Pfizer Joins PD-1xVEGF Bispecific Race with $1.25B 3SBio Deal

Pfizer has made a significant move in the rapidly evolving field of immuno-oncology, securing ex-China rights to 3SBio's PD-1xVEGF bispecific antibody SSGJ-707 for $1.25 billion upfront. This deal positions Pfizer as a major contender in the increasingly competitive landscape of bispecific antibodies targeting PD-1 and VEGF.

Deal Details and Financial Implications

The agreement between Pfizer and 3SBio involves a substantial upfront payment of $1.25 billion, with the potential for up to $4.8 billion in additional milestone payments. Pfizer has also committed to a $100 million equity investment in 3SBio and will pay tiered double-digit royalties on potential future sales of SSGJ-707.

This deal marks one of the largest upfront payments in recent biotech history, highlighting the perceived value of PD-1xVEGF bispecifics in the current market. It also underscores Pfizer's commitment to bolstering its oncology pipeline with innovative immunotherapy approaches.

Clinical Progress and Potential

SSGJ-707 is poised to enter phase 3 trials in China this year, with 3SBio having already initiated four phase 2 trials in 2024. These studies are evaluating the bispecific antibody in colorectal, ovarian, and non-small cell lung cancer (NSCLC).

Early clinical data from phase 2 trials have shown promising results:

• A 70.8% response rate in first-line, PD-L1-positive NSCLC patients
• Response rates up to 81.3% when combined with chemotherapy in first-line NSCLC patients
• A 33.3% response rate in third-line colorectal cancer patients, a population where 3SBio claims competitors have yet to demonstrate efficacy

These results have fueled optimism about the potential of PD-1xVEGF bispecifics to improve upon existing immunotherapy options, particularly in challenging indications.

Competitive Landscape

Pfizer's entry into the PD-1xVEGF bispecific field comes amid intense competition from other pharmaceutical giants and biotech companies:

• Summit Therapeutics and Akeso's ivonescimab previously demonstrated superiority over Merck's Keytruda in a head-to-head trial
• Merck invested $588 million to secure its own PD-1xVEGF bispecific candidate
• BioNTech paid $800 million for full rights to a similar bispecific antibody

With this deal, Pfizer positions itself behind Summit and BioNTech in the race for the U.S. market. Summit expects results from its first phase 3 study in mid-2025, while BioNTech initiated a phase 2/3 trial in January 2025.

Despite the enthusiasm surrounding this class of bispecifics, the field faced a setback in April 2025 when Akeso reported that ivonescimab failed to significantly reduce the risk of death compared to Keytruda in an interim NSCLC analysis. This development raises questions about the ability of PD-1xVEGF bispecifics to demonstrate overall survival benefits in Western trials, a critical factor for regulatory approval and market success.