AZ chalks up another win for Imfinzi, Lynparza duo

AstraZeneca’s efforts to combine two of its top cancer drugs – Imfinzi and Lynparza – has been rewarded with positive results in an endometrial cancer study that could lead to regulatory filings.

The new data from the DUO-E study found that PD-L1 inhibitor Imfinzi (durvalumab) and PARP inhibitor Lynparza (olaparib) – as well as Imfinzi alone – extended the time to disease progression or death in previously-untreated, advanced endometrial cancer patients when given on top of standard chemotherapy.

AZ said it is the is the first global phase 3 trial of immunotherapy plus PARP inhibition to show a benefit on progression-free survival in this type of cancer. Overall survival is also trending towards improvement for both Imfinzi and the combination of chemo alone, but as yet the differences aren’t statistically significant.

It comes just a few weeks after the combination showed efficacy in the DUO-O study in newly-diagnosed, advanced ovarian cancer, which is also being prepared for filing and could make Imfinzi the first immunotherapy for broad use in ovarian cancer, if approved.

In both DUO-O and DUO-E, Imfinzi and Lynparza were used as maintenance therapy after the initial treatment schedule.

There was a greater clinical benefit observed with the combination of Imfinzi and Lynparza as maintenance treatment in DUO-E, said AZ in a statement. The data will be presented at a medical conference in the coming months, and discussed with regulatory authorities.

If approved, the regimen would open up a new indication for both drugs, as neither is currently used to treat endometrial cancer – the sixth most common cancer in women, with around 417,000 cases diagnosed each year, according to 2020 figures from World Cancer Research Fund International. It killed around 97,000 women in the same year.

Imfinzi is currently approved for lung and biliary tract tumours, while Lynparza is used to treat ovarian, breast, pancreatic, and prostate cancer.

Analysts have said that combination use could expand the market of both drugs, which made $2.8 billion and $2.6 billion, respectively, last year, although AZ may have to wait for the OS survival data from the two DUO studies to come in before approval.

That’s because the safety of the PARP inhibitor class has lately come under some scrutiny. Last year, AZ and partner Merck & Co pulled use of Lynparza in heavily pre-treated, BRCA-positive ovarian cancer due to concerns that it may increase the risk of death, shortly after similar moves were made by other PARP drug manufacturers Clovis Oncology and GSK.