RESUMO
T- and NK-cell lymphomas (TCL) are a heterogenous group of lymphoid malignancies with poor prognosis. In contrast to B-cell and myeloid malignancies, there are few preclinical models of TCLs, which has hampered the development of effective therapeutics. Here we establish and characterize preclinical models of TCL. We identify multiple vulnerabilities that are targetable with currently available agents (e.g., inhibitors of JAK2 or IKZF1) and demonstrate proof-of-principle for biomarker-driven therapies using patient-derived xenografts (PDXs). We show that MDM2 and MDMX are targetable vulnerabilities within TP53-wild-type TCLs. ALRN-6924, a stapled peptide that blocks interactions between p53 and both MDM2 and MDMX has potent in vitro activity and superior in vivo activity across 8 different PDX models compared to the standard-of-care agent romidepsin. ALRN-6924 induced a complete remission in a patient with TP53-wild-type angioimmunoblastic T-cell lymphoma, demonstrating the potential for rapid translation of discoveries from subtype-specific preclinical models.
Assuntos
Antineoplásicos/farmacologia , Regulação Neoplásica da Expressão Gênica , Linfoma Extranodal de Células T-NK/tratamento farmacológico , Linfoma de Células T/tratamento farmacológico , Proteínas Nucleares/genética , Peptídeos/farmacologia , Proteínas Proto-Oncogênicas c-mdm2/genética , Proteínas Proto-Oncogênicas/genética , Proteína Supressora de Tumor p53/genética , Animais , Proteínas de Ciclo Celular , Depsipeptídeos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Humanos , Fator de Transcrição Ikaros/antagonistas & inibidores , Fator de Transcrição Ikaros/genética , Fator de Transcrição Ikaros/metabolismo , Imidazolinas/farmacologia , Janus Quinase 2/antagonistas & inibidores , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Linfoma Extranodal de Células T-NK/genética , Linfoma Extranodal de Células T-NK/metabolismo , Linfoma Extranodal de Células T-NK/patologia , Linfoma de Células T/genética , Linfoma de Células T/metabolismo , Linfoma de Células T/patologia , Camundongos , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/metabolismo , Ligação Proteica/efeitos dos fármacos , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Indução de Remissão , Transdução de Sinais , Proteína Supressora de Tumor p53/antagonistas & inibidores , Proteína Supressora de Tumor p53/metabolismo , Sequenciamento do Exoma , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: MYD88(L265P) and CXCR4(WHIM) mutations are highly prevalent in Waldenström's macroglobulinemia. MYD88(L265P) triggers tumor-cell growth through Bruton's tyrosine kinase, a target of ibrutinib. CXCR4(WHIM) mutations confer in vitro resistance to ibrutinib. METHODS: We performed a prospective study of ibrutinib in 63 symptomatic patients with Waldenström's macroglobulinemia who had received at least one previous treatment, and we investigated the effect of MYD88 and CXCR4 mutations on outcomes. Ibrutinib at a daily dose of 420 mg was administered orally until disease progression or the development of unacceptable toxic effects. RESULTS: After the patients received ibrutinib, median serum IgM levels decreased from 3520 mg per deciliter to 880 mg per deciliter, median hemoglobin levels increased from 10.5 g per deciliter to 13.8 g per deciliter, and bone marrow involvement decreased from 60% to 25% (P<0.01 for all comparisons). The median time to at least a minor response was 4 weeks. The overall response rate was 90.5%, and the major response rate was 73.0%; these rates were highest among patients with MYD88(L265P)CXCR4(WT) (with WT indicating wild-type) (100% overall response rate and 91.2% major response rate), followed by patients with MYD88(L265P)CXCR4(WHIM) (85.7% and 61.9%, respectively) and patients with MYD88(WT)CXCR4(WT) (71.4% and 28.6%). The estimated 2-year progression-free and overall survival rates among all patients were 69.1% and 95.2%, respectively. Treatment-related toxic effects of grade 2 or higher included neutropenia (in 22% of the patients) and thrombocytopenia (in 14%), which were more common in heavily pretreated patients; postprocedural bleeding (in 3%); epistaxis associated with the use of fish-oil supplements (in 3%); and atrial fibrillation associated with a history of arrhythmia (5%). CONCLUSIONS: Ibrutinib was highly active, associated with durable responses, and safe in pretreated patients with Waldenström's macroglobulinemia. MYD88 and CXCR4 mutation status affected responses to this drug. (Funded by Pharmacyclics and others; ClinicalTrials.gov number, NCT01614821.).
Assuntos
Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Tirosina Quinases/antagonistas & inibidores , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Macroglobulinemia de Waldenstrom/tratamento farmacológico , Adenina/análogos & derivados , Adulto , Tirosina Quinase da Agamaglobulinemia , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Hemoglobinas/análise , Humanos , Imunoglobulina M/sangue , Estimativa de Kaplan-Meier , Masculino , Pessoa de Meia-Idade , Mutação , Fator 88 de Diferenciação Mieloide/genética , Piperidinas , Estudos Prospectivos , Inibidores de Proteínas Quinases/efeitos adversos , Pirazóis/efeitos adversos , Pirimidinas/efeitos adversos , Receptores CXCR4/genética , Taxa de Sobrevida , Macroglobulinemia de Waldenstrom/sangue , Macroglobulinemia de Waldenstrom/genéticaRESUMO
We describe the case of a patient presenting with several weeks of symptoms related to pancytopenia associated with a maturation arrest at the late promyelocyte/early myelocyte stage of granulocyte differentiation. A diagnosis of acute promyelocytic leukemia was considered, but the morphologic features were atypical for this entity and conventional tests for the presence of a PML-RARA fusion gene were negative. Additional analysis using a custom next-generation sequencing assay revealed a rearrangement producing a STAT5B-RARA fusion gene, which was confirmed by reverse transcription polymerase chain reaction (RT-PCR) and supplementary cytogenetic studies, allowing the diagnosis of a morphologically atypical form of acute promyelocytic leukemia to be made. Analysis of the sequencing data permitted characterization of both chromosomal breakpoints and revealed two additional alterations, a small deletion in RARA exon 9 and a RARA R276W substitution, that have been linked to resistance to all-trans retinoic acid. This case highlights how next-generation sequencing can augment currently standard testing to establish diagnoses in difficult cases, and in doing so help guide selection of therapy.
RESUMO
Notch1 is a rational therapeutic target in several human cancers, but as a transcriptional regulator, it poses a drug discovery challenge. To identify Notch1 modulators, we performed two cell-based, high-throughput screens for small-molecule inhibitors and cDNA enhancers of a NOTCH1 allele bearing a leukemia-associated mutation. Sarco/endoplasmic reticulum calcium ATPase (SERCA) channels emerged at the intersection of these complementary screens. SERCA inhibition preferentially impairs the maturation and activity of mutated Notch1 receptors and induces a G0/G1 arrest in NOTCH1-mutated human leukemia cells. A small-molecule SERCA inhibitor has on-target activity in two mouse models of human leukemia and interferes with Notch signaling in Drosophila. These studies "credential" SERCA as a therapeutic target in cancers associated with NOTCH1 mutations.
Assuntos
Leucemia/genética , Leucemia/metabolismo , Receptor Notch1/genética , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/genética , Alelos , Animais , Canais de Cálcio/genética , Linhagem Celular Tumoral , Drosophila/genética , Drosophila/metabolismo , Ensaios de Seleção de Medicamentos Antitumorais , Inibidores Enzimáticos/farmacologia , Feminino , Pontos de Checagem da Fase G1 do Ciclo Celular/genética , Biblioteca Gênica , Ensaios de Triagem em Larga Escala , Humanos , Camundongos , Camundongos SCID , Mutação , Transplante de Neoplasias , Receptor Notch1/antagonistas & inibidores , ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático/antagonistas & inibidores , Transdução de Sinais/genética , Bibliotecas de Moléculas Pequenas , Tapsigargina/farmacologia , Transplante HeterólogoRESUMO
PURPOSE: Protein kinase C beta (PKCbeta) was identified by gene-expression profiling, preclinical evaluation, and independent immunohistochemical analysis as a rational therapeutic target in diffuse large B-cell lymphoma (DLBCL). We conducted a multicenter phase II study of a potent inhibitor of PKCbeta, enzastaurin, in patients with relapsed or refractory DLBCL. PATIENTS AND METHODS: Enzastaurin was taken orally once daily until disease progression or unacceptable toxicity occurred. Study end points included freedom from progression (FFP) for > or= two cycles (one cycle = 28 days), objective response, and toxicity. RESULTS: Fifty-five patients (median age, 68 years) were enrolled. Patients had received a median number of two prior therapies (range, one to five); six patients relapsed after high-dose therapy and autologous stem-cell transplantation. Only one grade 4 toxicity (hypomagnesemia) occurred. Grade 3 toxicities included fatigue (n = 2), edema (n = 1), headache (n = 1), motor neuropathy (n = 1), and thrombocytopenia (n = 1). No grade 3 or 4 neutropenia occurred. No deaths or discontinuations due to toxicity were reported. Fifteen patients completed less than one cycle of therapy. Twelve of 55 patients (22%; 95% CI, 13% to 46%) experienced FFP for two cycles, and eight patients remained free from progression for four cycles (15%; 95% CI, 6% to 27%). Four patients (7%; 95% CI, 2% to 18%), including three complete responders and one patient with stable disease, continue to experience FFP 20+ to 50+ months after study entry. CONCLUSION: Treatment with enzastaurin was well-tolerated and associated with prolonged FFP in a small subset of patients with relapsed or refractory DLBCL. Further studies of enzastaurin in DLBCL are warranted.