The approval allows adults with SLE on standard therapy to inject Saphnelo themselves.
It is supported by results from the Phase III TULIP-SC trial, which demonstrated that subcutaneous Saphnelo significantly reduced SLE disease activity compared to placebo in patients receiving standard care.
The safety results observed matched the previously established safety profile for the intravenous formulation of Saphnelo.
AstraZeneca biopharmaceuticals executive vice-president Ruud Dobber said: “Since its launch, Saphnelo IV infusion has helped tens of thousands of people with systemic lupus erythematosus achieve lower disease activity with fewer steroids and has been shown to help many achieve remission.
“The approval of the Saphnelo pen represents a significant step forward in expanding Saphnelo’s clinical benefits to more people living with systemic lupus erythematosus.”
SLE is an autoimmune condition where the immune system targets healthy tissues and organs, leading to a complex range of symptoms that can include fatigue, fevers, joint swelling, pain and rashes.
Subcutaneous Saphnelo use is already authorised in Japan and the European Union and remains under regulatory review in several other markets. The intravenous route is approved in more than 70 countries.
AstraZeneca obtained global rights to Saphnelo in 2004 through an exclusive agreement with biopharmaceutical company Medarex. The co-promotion option for Medarex lapsed when it was acquired by Bristol-Myers Squibb (BMS) in 2009.
According to the revised 2025 agreement, AstraZeneca will provide BMS with mid-teens royalties for US sales.
Earlier this year, AstraZeneca secured approval in the US for Calquence (acalabrutinib) plus venetoclax as the first all-oral, fixed-duration regimen to treat adults with chronic lymphocytic leukaemia (CLL) and small lymphocytic lymphoma (SLL) in the first-line setting.