The 5 Most Impactful Phase 3 Cancer Trial Results From September 2026

September brought results from several large phase 3 cancer trials, the final stage of testing before a treatment can be considered for approval or a change in standard care. Here are the five results most likely to shape care and what they could mean for people with cancer.

1. Can Ivonescimab Help People With Lung Cancer Live Longer Than Keytruda?

In the phase 3 HARMONi-2 trial, the investigational drug ivonescimab helped people with untreated advanced non-small cell lung cancer (NSCLC) live longer than Keytruda (pembrolizumab), a standard first immunotherapy. Ivonescimab helps the immune system find cancer cells. It also blocks VEGF, a protein tumors use to grow new blood vessels.

Half of the people who received ivonescimab lived longer than 30.8 months, compared with 22.6 months for those who received Keytruda, a 27% lower risk of death. The benefit was largest in people whose tumors had high levels of PD-L1, a protein that helps predict how well immunotherapy may work. No new safety concerns were reported, and side effects were similar between the groups. Ivonescimab is approved for this use in China but not in the United States.

2. Can Ris-Rez Help When Small Cell Lung Cancer Returns?

Small cell lung cancer (SCLC) is fast-growing and often returns after first treatment. In the phase 3 ARTEMIS-008 trial of 461 people in China, the investigational drug risvutatug rezetecan (Ris-Rez) nearly doubled median survival compared with Hycamtin (topotecan) chemotherapy, at 18.5 months vs. 10.3 months.

Ris-Rez is an antibody-drug conjugate, which carries a cancer-killing drug directly to cancer cells. Tumors shrank in 58.3% of people treated with Ris-Rez and 12.6% of those treated with Hycamtin. Serious side effects were less common with Ris-Rez (60.9% vs. 78.2%) and were mostly low blood counts.

3. What Is Etentamig, and How Did It Work in Relapsed Myeloma?

In the phase 3 CERVINO trial, the investigational drug etentamig outperformed standard treatments in 393 people with multiple myeloma that had returned after treatment with the three main classes of myeloma drugs. Etentamig is a bispecific antibody. It links myeloma cells to immune cells called T cells so the immune system can attack the cancer, and it is given once every four weeks.

The myeloma responded in 74% of people treated with etentamig, compared with 45.7% of those who received standard treatments. Etentamig also lowered the risk of cancer growth or death by 60%. The benefit held for people 75 and older and for those treated at community cancer centers.

Infections were more common with etentamig, mostly during the first six months. Cytokine release syndrome, an immune reaction that can cause fever and low blood pressure, occurred in 39.5% of people, almost always mild or moderate.

4. Is Enhertu a New First Treatment Option for HER2-Mutant Lung Cancer?

In the phase 3 DESTINY-Lung04 trial of 454 people, Enhertu (trastuzumab deruxtecan) kept HER2-mutant advanced NSCLC from growing longer than Keytruda plus chemotherapy as a first treatment. Half of the people who received Enhertu lived longer than 14.3 months without their cancer growing, compared with 8.3 months for those who received Keytruda plus chemotherapy. Overall survival results were hard to interpret because the groups went on to receive different later treatments.

Lung inflammation occurred in 20.8% of people treated with Enhertu, mostly mild to moderate. People taking Enhertu should tell their care team right away about new cough, shortness of breath or fever.

5. How Long Does Tagrisso's Benefit Last After Lung Cancer Surgery?

In the phase 3 ADAURA trial, people with EGFR-mutated stage 1B to 3A NSCLC took Tagrisso (osimertinib), a daily pill, or a placebo for up to three years after surgery. Eight years later, 79% of those who received Tagrisso were alive, compared with 64% of those who received placebo. This is the longest survival follow-up reported from a global phase 3 trial in this setting.

Dr. Roy Herbst of Dartmouth Cancer Center, the trial's lead investigator, stressed that people with lung cancer should have their tumors tested for EGFR mutations at diagnosis.

What Do These Results Mean for People With Cancer?

Several of these treatments are not yet approved in the United States for the uses studied, and a single trial does not always change care right away. People can ask their care team whether biomarker testing or a clinical trial may be right for them.

References

1. Akeso, Inc. "Ivonescimab Versus Pembrolizumab in First-Line PD-L1-Positive NSCLC: Positive Overall Survival Results From HARMONi-2 Presented at WCLC 2026." Sept. 13, 2026.
2. Oncology News Australia. "WCLC 2026: Phase 3 ARTEMIS-008 Trial Shows Risvutatug Rezetecan Significantly Improves Overall Survival in Relapsed Small-Cell Lung Cancer." Sept. 15, 2026.
3. OncLive. "Etentamig Improves Response and PFS vs Standard Therapies in Triple-Class Exposed Relapsed/Refractory Myeloma." Sept. 25, 2026.
4. Oncology News Australia. "WCLC 2026: Phase 3 DESTINY-Lung04 Trial Shows First-Line Trastuzumab Deruxtecan Significantly Improves Progression-Free Survival in HER2-Mutant NSCLC." Sept. 15, 2026.
5. International Association for the Study of Lung Cancer. "Eight-Year ADAURA Update Shows Sustained Overall Survival Benefit With Adjuvant Osimertinib in Resected EGFR-Mutated NSCLC." Sept. 14, 2026.
6. AstraZeneca. "Tagrisso Demonstrated Unprecedented Eight-Year Landmark Survival in Early-Stage EGFR-Mutated Lung Cancer in ADAURA Phase 3 Trial." Sept. 14, 2026.

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