Helen Toledano1,2, Gad Dotan3,4, Rivka Friedland3,5, Rony Cohen3,6, Iftach Yassur7, Hagit Toledano-Alhadef3,8, Shlomi Constantini3,8,9, Mika Shapira Rootman3,10. 1. Dept. of Pediatric Hematology-Oncology, Schneider Children's Medical Center, Petah Tikva, Israel. helent@clalit.org.il. 2. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. helent@clalit.org.il. 3. Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel. 4. Dept. of Pediatric Ophthalmology, Schneider Children's Medical Center, Petah Tikva, Israel. 5. Dept. of Pediatric Dermatology, Schneider Children's Medical Center, Petah Tikva, Israel. 6. Neurofibromatosis Clinic, Schneider Children's Medical Center, Petah Tikva, Israel. 7. Department of Ophthalmology, Rabin Medical Center, Petah Tikva, Israel. 8. The Gilbert Israeli Neurofibromatosis Center (GINFC), Tel Aviv, Israel. 9. Department of Pediatric Neurosurgery, Dana-Dwek Children's Hospital, Tel-Aviv Sourasky Medical Center, Tel Aviv, Israel. 10. Dept. of Pediatric Radiology, Schneider Children's Medical Center, Petah Tikva, Israel.
Abstract
INTRODUCTION: Plexiform neurofibromas (PNF) in neurofibromatosis type 1 (NF1) are usually diagnosed in childhood and can grow rapidly during this period. In 10% of patients, PNF involve the orbital-periorbital area and may cause visual problems including glaucoma, visual loss from amblyopia (deprivational, strabismic, or refractive), optic nerve compression, or keratopathy. Ptosis, proptosis, and facial disfigurement lead to social problems and decreased self-esteem. Complete surgical removal involves significant risks and mutilation, and regrowth after debulking is not uncommon. Inhibitors of the RAS/MAPK pathway have recently been investigated for their activity in PNF. We administered the oral MEK inhibitor trametinib to five young children with NF1 and PNF of the orbital area, with visual compromise and progressive tumor growth; and followed them clinically and by volumetric MRI. METHODS: Treatment was initiated at a mean age of 26.8 months (SD ± 12.8) and continued for a median 28 months (range 16-51). Doses were 0.025 mg/kg/day for children aged > 6 years and 0.032 mg/kg/day for those aged < 6 years. RESULTS: Volumetric MRI measurements showed a reduction of 2.9-33% at 1 year after treatment initiation, with maximal reductions of 44% and 49% in two patients, at 44 and 36 months, respectively. No change in visual function was recorded during treatment. One child reported decreased orbital pain after 2 weeks; and another, with involvement of the masseters, had increased ability to chew food. Toxicities were mostly to skin and nails, grades 1-2. CONCLUSIONS: Trametinib can decrease tumor size in some young children with orbital PNF and may prevent progressive disfigurement.
INTRODUCTION: Plexiform neurofibromas (PNF) in neurofibromatosis type 1 (NF1) are usually diagnosed in childhood and can grow rapidly during this period. In 10% of patients, PNF involve the orbital-periorbital area and may cause visual problems including glaucoma, visual loss from amblyopia (deprivational, strabismic, or refractive), optic nerve compression, or keratopathy. Ptosis, proptosis, and facial disfigurement lead to social problems and decreased self-esteem. Complete surgical removal involves significant risks and mutilation, and regrowth after debulking is not uncommon. Inhibitors of the RAS/MAPK pathway have recently been investigated for their activity in PNF. We administered the oral MEK inhibitor trametinib to five young children with NF1 and PNF of the orbital area, with visual compromise and progressive tumor growth; and followed them clinically and by volumetric MRI. METHODS: Treatment was initiated at a mean age of 26.8 months (SD ± 12.8) and continued for a median 28 months (range 16-51). Doses were 0.025 mg/kg/day for children aged > 6 years and 0.032 mg/kg/day for those aged < 6 years. RESULTS: Volumetric MRI measurements showed a reduction of 2.9-33% at 1 year after treatment initiation, with maximal reductions of 44% and 49% in two patients, at 44 and 36 months, respectively. No change in visual function was recorded during treatment. One child reported decreased orbital pain after 2 weeks; and another, with involvement of the masseters, had increased ability to chew food. Toxicities were mostly to skin and nails, grades 1-2. CONCLUSIONS:Trametinib can decrease tumor size in some young children with orbital PNF and may prevent progressive disfigurement.
Entities:
Keywords:
Neurofibromatosis type 1; Orbitofacial; Plexiform neurofibroma; Trametinib
Authors: Robert A Avery; James A Katowitz; Michael J Fisher; Gena Heidary; Eva Dombi; Roger J Packer; Brigitte C Widemann Journal: Ophthalmology Date: 2016-11-03 Impact factor: 12.079