Breast cancer
Breast cancer later returns in between a third and one half of cases post surgery Image Credit: Shutterstock

FRANKFURT: Novartis breast cancer drug Kisqali cut the risk of recurrence by a little more than 25 per cent in a pivotal trial on women diagnosed at an early stage, positioning the Swiss drugmaker to win new patients and challenging strong rival Eli Lilly.

The company on Friday said the relative risk reduction of cancer recurrence was 25.2 per cent and that the results were broadly consistent regardless of patients' menopausal status or cancer progression status. The results were presented at the annual meeting of the American Society of Clinical Oncology in Chicago.

Kisqali was used in the trial together with standard endocrine therapy to treat a type of cancer that grows in response to hormones and it was compared to endocrine therapy alone.

Novartis in March gave a brief preview of the Kisqali data, boosting its shares and growth prospects.

Kisqali has been approved to treat hormone-driven breast cancer that has spread to other parts of the body, where Novartis has taken market share from Pfizer's Ibrance.

But an earlier diagnosis, when tumours can still be surgically removed, is much more common, representing about 90 per cent of patients.

Still, better drugs are needed after surgery because the cancer later returns in between a third and one half of cases.

Eli Lilly is ahead with the approval of rival drug Verzenio in the early setting. But that is in a subset of women who are at high risk of recurrence after surgery, typically diagnosed based on signs of cancer in the lymph nodes.

Here, Novartis will face tough competition because the U.S.

drugmaker has said Verzenio reduces the risk of recurrence by 35 per cent in that group.

But Kisqali looks set to be a pioneer in a wider market because it was tested successfully in both high-risk and medium-risk patients, a population that is twice as large.

Analysts have said investors could be disappointed if the Kisqali read-out fell well short of Verzenio's efficacy.

Novartis stressed very low rates of symptomatic side effects in its trial, important to patients facing years-long treatment, with severe diarrhea affecting only 0.6 per cent of participants on Kisqali.

That compares with 8-20 per cent of the women in trials with Eli Lilly's Verzenio being affected by severe diarrhea.

"We know diarrhea can be a very troublesome, burdensome adverse event for patients taking anti-cancer medicines," said Jeff Legos, Head of Oncology & Hematology Development at Novartis.

The March trial update boosted market confidence in targets issued by CEO Vas Narasimhan for annual sales growth of 4 per cent through 2027 and a core operating income margin of 40 per cent from 2027, analysts have said.

Novartis will request approval for wider use in the U.S. and Europe before the end of the year, it added.