Pfizer has reported mixed late-stage results for its experimental cancer drug sigvotatug vedotin in a closely watched Phase 3 trial in advanced lung cancer, highlighting both a setback and a potential path forward in a difficult-to-treat disease.

 

In the SigVie-002 study of 703 patients with previously treated, locally advanced or metastatic non-squamous non-small cell lung cancer (NSCLC), the investigational antibody-drug conjugate did not meet its primary endpoint. Overall survival was not statistically improved versus standard chemotherapy docetaxel.

 

The company said the safety profile remained consistent with earlier studies and was considered manageable.

 

However, the data were not entirely discouraging. In a large subgroup—patients who had received only one prior line of therapy, representing about two-thirds of participants—Pfizer observed a stronger trend toward improved overall survival and progression-free survival compared with docetaxel. Exploratory analyses also showed no clear relationship between IB6 expression and treatment response.

 

“Patients with previously treated advanced NSCLC are a historically difficult-to-treat population, and there is clearly more work to be done to improve the outcomes for this population,” said Jeff Legos, Chief Oncology Officer, Pfizer. 

 

“Although the overall study results did not demonstrate superiority over docetaxel, it is encouraging that second-line patients treated with sigvotatug vedotin achieved strong efficacy outcomes compared to an established standard of care, alongside a manageable safety profile. 

 

"This observed clinical benefit, along with our Phase 1 combination data in the first-line setting, reinforces our confidence in the potential of the sigvotatug vedotin program, including an ongoing Phase 3 trial in combination with pembrolizumab in first-line advanced NSCLC.”

 

Independent clinical perspective echoed both the limitations and the signals of promise.

 

“It is important not to underestimate the activity of docetaxel as a comparator in this setting. Patients enrolled in this trial were heavily pre-treated, with most having previously received both platinum-based chemotherapy and immunotherapy, yet docetaxel continues to provide meaningful clinical benefit. 

 

"Although the study did not meet its overall survival endpoint, in second-line patients the data suggest a clinically meaningful survival benefit for sigvotatug vedotin over docetaxel, supporting continued scientific evaluation of sigvotatug vedotin in earlier lines in combination with immunotherapy,” said Solange Peters, Chair of Medical Oncology & Thoracic Cancers Clinic, Lausanne University Hospital, Switzerland. 

 

“The ability of sigvotatug vedotin to induce immunogenic cell death provides a strong rationale for combination approaches with immunotherapy, particularly in earlier treatment settings where immune competence is better preserved. In this context, the promising phase 1 efficacy signals observed in treatment-naïve patients with high PD-L1 expression warrant further evaluation and may represent a more effective clinical application of this strategy.”

 

Pfizer noted that IB6 is expressed in roughly 90% of NSCLC tumors and is linked to poor prognosis, making it an attractive target. Sigvotatug vedotin is designed to selectively target IB6 and deliver a cancer-killing payload directly into tumor cells while limiting damage to healthy tissue.