Tags: oncology, lung cancer, ADC, clinical trials, competitive intelligence, Pfizer, Seagen, Merck, AstraZeneca, Daiichi Sankyo, Gilead Sciences

Pfizer drug acquired in Seagen deal disappoints in lung cancer study

By FieldPulse Editorial · June 23, 2026

Pfizer's Seagen-linked ADC missed a key phase 3 lung cancer study, raising the stakes for the company's next major oncology readout.

Pfizer's sigvotatug vedotin just ran into a setback that oncology field teams should expect to hear about.

According to BioPharma Dive, the antibody-drug conjugate did not significantly extend survival versus chemotherapy in a phase 3 study in previously treated metastatic non-squamous non-small cell lung cancer.

Pfizer said the topline result came from a study in advanced disease, but it did not release detailed efficacy numbers yet and said those details will be presented at a future medical meeting.

That matters because sigvotatug vedotin is not just another pipeline asset.

It is one of the Seagen-derived ADC programs tied to Pfizer's $43 billion acquisition of Seagen, a deal Pfizer has pointed to as a major source of future oncology growth.

BioPharma Dive noted that Pfizer has already recorded roughly $4.5 billion in write-offs tied to development setbacks, competition, and lower commercial expectations across inherited assets.

This latest miss adds more pressure to the question many oncologists, investors, and internal teams are already asking: when does the Seagen pipeline start producing clearer commercial wins? For Pfizer oncology reps, the immediate issue is message discipline.

The source supports saying the second-line study missed on survival, but it does not support filling in detailed reasons or rescue narratives that have not been disclosed.

Reps should expect questions about whether this changes the overall thesis behind Pfizer's ADC strategy.

It also increases the importance of keeping future trial readouts in context, especially the more closely watched first-line study pairing sigvotatug vedotin with Merck's Keytruda.

That first-line combination is still the bigger commercial swing.

BioPharma Dive reported that Pfizer remains optimistic about the program and is still running a study of sigvotatug vedotin plus Keytruda in first-line lung cancer, with results expected in 2027.

Pfizer also pointed to a stronger trend on survival and progression in pat.