Two Drugs. Two Very Different Situations.

Lung cancer kills more Americans than any other cancer — roughly 125,000 deaths per year, according to the American Cancer Society. When two drugs post major survival numbers in the same news cycle, the details determine whether they're actually equivalent.

Ivonescimab: Promising. Also China-Only.

Summit Therapeutics and its Chinese biotech partner Akeso announced Sunday that their experimental drug ivonescimab reduced the risk of death by 34% in patients with squamous non-small-cell lung cancer. The results come from the Harmoni-6 Phase 3 trial, presented at the American Society of Clinical Oncology's annual meeting.

Patients on ivonescimab plus chemotherapy lived a median of four months longer than those on the standard combo of immunotherapy and chemotherapy. That gap was statistically significant.

The critical limitation: the entire trial was conducted in China, on Chinese patients.

Dr. Suresh Ramalingam, executive director of the Winship Cancer Institute at Emory University, told CNBC: "I'm mindful of the fact that this trial was done exclusively in China, and that brings up the question of how do these data apply to patient populations outside of China."

Genetics, diet, environmental exposures, and co-existing conditions can all affect how cancer drugs perform across different populations. A drug that works in a Chinese trial doesn't automatically translate to the same results for patients in Ohio or Texas. A global Phase 3 study is ongoing, but those results don't exist yet.

What the Drug Actually Does

Ivonescimab is a bispecific antibody that hits two targets simultaneously: PD-1, the same target as Merck's blockbuster drug Keytruda, and VEGF, targeted by Roche's Avastin. According to CNBC, PD-1 helps cancer cells hide from the immune system, while VEGF promotes blood vessel growth that feeds tumors.

The theory is that hitting both at once is better than hitting either alone. The oncology world has seen this story before — a promising mechanism generates enormous attention, then disappoints in broader trials. TIGIT-targeting drugs followed that same arc.

The Stock Story Is Getting Ahead of the Science

Shares of Summit Therapeutics have skyrocketed nearly 600% over the past two years, according to CNBC, after an earlier China trial showed ivonescimab outperformed Keytruda on tumor control. The stock then pulled back over the past month on concerns the drug won't replicate those results in global populations.

That volatility reflects investor uncertainty. The company is banking on China-only data for a drug not yet approved anywhere outside China. Most mainstream financial coverage is treating these China trial results like confirmation, when they're preliminary data requiring global validation.

Imdelltra: This One Is Real and Available Now

Meanwhile, Amgen scored a significant win that deserves more attention.

On November 19, 2025, the FDA granted full approval to Amgen's Imdelltra (tarlatamab-dlle) for adults with extensive stage small cell lung cancer whose disease progressed after platinum-based chemotherapy. This isn't experimental. It's approved.

The data behind that approval are substantial. The global Phase 3 DeLLphi-304 study showed Imdelltra reduced the risk of death by 40% compared to standard chemotherapy. Median overall survival was 13.6 months versus 8.3 months — more than five additional months of life. According to Amgen's announcement, the hazard ratio was 0.60 with a p-value under 0.001.

The safety profile was also notably better than chemotherapy. Grade 3 or higher adverse events hit 54% of Imdelltra patients versus 80% on chemo. Less toxic and more effective.

The National Comprehensive Cancer Network has already updated its clinical guidelines to list tarlatamab as the only Category 1 preferred treatment for this patient population after first-line failure, according to Amgen.

Small cell lung cancer is one of the deadliest cancers on the planet. It moves fast and has historically had almost no good options after initial treatment fails. Imdelltra changes that equation — right now, for real patients.

What Mainstream Coverage Is Getting Wrong

Most outlets covering ASCO this week are leading with the ivonescimab results because Summit's stock is dramatic and the "Keytruda killer" narrative is irresistible.

The Imdelltra full approval from November 2025, based on a global Phase 3 trial with a 40% death risk reduction, is the stronger near-term story for actual patients. It's approved. It works. Doctors can prescribe it today.

Ivonescimab is compelling science that still needs to prove itself outside of China. It deserves coverage — but not as equivalent to an FDA-approved drug with global trial data.

What This Means for Real People

If you or someone you know has extensive stage small cell lung cancer that's progressed after initial chemo, Imdelltra exists, it's FDA-approved, and it adds meaningful months of life. Ask your oncologist about it.

If you're watching ivonescimab, watch the global trial data when they arrive. The science will determine its real value.