Cancer Treatment Today

Histiocytosis is a rare  disease that involves hystiocytes. The disease can range from limited involvement that spontaneously regresses to progressive multiorgan involvement that can be chronic and debilitating. In some cases, the disease can be life-threatening. It is approximated that histiocytosis affects 1 in 200,000 children born each year in the United States. The disease us rare and not much is known securely about how to treat it. Because of its rarity, prospective studies are not possible.

In 2009, a guideline was published by the Hystiocytosis Soceity It recommends an initial 6-week course of therapy with vinblastine and prednisone  for all patients with MS-LCH regardless of risk organ involvement.It is also recommended that all patients who have complete disease resolution (NED)
after 6-12 weeks of initial therapy continue with maintenance therapy. Maintenance therapy consists of pulses of vinblastine and prednisone every 3 weeks and daily continuous 6-mercaptopurine (6MP) for a total treatment duration of 12 months. Currently, there is insufficient evidence to support an optimal course of treatment for use with patients suffering from severe progressive MS-LCH who do not respond to standard therapy. Recently, promising results have been reported for patients treated with a combined regimen of 2-chlorodeoxyadenosine (2-CdA, Cladribin, Leustatin) and cytarabine (Ara-C) (12); as well as stem cell transplantation after reduced intensity conditioning regimen (RIC-SCT). However, the results generated by both reports are based on limited observations and must be validated by the prospective clinical trials.

As far as Revlmid, Strurz reported a case of successful treatment with this agent, and there is another case report and  a case series of 4 cases:

Uppuluri R, Ramachandrakurup S, Balaji R, Subburaj D, Bakane A, Raj R.Successful Treatment of Refractory Langerhans Cell Histiocytosis of the Choroid Plexus in a Child With Pulse Dexamethasone and Lenalidomide.J Pediatr Hematol Oncol. 2017 Mar;39(2):e74-e78.

R Uppuluri et al.Excellent Remission Rates With Limited Toxicity in Relapsed/Refractory Langerhans Cell Histiocytosis With Pulse Dexamethasone and Lenalidomide in Children
Pediatr Blood Cancer 64 (1), 110-112. 2016 Aug 24.

Both, and the case report by Sztutz bring us to six cases in the literature,which is not sufficient to establish a SOC.

and a study is ongoing: A Study of Lenalidomide for Adult Histiocyte Disorders, NCT02523040.

LANGERHANS CELL HISTIOCYTOSIS Histiocyte Society Evaluation and Treatment Guidelines April 2009

Szturz P, Adam Z, Rehák Z, Koukalová R, Slaisová R, Stehlíková O, Chovancová J, Klabusay M, Krej?í M, Pour L, Hájek R, Mayer J. Lenalidomide proved effective in multisystem Langerhans cell histiocytosis. Acta Oncol. 2012 Mar;51(3):412-5. doi: 10.3109/0284186X.2011.631581. .

Histiocyte Society 26th Annual Meeting Abstracts, Boston, Massachusetts
Article first published online: 4 FEB 2011
Pediatric Blood & Cancer Volume 56, Issue 4, pages 689–703, April 2011

Bernard F, Thomas C, Bertrand Y, Munzer M, Landman Parker J, Ouache M,
et al. Multi-centre pilot study of 2-chlorodeoxyadenosine and cytosine arabinoside
combined chemotherapy in refractory Langerhans cell histiocytosis with
haematological dysfunction. Eur J Cancer 2005;41(17):2682-9.

Steiner M, Matthes-Martin S, Attarbaschi A, Minkov M, Grois N, Unger E, et al. Improved outcome of treatment-resistant high-risk Langerhans cell histiocytosis after allogeneic stem cell transplantation with reduced-intensity conditioning. Bone Marrow Transplant 2005;36(3):215-25.

MEK may be helpful, but results are very preliminary at this time. See https://www.investorvillage.com/smbd.asp?mb=1086&mn=16747&pt=msg&mid=17850518

Read the Layperson version here.