Head-to-Head Challenge Against Keytruda! 3SBio Launches First Phase III Trial for PD-1/VEGF Bispecific Antibody

On May 20, 2025, 3SBio registered a Phase III clinical trial of its PD-1/VEGF bispecific antibody SSGJ-707 on ClinicalTrials.gov for first-line treatment of PD-L1 positive advanced non-small cell lung cancer (NSCLC). This marks the first Phase III clinical study for this drug candidate.

The study plans to enroll 420 patients with locally advanced or metastatic NSCLC. SSGJ-707 will be used as a monotherapy in a head-to-head comparison against Merck’s PD-1 monoclonal antibody Keytruda (pembrolizumab). The primary endpoint data is expected to be completed by July 2026.

On the same day, 3SBio announced that it had licensed the global rights (excluding China) of SSGJ-707 to Pfizer. The deal is valued at up to $6.05 billion, including a record-breaking $1.25 billion upfront payment — the highest upfront payment ever for a Chinese innovative drug license deal. The agreement also includes $4.8 billion in milestone payments and a $100 million equity investment by Pfizer.

About SSGJ-707

SSGJ-707 is an innovative drug independently developed by 3SBio and is undergoing multiple clinical studies in China. These include the now-approved Phase III trial for PD-L1 positive locally advanced or metastatic NSCLC, for which it has received China’s Breakthrough Therapy Designation. Additionally, it is in several Phase II studies targeting advanced NSCLC, metastatic colorectal cancer, and advanced gynecologic tumors.

Boosted by this news, 3SBio’s stock (3SBio) surged over 40% during Tuesday trading on the Hong Kong Stock Exchange, hitting a record high of HKD 22. At the time of writing, the stock has risen another 7% today, continuing its strong upward momentum.

Rising Star: PD-1/VEGF Bispecific Antibodies

In recent years, PD-1/VEGF bispecific antibodies have gained traction as standout candidates in the innovative antibody space due to their synergistic mechanism and promising prospects. The surge in global collaboration enthusiasm for this modality was ignited by Akeso's Ivonescimab.

Back in December 2022, Akeso signed a co-development deal with Summit for Ivonescimab, involving a $500 million upfront payment and a total deal value of $5 billion — setting a record for Chinese innovative drug licensing at the time. Following that, Transcenta partnered with BioNTech for a PD-L1/VEGF bispecific antibody deal worth over $1 billion.

On May 24, 2024, Ivonescimab was officially approved for marketing in China. At ASCO, its Phase III trial results were unveiled: median progression-free survival (mPFS) extended to 7.06 months (HR=0.46), and objective response rate (ORR) reached 50.6%, marking a major breakthrough for PD-1/VEGF bispecifics in clinical practice.

Subsequently, the HARMONi-2 trial delivered another milestone: PD-1/VEGF bispecific AK112 achieved a statistically significant positive result for progression-free survival (PFS) in a head-to-head Phase III trial against Keytruda. On the day the news broke, Summit’s stock soared 272%, and Akeso’s shares jumped 40%. Soon after, Baker Brothers made a $200 million exclusive investment, signaling mainstream U.S. fund entry into the space.

The momentum in the PD-1/VEGF bispecific race continues to build. Several Chinese biopharmas are expanding overseas. In August 2024, Eucure Biopharma licensed its PD-L1/VEGF bispecific and CTLA-4 antibody to Instil Bio in a deal worth over $2 billion. In November of the same year, Merck paid a $588 million upfront as part of a $3.3 billion agreement to license LaNova’s PD-1/VEGF bispecific, further affirming the global value of this target.

Against this backdrop, 3SBio’s SSGJ-707 and Akeso’s AK112 are emerging as representative Chinese innovative drugs in the bispecific antibody race, continuing to draw attention from global pharmaceutical companies and capital markets.