Phase III randomized multicenter study of a humanized anti-CD33 monoclonal antibody, lintuzumab, in combination with chemotherapy, versus chemotherapy alone in patients with refractory or first-relapsed acute myeloid leukemia.

PURPOSE: Lintuzumab (HuM195) is an unconjugated humanized murine monoclonal antibody directed against the cell surface myelomonocytic differentiation antigen CD33. In this study, the efficacy of lintuzumab in combination with induction chemotherapy was compared with chemotherapy alone in adults with first relapsed or primary refractory acute myeloid leukemia (AML). PATIENTS AND METHODS: Patients with relapsed or primary resistant AML (duration of first response, zero to 12 months) were randomly assigned to receive either mitoxantrone 8 mg/m(2), etoposide 80 mg/m(2), and cytarabine 1 g/m(2) daily for 6 days (MEC) in combination with lintuzumab 12 mg/m(2), or MEC alone. Overall response, defined as the rate of complete remission (CR) and CR with incomplete platelet recovery (CRp), was the primary end point of the study, with additional analyses of survival time and toxicity. RESULTS: A total of 191 patients were randomly assigned from November 1999 to April 2001. The percent CR plus CRp with MEC plus lintuzumab was 36% v 28% in patients treated with MEC alone (P = .28). The overall median survival was 156 days and was not different in the two arms of the study. Apart from mild antibody infusion-related toxicities (fever, chills, and hypotension), no differences in chemotherapy-related adverse effects, including hepatic and cardiac dysfunction, were observed with the addition of lintuzumab to induction chemotherapy. CONCLUSION: The addition of lintuzumab to salvage induction chemotherapy was safe, but did not result in a statistically significant improvement in response rate or survival in patients with refractory/relapsed AML.

Bortezomib, liposomal doxorubicin and dexamethasone followed by thalidomide and dexamethasone is an effective treatment for patients with newly diagnosed multiple myeloma with Internatinal Staging System stage II or III, or extramedullary disease.

We evaluated sequential bortezomib, liposomal doxorubicin and dexamethasone (BDD) followed by thalidomide and dexamethasone (TD) if ≥ partial response (PR) or bortezomib and TD (BTD) if < PR in untreated patients with multiple myeloma with International Staging System stage II/III or extramedullary disease. Of the 42 patients enrolled, two-thirds had cytogenetic abnormalities including high-risk findings [del(13q) by karyotype, t(4;14), loss of p53 or gain 1q] in one-third. After the planned three cycles of BDD, the overall response rate (ORR) was 81% with 40% ≥ very good partial response (VGPR), including 26% near complete and complete responses (nCR/CR). After the additional two cycles of TD or BTD, ORR was 83% with 60% ≥ VGPR including 43% nCR/CR, indicating deeper responses following sequential therapy (p = 0.008). Two-thirds of patients who presented with significant renal impairment had improved renal function. All patients undergoing stem cell harvest had a successful collection. BDD followed by TD or BTD is effective initial therapy for this population with higher-risk myeloma and results in rapid disease control and a high response rate.

High dose cytarabine plus gemtuzumab ozogamicin for patients with relapsed or refractory acute myeloid leukemia: Cancer and Leukemia Group B study 19902.

Gemtuzumab ozogamicin (GO), an anti-CD33 immunoconjugate, was combined with high dose cytarabine (HiDAC; cytarabine 3g/m(2) over 3h daily for 5 days) for adults with relapsed or refractory AML. HiDAC plus GO 9mg/m(2) on day 7 and 4.5mg/m(2) on day 14 was not tolerated, but HiDAC followed by GO 9mg/m(2) on day 7 was safe: 12/37 (32%) patients with relapsed AML achieved complete remission. Median overall survival was 8.9 months. No grade 4 hepatic veno-occlusive disease was observed. This regimen merits further study, both in this setting and as a remission consolidation therapy.

Phase I trial of weekly and twice-weekly bortezomib with rituximab, cyclophosphamide, and prednisone in relapsed or refractory non-Hodgkin lymphoma.

PURPOSE: To determine the safety and efficacy of substituting weekly or twice-weekly bortezomib for vincristine in the R-CVP (rituximab, cyclophosphamide, vincristine, and prednisone) regimen in patients with relapsed/refractory indolent and mantle cell lymphoma (MCL). EXPERIMENTAL DESIGN: Of the 57 patients in this phase I trial, 55 participated in 1 of 2 dosing schedules that included rituximab (375 mg/m(2)) and cyclophosphamide (750 or 1,000 mg/m(2)) administered on day 1 of each 21-day cycle and prednisone (100 mg orally) days 2 to 6. In the once-weekly schedule, bortezomib was administered on days 2 and 8; on the twice-weekly schedule, bortezomib was given on days 2, 5, 9, and 12. Bortezomib and cyclophosphamide were alternately escalated. A separate cohort of 10 patients in the twice-weekly schedule received concurrent pegfilgrastim (PegG) on day 2. RESULTS: Both schedules of R-CBorP (rituximab, cyclophosphamide, bortezomib, and prednisone) were well tolerated. Most toxicities across all dose levels and cycles were grade 1 or 2. The overall response rates for patients on the weekly (n = 13) and twice-weekly (n = 33) schedules were 46% [23% complete response/complete response unconfirmed (CR/CRu)] and 64% (36% CR/CRu), respectively. Concurrent PegG did not increase hematologic toxicities in this regimen. A randomized phase II study is under way to further compare toxicity and efficacy of the 2 dosing schedules. CONCLUSIONS: R-CBorP is a safe and effective regimen in patients with relapsed/refractory indolent and MCLs. Most toxicities were grade 1 or 2, and a promising response rate was seen in this phase I study.

B-cell chronic lymphocytic leukemia cells express a surface membrane phenotype of activated, antigen-experienced B lymphocytes.

B-cell chronic lymphocytic leukemia (B-CLL) is considered an accumulative disease of antigen-naive CD5(+) B lymphocytes that circulate in the resting state. However, to evaluate the possibility that B-CLL cells resemble antigen-experienced and activated B cells, we analyzed the expression of markers of cellular activation and differentiation on CD5(+)CD19(+) cells from B-CLL patients and from age-matched healthy donors. The leukemic cells from all B-CLL patients, including those that lack significant numbers of V gene mutations, bear the phenotype of activated B cells based on the overexpression of the activation markers CD23, CD25, CD69, and CD71 and the underexpression of CD22, Fcgamma receptor IIb, CD79b, and immunoglobulin D that are down-regulated by cell triggering and activation. Furthermore, these leukemic cells resemble antigen-experienced lymphocytes in the underexpression of molecules that are down-regulated by cell triggering and in the uniform expression of CD27, an identifier of memory B cells. A comparison of the phenotypes of B-CLL patients with and without immunoglobulin V gene mutations suggests that the 2 subgroups differ both in specific marker expression (CD69, CD71, CD62 L, CD40, CD39, and HLA-DR) and in the time since antigenic stimulation, based on the reciprocal relationship of CD69 and CD71 expression. These findings imply that the leukemic cells from all B-CLL cases (irrespective of V gene mutations) exhibit features of activated and of antigen-experienced B lymphocytes and that the B-CLL cells that differ in immunoglobulin V genotype may have different antigen-encounter histories.