Hematopoietic Stem Cell Support in Vasculitis
Hematopoietic Stem Cell Support in Vasculitis
The systemic vasculitis is a wide-ranging group of diseases that are characterized by the
 presence of blood vessel inflammation (1). Despite this common feature, each type of
 vasculitis has a unique variety of clinical manifestations that influences its degree of
 disease severity and ultimately its management. Immunosuppressive therapy forms the
 foundation of treatment for almost all forms of systemic vasculitis.

 The systemic necrotizing vasculitis (SNV) are a subset of vasculitis with significant
 morbidity and mortality (2). The SNV are Wegener's granulomatosis, allergic angiitis and
 granulomatosis (AAG) (also known as Churg-Strauss syndrome), polyarteritis nodosum (PAN),
 microscopic polyangiitis (MPA), and overlap syndrome. In spite of modern therapeutic immune
 suppressive agents, there remains a not inconsequential morbidity and mortality associated
 with SNV. The current standard therapy for SNV is chronic oral cyclophosphamide (1-3
 mg/kg/day) and corticosteroids (3-6). Transplant doses of cyclophosphamide at 200 mg/kg
 infused over 4 days is the most common worldwide transplant regimen for systemic lupus
 erythematosus (SLE) (7). Like SLE, SNV are cyclophosphamide responsive disease. We,
 therefore, propose a trial of high dose cyclophosphamide with anti-thymocyte globulin (ATG)
 for patients with SNV.
Selection of High Dose Immunosuppressive Therapy and Autologous HSCT Strategy for this Trial

 Selection of the Regimen for High-Dose Immunosuppressive Therapy Cyclophosphamide with ATG
 (Cy/ATG) is a common conditioning regimen with two decades of experience in the treatment of
 aplastic anemia and has been used safely without reported mortality in the treatment of
 autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Cy/ATG not
 only has less acute toxicity, it has less chronic side effects. Cy/ATG is not associated with
 late malignancies or cataracts. Cyclophosphamide and anti-thymocyte globulin (horse or rabbit
 ATG) and rituximab are potent immunosuppressive agents. Rituximab and ATG contribute
 additional immunosuppression without additional cytotoxicity. Rituximab and ATG given shortly
 pre-transplant will contribute to the elimination of host T lymphocytes that survive
 cyclophosphamide or that contaminate the CD34+selected graft. SLE, an autoimmune disease
 responsive to cyclophosphamide, responds well to a Cy/ATG/rituximab conditioning regimen. For
 these reasons, Cy/ATG/rituximab will be the conditioning regimen utilized in this study.

 To justify any new therapy such as HSCT, the risk of dying from the disease must be higher
 than that expected from its treatment, or the morbidities associated with the disease must
 justify the treatment risks. Autologous stem cell transplantation has a mortality of 1-3% in
 breast cancer patients using intense conditioning regimens with multiple alkylating agents,
 and up to 10-15% in patients with lymphomas and other malignancies. The latter patients
 usually have been heavily treated before transplant and the accumulation of treatment
 toxicities is thought to play a role in their increased transplant-related mortality.
 Cyclophosphamide and ATG/rituximab have been used to transplant of extremely ill patients
 with systemic lupus erythematosus and multiple organ dysfunction at Northwestern University
 without mortality.

 Since patients in this study are earlier in the disease course, a conditioning regimen that
 has historically been associated with less toxicity will be employed. The regimen will be
 Cyclophosphamide at 200 mg/kg with ATG 5.5 mg/kg and rituximab 1000 mg divided over 2 doses.
 Cyclophosphamide 200mg/kg with or without ATG has been used safely and effectively in a
 variety of autoimmune diseases including systemic lupus erythematosus, rheumatoid arthritis,
 and aplastic anemia. Rabbit ATG will be used instead of equine ATG due to the lower incidence
 of hypersensitivity and fever with rabbit ATG compared to equine.

 Method of Harvesting Stem Cells Based on the experience of the pilot studies, the current
 protocol will mobilize stem cells with cyclophosphamide and granulocyte-colony stimulating
 factor (G-CSF), and collect stem cells by apheresis, with subsequent bone marrow harvest
 performed only if needed to supplement the peripheral blood stem cells (PBSC). Based on
 experience of autoimmune flares in patients receiving G-CSF alone for mobilization (56),
 patients will be mobilized with cyclophosphamide 2.0 g/m2 and G-CSF 10 mcg /kg.

 Regimen for Autologous HSCT

 Cyclophosphamide Cyclophosphamide is an active agent in patients with a wide variety of
 malignancies. It is used frequently in the therapy of lymphoid malignancies and has potent
 immunosuppressive activity. It is frequently used as a cytotoxic and immunosuppressive agent
 in patients undergoing marrow transplants and as a treatment for patients with autoimmune
 diseases. It is an alkylating agent that requires hepatic metabolism to the active
 metabolites, phosphoramide mustard and acrolein. These active metabolites react with
 nucleophilic groups. It is available as an oral or intravenous preparation. Bioavailability
 is 90% when given orally. The half-life of the parent compound is 5.3 hours in adults, and
 the half-life of the major metabolite phosphoramide mustard is 8.5 hours. Liver or renal
 dysfunction will lead to prolonged serum half-life. CY is administered intravenously at a
 dosage of 50 mg/kg on each of two successive days (use adjusted ideal body weight if
 patient's actual body weight is greater than 100% ideal body weight). The major dose limiting
 side effect at high doses is cardiac necrosis. Hemorrhagic cystitis can occur and is mediated
 by the acrolein metabolite. This can be prevented by co-administration of MESNA or bladder
 irrigation. Other notable side effects include nausea, vomiting, alopecia, myelosuppression
 and SIADH. Refer to institutional manuals for more information about administration, toxicity
 and complications.

 Rabbit-Derived Anti-Thymocyte Globulin (ATG) Rabbit-derived anti-thymocyte globulin (ATG) is
 a gamma globulin preparation obtained from hyperimmune serum of rabbits immunized with human
 thymocytes. ATG has been used predominately in solid organ transplant immunosuppressive
 regimens. ATG is a predominantly lymphocyte-specific immunosuppressive agent. It contains
 antibodies specific to the antigens commonly found on the surface of T cells. After binding
 to these surface molecules, ATG promotes the depletion of T cells from the circulation
 through mechanisms, which include opsonization and complement-assisted, antibody- dependent,
 cell-mediated cytotoxicity. The plasma half-life ranges from 1.5-12 days. ATG is administered
 intravenously at a dose of 0.5 mg/kg recipient body weight on day -6 and a dose of 1.0 mg/kg
 recipient body weight on days -5, -4, -3, -2 and -1. Unlike equine ATG, rabbit ATG does not
 require a pre-infusion skin test to check for hypersensitivity. Methylprednisolone 1 gram
 will be given before every dose of ATG. Additional medications such as diphenhydramine may be
 given at the discretion of the attending physician. Although rare, the major toxicity is
 anaphylaxis. Chills, fever, pruritus or serum sickness may occur.

 Regimen for allogeneic HSCT

 Cyclophosphamide (Cytoxan) Cyclophosphamide (CY) is administered intravenously at a dosage of
 50 mg/kg on each of four successive days (use adjusted ideal body weight if patient's actual
 body weight is greater than 100% ideal body weight). The major dose limiting side effect at
 high doses is cardiac necrosis. Hemorrhagic cystitis can occur and is mediated by the
 acrolein metabolite. This can be prevented by co-administration of MESNA or bladder
 irrigation. Other notable side effects include nausea, vomiting, alopecia, myelosuppression
 and SIADH. Refer to institutional manuals for more information about administration, toxicity
 and complications.

 Fludarabine Fludarabine phosphate is rapidly dephosphorylated to 2-fluoro-ara-A and then
 phosphorylated intracellularly by deoxycytidine kinase to the active triphosphate,
 2-fluoro-ara-ATP. This metabolite appears to act by inhibiting DNA polymerase alpha,
 ribonucleotide reductase and DNA primase, thus inhibiting DNA synthesis. The mechanism of
 action of this antimetabolite is not completely characterized and may be multi-faceted.

 Phase I studies in humans have demonstrated that fludarabine phosphate is rapidly converted
 to the active metabolite, 2-fluoro-ara-A, within minutes after intravenous infusion.
 Consequently, clinical pharmacology studies have focused on 2-fluoro-ara-A pharmacokinetics.
 After the five daily doses of 25 mg 2-fluoro-ara-AMP/m2 to cancer patients infused over 30
 minutes, 2-fluoro-ara-A concentrations show a moderate accumulation. During a 5-day treatment
 schedule, 2-fluoro-ara-A plasma trough levels increased by a factor of about 2. The terminal
 half-life of 2-fluoro-ara-A was estimated as approximately 20 hours. In vitro, plasma protein
 binding of fludarabine ranged between 19% and 29%.

 CAMPATH Campath-1H is a humanized fusion protein that is directed to CD52 antigen that is
 expressed on all lymphocytes, monocytes and macrophages. It has very potent immunosuppressive
 property and is effective for prevention of graft-versus-host disease. 30 mg/day of CAMPATH
 will be given intravenously over 2 hours on days -4, -3 and -2. The most commonly reported
 adverse reactions are infusion reactions fever, chills, hypotension, urticaria, nausea, rash,
 tachycardia, dyspnea), cytopenias (neutropenia, lymphopenia, thrombocytopenia, anemia), and
 infections (CMV viremia, CMV infection, other infections). In clinical trials, the frequency
 of infusion reactions was highest in the first week of treatment. Other commonly reported
 adverse reactions include vomiting, abdominal pain, insomnia and anxiety. The most commonly
 reported serious adverse reactions are cytopenias, infusion reactions, and
 immunosuppression/infections. About 30 minutes before the patient gets Campath, he/she will
 be given other medications (such as acetaminophen or diphenhydramine, given orally, not IV)
 to help reduce side effects.
Inclusion Criteria:

 -  1. Age 16 to 60 years old at the time of pretransplant evaluation.

 -  2. An established diagnosis of systemic necrotizing vasculitis (Wegener's
 granulomatous, polyarteritis nodosum (PAN), allergic angiitis granulomatous (AAG, also
 known as Churg Strauss syndrome), microscopic polyangiitis (MPA), or overlap
 syndrome)Temporal arteritis, or mixed cryoglobulinemia or primary central nervous
 system vasculitis AND failure of corticosteroids and any of the following at least 6
 months of oral or IV cytoxan, rituximab, or cellcept. (Failure defined as: a) patients
 with a high disease activity and involvement of internal organs as measured by
 increased FFS > 2 and/or BVAS > 20, or b) patients who develop recurrent flares with
 subsequent progressive organ damage.)

 OR

 Neurovascular Behcets with recurrent oral and/or genital lesions confirmed by culture to be
 herpes negative, MRI findings consistent with CNS vasculitis, recurrent neurological
 symptoms, and clinical confirmation by a Neurologist (e.g., Dr. Rama Gourimeni) AND failure
 of at least 3 months of oral or IV cytoxan.

 OR

 Pulmonary or neurovascular Sjogrens with positive SSA/SSB confirmed by a rheumatologist and
 neurologist (if CNS involved) or pulmonologist (if lungs involved) and either recurrent
 neurologic attacks or progressive pulmonary compromise (dyspnea on exertion, decreased DLCO
 or CT findings of active disease) despite at least 6 months of intravenous monthly pulse
 cyclophosphamide.

 -  3. Patient eligibility must be confirmed by two Rheumatologists. For patients with
 neurovascular Behcets, eligibility need only be confirmed by a neurologist.

 -  4. A minimum CD34+ cell dose of 2.0 x 10e6/kg post-selection.

 Exclusion Criteria:

 -  1. Significant end organ damage such as:

 1. LVEF <40% or deterioration of LVEF during exercise test on MUGA or echocardiogram
 unless due to active disease.

 2. Untreated life-threatening arrhythmia.

 3. Active ischemic heart disease or heart failure.

 4. DLCO < 40% of predicted value unless due to active disease.

 5. Serum creatinine > 2.5 mg/dl, unless due to active disease.

 6. Liver cirrhosis, transaminases >3x of normal limits, or bilirubin >2.0 unless due
 to Gilberts disease.

 -  2. HIV positive.

 -  3. Uncontrolled diabetes mellitus, or any other illness that in the opinion of the
 investigators would jeopardize the ability of the patient to tolerate aggressive
 treatment.

 -  4. Prior history of malignancy except localized basal cell or squamous skin cancer.
 Other malignancies for which the patient is judged to be cured by local surgical
 therapy, such as (but not limited to) head and neck cancer, or stage I or II breast
 cancer will be considered on an individual basis.

 -  5. Positive pregnancy test, inability or unable to pursue effective means of birth
 control, failure to willingly accept or comprehend irreversible sterility as a side
 effect of therapy.

 -  6. Psychiatric illness or mental deficiency making compliance with treatment or
 informed consent impossible.

 -  7. Inability to give informed consent.

 -  8. Active infection, excluding asymptomatic bacteruria or vaginal candidiasis.

 -  9. Active hepatitis B (HBSAg positive) or active hepatitis C (PCR positive blood
 lymphocytes).