Progression of chronic myeloid leukemia to blast crisis during treatment with imatinib mesylate

Synthesis, Biological Activities and Docking Studies of Novel 4-(Arylaminomethyl)benzamide Derivatives as Potential Tyrosine Kinase Inhibitors

A number of new compounds containing the 4-(aminomethyl)benzamide fragment as a linker were designed and synthesized, and their biological activities were evaluated as potential anticancer agents. The cytotoxicity activity of the designed compounds was studied in two hematological and five solid cell lines in comparison with the reference drugs. Targeted structures against eight receptor tyrosine kinases including EGFR, HER-2, HER-4, IGF1R, InsR, KDR, PDGFRa, and PDGFRb were investigated. The majority of the compounds showed a potent inhibitory activity against the tested kinases. The analogues 11 and 13 with the (trifluoromethyl)benzene ring in the amide or amine moiety of the molecule were proven to be highly potent against EGFR, with 91% and 92% inhibition at 10 nM, respectively. The docking of synthesized target compounds for nine protein kinases contained in the Protein Data Bank (PDB) database was carried out. The molecular modeling results for analogue 10 showed that the use of the 4-(aminomethyl)benzamide as a flexible linker leads to a favorable overall geometry of the molecule, which allows one to bypass the bulk isoleucine residue and provides the necessary binding to the active center of the T315I-mutant Abl (PDB: 3QRJ).

Erythroid blast crisis in chronic myelogenous leukemia: Case report and review of literature

Chronic myelogenous leukemia (CML) is a myeloproliferative disorder where over a period of time 15–20% of patients show blastic transformation with majority transforming into acute myeloid leukemia, most of which are of granulocytic lineage. Erythroid blast phase of CML is relatively rare with the incidence ranging from 0–10%. Further the incidence of acute erythroid leukemia by itself is fairly low amongst all acute leukemias. We report a case of 41-year-old patient with CML who failed to achieve cytogenetic remission, transformed to acute erythroid leukemia and eventually succumbed to the disease over a short period of time. Related literature is also reviewed

Rapid Evolution to Blast Crisis Associated with a Q252H ABL1 Kinase Domain Mutation in e19a2 BCR-ABL1 Chronic Myeloid Leukaemia

A minority of chronic myeloid leukaemia (CML) patients express variant transcripts of which the e19a2 BCR-ABL1 fusion is the most common. Instances of tyrosine kinase inhibitor (TKI) resistance in e19a2 BCR-ABL1 CML patients have rarely been reported. A case of e19a2 BCR-ABL1 CML is described in whom imatinib resistance, associated with a Q252H ABL1 kinase domain mutation, became apparent soon after initiation of TKI therapy. The patient rapidly transformed to myeloid blast crisis (BC) with considerable bone marrow fibrosis and no significant molecular response to a second generation TKI. The clinical course was complicated by comorbidities with the patient rapidly succumbing to advanced disease. This scenario of Q252H-associated TKI resistance with rapid BC transformation has not been previously documented in e19a2 BCR-ABL1 CML. This case highlights the considerable challenges remaining in the management of TKI-resistant BC CML, particularly in the elderly patient.

Activity of dual SRC-ABL inhibitors highlights the role of BCR/ABL kinase dynamics in drug resistance

Mutation in the ABL kinase domain is the principal mechanism of imatinib resistance in patients with chronic myelogenous leukemia. Many mutations favor active kinase conformations that preclude imatinib binding. Because the active forms of ABL and SRC resemble one another, we tested two dual SRC-ABL kinase inhibitors, AP23464 and PD166326, against 58 imatinib-resistant (IM(R)) BCR/ABL kinase variants. Both compounds potently inhibit most IM(R) variants, and in vitro drug selection demonstrates that active (AP23464) and open (PD166326) conformation-specific compounds are less susceptible to resistance than imatinib. Combinations of inhibitors suppressed essentially all resistance mutations, with the notable exception of T315I. Guided by mutagenesis studies and molecular modeling, we designed a series of AP23464 analogues to target T315I. The analogue AP23846 inhibited both native and T315I variants of BCR/ABL with submicromolar potency but showed nonspecific cellular toxicity. Our data illustrate how conformational dynamics of the ABL kinase accounts for the activity of dual SRC-ABL inhibitors against IM(R)-mutants and provides a rationale for combining conformation specific inhibitors to suppress resistance.

Sudden blast crisis in patients with Philadelphia chromosome-positive chronic myeloid leukemia who achieved complete cytogenetic remission after imatinib therapy

BACKGROUND

Most patients with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML) in chronic phase (CP) who receive treatment with imatinib achieve complete cytogenetic remission (CCR), which is correlated tightly with long-term progression-free survival. In these patients, the occurrence of blastic crisis (BC) is rare, and its clinical biologic characteristics are not well known.

METHODS

Among 164 patients who received imatinib and were followed for a median of 35 months, 11 patients (6.7%) developed a BC; this was sudden (i.e., it occurred within 3 months of a documented CCR) in 6 patients (54.5%). Those patients were analyzed with respect to their clinical and biologic features and were compared with previous reports.

RESULTS

At the time of diagnosis, there were 3 low-risk patients and 3 intermediate-risk patients; 4 patients had received pretreatment with interferon, and 2 patients received only imatinib. The median CP was 18 months, and the median duration of imatinib therapy was 7 months. The median time to CCR was 3 months, and the median time from CCR to BC was 4 months. BC phenotype was lymphoid in 2 patients, myeloid in 3 patients (including 2 patients who had extramedullary localization), and biclonal in 1 patient. Karyotype evolution was detected in 4 patients, whereas a Ph-positive/Ph-negative mosaicism was evident in all 6 patients. One patient presented an M351T mutation. The overall median survival was 3 months.

CONCLUSIONS

Sudden BC generally is an uncommon phenomenon that may be relatively frequent in patients with CML who receive imatinib. Clinical and biologic features also seem to characterize this peculiar type of abrupt disease evolution, which intervenes in patients' response to this drug. Close monitoring of disease markers and full disease eradication are warranted.

Inhibition of angiogenesis in cancer patients

Treatment with antiangiogenic agents as standard anticancer therapy with or without classical chemotherapy is rapidly approaching. The clinical efficacy of bevacizumab in colorectal cancer in combination with chemotherapy caused a revival of the antiangiogenic strategy. By combining this agent with a tyrosine kinase receptor epidermal growth factor receptor blocker (erlotinib), remarkable responses were seen in renal cell cancer. It has been thought that blocking these biological pathways would cause no drug-related toxicity, but a whole new pattern of relatively mild side effects compared with classical chemotherapy, including skin rash, fatigue and hypertension, has been observed. In combination with chemotherapy, other serious side effects, such as bleeding and thrombosis, also occur. Here, the preclinical and clinical data of antiangiogenic agents in clinical trials at this moment are summarised.