The overall objective of this DPSS is to describe the occurrence of pregnancy and maternal complications, adverse effects on the developing fetus and neonate, and adverse effects on the infant associated with exposure to eplontersen during pregnancy and/or lactation.

Currently, there are no clinical studies of eplontersen use in pregnant individuals. Although it is expected that exposure to eplontersen during pregnancy or lactation is very rare, it is important to capture as many exposed cases as possible. This descriptive pregnancy safety study (DPSS) will add to the current body of knowledge regarding the safety of eplontersen exposure during pregnancy and lactation and maternal, fetal, and infant outcomes following exposure to eplontersen. The study is designed to fulfill health authorities' post-marketing requirements. This DPSS will analyze secondary data on cases of eplontersen-exposed pregnant and lactating individuals collected through a PRegnancy outcomes Intensive Monitoring (PRIM) enhanced pharmacovigilance (PV) approach utilizing AstraZeneca's PV Global Safety Database (PV-Argus). Data sources:

All eplontersen-exposed cases reported to AstraZeneca PV-Argus as notifiable events related to pregnancy and lactation; and cases reported from clinical trials, spontaneous post-marketing reports, post-marketing observational studies, patient-oriented programs, published literature, and personal communication by healthcare providers will be eligible for inclusion in the analysis. Data on eplontersen-exposed cases will be captured and processed using a pre-specified follow-up schedule and questionnaires. In case of missing data, there will be several attempts to collect data using all contact methods supplied by the reporters at the time of initial report.

Study size:

This DPSS is descriptive in nature, and a formal sample size calculation is not performed. Feasibility calculations indicate that the DPSS may capture five exposed pregnancies over the study period. Data analysis:

Analyses will be conducted in accordance with the study objectives, table/listing shells, and applicable guidelines. Demographics, medical and obstetric history, and disease characteristics will be summarized using descriptive statistics. The outcomes will be reported as a proportion and 95% confidence interval (if applicable) and calculated by dividing the number of cases of the outcome by the appropriate denominator for the particular outcome. If fewer than ten cases are reported, formal analyses will not be performed, and reporting will be limited to case narratives.

Inclusion Criteria:

• all pregnancy and/or lactation cases with exposure to eplontersen and a diagnosis of an approved indication for treatment with eplontersen
• all adverse event reports in infants in the first 12 months of age that are or can be linked to pregnancy or lactation reports in individuals previously diagnosed with an approved indication and exposed to eplontersen during pregnancy or lactaction

Exclusion Criteria:

• all case reports considered invalid (i.e. minimum data is not provided at first report nor follow-up), or where reporter indicates that they do not wish to be contacted to obtain follow-up information, or the reporter/patient cannot be identified

Pregnant and/or lactating individuals

The study population will include all PV reports of pregnant and/or lactating individuals diagnosed with an indication approved for use of eplontersen who administered at least one dose of eplontersen during pregnancy or lactation

The enhanced pharmacovigilance approach used in the study involves extraction of targeted safety questionnaire for pregnant or breastfeeding women exposed to eplontersen and reporting to AZ as part of routine pharmacovigilance