Phase II Trial to Evaluate the Role of PEG L-Asparaginase in Multiple Myeloma
Therapy for Multiple Myeloma has not changed the patient survival or response since the introduction of Melphalan and Prednisone in the early 1960's. L-Asparaginase is an enzyme that depletes L-Asparagine "an important nutrient for cancer cells" resulting in cancer cell starvation and death. The drug used in this regimen ( PEG L-Asparaginase, ONCOSPAR®) is approved by the Food and Drug Administration (FDA) and is commercially available.
Diagnosis of multiple myeloma.
Relapsed or refractory multiple myeloma of any stage.
ECOG performance status of less than or equal to 2.
18 years or older.
Signed consent form.
Patient with overt or active infection requiring IV antibiotics.
Patients who have received any chemotherapeutic regimen <4 weeks prior to therapy and blood counts have not recovered.
Total bilirubin > 2.0 gm/dl, SGOT, or SGPT > 3 x ULN.
Prior thrombotic disorder.
Previous radiation therapy to areas encompassing the pancreas with doses 25 cGY
Prior treatment with Asparaginase.
Elevated PT or PTT (> 1.5 x normal).
Platelets < 50,000.
Patients with pancreatitis or a history of pancreatitis.
Patients on anticoagulant therapy with coumarin, heparin, aspirin, dipyridamole.
Patients with CHF or history of CHF less than 6 months prior to planned therapy.
Advances in the therapy for Multiple Myeloma over the past 30 years have resulted in increasing survival from less than 1 year without therapy to more than 3 years with therapy. Agents which include alkylator, steroids, natural products and biological response modifiers have proven to result in a response rate of about 60% with initial therapy and survival at a median duration of 48 months (1-3). Unfortunately, patients who do not respond to initial therapy are not likely to respond to other types of therapy and have a survival rate of around 15 months. Multiple Myeloma remains a disease to which cure is a rarity, despite the advances in therapy.
Role of L-Asparaginase in Myeloma:
Because of the lymph node origin of malignant B cells in Multiple Myeloma, L-Asparagine may be an essential amino acid for their cell metabolism, and, consequently, L-Asparaginase may be of value in managing the disease. Ohnuma, T. et al have studied the L-Asparagine requirements of human T-lymphocytes and B lymphocytes in vitro. They demonstrated that T-cells were 800 to 2000 times more sensitive to E. coli L-Asparaginase than were B cells. The cytotoxic effects of a high concentration of L-Asparaginase on B cells were not related to the hydrolysis of L-Asparagine but were due to heat labile and heat resistant substances in the enzyme (4). Clinical data employing L-Asparaginase in myeloma patients is very limited. In a study published by Chauduri TK, et al, 14CO2 excretion in the breath was measured after IV administration of 14C-labeled L-Asparagine to two patients with plasmablastic myeloma and lymphoblastic leukemia. Excretion was measured before and after therapy with L-Asparaginase The two patients demonstrated increased 14C02 excretion following14C-Asparagine administration, after therapy compared with before therapy with L-Asparaginase. Preclinical data suggest myeloma cells may be sensitive to L-Asparaginase, but clinical trials investigating its efficacy are limited and inconclusive (5-7)
The humoral immune system:
The humoral immune system is usually compromised in-patients who have multiple myeloma. It could be hypothesized that allergic and anaphylactic reactions to L-Asparaginase would be decreased. (8)
Page Last Updated 08/12/2003 07:23:42 PM