In another Lynparza flop, AstraZeneca, Merck pull the plug on a colorectal cancer trial

Sometimes you swing and miss. As AstraZeneca and Merck try to prove Lynparza across tumor types, the companies stopped a phase 3 trial investigating the drug in colorectal cancer after the study was found  unlikely to suceed.

In the current LYNK-003 trial, Lynparza was being tested by itself and alongside Avastin as a first-line maintenance treatment for colorectal cancer that has not progressed following first-line induction. At an interim analysis, an indpendent data monitoring panel found neither regimens could improve upon Avastin's combination with chemotherapy in terms of stalling tumor progression or death.

Both experimental arms were discontinued upon the recommendation of the data monitoring committee. No new safety signals were observed in the trial, Merck said in a statement.

The latest trial flop marks Lynparza's second in months. Earlier this year, Lynparza paired with Keytruda failed to stall tumor progression in previously treated metastatic castration-resistant prostate cancer. The combo also had a higher rate of drug-related serious side effects. The trial was cancelled early.

Despite the trial flops, Lynparza had an early lead as a top-selling PARP inhibitor. That lead was recently reinforced with a first-in-class FDA approval for patients with high-risk early breast cancer that's germline BRCA-mutant and HER2-negative.


Colorectal cancer is the third most common cancer and the second leading cause of cancer death. In the U.S., it is estimated that there will be nearly 53,000 deaths from the cancer in 2022.

Lynparza's initial approval made it the first targeted treatment to potentially exploit DNA damage response pathway deficiencies to potentially kill cancer cells. Last year, it brought in $2.35 billion in sales for AstraZeneca, a 30% increase from 2020.