Phase II High-Dose Cyclophosphamide for Multiple Sclerosis

Multiple sclerosis (MS) is the major disabling neurologic disease of young adults,and
represents the most common immune-mediated inflammatory and demyelinating disorder of the
central nervous system (CNS). Active inflammatory lesions contain components that include T
cells, macrophages, and activated microglia. Within these lesions myelin is removed, axons
are damaged and oligodendrocytes may be lost. In lesions undergoing inflammatory
demyelination axonal injury also occurs. The disability MS produces is underscored by the
nearly fifty percent of patients who will require ambulatory aids within 15 years after
disease onset.

Currently, there is no cure for MS. Therapy is targeted at changing the short-term natural
history of MS: to decrease attack rates and to postpone long-term disability. At present,
interferon beta and glatiramer acetate form the foundation of therapy for relapsing MS.
Mitoxantrone is approved for more severe cases of relapsing MS, such as those with rapidly
accumulating neurologic impairments.

High-dose cyclophosphamide (HDC) is a non-bone marrow transplant treatment option for those
afflicted by severe, refractory immune-mediated illnesses by pathologic autoreactive
lymphocytes. The goal of this therapy is to induce immunoablation without myeloablation: that
is, to eradicate offending B and T cells responsible for the illness while sparing the
pluripotent blood stem cell of any ill effect. Since 1966, multiple publications on numerous
immune-mediated illnesses have shown HDC without stem-cell rescue to decrease disease
activity and improve quality of life

In this protocol we study HDC for severe, refractory MS. The primary goal is to assess the
safety of HDC in this population, where no data exists regarding the tolerability of
high-dose chemotherapy without stem-cell rescue. The treatment goal is not to induce disease
regression (resolution of fixed neurologic deficits), but rather to stop disease progression
without further remittive therapy.

Inclusion Criteria:

- Diagnosis of secondary progressive (SPMS), primary progressive (PPMS) or progressive
relapsing (PRMS) multiple sclerosis

- A diagnosis of MS will be established by fulfilling criteria "Recommended Diagnostic
Criteria for Multiple Sclerosis: Guidelines from the Internal Panel on the Diagnosis
of Multiple Sclerosis"

- The subtype of MS will be established by the natural history of the disease

- Age >18 but < 75 years

- An extended disability status scale (EDSS) score of >3.5 after two standard treatment
regimens IFNB1a IFNB1b Glatiramer acetate Mitoxanthrone Steroids, plasmapheresis or
IVIG individually or in combination constitute a single treatment regimen

- Patient must have a left ventricular ejection fraction of > 45%

- Serum Creatinine <3mg/dL

- For women of childbearing potential, serum βHCG (less than seven days before start of
cyclophosphamide)

- Willingness to participate in a clinical trial

Exclusion Criteria:

- Patients who are preterminal or moribund

- Patients with active malignancies

- Patients with chromosomal abnormalities or peripheral blood counts suggestive of
myelodysplastic syndrome

- Patients with active bacterial or fungal infections requiring oral or intravenous
antimicrobials are not eligible until resolution of the infection

- Pregnant women and breast-feeding women

- Patients with known intolerance to G-CSF