A targeted lung-cancer drug once brought a tumor under control, but the disease later began to progress again. A new study then reports a regimen that still contains that same drug, now combined with another targeted medicine. The approach sounds somewhat counterintuitive: if resistance has developed, why keep using it?
This question is what makes one study at the 2026 ESMO Congress worth examining. In the global phase 3 SAFFRON trial, savolitinib, developed through a collaboration between HUTCHMED and AstraZeneca, was combined with osimertinib to provide new evidence for a subset of patients whose lung cancer had progressed after osimertinib. The full study was published in the New England Journal of Medicine on October 25. [1][2]
To understand the result, we first need to unpack “resistance.” The word describes a treatment’s inability to keep controlling the disease. It does not automatically tell us what changed in the tumor.
The tumor may have found a bypass route
Osimertinib is an oral targeted medicine that inhibits EGFR signaling. In lung cancers with particular EGFR mutations, blocking this growth signal can have a therapeutic effect. Tumors change, however, and some cells may regain the ability to grow and survive through other routes.
MET is one possible route. It, too, is a receptor on the cell surface that can transmit growth-related signals. When MET protein expression is very high, or the corresponding gene is amplified, some tumors may use this pathway to keep growing even while EGFR remains inhibited. [1][2]
A limited traffic analogy may help: when the road the tumor mainly relied on is blocked, it opens a bypass. The combination’s rationale is to maintain inhibition of the original EGFR signal while using savolitinib to inhibit MET signaling.
The analogy explains a treatment rationale, but tumors are far more complex than roads. Different tumor-cell populations may coexist in a patient, and resistance may involve other changes as well. Whether this approach applies therefore depends first on finding resistance features that match those studied.
Which patients did the study select?
SAFFRON was an international, multicenter, randomized, open-label phase 3 trial enrolling 338 patients. They had EGFR-mutated, locally advanced or metastatic non-small-cell lung cancer that had progressed after osimertinib and met the study’s predefined criteria for high MET expression or gene amplification. [1]
Patients were randomly assigned to savolitinib plus osimertinib or platinum-based chemotherapy plus pemetrexed. The primary endpoint was progression-free survival assessed by independent central review. Overall survival and safety were also evaluated. [1]
One condition is easily lost in news headlines: these were selected patients. The appearance of “MET” on a report, or even a broad description of a “MET abnormality,” does not automatically establish that someone meets this trial’s criteria. Protein expression and gene amplification use different testing methods. The degree of abnormality, the sample’s source, and changes in the disease also require specific assessment.
“Resistance has developed” is only the starting point. The resistance mechanism identified determines whether a corresponding treatment rationale can guide the next step.
What results did the combination produce?
Median progression-free survival was 7.6 months in the combination group and 5.4 months in the chemotherapy group, with a hazard ratio for progression or death of 0.55. The overall-survival analysis showed medians of 17.8 and 12.9 months, respectively, with a hazard ratio for death of 0.68. [1][2]
These times are measured from the trial’s specified starting point and describe statistical results for two groups. They cannot directly predict how many extra months a particular person will live. Progression-free and overall survival measure different events. Differences between medians cannot be treated as additions or subtractions on an individual patient’s timetable.
The study’s significance is that it used a randomized comparison to test a treatment path derived from a resistance mechanism. First came the explanation that MET might become a bypass in some patients. Researchers then selected the corresponding population and finally examined whether inhibiting both pathways improved clinical outcomes.
This makes “precision treatment” concrete. A test result must connect to a treatment hypothesis that can be tested. That hypothesis must then demonstrate its value through research in patients.
Two oral drugs still require a separate assessment of treatment burden
Oral dosing can change how patients organize visits and treatment, but the route of administration alone cannot establish how easy treatment will be.
The company announcement reported treatment-emergent grade ≥3 adverse events, regardless of whether they were judged drug-related, in 64% and 63% of the two groups. Median treatment exposure was also longer in the combination group: 8.5 versus 3.5 months. [2] These figures cover all-cause events during treatment. They cannot be compared directly with “treatment-related adverse events” reported in other trials.
Assessing the combination also requires examining specific events, their management, dose reductions and discontinuations, symptoms, and quality of life. Longer treatment may increase the opportunity for events to be recorded cumulatively. The side effects that actually occur also shape how patients experience that time.
When we read “an all-oral regimen,” we can therefore understand it as a feature of how treatment is organized, then continue checking its specific effects on patients’ lives.
Why is there no single regimen for “after resistance”?
Different patients’ tumors may undergo different changes after progression on a targeted lung-cancer treatment. Even when a MET abnormality is found, its degree and the study’s scope of applicability need confirmation. The same cancer type and treatment history do not guarantee that the next problem is the same.
This is also why SAFFRON and other studies after resistance need to be read separately. Some explore new antibody–drug conjugates (ADCs); others target particular bypass signals; still others examine new combinations and treatment sequences. Their eligibility requirements and control regimens differ. Each result must be interpreted within its own scope.
SAFFRON also did not directly establish how this combination compares with every other new regimen, or how best to sequence treatment for different patients. Those questions still require additional research, follow-up, and clinical experience.
When a drug has “become ineffective because of resistance,” the most useful question is what that change actually means. Does the old growth signal remain important? Has the tumor developed a new dependency? Does the available evidence support addressing both at once?
The study offers a way to understand treatment changes: after progression, learn as much as possible about the tumor again, then test the basis for the next treatment. For patients who meet the relevant conditions, that understanding may become one more option worth serious consideration.
References
- Lu S, et al. Osimertinib–Savolitinib in Advanced NSCLC after Progression during EGFR-TKI Therapy. New England Journal of Medicine, 2026-10-25. doi: 10.1056/NEJMoa2611335. The original study includes eligibility criteria, randomized design, and efficacy and safety assessments.
- HUTCHMED: Original company announcement of the global phase 3 SAFFRON results, 2026-10-26. Includes MET selection criteria, overall-survival results, treatment exposure, and safety data. This article uses the body of the company’s original announcement.
Information current through October 27, 2026. This article is for general education. Consult an oncologist about specific treatment.
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