Right now, there are no HER2-targeting drugs approved in non-small cell lung cancer (NSCLC), but partners AstraZeneca and Daiichi Sankyo are hoping to change that. To that end, they rolled out encouraging phase 2 data Friday supporting antibody-drug conjugate Enhertu.
An interim look at the phase 2 DESTINY-Lung01 study, presented at the World Conference on Lung Cancer, showed Enhertu could spur a benefit in 24.5% of heavily pretreated patients with HER2-overexpressing NSCLC.
Those responses lasted for a median six months, with patients living a median 11.3 months—figures Dave Fredrickson, executive vice president and global head of AstraZeneca’s oncology business unit, called “really nice signs of promising efficacy.”
And Friday wasn’t the first time AZ and Daiichi unveiled positive results from DESTINY-Lung01, either. At last year’s American Society of Clinical Oncology virtual annual meeting, they trumpeted results from a separate cohort—those with HER2-mutated lung cancer—showing Enhertu could shrink tumors in 61.9% of patients.
While both the HER2-overexpressing and HER2-mutant NSCLC patient pools are “relatively modest” in terms of their percentage of the wider NSCLC market, because that market is so large, “even small percentages … are, on an absolute basis, rather sizable,” Fredrickson said.
Between 2% and 4% of NSCLC patients have HER2-mutated cancer, while HER2 over-expression impacts as many as one-third of those with the disease. But within that over-expression group, “more work needs to be done to refine and understand whether there are certain levels of over-expression that have a better response” to Enhertu than others, Fredrickson noted.
But while AZ and Daiichi may not currently know the extent of Enhertu’s commercial opportunity in lung cancer, the second DESTINY-Lung01 win bodes well, they figure. “What we are seeing for Enhertu is really a continued momentum of proof points coming against the investment thesis for why we did the deal in the first place,” Fredrickson said.
The pharma giant made that deal—a pact worth close to $7 billion overall and $1.35 billion upfront—based on three pillars, he explained: the drug’s promise in HER2-positive breast cancer, where it’s currently off to a hot start; its potential in cancers outside of breast cancer, such as gastric cancer, where it scored an FDA OK earlier this month; and HER2-low disease, for which the companies are expecting data later this year.
In the meantime, the British and Japanese drugmakers will be discussing the latest lung cancer data with regulators and “quickly moving into phase 3 work in order to be able to secure labels within these populations,” Fredrickson said, adding, “that’s something that will need to be done whether it’s for the purpose of a confirmatory study or the primary data set for registration.”
Also on Friday, the companies spotlighted positive results for another shared antibody-drug conjugate—TROP-2 prospect datopotamab deruxtecan. In a phase 1 study, that candidate posted a response rate ranging from 21% to 25%, dependent on dose.