Constantine S. Tam

Ibrutinib versus ofatumumab in previously treated chronic lymphoid leukemia

BACKGROUND In patients with chronic lymphoid leukemia (CLL) or small lymphocytic lymphoma (SLL), a short duration of response to therapy or adverse cytogenetic abnormalities are associated with a poor outcome. We evaluated the efficacy of ibrutinib, a covalent inhibitor of Brutons tyrosine kinase, in patients at risk for a poor outcome. METHODS In this multicenter, open-label, phase 3 study, we randomly assigned 391 patients with relapsed or refractory CLL or SLL to receive daily ibrutinib or the anti-CD20 antibody ofatumumab. The primary end point was the duration of progression-free survival, with the duration of overall survival and the overall response rate as secondary end points. RESULTS At a median follow-up of 9.4 months, ibrutinib significantly improved progression-free survival; the median duration was not reached in the ibrutinib group (with a rate of progression-free survival of 88% at 6 months), as compared with a median of 8.1 months in the ofatumumab group (hazard ratio for progression or death in the ibrutinib group, 0.22; P<0.001). Ibrutinib also significantly improved overall survival (hazard ratio for death, 0.43; P=0.005). At 12 months, the overall survival rate was 90% in the ibrutinib group and 81% in the ofatumumab group. The overall response rate was significantly higher in the ibrutinib group than in the ofatumumab group (42.6% vs. 4.1%, P<0.001). An additional 20% of ibrutinib-treated patients had a partial response with lymphocytosis. Similar effects were observed regardless of whether patients had a chromosome 17p13.1 deletion or resistance to purine analogues. The most frequent nonhematologic adverse events were diarrhea, fatigue, pyrexia, and nausea in the ibrutinib group and fatigue, infusion-related reactions, and cough in the ofatumumab group. CONCLUSIONS Ibrutinib, as compared with ofatumumab, significantly improved progression-free survival, overall survival, and response rate among patients with previously treated CLL or SLL. (Funded by Pharmacyclics and Janssen; RESONATE ClinicalTrials.gov number, NCT01578707.).

Long-term results of the fludarabine, cyclophosphamide, and rituximab regimen as initial therapy of chronic lymphocytic leukemia

Early results of the fludarabine, cyclophosphamide, and rituximab (FCR) regimen in 224 patients showed that it was highly active as initial therapy of chronic lymphocytic leukemia. In this report, we present the final results of all 300 study patients at a median follow up of 6 years. The overall response rate was 95%, with complete remission in 72%, nodular partial remission in 10%, partial remission due to cytopenia in 7%, and partial remission due to residual disease in 6%. Two patients (< 1%) died within 3 months of starting therapy. Six-year overall and failure-free survival were 77% and 51%, respectively. Median time to progression was 80 months. Pretreatment characteristics independently associated with inferior response were age 70 years or older, beta2-microglobulin twice the upper limit of normal (2N) or more, white cell count 150 x 10(9)/L or more, abnormal chromosome 17, and lactate dehydrogenase 2N or more. No pretreatment characteristic was independently associated with decreased complete remission duration. The risk of late infection was 10% and 4% for the first and second years of remission, respectively, and less than 1.5% per year for the third year onward. In a multivariate analysis of patients receiving fludarabine-based therapy at our center, FCR therapy emerged as the strongest independent determinant of survival.

Ibrutinib as Initial Therapy for Patients with Chronic Lymphocytic Leukemia

BACKGROUND Chronic lymphocytic leukemia (CLL) primarily affects older persons who often have coexisting conditions in addition to disease-related immunosuppression and myelosuppression. We conducted an international, open-label, randomized phase 3 trial to compare two oral agents, ibrutinib and chlorambucil, in previously untreated older patients with CLL or small lymphocytic lymphoma. METHODS We randomly assigned 269 previously untreated patients who were 65 years of age or older and had CLL or small lymphocytic lymphoma to receive ibrutinib or chlorambucil. The primary end point was progression-free survival as assessed by an independent review committee. RESULTS The median age of the patients was 73 years. During a median follow-up period of 18.4 months, ibrutinib resulted in significantly longer progression-free survival than did chlorambucil (median, not reached vs. 18.9 months), with a risk of progression or death that was 84% lower with ibrutinib than that with chlorambucil (hazard ratio, 0.16; P<0.001). Ibrutinib significantly prolonged overall survival; the estimated survival rate at 24 months was 98% with ibrutinib versus 85% with chlorambucil, with a relative risk of death that was 84% lower in the ibrutinib group than in the chlorambucil group (hazard ratio, 0.16; P=0.001). The overall response rate was higher with ibrutinib than with chlorambucil (86% vs. 35%, P<0.001). The rates of sustained increases from baseline values in the hemoglobin and platelet levels were higher with ibrutinib. Adverse events of any grade that occurred in at least 20% of the patients receiving ibrutinib included diarrhea, fatigue, cough, and nausea; adverse events occurring in at least 20% of those receiving chlorambucil included nausea, fatigue, neutropenia, anemia, and vomiting. In the ibrutinib group, four patients had a grade 3 hemorrhage and one had a grade 4 hemorrhage. A total of 87% of the patients in the ibrutinib group are continuing to take ibrutinib. CONCLUSIONS Ibrutinib was superior to chlorambucil in previously untreated patients with CLL or small lymphocytic lymphoma, as assessed by progression-free survival, overall survival, response rate, and improvement in hematologic variables. (Funded by Pharmacyclics and others; RESONATE-2 ClinicalTrials.gov number, NCT01722487.).

Mature results of the M. D. Anderson Cancer Center risk-adapted transplantation strategy in mantle cell lymphoma

In this study, we analyzed the long-term outcome of a risk-adapted transplantation strategy for mantle cell lymphoma in 121 patients enrolled in sequential transplantation protocols. Notable developments over the 17-year study period were the addition of rituximab to chemotherapy and preparative regimens and the advent of nonmyeloablative allogeneic stem cell transplantation (NST). In the autologous transplantation group (n = 86), rituximab resulted in a marked improvement in progression-free survival for patients who received a transplant in their first remission (where a plateau emerged at 3-8 years) but did not change the outcomes for patients who received a transplant beyond their first remission. In the NST group, composed entirely of patients who received a transplant beyond their first remission, durable remissions also emerged in progression-free survival at 5 to 9 years. The major determinants of disease control after NST were the use of a peripheral blood stem cell graft and donor chimerism of at least 95%, whereas the major determinant of death was immunosuppression for chronic graft-versus-host disease. Our results show that long-term disease-free survival in mantle cell lymphoma is possible after rituximab-containing autologous transplantation for patients in first remission and after NST for patients with relapsed or refractory disease.

Fludarabine, cyclophosphamide, and rituximab treatment achieves long-term disease-free survival in IGHV-mutated chronic lymphocytic leukemia.

Accurate identification of patients likely to achieve long-progression-free survival (PFS) after chemoimmunotherapy is essential given the availability of less toxic alternatives, such as ibrutinib. Fludarabine, cyclophosphamide, and rituximab (FCR) achieved a high response rate, but continued relapses were seen in initial reports. We reviewed the original 300 patient phase 2 FCR study to identify long-term disease-free survivors. Minimal residual disease (MRD) was assessed posttreatment by a polymerase chain reaction-based ligase chain reaction assay (sensitivity 0.01%). At the median follow-up of 12.8 years, PFS was 30.9% (median PFS, 6.4 years). The 12.8-year PFS was 53.9% for patients with mutated immunoglobulin heavy chain variable (IGHV) gene (IGHV-M) and 8.7% for patients with unmutated IGHV (IGHV-UM). 50.7% of patients with IGHV-M achieved MRD-negativity posttreatment; of these, PFS was 79.8% at 12.8 years. A plateau was seen on the PFS curve in patients with IGHV-M, with no relapses beyond 10.4 years in 42 patients (total follow-up 105.4 patient-years). On multivariable analysis, IGHV-UM (hazard ratio, 3.37 [2.18-5.21]; P < .001) and del(17p) by conventional karyotyping (hazard ratio, 7.96 [1.02-61.92]; P = .048) were significantly associated with inferior PFS. Fifteen patients with IGHV-M had 4-color MRD flow cytometry (sensitivity 0.01%) performed in peripheral blood, at a median of 12.8 years posttreatment (range, 9.5-14.7). All were MRD-negative. The high rate of very long-term PFS in patients with IGHV-M after FCR argues for the continued use of chemoimmunotherapy in this patient subgroup outside clinical trials; alternative strategies may be preferred in patients with IGHV-UM, to limit long-term toxicity.

De novo deletion 17p13.1 chronic lymphocytic leukemia shows significant clinical heterogeneity: the M. D. Anderson and Mayo Clinic experience

To determine the clinical fate of patients with de novo deletion 17p13.1 (17p-) chronic lymphocytic leukemia (CLL), we retrospectively studied the outcome of 99 treatment-naive 17p- CLL patients from the M. D. Anderson Cancer Center (n = 64) and the Mayo Clinic (n = 35). Among 67 asymptomatic patients followed for progression, 53% developed CLL requiring treatment over 3 years. Patients who had not progressed by 18 months subsequently had stable disease, with 3 of 19 patients progressing after follow-up of up to 70 months. Risk factors for progressive disease were Rai stage of 1 or higher and unmutated immunoglobulin variable region heavy chain (IgVH). The overall survival rate was 65% at 3 years. Rai stage 1 or higher, unmutated IgVH, and 17p- in 25% or more of nuclei were adverse factors for survival. The 3-year survival rates of patients with 1 or fewer, 2, and 3 of these factors were 95%, 74%, and 22%, respectively (P < .001). Response rates to therapy with rituximab (n = 6); purine analogues and rituximab (n = 25); and purine analogues, rituximab, and alemtuzumab (n = 16) combinations were 50%, 72%, and 81%, respectively. Patients with 17p- CLL exhibit clinical heterogeneity, with some patients experiencing an indolent course. Survival can be predicted using clinical and biologic characteristics.

Failure to achieve a major cytogenetic response by 12 months defines inadequate response in patients receiving nilotinib or dasatinib as second or subsequent line therapy for chronic myeloid leukemia

To determine when patients with incomplete responses on second-line tyrosine kinase inhibitor (2TKI) therapy should consider alternative treatment, we analyzed the outcome of 113 patients receiving nilotinib (n = 43) or dasatinib (n = 70) after imatinib failure. After 12 months of 2TKI therapy, patients achieving a major cytogenetic response (12MMCyR) had a significant survival advantage over patients in minor cytogenetic response or complete hematologic response, with a projected one-year survival of 97% and 84% respectively (P = .02). Projected 1-year progression to hematologic failure, accelerated phase, or blast phase was also significantly different (3% vs 17%, P = .003). Early cytogenetic response was strongly predictive of achievement of 12MMCyR, with less than 10% of patients showing no cytogenetic response at 3 to 6 months eventually attaining the target of 12MMCyR. These results suggest that patients receiving 2TKI with no cytogenetic response at 3 to 6 months should be considered for alternative therapies.

Long-term outcome of patients with chronic myeloid leukemia treated with second-generation tyrosine kinase inhibitors after imatinib failure is predicted by the in vitro sensitivity of BCR-ABL kinase domain mutations.

Secondary imatinib resistance in chronic myeloid leukemia (CML) is associated in approximately 50% of cases with mutations in the BCR-ABL kinase domain, necessitating switch to one of several new tyrosine kinase inhibitors (TKIs) that act differentially on mutated BCR-ABL. We assess here whether scoring mutation based on in vitro inhibitory concentration of each TKI-mutation pair can predict long-term clinical outcome. Among 169 patients with CML after imatinib failure, mutations were detected before TKI switch in 41 (48%) treated with dasatinib and 45 (52%) treated with nilotinib. Inhibitory concentration values for each TKI-mutation pair were stratified into high (n = 42), intermediate (n = 25), low (T315I, n = 9), or unknown sensitivity (n = 10). Hematologic and cytogenetic response rates were similar for patients with or without mutations. For patients in chronic phase, hematologic and cytogenetic responses correlated with mutation score; tumors with low and intermediate scores had lower response rates than those with highly sensitive mutations, and worse event-free and overall survival. These correlations with overall survival were not seen for advanced phases. Mutation scoring can predict outcome in CML-chronic phase with imatinib failure treated with second-generation TKIs and can help in therapy selection. More complex prognostic models will be required for advanced stages of disease.

Ibrutinib treatment affects collagen and von Willebrand factor-dependent platelet functions.

The oral Brutons tyrosine kinase inhibitor, ibrutinib, has recently demonstrated high efficiency in patients with relapsed B-cell malignancies. Occurrence of bleeding events has been reported in a subgroup of ibrutinib-treated patients. We demonstrate that ibrutinib selectively inhibits platelet signaling and functions downstream of the collagen receptor glycoprotein VI and strongly affects firm platelet adhesion on von Willebrand factor (VWF) under arterial flow. A longitudinal study of 14 patients indicated a correlation between occurrence of bleeding events and decreased platelet aggregation in response to collagen in platelet-rich plasma and firm adhesion on VWF under arterial flow. The addition of 50% untreated platelets was sufficient to efficiently reverse the effects of ibrutinib, and platelet functions recovered after treatment interruption as physiological platelet renewal occurred. These data have important clinical implications and provide a basis for hemostasis management during ibrutinib treatment.

The natural history and treatment outcome of blast phase BCR-ABL- myeloproliferative neoplasms.

We analyzed the outcomes of 74 patients diagnosed with BCR-ABL(-) myeloproliferative neoplasms in blast phase receiving induction chemotherapy (55%), low-intensity therapy (16%), stem cell transplantation (SCT; 3%), or supportive care (26%). Median survival from the date of blastic transformation was 5 months. Patients receiving supportive therapy had a median survival of 6 weeks. Complete remission with or without blood recovery was achieved in 46% of patients receiving induction chemotherapy, but remissions were not durable with a median progression-free survival of only 5 months. Eight patients received SCT either as first therapy or after responding to antileukemia therapy. These patients had a markedly superior survival, with 73% alive at a median follow-up of 31 months. JAK2V617F kinetics were assessed in 16 patients: 0 of 4 negative patients became positive at transformation, and among 12 positive patients, 1 had an increase in JAK2V617F% at transformation, 7 had a substantial decrease, and 4 had stable levels. Myeloproliferative neoplasm blast phase is associated with a dismal prognosis. Responses to chemotherapy can be achieved but are not durable. Long-term survivors had all received SCT either as first therapy or in first remission.