The Lung Cancer Drug That Just Beat the King of Immunotherapy
A first-in-class bispecific antibody just cut the risk of death by 34% in lung cancer, outperforming a modern immunotherapy combo. The catch? The entire trial was run in China, and Wall Street wanted more.
A First in Lung Cancer
Pembrolizumab (brand name Keytruda) is the undisputed heavyweight champion of cancer immunotherapy, generating tens of billions in annual revenue. It's the standard of care for first-line non-small cell lung cancer (NSCLC), and every challenger that's stepped into the ring has walked away with a loss.
Until now, possibly.
At the 2026 ASCO Annual Meeting, Akeso and its U.S. partner Summit Therapeutics unveiled overall survival data for ivonescimab, a first-in-class bispecific antibody that attacks tumors from two angles at once. The results from the HARMONi-6 trial: a 34% reduction in the risk of death compared to a modern PD-1 inhibitor plus chemotherapy. That earned the drug a coveted spot in ASCO's Plenary Session, the Super Bowl of oncology presentations.
But before you start writing the obituary for Keytruda, there are some important asterisks.
Two Weapons, One Molecule
To understand why ivonescimab matters, think of it like a Swiss Army knife for cancer treatment. Most immunotherapies do one thing: they block PD-1, a protein that tumors exploit to hide from the immune system. That's what Keytruda does. Separately, drugs like bevacizumab (Avastin) block VEGF, a signal that tumors use to grow new blood vessels and feed themselves.
Ivonescimab does both simultaneously. It's a single molecule engineered to block PD-1 and VEGF at the same time. The theory: cutting off the tumor's blood supply while unleashing the immune system should work better than doing either alone. Doctors have tried combining separate PD-1 and VEGF drugs before, with mixed results. Packaging both into one molecule could optimize how the drug reaches and acts on the tumor.
The HARMONi-6 trial tested this theory in first-line advanced squamous NSCLC, one of the toughest forms of lung cancer. Patients received either ivonescimab plus platinum chemotherapy or tislelizumab (another PD-1 inhibitor, sold as Tevimbra) plus chemo.
The Numbers That Matter
The headline result is hard to argue with. At a median follow-up of 21.4 months, patients on ivonescimab lived meaningfully longer. The , which translates to that 34% reduction in death risk. In absolute terms, , compared to 48.6% in the control arm.
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hazard ratio for overall survival was 0.66
64.7% of ivonescimab patients were alive at two years
Median overall survival hit roughly 27.9 months for ivonescimab versus 23.7 months for the standard PD-1 combo. That's about a four-month advantage, and the statistical significance was clear (p=0.0017).
This is the first time any PD-1/VEGF bispecific has demonstrated a statistically significant survival benefit over a PD-1 inhibitor in a randomized lung cancer trial. That alone makes it a landmark moment for the class.
So Why Isn't Wall Street Throwing a Parade?
Because the story has layers. Analysts heading into ASCO had generally set a bar of 20-30% death risk reduction as "clinically meaningful." Ivonescimab cleared that bar. But some investors, notably analysts at Cantor Fitzgerald, were reportedly looking for a six-month absolute survival advantage. The four-month gap, while substantial in squamous NSCLC (where progress is measured in weeks, not months), left some shareholders wanting more.
Then there's the geography problem.
HARMONi-6 was conducted entirely in China. Every patient, every site, every data point. That's not unusual for Akeso, a Chinese biotech, but it creates a real headache for global interpretation. Patterns of comorbidities, access to follow-up treatments, and supportive care infrastructure all differ between Chinese and Western populations. Several experts, including Suresh Ramalingam of Emory's Winship Cancer Institute, characterized the data as good news for Chinese patients while questioning how well results would translate overseas.
Interestingly, the control arm patients lived about six months longer than expected based on historical benchmarks. That could mean the trial sites provided unusually good care overall, which would actually mask some of ivonescimab's true benefit. Or it could mean the comparison isn't as clean as it looks.
The Bleeding Question
When you block VEGF, you mess with blood vessel biology. That's the point, but it comes with side effects. Grade 3 or higher hemorrhage events occurred in about 2.6% of ivonescimab patients, with most VEGF-related adverse events being grade 1-2. Treatment-related serious adverse events were also higher: 32.3% versus 30.2%.
Clinicians described this as expected and manageable for a VEGF-active drug, but it's a trade-off that will matter for patient selection. Worth noting: the trials excluded patients at high bleeding risk (those with tumors near major blood vessels), meaning real-world bleeding rates could be higher.
The Comparator Conundrum
HARMONi-6 compared ivonescimab to tislelizumab, not pembrolizumab. For U.S. and European oncologists, that distinction matters. Tislelizumab is a solid PD-1 inhibitor, but it's not the global gold standard. Think of it this way: beating the third-ranked boxer is impressive, but the champion still wants to see you in the ring.
Akeso does have that fight on record, sort of. An earlier trial called HARMONi-2 tested ivonescimab as a monotherapy directly against pembrolizumab in PD-L1-positive first-line NSCLC. It showed a progression-free survival (PFS) advantage of 11.14 months versus 5.82 months, with a hazard ratio of 0.51. But PFS measures how long until a cancer starts growing again; it doesn't always predict whether patients actually live longer. And HARMONi-2 was also conducted only in China.
The Road to the FDA
Summit Therapeutics, Akeso's U.S. partner, has already filed a Biologics License Application (BLA) with the FDA. The agency accepted it for review in January 2026, with a PDUFA goal date of November 14, 2026. But the initial filing is for a different indication: EGFR-mutated NSCLC after prior targeted therapy, based on a separate trial called HARMONi.
For the first-line squamous NSCLC indication that HARMONi-6 covers, global confirmatory data will likely be needed. The FDA has historically scrutinized single-country trials, particularly when the question of cross-population generalizability looms large.
The Bigger Picture
Ivonescimab isn't alone in this space anymore. Merck is developing its own PD-1/VEGF bispecific (MK-2010), essentially building a backup plan in case this class threatens Keytruda. BioNTech spent $800 million to acquire Biotheus and its PD-L1/VEGF bispecific program. Pfizer's 3SBio-partnered candidate is posting competitive early response rates.
But ivonescimab is the only one with Phase 3 survival data in hand. John Heymach, chair of thoracic oncology at MD Anderson, has noted the significance of the dual PFS and OS benefit.
The 34% death risk reduction validates the entire PD-1/VEGF bispecific concept. It proves these two-in-one molecules can outperform standalone PD-1 inhibitors on the hardest endpoint in oncology: keeping patients alive. Whether that translates into a global standard-of-care shift depends on what happens next, in Western populations, in regulatory review, and in the inevitable comparison everyone will demand against Keytruda on its home turf.
For now, the king still has the crown. But there's a credible challenger in the ring, and the next few rounds will be fascinating to watch.
Clinical & Regulatory
4 min read
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