3 More Lung Cancer Breakthroughs From WCLC 2026

The 2026 World Conference on Lung Cancer (WCLC) in Seoul kept delivering after the opening headlines covered in CURE's top 3 takeaways from WCLC 2026. Three more studies stood out as the meeting continued, spanning a new biomarker-targeted therapy, an early but striking EGFR combination and a long-overdue advance for relapsed small cell lung cancer (SCLC). None of these treatments are approved yet, but each addresses a gap where patients have had few good options.

Zidesamtinib Shows a 94% Response Rate in ROS1-Positive Lung Cancer

ROS1-positive non-small cell lung cancer (NSCLC) is a rare subtype driven by a gene rearrangement that fuels tumor growth, and it can be targeted with drugs designed specifically to block that rearrangement. In the phase 1/2 ARROS-1 trial, the targeted therapy zidesamtinib produced a response in 94% of people with treatment-naive, advanced ROS1-positive NSCLC, including complete responses, meaning no detectable cancer remaining, in 15% of patients.

The drug also showed unusually strong activity in the brain, a common site where ROS1-positive lung cancer spreads. Among the 10 patients with measurable brain metastases at the study's start, all had their tumors shrink, and 70% saw their brain metastases disappear entirely. Most responses to the drug overall were still ongoing a year later, and 90% of patients had not seen their cancer progress at that point.

The most common side effects were swelling in the arms or legs, an increase in a muscle enzyme called CPK, and constipation. Few patients needed a lower dose or stopped treatment because of side effects, suggesting the drug was generally manageable.

Iza-Bren Plus Osimertinib Reaches 100% Response Rate in Frontline EGFR-Mutant NSCLC

Osimertinib is already a standard first treatment for EGFR-mutated NSCLC, but researchers are testing whether pairing it with newer drugs can push responses even further. Izalontamab brengitecan (iza-bren), an antibody-drug conjugate, was combined with osimertinib in a phase 2 study of 154 people with previously untreated, EGFR-mutated NSCLC. At the combination's optimized dose, every patient treated had their tumor shrink, for a 100% response rate.

Across the full study population, which included other doses, the response rate was 84%, and 96% of patients were alive a year after starting treatment. Those numbers are still early, and it's not yet clear how this combination compares with osimertinib alone over the long run, but the initial results are among the strongest reported so far in this setting.

The combination's most common side effects involved lower blood cell counts, including anemia and low levels of infection-fighting white blood cells. About 13% of patients stopped treatment because of side effects, and two patients developed a lung condition called interstitial lung disease, a known risk with this type of drug that doctors monitor closely.

Two New Drugs Beat Topotecan in Relapsed Small Cell Lung Cancer

For decades, topotecan has been the default option after SCLC returns following platinum-based chemotherapy, despite modest results and a side effect profile that many patients find difficult to tolerate. Two separate phase 3 trials presented at WCLC 2026 challenged that standard, and both showed real gains in how long patients lived.

Risvutatug rezetecan extended median overall survival to 18.5 months, compared with 10.3 months with topotecan, in the 461-patient ARTEMIS-008 trial. Separately, tambotatug pelitecan extended median overall survival to 13.3 months, compared with 9.4 months with topotecan, in the 451-patient TAISHAN-302 trial. Both drugs are antibody-drug conjugates that target a protein called B7-H3, which is found on the surface of many SCLC tumor cells, allowing the drug to deliver chemotherapy directly to the cancer while sparing more healthy tissue.

Both drugs also caused fewer severe side effects overall than topotecan, though each carried a higher rate of a lung side effect called interstitial lung disease or pneumonitis, which patients and doctors will need to watch for. Given how few new options have reached this stage of testing in SCLC, having two positive phase 3 trials read out at the same meeting is itself notable.

Taken together, these three studies point in different directions: a biomarker-driven win in a rare lung cancer subtype, an early but eye-catching combination for a more common one, and the first real challenge to a decades-old standard in relapsed SCLC. None of these are ready for the clinic yet, but they give patients and doctors more reasons to watch this space closely in the months ahead.

References

1. Zidesamtinib Yields High Response Rates in TKI-Naive Advanced ROS1+ NSCLC — OncLive
2. Iza-Bren Plus Osimertinib Elicits 100% ORR in Frontline EGFR-Mutant NSCLC — OncLive
3. Ris-Rez Extends Median OS to 18.5 Months vs Topotecan in Relapsed SCLC — OncLive
4. Tam-Peli Reduces Risk of Death by 54% vs Topotecan in Relapsed SCLC — OncLive

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