This research study is a Phase II clinical trial. Phase II clinical trials test the
effectiveness of an investigational drug to learn whether the drug works in treating a
specific disease. "Investigational" means that the drug is still being studied and that
research doctors are trying to find out more about it-such as the safest dose to use, the
side effects it may cause, and if the drug is effective for treating different diseases. It
also means that the FDA has not yet approved clofarabine for your disease.
Clofarabine is a chemotherapy drug that has been used in the treatment of leukemia in
children and adults. Information from other research studies suggests that this drug may also
be effective in patients with LCH.
The purpose of this study is to estimate the response rates of participants with recurrent
LCH to clofarabine within each of two strata: a) low-risk participants with disease
reactivation, and b) high-risk participants with risk-organ involvement.
Other purposes are to estimate the progression-free survival after clofarabine treatment,
estimate survival of participants with refractory multi-system LCH with risk organ
involvement treated with clofarabine and to describe toxicities of clofarabine in
participants with LCH.