FDA knocks back AstraZeneca's self-injected lupus drug

AstraZeneca's new formulation of systemic lupus erythematosus (SLE) therapy Saphnelo has been turned down by the FDA, despite getting the go-ahead in Europe a few weeks ago.

The US regulator has issued a complete response letter for the self-injected, subcutaneous version of Saphnelo (anifrolumab), which is intended to replace the current intravenous formulation, which was approved in 2021.

AZ did not go into detail about the deficiencies in its marketing application that resulted in the CRL, but said it has already provided additional information to the FDA and is hoping for a decision on the updated filing "in the first half of 2026."

The IV formulation – which will remain commercially available – is used as an add-on therapy to standard treatment for adults with moderate to severe SLE, and has been growing well, with sales rising 48% to reach $483 million in the first nine months of 2025.

AZ's marketing application is based on the TULIP-SC trial, in which a once-weekly injection with Saphnelo demonstrated a statistically significant and clinically meaningful reduction in disease activity compared to placebo. According to the company, the efficacy was consistent with the current IV version, which is given every four weeks, and also helped patients taper their use of oral corticosteroids.

AZ has previously predicted that sales of Saphnelo, fuelled by the rollout of the self-injected formulation, could reach $1 billion to $3 billion in peak annual sales.

Saphnelo ended a 10-year drought in new therapies for SLE when it was approved by the FDA, and is the first biologic drug for SLE not restricted to patients with a high degree of disease activity.

It can be used in a broader patient population than GSK's blockbuster BLyS inhibitor Benlysta (belimumab), which is dosed subcutaneously once a week with an autoinjector. Benlysta sales were £2.7 billion ($3.69 billion) in the first three quarters of 2025, coming from its use in SLE and lupus nephritis.

Datroway gets FDA priority review for TNBC

There was better news from the FDA for AZ today with the news that Datroway (datopotamab deruxtecan), its Daiichi Sankyo-partnered antibody-drug conjugate (ADC) directed at TROP2, was granted a priority review for the treatment of metastatic triple-negative breast cancer (TNBC) patients ineligible for PD-(L)1 inhibitor immunotherapy.

The new application is based on the TROPION-Breast02 presented at last year's ESMO cancer conference, in which Datroway improved overall survival (OS) by 21% and progression-free survival (PFS) by 43% compared to investigator’s choice of chemotherapy as first-line treatment. According to AZ, Datroway is the only medicine to significantly improve OS compared to chemotherapy in this patient population.

Datroway is already approved in the US to treat previously treated, metastatic HR-positive, HER2-negative breast cancer and EGFR-mutated non-small cell lung cancer (NSCLC).

TNBC accounts for about 15% of all breast cancer cases and is often difficult to treat, with a five-year survival rate of only about 15% for patients diagnosed with advanced, metastatic disease. Around 60% of patients with metastatic TNBC have tumours that do not express PD-L1, making them less likely to respond to PD-1/PD-L1 checkpoint inhibitors.

If approved in the new indication, Datroway may compete with Gilead Sciences' Trodelvy (sacituzumab govitecan), which also topped first-line chemo on PFS in the ASCENT-03 trial reported at ESMO, although OS data are still immature.