LEUKOCYTAPHERESIS TREATMENT FOR PATIENTS WITH ACUTE LEUKEMIA ANDBLAST CRISIS ENABLES A HIGH PERCENTAGE OF PATIENTS TO UNDERGO INDUCTION CHEMOTHERAPY. JC Hofmann1,2, SJ Smith1, DD Kiprov1,2. 1Apheresis Care Group, Fresenius Apheresis Services, and2Division of Immunotherapy, CaliforniaPacificMedicalCenter, San Francisco, CA.
Introduction: Several retrospective, cohort studies have demonstrated that leukocytapheresis (leukapheresis) treatment in patients (pts) with acute leukemia and blast crisis decreases short-term mortality rate, but does not increase overall survival. However, pts selected in these studies for leukapheresis treatment are often sicker and have a higher underlying mortality rate (than pts who do not receive such treatment). No randomized controlled trial assessing the efficacy of leukapheresis in acute leukemia has been performed, and given the current standard of care it is ethically unlikely that such a trial will be conducted.
Methods and Clinical Presentation: Between January, 2006 and September, 2009, Apheresis Care Group (ACG) treated 1,363 pts performing 11,324 therapeutic apheresis treatments (txs). Of this patient cohort, 107 (7.9%) pts had acute leukemia with clinical and/or laboratory evidence of blast crisis and received leukapheresis treatment. 65 pts had acute myelogenous leukemia (AML) and received 149 leukapheresis txs; 42 pts had acute lymphoblastic leukemia (ALL) and received 135 txs. AML pts presented with median WBC 200 x 109/L (range 66-408 x 109/L) and 86% pts had blast crisis (defined as blast percent >75% or blast count >100 x 109/L). Median age was 56 years (6.5-85 years); 63% pts were male. Of CNS or pulmonary symptoms (sxs) of leukostasis (CNS sxs defined as: headache, lethargy, confusion, or visual abnormalities; pulmonary sxs defined as: shortness of breath, hypoxia, or chest x-ray infiltrates without evidence of pneumonia), 14% pts had no sxs, 52% pts had 1 sx, and 34% pts had 2 sxs. ALL pts presented with median WBC 325 x 109/L (104-736 x 109/L) and 83% pts had blast crisis. Median age was 23 years (4-80 years); 65% pts were male. Of sxs of leukostasis, 24% pts had no sxs, 64% pts had 1 sx, and 12% pts had 2 sxs.
Treatment: All pts received a course of leukapheresis (Lp) with the following objectives: 1) decreasing the risk of thrombotic and hemorrhagic complications related to leukostasis, and 2) stabilizing pts for induction chemotherapy. WBC treatment goals were defined as: WBC count (ct) <55 x 109/L for AML pts, and WBC ct <80 x 109/L for ALL pts. AML pts received a median of 2 Lp txs (range 1-5 txs); ALL pts underwent a median of 2 Lp txs (1-7 txs).
Results: Outcomes were evaluated by the percentage of pts who: 1) reached the WBC treatment goal and, 2) received induction chemotherapy. “Improved” outcome was defined as pts who reached their WBC treatment goal during leukapheresis therapy; “stabilized” was defined as pts who achieved >50% reduction in WBC ct, but did not reach their WBC goal; and “unchanged” was defined as pts who achieved neither. In the AML cohort, 77% pts improved, 22% pts stabilized, and 1% pts were unchanged. In the ALL cohort, 64% pts improved, 33% pts stabilized, and 3% pts were unchanged. For AML pts, the median final WBC ct was 51 x 109/L (range 17-133 x 109/L)and 92% pts received induction chemotherapy. For ALL pts, the median final WBC ct was 74 x 109/L (range 30-294 x 109/L)and 98% pts received induction chemotherapy. 6 (9%) AML pts and 1 (2%) ALL pt expired within 1-4 days after completing course of leukapheresis. Of the 7 expired pts, 71% had both blast crisis and 2 sxs of leukostasis; 43% had intracranial hemorrhage or CVA;and 86% were hypotensive, receiving mechanical ventilation, and unable to tolerate induction chemotherapy.
Conclusion: Carefully selected patients with acute leukemia and evidence of impending thrombosis benefit significantly from leukapheresis therapy. A limited number of treatments (median of 2 treatments) can enable a high percentage of patients to receive induction chemotherapy and may improve short-term clinical outcomes (in patients with a high underlying mortality rate). Leukapheresis treatments are considered emergency procedures as they are often life saving.
Hofmann JC, Smith SJ, Kiprov DD. “Leukocytapheresis treatment for patients with acute leukemia and blast crisis enables a high percentage of patients to undergo induction chemotherapy.” J Clin Apheresis 2010; 25 (1): 4-5. Presented in the plenary oral presentation at the 31st Annual Meeting of the American Society For Apheresis on May 27th, 2010 in New Orleans, LA.
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