Johnson & Johnson said on Tuesday its chemotherapy-free combination treatment showed a meaningful improvement in extending lives of patients with a type of lung cancer, compared to AstraZeneca's blockbuster drug Tagrisso.

The combination of J&J's cancer drugs Rybrevant and lazertinib was approved in August for a type of non-small cell lung cancer (NSCLC), based on data that it helps patients live without their disease worsening. At the time, the survival benefit of the combination was not known.

While J&J said on Tuesday its study showed a significant improvement in overall survival, it did not disclose exact details on life extension compared to AstraZeneca's Tagrisso. The rival drug has been shown to help extend lives of NSCLC patients by 38.6 months on average in a separate study. AstraZeneca did not immediately respond to a request for comment.

Some analysts have previously said that doctors might prefer a single therapy over combinations for previously untreated patients, but a better survival rate could tip the scale in the latter's favor. Stephen Liu, associate professor at Georgetown University School of Medicine, said the survival benefit gives J&J's treatment an advantage over other combination therapies.

Liu, who has served as a consultant to both J&J and AstraZeneca, expects patients already receiving a combination treatment to switch to J&J's regime.

J&J said it will share full overall survival data at an upcoming medical meeting and with health authorities. "Our expectation (is) that we're going to see an improvement in that median overall survival exceeding a year," said Mark Wildgust, who heads J&J's global medical affairs for oncology. Wildgust added that survival benefit with J&J's regimen "could go beyond four years" - beating Tagrisso's benefit from previous studies.

NSCLC is the most common type of lung cancer in the United States, according to data from the American Lung Association.