AstraZeneca has announced the launch of the PRIMULA Preg study, a comprehensive observational research initiative designed to evaluate the safety of anifrolumab during pregnancy in patients with systemic lupus erythematosus (SLE). The study, officially titled "Prospective Registry Investigating Maternal and Infant Outcomes in Anifrolumab Users," represents a significant step in addressing critical safety questions surrounding the use of this lupus treatment during pregnancy.
Study Design and Objectives
The PRIMULA Preg study is structured as a prospective, observational cohort study that will assess the impact of anifrolumab exposure during pregnancy on maternal, fetal, and infant outcomes. The research divides participants into two distinct groups: pregnant individuals with SLE who are exposed to anifrolumab at any time during pregnancy, and those who are not exposed to the treatment.
As an observational study, researchers will monitor outcomes without intervening in patient care, collecting information from existing medical records without requiring additional tests. This approach allows for real-world data collection while minimizing additional burden on participants.
Regulatory Significance
The study fulfills an FDA post-marketing requirement, highlighting the regulatory importance of gathering comprehensive safety data for anifrolumab use during pregnancy. This requirement underscores the need for robust evidence regarding the drug's safety profile in this vulnerable population, where treatment decisions must carefully balance maternal health needs with potential fetal risks.
Anifrolumab Background and Mechanism
Anifrolumab, marketed under the brand name Saphnelo, is a human monoclonal antibody that binds to subunit 1 of the type 1 interferon receptor. The drug was developed based on evidence supporting the role of the type 1 interferon pathway in SLE pathogenesis.
The therapeutic efficacy of anifrolumab has been demonstrated through pivotal clinical trials. In the TULIP 1 and TULIP 2 studies, monthly intravenous administration of anifrolumab resulted in a higher percentage of patients achieving response, as assessed with the British Isles Lupus Assessment Group–based Composite Lupus Assessment, compared with patients receiving placebo.
Additionally, the phase II MUSE study showed that anifrolumab administration substantially reduced disease activity, as measured by the SLE Responder Index, compared to patients receiving placebo. These clinical trial results supported the drug's regulatory approval.
Regulatory Approvals and Current Status
Anifrolumab received FDA approval in July 2021 and European Medicines Agency (EMA) approval in February 2022 for the treatment of adult patients with moderate to severe SLE who are receiving standard therapy. The drug represents an important therapeutic option for patients with this complex autoimmune condition.
Study Timeline and Progress
The PRIMULA Preg study commenced on August 29, 2025, with the most recent update submitted on July 8, 2025. While the estimated primary completion date has not yet been announced, the study is actively ongoing and continues to enroll participants.
Market and Clinical Implications
The study's findings could have significant implications for both clinical practice and market dynamics. Safety data from the PRIMULA Preg study may potentially expand anifrolumab's market use by providing healthcare providers with evidence-based guidance for treating pregnant patients with SLE. This could address an important unmet medical need, as pregnancy management in SLE patients requires careful consideration of both maternal disease control and fetal safety.
The availability of comprehensive pregnancy safety data could influence treatment decisions and potentially impact AstraZeneca's market position in the competitive SLE treatment landscape. As the study progresses, stakeholders will be monitoring for interim updates and eventual results that could shape clinical guidelines and regulatory labeling for anifrolumab use during pregnancy.
