

Instead, enrollment is continuing in the Phase III IDeate-Lung02 trial.

The study is evaluating the safety and efficacy of ifinatamab deruxtecan against chemotherapy options, including amrubicin, lurbinectedin, and topotecan, in patients whose disease has progressed after one line of platinum-based treatment.

Daiichi Sankyo said enrolment in the trial is nearing completion.

The companies plan to use the results to assess a potential future regulatory submission in the US and other markets.

Development programme expands beyond lung cancer

Abderrahmane Laadem, head of Oncology Development at Daiichi Sankyo Therapeutic Area, said patients with ES-SCLC still need additional treatment options and highlighted progress in the IDeate-Lung02 study.

Ifinatamab deruxtecan is also being evaluated in other Phase III studies.

The IDeate-Prostate01 trial is investigating the medicine in castration-resistant prostate cancer, while IDeate-Esophageal01 is assessing it in oesophageal squamous cell carcinoma.

The drug was discovered by Daiichi Sankyo and is being developed with MSD.

It uses Daiichi Sankyo’s DXd ADC technology, combining a humanised anti-B7-H3 IgG1 monoclonal antibody with a topoisomerase I inhibitor payload.

The components are connected through cleavable tetrapeptide-based linkers.

Regulatory path remains under review

The withdrawal changes the immediate US regulatory path for the ES-SCLC indication, but the ongoing Phase III programme provides the companies with another source of clinical data.

Ifinatamab deruxtecan’s broader development also reflects continued industry interest in B7-H3 as a target for ADC therapies across solid tumours.

In April 2026, the FDA granted priority review to the companies’ BLA for ifinatamab deruxtecan for ES-SCLC.

The latest decision means that the application will no longer proceed in its current form, while the companies continue to generate data through the Phase III programme.

Sign up HERE to receive our email newsletters with the latest news and insights from Africa and around the world, and follow us on LinkedIn for updates.