The median progression-free survival was 18.9 months for TAGRISSO vs 10.2 months for erlotinib or gefitinib.

In the same clinical study, median overall survival was 38.6 months for TAGRISSO vs 31.8 months for erlotinib or gefitinib.

Median is the middle number in a range of numbers.

Progression-free survival (PFS) is the median length of time people are on treatment before their cancer started growing or spreading.

Overall survival (OS) is the length of time people are on treatment and still living.