PASS of Paediatric Patients Initiating Selumetinib

Neurofibromatosis type 1 (NF1) is a rare, autosomal dominant genetic disorder that is caused by germline mutations in the NF1 tumour suppressor gene, which encodes the tumour suppressor protein neurofibromin 1. Plexiform neurofibromas (PN) are histologically benign nerve sheath tumours, which typically grow along large nerves and plexi.

On 5 March 2020, a centralized Marketing Authorisation Application was submitted to the European Medicines Agency (EMA), Marketing Authorization in EU was granted on 17 Jun 2021.

As part of the approval process, a Risk Management Plan (RMP) was developed and submitted to the EMA to summarise the safety concerns emerging from the clinical development program. The RMP included additional pharmacovigilance plans for a non-interventional Post-authorisation Safety Study (PASS) to further characterise the safety of selumetinib in paediatric patients with NF1-related PN in routine clinical practice.

The RMP version 1.0 (succession 4) approved by EMA on 22 April 2021 had 1 important identified risk with selumetinib treatment:

-LVEF reduction

The RMP also identified 5 important potential risks with selumetinib treatment:

• Physeal dysplasia

• Ocular toxicity

• Myopathy

• Hepatotoxicity

• Choking on the capsule Long-term exposure (including long-term safety data on developmental toxicity in children) was identified in the RMP as an area of missing information.

The planned non-interventional PASS will address gaps in knowledge identified by the RMP, including the important identified risk and some of the potential risks and missing information on long-term developmental toxicity in children, by characterising the safety profile associated with selumetinib use among paediatric patients (aged d 8 to < 18 years old) with a diagnosis of NF1 with symptomatic, inoperable PN.

This study is a specific obligation in the context of a conditional marketing authorisation for selumetinib (ie, Category 2 PASS). Study results will contribute to updating the safety profile of selumetinib in a relatively large population of patients with different personal characteristics across multiple health care systems and patterns of real-world clinical practice in up to 52 specialist clinics for the treatment of pediatric patients with NF1 across up to 12 European countries and in Israel.

The primary objective of this study is:

• To characterise the safety of selumetinib, including up to 6 years of long-term safety, in paediatric patients with NF1-related symptomatic, inoperable PN, 8 to < 18 years old who have not reached Tanner Stage V at the start of selumetinib treatment (Nested Prospective Cohort).

The secondary objective of this study is:

• To describe the demographic and clinical profile of the paediatric population 3 to < 18 years old with NF1-related symptomatic inoperable PN who start selumetinib in routine clinical practice (Base Cohort).

The study observation period was anticipated to begin in Q2 of 2022, with some variation by country (actual start date was 23 May 2022). Patients will be enrolled after selumetinib access is commercially available and patients are able to receive the medicine as part of local clinical practice.

The target population for this study are patients with NF1 in the EU with symptomatic, inoperable PN who have been prescribed at least 1 dose of selumetinib and who are aged 3 to < 18 years at the start of selumetinib treatment, except for those patients receiving treatment with a mitogen-activated protein kinase inhibitor before the index date.

The study will enrol 2 cohorts:

1. The Base Cohort includes all enrolled patients aged 3 to < 18 years.

2. The Nested Prospective Cohort will include the subset of Base Cohort patients aged 8 to < 18 years who have not reached Tanner Stage V on the index date.

Patient screening will be conducted throughout the enrolment period and baseline data for all patients will be abstracted from medical records. Those meeting the criteria for enrolment in the Nested Prospective Cohort will be followed up during their routine standard of care visits with the treating clinician (expected to occur every 6 to 12 months) for up to 6 years.