Response to dasatinib in a patient with concomitant chronic myeloid leukemia and chronic lymphocytic leukemia

Combined chronic myeloid leukaemia and chronic lymphocytic leukaemia in five patients, including one with 17p deletion

We report a series of five Australian cases of chronic lymphocytic leukaemia (CLL) occurring concurrently with chronic myeloid leukaemia (CML). Patient management including therapies and response together with clinical progress was obtained from medical records and laboratory information systems. Prior to CML diagnosis, all five had a preceding diagnosis of CLL. Three had received prior fludarabine. All received tyrosine kinase inhibitors (TKI). None required subsequent therapy for CLL. One patient had 17p deletion CLL and another patient had normal CLL cytogenetics. All currently have satisfactory blood counts with quantitative polymerase chain reaction for CML showing molecular response. All remain alive. Thus, such cases can be successfully managed by treating each haematological disorder in the usual manner. The control achieved in CML with the TKI enables satisfactory marrow function to recover in patients with concomitant CLL. The role for allograft in patients with dual malignancies is uncertain and needs to be individualised depending on control of each malignancy.

In vivo, ex vivo and in vitro dasatinib activity in chronic lymphocytic leukemia

Dasatinib inhibits the breakpoint cluster region-Abelson murine leukemia 1 (BCR-ABL1) gene along with other kinases known to be overexpressed and abnormally active in patients with chronic lymphocytic leukemia (CLL). The current study used primary leukemic cells obtained from 53 patients with CLL that were treated with dasatinib. A 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) assay and Annexin V staining was performed to assess the cytotoxic effects of dasatinib treatment. The XTT assay revealed that the median cytotoxicity of dasatinib was 8.30% (range, 0.00–77.89%). Due to high dispersion of dasatinib activity, patients were divided into sensitive (n=27; 50.94%; median cytotoxicity, 22.81%) and resistant groups (n=26; 49.06%; median cytotoxicity, 0.00%). A median cytotoxicity of 8.30% was selected as a cut off value. Using Annexin V staining and flow cytometry on exemplary sensitive and resistant CLL samples, it was revealed that 17.71 and 1.84% of cells were apoptotic, respectively. The current study presented a case of a patient with concomitant occurrence of CLL and chronic myeloid leukemia (CML) with a major molecular response after dasatinib treatment. A simultaneous reduction of circulating CLL cells indicated in vivo anti-CLL activity induced by dasatinib. After an in vitro culture of the patient's mononuclear cells with subsequent dasatinib treatment, a higher percentage of CLL cells undergoing apoptosis was obsevered when compared with untreated samples (38.19 vs. 21.99%, respectively). Similarly, the percentage of CLL apoptotic cells (ΔΨm^low) measured by chloromethyl-X-rosamine was higher after incubation with dasatinib (7.28%) than in the negative control (2.86%). In conclusion, dasatinib induced antileukemic effects against CML and CLL cells. The results of the current study indicated that dasatinib may induce apoptosis ex vivo, in vitro and in vivo in CLL.

Chronic Myelogenous Leukemia Diagnosed in the Setting of Untreated Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

Chronic myeloid leukemia (CML) is rarely reported to occur in treated chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). In this article, we report a woman in her 70s, diagnosed with CLL/SLL in 2000, untreated, who subsequently presented 12 years later with de novo CML, BCR-ABL1+. Her IGHV mutated CLL/SLL based on the initial sample in our laboratory showed homozygous and heterozygous 13q14.3 deletions, whereas her CML, at presentation, showed a 46,XX,t(9;22)(q34;q11.2)[7]/46,XX[18] karyotype with a p190 BCR-ABL1 transcript. The tumor burden of each clone varied with treatment, including when treated with dasatinib, used to target both clones. In addition, the cytogenetic abnormalities evolved over time and treatments and included acquisition of an extra chromosome 8 in the CML clone and a novel K1992T ATM missense mutation (47% allele frequency) in the CLL/SLL clone. The patient's last bone marrow biopsy, 5 years after her CML diagnosis and 17 years after the CLL/SLL diagnosis, showed residual CML with extensive involvement by CLL/SLL (80%). Cytogenetic studies showed a 46,XX karyotype, while FISH identified 13q14.3 deletion and the BCR-ABL1 translocation in the CLL/SLL and CML clones, respectively. To date, this is the fourth case of concurrent CML, BCR-ABL1+ arising in untreated CLL/SLL. Here we show dynamic variation in the size of the 2 clonal processes reflecting the variable responsiveness to specific therapies. In addition to the unusual BCR-ABL1+ p190 transcript in the patient's CML, a novel ATM K1992T mutation was identified in the CLL/SLL population.

B-Cell Chronic Lymphocytic Leukemia with 11q22.3 Rearrangement in Patient with Chronic Myeloid Leukemia Treated with Imatinib

The coexistence of two diseases chronic myeloid leukemia (CML) and B-cell chronic lymphocytic leukemia (B-CLL) is a rare phenomenon. Both neoplastic disorders have several common epidemiological denominators (they occur more often in men over 50 years of age) but different origin and long term prognosis. In this paper we described the clinical and pathological findings in patient with CML in major molecular response who developed B-CLL with 11q22.3 rearrangement and Coombs positive hemolytic anemia during the imatinib treatment. Due to the presence of the symptoms of autoimmune hemolytic anemia and optimal CML response to the imatinib treatment, the decision about combined therapy with prednisone and imatinib was made. During the follow-up, the normalization of complete blood count and resolution of peripheral lymphadenopathy were noted. The hematologic response of B-CLL was diagnosed. The repeated FISH analysis of cultured peripheral blood lymphocytes showed 2% of cells carrying 11q22.3 rearrangement. At the same time, molecular monitoring confirmed the deep molecular response of CML. The effectiveness of such combination in the described case raises the question about the best therapeutic option in such situation, especially in patients with good imatinib tolerance and optimal response.

BTK inhibition targets in vivo CLL proliferation through its effects on B-cell receptor signaling activity

Bruton agammaglobulinemia tyrosine kinase (BTK), a cytoplasmic protein tyrosine kinase, is a component of the B-cell receptor signaling pathway. Ibrutinib, a BTK inhibitor, has demonstrated a significant clinical activity against chronic lymphocytic leukemia (CLL) in early clinical trials. Understanding the molecular mechanisms of action would shed light on CLL pathophysiology and provide additional opportunities for the development of new therapies. In this study, we have chosen an in vivo approach by employing an ongoing phase 1b trial of ibrutinib. We prospectively collected and analyzed serial samples from the CLL patients before and after the initiation of ibrutinib. We found that the blockage of cell proliferation was one of the primary effects of ibrutinib against leukemic CLL cells in vivo. Using a co-culture system that induces CLL proliferation in vitro, analysis of several parameters, including Ki-67 expression and bromodeoxyuridine (BrdU) incorporation, revealed that the proliferation of CLL cells was directly inhibited by ibrutinib. Furthermore, activities of BTK and phospholipase Cγ2 as well as downstream signaling molecules, AKT and ERK, were all coordinately downregulated over time in ibrutinib-treated patients. Our findings suggest that the cell proliferation is one of the essential properties of CLL. Blocking cell proliferation via inhibition of BTK-mediated signaling may contribute to clinical responses in ibrutinib-treated patients.

Dasatinib-responsive chronic lymphocytic leukemia in a patient treated for coexisting chronic myeloid leukemia

We herein present a case of concurrent chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL). Two different clones, a Philadelphia (Ph) clone and a CLL clone with a 13q deletion, were identified using fluorescent in situ hybridization. Dasatinib was administered to inhibit Bcr-Abl and Lyn kinase. The patient exhibited a molecular response for CML and a partial response for CLL. To our knowledge, this is the first report to describe the occurrence of a gradual increase in the Bcr-Abl transcript level prior to the diagnosis of Ph-positive CML in an individual with CLL who was successfully treated with dasatinib as the first-line therapy.

The coexistence of chronic lymphocytic leukemia and myeloproliperative neoplasms: a retrospective multicentric GIMEMA experience

Although the coexistence of chronic lymphocytic leukemia (CLL) and myeloproliferative neoplasms (MPN) has been sporadically reported in the literature, no systematic studies on this disease association are available. We retrospectively analyzed 46 patients affected by CLL/MPN referred by 15 Italian GIMEMA centers. The aim of this retrospective multicenter study was to define the following: clinico-biological characteristics, possible familiarity, clinical course of both diseases, and influence of MPN chemotherapy on the course of CLL. Among 46 patients, 30 patients were males, 16 patients were females; median age was 71 years. Only one case had familiar CLL. Myeloproliferative disorders consisted of essential thrombocytemia in 18 cases, polycythemia vera in 10 cases, chronic myeloid leukemia in 9 cases, primary myelofibrosis in 6 cases, and MPN/myelodysplastic syndrome in 3 cases. The lymphoproliferative disorder was diagnosed as monoclonal B-cell lymphocytosis in 8 patients and as Binet Stage A CLL in 38 patients. After a median follow-up of 49 months, 9 patients experienced progressive CLL and only 6 patients required treatment after a median of 57.5 months. The biological profile confirmed a subset of low-risk CLL. Twenty patients received chemotherapy for MPN without influence on the course of CLL: lymphocyte counts remained unchanged after 3, 6, and 12 months of treatment. This series is the largest so far reported in literature. The diagnosis of concomitant CLL/MPN is a rare event and lymphoproliferative disorders present a clinical indolent course with a low-risk biological profile. MPN therapy does not interfere with the prognosis of patients with CLL.

Treatment of chronic lymphocytic leukemia requires targeting of the protective lymph node environment with novel therapeutic approaches

Chronic lymphocytic leukemia (CLL) remains associated with low complete response rates and high relapse rates. This is in part due to poor understanding of CLL biology and thus inadequate targeting of therapy. For years CLL has been proposed as bi-compartmental: the quiescent tumor in the periphery and the proliferating cells within specific microenvironments. Historically the bone marrow was considered the major tissue of the CLL microenvironment. However, many recent innovative studies have categorically shown that peripheral CLL cells are derived from the lymph nodes (LN). Proliferation here is largely driven by helper T cells via CD40-CD40L engagement. Critically, in vitro studies have shown that such engagement additionally protects LN CLLs from apoptosis. Agents inducing apoptosis in non-CD40 engaged CLL cells are frequently ineffective against those continually engaged with CD40L. This emphasizes that, in order to improve responses and prevent relapse, novel therapies must be assessed against CD40L engaged CLL cells to show effective targeting against the LN. This review discusses the evidence supporting the superior involvement of the LN in CLL, how CD40L engaged CLL studies should be conducted, and the novel therapies studied in vitro and in vivo that have been proposed to be effective in this setting.

Malignancies occurring during therapy with tyrosine kinase inhibitors (TKIs) for chronic myeloid leukemia (CML) and other hematologic malignancies

Success of tyrosine kinase inhibitors (TKIs) in chronic myeloid leukemia (CML) has given patients hope for a long disease-free-survival. A longer survival raises the question of late effects, including development of another malignancy. Records of 1445 patients with CML/myeloproliferative neoplasm or other hematologic malignancies treated with TKIs were reviewed to investigate frequency and characteristics of second malignancies (other than acute myeloid leukemia, acute lymphocytic leukemia, or myelodysplastic syndrome). The number of second cancers was compared with the number expected from the Surveillance, Epidemiology, and End Results database. After a median follow-up of 107 months (range, 13-362 months) after CML/myeloproliferative neoplasm diagnosis, 66 patients (4.6%) developed 80 second cancers, including skin (31%), prostate (15%), melanoma (13%), digestive system (10%), kidney (4%), thyroid (4%), breast (3%), chronic lymphocytic leukemia (3%), hepatobiliary (3%), and other cancers (14%). Excluding nonmelanoma skin cancers, 55 second cancers were seen in 51 (3.5%) of all patients treated. The risk of second cancer was lower than expected (observed-to-expected ratio, 0.6; 95% confidence interval, 0.44-0.81). Second cancers occur in a small percentage of patients receiving therapy with TKIs for hematologic malignancies, mostly CML. No evidence at the moment suggests that exposure to TKIs increases the risk of developing second cancers.