AstraZeneca stock tumbled Wednesday after its experimental drug led to only a month's benefit over chemotherapy in lung cancer patients.
AstraZeneca and partner Daiichi Sankyo tested their drug, dubbed datopotamab deruxtecan, in non-small cell lung cancer patients who worsened while undergoing a previous treatment. At the median, patients lived for 4.4 months before their cancer worsened — a measure known as progression-free survival. But that was only minimally better than 3.7 months for chemo recipients.
RBC Capital Markets analyst Brian Abrahams says this highlights some challenges for the drug class. Datopotamab deruxtecan is an antibody drug conjugate, or ADC. Think of these drugs like smart bombs that send chemotherapy directly to cancer cells. AstraZeneca's drug zeros in on a protein called TROP2. The approach looked promising in breast cancer, but less so in lung cancer.
"Marginal AstraZeneca non-small cell lung cancer data raise some questions about the potential benefits of the class and the next key readout for the important growth-driving lung cancer (use)," he said in a report to clients.
On the stock market today, AstraZeneca stock sank 5.8% to 65.24. Shares of Gilead Sciences, which makes a rival drug called Trodelvy, dipped 1%, closing at 79.67.
AstraZeneca Stock: A Big Opportunity
Non-small cell lung cancer is the most common form of lung cancer. So, it offers a lucrative opportunity for drug developers. This was the first big test for AstraZeneca and Daiichi Sankyo's drug.
But the results weren't statistically significant in lung cancer patients. Importantly, just 3.4% of patients experienced serious interstitial lung disease, a known side effect of Enhertu. That's better than the 5% rate doctors had viewed as acceptable, Abrahams said. Enhertu is another ADC from AstraZeneca and Daiichi Sankyo. It targets a different protein and is approved for non-small cell lung cancer patients.
"If AstraZeneca is able to ultimately show overall survival benefits, datopotamab deruxtecan's tolerability profile regarding interstitial lung disease may not be as disadvantageous as expected," he said.
Further, this could be a class effect. It's possible patients can't receive TROP2-targeting ADCs in the lungs long enough to derive a stronger benefit than chemotherapy, he said. Gilead could have the same trouble when it unveils the results for its rival drug, Trodelvy, next year.
Abrahams kept his sector perform rating on Gilead stock, but didn't list a rating for AstraZeneca stock.
Promising Breast Cancer Treatment
More promisingly, AstraZeneca and Daiichi Sankyo's drug staved off progression by a median of 6.9 months in breast cancer patients. In comparison, chemotherapy had a 4.9-month benefit on progression-free survival. There were also no cases of interstitial lung disease, Abrahams said.
"Given that progression-free survival benefits typically translate to overall survival benefits, we believe datopotamab deruxtecan will likely show a competitive clinical outcome in overall survival," he said.
This could line AstraZeneca up to rival Gilead's Trodelvy, which is already approved in some breast cancer patients.
But AstraZeneca stock fell near the lower boundary of a consolidation with a buy point at 76.56, according to MarketSmith.com. Shares have a strong IBD Digital Composite Rating of 95, putting them in the leading 5% of all stocks when it comes to technical and fundamental measures.
Follow Allison Gatlin on X, the platform formerly known as Twitter, at @IBD_AGatlin.
