Pfizer's Lung Cancer Treatment Sigvotatug Vedotin Falls Short in Phase 3 Trial

Pfizer (PFE) disclosed that its antibody-drug conjugate sigvotatug vedotin failed to meet the primary endpoint in a Phase 3 trial for patients with previously treated metastatic non-small cell lung cancer (NSCLC). The drug, which targets ROR1-expressing tumor cells, was evaluated as a later-line therapy in a population with limited existing treatment options. Pfizer said the trial did not demonstrate overall benefit for the broad patient population, though a small subset of patients showed signs of activity.

The result is a setback for Pfizer's oncology pipeline at a moment when the company is executing on multiple clinical programs to offset declining Paxlovid and Comirnaty revenues. Sigvotatug vedotin was one of several ADCs Pfizer acquired through its $43 billion Seagen acquisition in 2023; that deal brought a full ADC platform expected to yield multiple oncology approvals through 2030. The Phase 3 miss in NSCLC does not invalidate the broader ADC strategy — Pfizer has other Seagen-derived programs in bladder cancer and cervical cancer — but it narrows the near-term pipeline optionality.

Pfizer shares have underperformed the S&P 500 significantly over the past two years as pandemic-era tailwinds reversed. Investors will watch the company's upcoming conference call for any update on whether sigvotatug vedotin will be pursued in different indications or combination regimens, or whether the program will be discontinued.