# Effective vemurafenib monotherapy for refractory Langerhans cell histiocytosis with sustained results post-withdrawal for over two years: a case report

## TL;DR

A young girl with a severe, treatment-resistant form of Langerhans cell histiocytosis showed long-term remission after vemurafenib treatment and remained disease-free for over two years after stopping the drug.

## Contribution

This case report demonstrates the long-term efficacy of vemurafenib monotherapy in a pediatric patient with refractory LCH.

## Key findings

- Vemurafenib monotherapy rapidly improved the patient's condition with a BRAFV600E mutation.
- The patient remained disease-free for over two years after discontinuing vemurafenib.
- The treatment was effective in a high-risk, chemotherapy-resistant case of LCH.

## Abstract

Langerhans cell histiocytosis (LCH) is a rare, inflammatory myeloid neoplasm. Mitogen-activated protein kinase (MAPK) inhibitors, such as vemurafenib, can quickly control active disease in patients resistant to vinblastine and prednisone, but recurrence often occurs within a year after stopping treatment.

We report the case of a 15-month-old girl with high-risk multisystem LCH and BRAFV600E
mutation. The patient initially received treatment according to the LCH-III chemotherapy protocol but exhibited disease progression after two months of maintenance chemotherapy. Following initiation of vemurafenib monotherapy, the patient’s condition improved rapidly. The duration of vemurafenib monotherapy was one year and nine months. The patient remained disease-free for over two years after vemurafenib withdrawal.

This case highlights the potential of MAPK inhibitor monotherapy for pediatric refractory LCH.