AACR: Chi-Med, AstraZeneca's savolitinib helps some Tagrisso-resistant EGFR lung cancer patients

AstraZeneca is helping fund development of Chi-Med's savolitinib under a pact first inked in 2011. (AstraZeneca)

ATLANTA—AstraZeneca’s Tagrisso has taken the EGFR lung cancer market by storm, but some patients develop resistance to the therapy. Enter Chi-Med.

The Chinese company Sunday rolled out phase 1b results demonstrating certain treatment-resistant patients showed improvement after receiving a combination of Tagrisso, which targets the EGFR gene mutation, and Chi-Med’s savolitinib, a MET inhibitor it’s developing with help from AZ.

Specifically, the study enrolled patients who developed resistance to EGFR drugs because of an MET gene amplification. In the first cohort of patients, who developed resistance after receiving a first- or second-generation tyrosine kinase inhibitor—such as AstraZeneca’s Iressa or Roche’s Tarceva—and tested negative for the T790M mutation, the combination produced a response rate of 52%. Those responses lasted a median 7.1 months.

A second group of patients received the combo after acquiring MET-driven resistance with Tagrisso, which is a third-generation TKI, or another third-generation drug in development. Twenty-eight percent of those patients responded to therapy, with the median response lasting 9.7 months.

RELATED: AstraZeneca's Tagrisso just got the lung cancer nod it needs to hit $3B in sales

That second cohort may be the more relevant one going forward, thanks to Tagrisso’s approval in previously untreated patients. The drug snagged its first-line go-ahead last April after showing it could slash the risk of disease progression or death by 54% when squaring off against Iressa and Tarceva.

But there was also a downside to receiving savolitinib on top of Tagrisso, lead study investigator Lecia Sequist noted in a statement. Adding savolitinib to Tagrisso caused an increase in side effects, forcing some patients to discontinue treatment.

Chi-Med is working to bring savolitinib to market after scoring a historic approval for a different drug last September. The company’s colorectal cancer therapy Elunate became the first China-made oncology med to pick up a green light from that country's National Medical Products Administration.

RELATED: Chi-Med expands PhIII effort on savolitinib with AstraZeneca with amended royalty pact

And as it did with Elunate—which it's developing with partner Eli Lilly—Chi-Med is getting some Big Pharma assistance with savolitinib. It first partnered with AstraZeneca on the MET inhibitor back in 2011, and the pair amended its licensing deal in the summer of 2016 to add as much as $50 million over three years.