Dramatic Improvement of a Massive Plexiform Neurofibroma After Administration of Selumetinib

Characterization of Cardiac Function by Echocardiographic Global Longitudinal Strain in a Cohort of Children with Neurofibromatosis Type 1 Treated with Selumetinib

BACKGROUND

Plexiform neurofibromas are benign neoplasms that develop in 20-50% children with neurofibromatosis type 1 (NF1). Selumetinib was approved as treatment for symptomatic and inoperable plexiform neurofibromas. Subclinical left ventricular ejection fraction reduction is a less common effect of selumetinib.

OBJECTIVE

We aimed to investigate the contractile function of the heart in a cohort of children with NF1 treated with selumetinib.

METHODS

We designed a cross-sectional study including 17 patients with NF1 who received selumetinib. Echocardiographic parameters were compared with a cohort of 17 healthy children matched by sex and age and another group of 17 children with untreated NF1.

RESULTS

Compared with healthy controls, patients with NF1 treated with selumetinib had lower mean values of global longitudinal strain (- 22.9 ± 2% vs -25.5 ± 2%; p = 0.001), fractional shortening (36 ± 4% vs 43 ± 8%; p = 0.02) and tricuspid annular plane systolic excursion (19 ± 3 mm vs 23 ± 2 mm; p = 0.001); no difference was found in left ventricular ejection fraction (63 ± 4% vs 65 ± 3%; p = 0.2 respectively). Median treatment time with selumetinib at the time of the echocardiographic evaluation was 22 ± 16 months.

CONCLUSIONS

Patients with NF1 treated with selumetinib may experience subtle changes in systolic function identified by global longitudinal strain and not revealed by left ventricular ejection fraction. Global longitudinal strain might be useful to monitor cardiac function in this cohort of patients for the duration of therapy.

Selumetinib in the Treatment of Symptomatic Intractable Plexiform Neurofibromas in Neurofibromatosis Type 1: A Prospective Case Series with Emphasis on Side Effects

BACKGROUND

Plexiform neurofibromas (PN) are congenital tumors that affect up to 50% of individuals with neurofibromatosis type 1. Despite their benign nature, they can grow rapidly and cause severe morbidities. Selumetinib, an inhibitor of mitogen-activated protein kinase (MEK) 1 and 2, was reported to induce a clinical response in pediatric subjects with inoperable PN.

OBJECTIVE

The aim of this paper is to describe a prospective case series of patients treated with selumetinib with emphasis on drug adverse events.

PATIENTS AND METHODS

All the subjects who received selumetinib at the Pediatric Department of Scientific Research Institute and Hospital "Burlo Garofolo", from November 2017 to January 2020, were progressively included. We monitored the patients with a follow-up visit every 3 months. MRI or CT scans to monitor the growth of the tumor were performed after 3 months of treatment, and then every 6-9 months.

RESULTS

Selumetinib was prescribed to nine children, with a total of 17 inoperable PN. The mean follow-up period was 12 months. During the follow-up, one patient experienced an ischemic stroke, unrelated to the treatment. Only minor adverse events were observed: six individuals developed gastrointestinal side effects, seven patients presented a mild form of acne, six had paronychia, four developed irritability, and two showed a mild increase in creatine kinase. None of the patients stopped the treatment. Tumor reduction > 20% was recorded in 16 out of 17 PN (94%). One PN remained stable. No tumor growth was recorded during the treatment.

CONCLUSIONS

In this case series, selumetinib appears to be effective and safe for the pediatric population.