Who is this trial for?
This trial was for adults with non-small-cell lung cancer that had been completely removed by surgery — and whose tumour had a specific gene change called an EGFR mutation.
People in the trial had:
- Stage IB, II, or IIIA non-small-cell lung cancer (NSCLC) — earlier stages where surgery with intent to cure is possible.
- An EGFR gene mutation — specifically an exon 19 deletion or L858R mutation, the two most common types.
- Complete surgical removal of all visible cancer (with or without adjuvant chemotherapy after surgery).
- Good general health and ability to carry out normal daily activities.
What kind of trial is this?
This trial tested whether a targeted pill could prevent lung cancer from coming back after surgery had removed it.
Background: why researchers asked this question
Even when lung cancer is completely removed by surgery, it often comes back. Microscopic cancer cells too small to see or feel can remain in the body, and over months or years they can regrow. For stage II–IIIA disease, the cancer returns in over half of patients — even after chemotherapy.
For EGFR-mutated lung cancer, a daily pill called osimertinib had already proven highly effective in metastatic (spread) disease. Researchers asked: could giving osimertinib for three years right after surgery prevent those microscopic cells from ever growing back?
The trial: what was tested and how
ADAURA enrolled 682 people with stage IB–IIIA EGFR-mutated NSCLC who had had their cancer completely removed by surgery. Some had also received adjuvant (post-surgery) chemotherapy. They were randomly assigned 1:1 to one of two groups:
- Osimertinib: 80 mg once daily for up to three years.
- Placebo: a dummy pill once daily for up to three years.
The main measure was disease-free survival (DFS) in stage II–IIIA patients — how long until the cancer came back or until death. The trial was stopped early because the benefit was so clear it would have been unethical to continue without offering osimertinib to the placebo group.
A note before the results
The ability to prevent recurrence after lung cancer surgery is something we have sought to perfect for more than two decades. With traditional chemotherapy, we often quoted a benefit of only a few percent, and outcomes after surgery were quite poor, with most people experiencing a recurrence of their cancers within two years. This paper exemplifies a new era in cancer recurrence prevention — targeting the cancer with a single type of bullet, not a bomb.
Results: what they found
Osimertinib dramatically reduced the chance of cancer coming back — particularly in higher-stage disease. The benefit was striking at four years.
Osimertinib vs placebo — at 4 years after surgery
More than twice as many people remained cancer-free at four years with osimertinib — a 77% reduction in the risk of recurrence or death (HR 0.23).
Across all eligible stages combined, nearly twice as many people were cancer-free at four years (HR 0.27).
Osimertinib dramatically reduced the risk of cancer spreading to the brain — a known site of recurrence for EGFR-mutated lung cancer. 76% lower risk of brain recurrence or death in this analysis.
The safety profile was consistent with what was known about osimertinib from other trials. Common side effects included diarrhoea, rash, and dry skin. Interstitial lung disease (ILD) — a rare but serious lung inflammation — occurred in a small percentage of patients, consistent with the known profile of the drug.
What about overall survival?
Overall survival data were not yet mature at the time of this 2023 analysis — the study had not been running long enough for a reliable OS comparison. The disease-free survival benefit was so large that the trial was stopped early. OS results from ADAURA were subsequently reported and confirmed a survival benefit with osimertinib.
The bottom line
For people with stage IB–IIIA EGFR-mutated non-small-cell lung cancer who had surgery, taking osimertinib daily for three years reduced the risk of cancer returning by over 75% in higher-stage disease at four years. It also dramatically reduced brain recurrence. ADAURA changed the standard of care: adjuvant osimertinib is now recommended for eligible patients after surgery.
What this could mean for you
- EGFR testing is essential. This treatment is only for people whose lung cancer has an EGFR mutation — testing is now routine at diagnosis.
- It follows surgery, it isn’t instead of it. Osimertinib is given after the tumour is removed, to stop microscopic remaining cells from causing the cancer to return.
- It’s a daily pill for three years. Adherence matters; your team will monitor you for side effects, including rare lung inflammation (ILD).
- OS data are available. Since this 2023 analysis, survival data have confirmed a meaningful overall survival benefit with adjuvant osimertinib.
An oncologist’s perspective
Osimertinib given for three years after surgery (and sometimes after three months of chemotherapy) is extremely well tolerated. Most of the side effects are related to nail changes (like split skin at fingertips), and rashes. Patients are extremely happy to have this extra “insurance” that offers a significantly higher chance of cure with this simple pill.
Questions & comments
Have a question about this trial? Ask below. Questions are read and answered by the site. We can’t give personal medical advice, but we’re glad to explain the research more clearly.