Responses To Lmb2 In Hcl Patients

All four patients with HCL, who had failed at least cladribine and interferon, had major responses.69 Patient 30 [see Figure 33.2(a)] prior to treatment had pancytopenia, with a pretransfusion hemoglobin as low as 8.5 g/dL, a platelet count of 47,000/mm3, an absolute neutrophil count (ANC) of 360/mm3, and an enlarged spleen and precarinal lymph nodes. The pan-cytopenia resolved with elimination of the tumor cells. The hairy cell count of 478/^L decreased >90% from just one dose of LMB-2, as assessed on day 3. By day 8, the HCL count had decreased by >99%, and was cleared following cycle 2. Flow cytometry is able to quantify HCL cells making up <0.01% of the lymphocytes. The CR in patient 30 was associated with resolution of baseline splenomegaly and precarinal adenopa-thy, and transfusion independence. Recovery of normal counts is shown in Figure 33.2(a), with the platelet count first to recover, improving from a pre-treatment baseline of 53,000-133,000/^L by day 22.

The granulocyte count improved next, from a baseline of 390-1430/^L by 66 days after beginning LMB-2. The hemoglobin improved to normal by 150 days, and has remained above 11 for >6 years without further treatment. Three patients had PR to LMB-2 after one cycle of 30, 63, and 40 ^g/kg q.o.d. X 3, with >98-99.8% decreases in circulating HCL cells. CR was not achieved in these patients, probably because they could not be effectively retreated.

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