- Fresh results from a late-stage study of AstraZeneca's immunotherapy Imfinzi should help to strengthen the drug's emerging position as a go-to choice for treating Stage 3 lung cancer that can't be removed through surgery.
- Treatment with Imfinzi helped more than two-thirds of non-small cell lung cancer (NSCLC) patients with locally advanced tumors stay alive past two years compared to about 56% of those given placebo, data presented Tuesday at the World Conference on Lung Cancer in Toronto showed.
- The overall survival results come one day after AstraZeneca announced the European Commission had approved Imfinzi for that treatment setting. A crucial OK from the Food and Drug Administration came in February, markedly boosting the drug's profile.
AstraZeneca may trail its immuno-oncology rivals in metastatic lung cancer, but the British pharma has secured a commanding lead in the earlier, locally advanced setting.
The FDA approved Imfinzi for Stage 3 NSCLC based on initial data which had shown the drug extended progression-free survival by nearly a year.
Then, in May, AstraZeneca announced its study, called PACIFIC, had also met its overall survival goal. Physicians and investors following updates from Toronto now have a better sense of what that means.
After more than two years of follow-up, median overall survival among patients given Imfinzi had not been reached — indicating that more than half remain alive — versus 28.7 months in the placebo group. That translated to a risk reduction of 32% between the two arms.
Analysts at Cowen predicted ahead of WCLC that a risk reduction above 25% would rate as clinically significant and could drive further uptake of Imfinzi.
More patients on Imfinzi, 15%, discontinued due to an adverse event than did trial participants given placebo (9.8%). Serious adverse events occurred in about 30% of Imfinzi-treated patients and 23% in the control arm.
Usually, patients with locally advanced NSCLC are treated first with platinum-based chemotherapy paired with radiotherapy. Only between 15% and 30% remain alive after five years. Patients in PACIFIC received Imfinzi following chemoradiotherapy.
AstraZeneca's study is the first trial to show a survival benefit following chemoradiotherapy in this setting, researchers wrote in a study abstract.
That pole position in Stage 3 NSCLC has translated into rapid revenue growth from Imfinzi. Sales totaled just over $120 million in the second quarter, nearly doubling from the first three months of the year on the back of that U.S. approval.
"The vast majority of these sales are from the lung indication — a very, very small portion coming from bladder," said David Fredrickson, head of AstraZeneca's cancer business unit, on an earnings conference call in July.
"We do see that roughly half of the PACIFIC-eligible patients in this setting are getting immunotherapy and the majority of those are getting Imfinzi," he added.
AstraZeneca estimates Imfinzi has an 18- to 24-month lead over potential competitors from Merck & Co, Bristol-Myers Squibb and Roche.
More broadly, though, Imfinzi widely trails in the overall cancer immunotherapy market. AstraZeneca is hoping an overall survival readout coming later this year for Imfinzi plus another checkpoint inhibitor in first-line metastatic NSCLC could help it catch up.
Results last July, however, were negative on progression-free survival, dimming hopes for the immunotherapy combo in NSCLC.
AstraZeneca is also studying Imfinzi paired with that other drug, called tremelimumab, in head and neck, small cell lung and bladder cancers.