AstraZeneca PLC (LSE:AZN) has seen £2 billion added to its market value after reporting positive results from a breast cancer drug trial.
The experimental treatment, camizestrant, improved patient survival without the disease worsening, according to an interim analysis.
The trial tested the discovery with a standard therapy designed to block proteins that drive tumour growth.
The combination showed progress in delaying disease progression when used as a first-line treatment. The study will continue as planned.
Susan Galbraith, AstraZeneca's head of oncology R&D, said the results move the drug closer to becoming a standard treatment.
Analysts expect the drug to achieve peak annual sales of $5 billion, comfortably achieving blockbuster status.
The trial focused on advanced breast cancer patients with a mutation that makes tumours grow when exposed to hormones.
Researchers used DNA from tumour cells in the bloodstream to detect resistance to standard treatment and switch patients to camizestrant. AstraZeneca's cancer portfolio has become increasingly important to its long-term strategy.
The stock was up 1.2% at 12,072p.