Efficacy and tolerability of Alemtuzumab (CAMPATH-1H) in the salvage treatment of B-cell chronic lymphocytic leukemia -: Change of regimen needed?

We report on the response rate and tolerability of Alemtuzumab (Campath-1H) in a series of heavily pretreated patients with B-CLL with a special focus on treatment-related problems. All patients tested positive for CD52 on B-lymphocytes before entering the trial. Thirteen patients with B-chronic lymphocytic leukemia (B-CLL), 1 prolymphocytic leukemia (PLL), 1 mantle cell lymphoma (MCL) and 1 leukemic immunocytoma (IC) transformed into a high-grade NHL were included. Median age was 62 years (range 40 - 73), and pretreatment consisted of median 3 prior regimens (range 1-11). All patients received 3, 10 and 30 mg of Campath-1H on sequential days, and then were subsequently scheduled for 30 mg 3 times weekly. Nine out of 16 patients responded. One patient attained complete remission (CR), 8 patients achieved partial remission (PR), while 4 patients had stable disease (SD). Three patients had progressive disease (PD). Beginning with initiation of treatment recurrent profound leukopenia became evident in 13 out of 16 patients leading to treatment discontinuation. Severe nonhematological toxicity (WHO grade IV bronchospasm) occurred in the first patient of this series, who initially had no concomitant steroids. Therefore, we developed a steroid co-medication regimen for the first 4 Campath-1H applications with quick tapering thereafter. Following this regimen, no infusion associated side effects WHO grade > II were observed. Infectious complications leading to treatment discontinuation consisted of pulmonary aspergillosis in one and bacterial pneumonia in another case. One patient with refractory B-CLL and Pneumocystis carinii pneumonia plus CMV reactivation died. In summary, Campath-1H appears to be effective against leukemic low-grade B-NHL, also in advanced stage. In our series, application 3 times weekly was not possible due to hematotoxicity. We recommend, therefore, flexible time intervals depending on the leukocyte counts. Whether a cumulative dosage according to 3 x 30 mg Campath-1H for 12 weeks is needed still remains to be clarified.