3SBio and Pfizer’s PD-1×VEGF Bispecific Shows Durable PFS Gains in First-Line NSCLC

Tivunatamig (PF-08634404/SSGJ-707), a PD-1×VEGF bispecific antibody developed by 3SBio and licensed to Pfizer, produced a median progression-free survival (PFS) of 13.8 months in non-squamous and 13.6 months in squamous non-small cell lung cancer (NSCLC) when combined with chemotherapy in a phase 2 study in China, according to long-term follow-up data presented at the European Society for Medical Oncology (ESMO) Congress 2026.¹ In the study’s control arms, which paired the PD-1 inhibitor tislelizumab with chemotherapy, median PFS was 9.7 months and 8.3 months, respectively.¹

How does tivunatamig work?

Tivunatamig is a single antibody that targets both PD-1, an immune checkpoint on T cells, and vascular endothelial growth factor (VEGF), which drives the blood vessel growth that tumors depend on.¹˒² According to 3SBio, combining PD-1 blockade with stronger VEGF inhibition is designed to activate immune responses in the tumor microenvironment.¹

The approach puts tivunatamig in a growing class of PD-(L)1×VEGF bispecifics. Summit Therapeutics and Akeso’s ivonescimab has a Biologics License Application under FDA review in EGFR-mutated non-squamous NSCLC, with a target action date of November 14, 2026.³ In June, BioPharm International® reported phase 2 data for BioNTech and Bristol Myers Squibb’s PD-L1×VEGF-A bispecific pumitamig in first-line NSCLC.

What did the phase 2 study show?

The study enrolled 261 patients with previously untreated advanced NSCLC, including 122 with non-squamous and 139 with squamous disease.¹ Half were 65 or older, 80% had a history of smoking, and more than 40% had a PD-L1 tumor proportion score below 1%.¹

At the selected dose of 10 mg/kg every three weeks, the confirmed objective response rate (ORR) was 77.5% with tivunatamig plus carboplatin and pemetrexed in non-squamous NSCLC, compared with 44.7% for tislelizumab plus the same chemotherapy.¹ In squamous NSCLC, the confirmed ORR was 80.7% with tivunatamig plus carboplatin and paclitaxel, compared with 67.7% in the control arm.¹ The response-evaluable groups were small, ranging from 31 to 57 patients per arm in these comparisons.¹

The PFS figures come from an August 6, 2026 data cutoff.¹ 3SBio said the median PFS is the longest reported to date among PD-1×VEGF bispecifics, though no head-to-head comparisons have been conducted.¹

The company also reported circulating tumor DNA (ctDNA) results. Of 126 patients with detectable ctDNA at baseline, 61.9% had cleared it by the start of the third treatment cycle, at about nine weeks.¹ Median PFS was 16.4 months in patients who cleared ctDNA, compared with 9.6 months in those who did not, which the company said suggests ctDNA clearance could serve as an early predictor of benefit.¹

The rate of Grade 3 or higher treatment-related adverse events was broadly comparable to the tislelizumab control arms, and no new Grade 5 treatment-related events have occurred with tivunatamig since data were last reported at the Society for Immunotherapy of Cancer (SITC) Annual Meeting in 2025.¹

What is Pfizer’s role?

Pfizer licensed global rights to tivunatamig outside China in May 2025, paying $1.25 billion upfront and making a $100 million equity investment, with up to $4.8 billion in additional milestones.² The agreement also gives Pfizer an option on rights in China, for option payments of up to $150 million.⁴ 3SBio said tivunatamig is now in 11 international clinical trials, including multiple global pivotal phase 3 studies.¹

The deal is one of several large licensing agreements bringing China-developed antibodies to global partners. In a BioPharm International interview at BIO 2026, Oren Livne, co-chair of the North America Healthcare and Life Sciences Group at Baker McKenzie, said such deals need structures that can adapt as policy conditions change over long development timelines. “Just because we’re talking about these policy issues today doesn’t mean 7 to 10 years from now, when these products actually launch, that you’re going to see those same issues,” Livne said.

What happens next?

The phase 2 results come from a study in China, and confirmation will depend on Pfizer’s ongoing global phase 3 program.¹ 3SBio said the sustained PFS benefit with longer follow-up supports advancing tivunatamig in confirmatory phase 3 trials.¹

References

1. Median PFS approaches 14 months! 3SBio’s PD-1/VEGF bispecific antibody posts impressive data at ESMO 2026. News release. 3SBio Inc. October 28, 2026. Accessed October 28, 2026.
2. Pfizer enters into exclusive licensing agreement with 3SBio. News release. Pfizer. May 19, 2025. Accessed October 28, 2026.
3. Updated HARMONi data presented at WCLC 2026 demonstrate consistent overall survival results with ivonescimab plus chemotherapy in Western and Asian patients. News release. Summit Therapeutics. September 15, 2026. Accessed October 28, 2026.
4. Pfizer completes licensing agreement with 3SBio. News release. Pfizer. July 24, 2025. Accessed October 28, 2026.