AstraZeneca plc (AZN) got mixed regulatory news this week, with the FDA putting the brakes on one drug while fast-tracking another. Here's what happened.
The FDA issued a complete response letter on Tuesday regarding AstraZeneca's application for a subcutaneous version of Saphnelo (anifrolumab), a treatment for systemic lupus erythematosus. Think of this as the FDA saying "not yet" rather than "no" – they want more information before approving the self-injectable version of the drug.
The good news? AstraZeneca didn't waste time. The company has already submitted the information the FDA requested. A decision on the updated application is now expected in the first half of 2026. In the meantime, the intravenous version of Saphnelo remains available for patients who need it.
The Data Behind the Lupus Treatment
AstraZeneca's original application was built on a planned interim analysis from the Phase 3 TULIP-SC trial, which evaluated the subcutaneous administration of Saphnelo. That trial hit its primary endpoint, showing a statistically significant and clinically meaningful reduction in disease activity compared to placebo.
When the full analysis came in, the numbers looked solid. At Week 52, 56.2% of patients who received Saphnelo achieved a reduction in disease activity versus 37.1% receiving placebo. Those results lined up nicely with previous trials, which is exactly what you want to see – consistency matters in drug development.
The safety profile in TULIP-SC was consistent with what doctors already knew from the intravenous version of Saphnelo, meaning no unexpected surprises showed up in the data.
Interestingly, while the FDA is taking more time with the US application, Europe has already moved forward. In December 2025, AstraZeneca announced approval of Saphnelo for subcutaneous administration in the European Union for adult patients with moderate to severe systemic lupus erythematosus.
Breast Cancer Drug Gets Priority Review
On the flip side, AstraZeneca and Daiichi Sankyo scored a win with their breast cancer drug. The FDA has accepted their supplemental Biologics License Application for Datroway (datopotamab deruxtecan) and granted it priority review for treating adult patients with unresectable or metastatic triple-negative breast cancer who aren't candidates for PD-1/PD-L1 inhibitor therapy.
Priority review means the FDA will make a decision faster than usual. The target date under the Prescription Drug User Fee Act is sometime during the second quarter of 2026.
The application is backed by results from the TROPION-Breast02 Phase 3 trial, and the numbers are pretty compelling. Datroway delivered a statistically significant and clinically meaningful 5-month improvement in median overall survival. It also reduced patients' risk of disease progression or death by 43% compared to chemotherapy as first-line treatment in this patient population.
The drug also showed durable treatment responses. The objective response rate hit 62.5% with a duration of response of 12.3 months, compared to just 29.3% and 7.1 months with chemotherapy. When you're talking about cancer treatment, those kinds of improvements matter enormously to patients and their families.
Price Action: AZN stock was up 0.67% at $189.67 during the premarket session on Tuesday.
