The expanding role of nilotinib in chronic myeloid leukemia

Importance of the field: Several therapeutic options, including tyrosine kinase inhibitors, exist for the treatment of patients with Philadelphia chromosome (Ph)-positive chronic myeloid leukemia (CML). Despite impressive results, there is room for improvement for those patients who are either resistant or intolerant to imatinib.

Areas covered in this review: An overview is given on the clinical results with nilotinib, a rationally designed second-generation tyrosine kinase inhibitor, as first- and second-line therapy in patients with Ph-positive CML. Important factors in predicting resistance to nilotinib and guiding therapeutic decisions are addressed.

What the reader will gain: Knowledge on the clinical efficacy and safety of nilotinib after imatinib failure and as first-line treatment. Point mutations in the kinase domain (KD) of BCR-ABL1 are important determinants of clinical sensitivity to currently available tyrosine kinase inhibitors, including nilotinib. Information on specific BCR-ABL1 KD mutations and safety profiles assist in therapeutic decision making.

Take home message: Nilotinib is a highly effective and well-tolerated therapeutic option in patients with Ph-positive CML after imatinib failure. Early evidence demonstrating increased efficacy has allowed expanding nilotinib to previously untreated patients in chronic phase. Insights into mechanisms of resistance to tyrosine kinase inhibitors and predictive factors for response will allow for a more individualized use of these agents.     

Dasatinib for the treatment of Philadelphia chromosome-positive chronic myelogenous leukaemia after imatinib failure

Dasatinib, a potent, oral kinase inhibitor, is presently approved for Philadelphia-positive chronic myelogenous leukaemia (CML) following imatinib failure. In an in vitro study, dasatinib had 325-fold greater potency than imatinib for inhibiting unmutated BCR-ABL. Phase I and II data show that dasatinib 70 mg b.i.d. is effective after imatinib failure in various phases of CML. Comparative data of dasatinib versus high-dose imatinib in patients with resistance or intolerance to imatinib demonstrated that dasatinib was associated with improved response rates and progression-free survival. Side effects of dasatinib, including pleural effusions, are manageable with modification of dose or schedule. Phase III dose optimisation studies and future indications are also discussed.     

Nilotinib for the treatment of Philadelphia-chromosome-positive chronic myeloid leukemia

Importance of the field: Although the introduction of imatinib revolutionized the management of chronic myeloid leukemia (CML), some patients exhibit resistance or intolerance to the drug. Nilotinib induces high and rapid rates of cytogenetic and molecular responses. With recent approval for newly diagnosed patients with chronic phase CML, the current algorithm for treatment will probably be transformed.

Areas covered in this review: This review will describe evaluations of nilotinib in all phases of CML from 1995 to the present. Early preclinical data and Phase I, Phase II and Phase III evaluations will demonstrate the role of nilotinib in newly diagnosed CML, as well as in imatinib-resistant or imatinib-intolerant disease.

What the reader will gain: Mutations in the BCR-ABL kinase domain are responsible for the majority of resistance to imatinib. In comparison with imatinib, nilotinib displays increased selectivity and potency at inhibiting proliferation of BCR-ABL expressing cells. Although several mutations, including T315I, remain resistant to nilotinib, activity in all phases of CML has been reported.

Take home message: Nilotinib induces high and rapid rates of cytogenetic and molecular response, with less progression to advanced forms of disease compared with imatinib. Considering that the rapid achievement of these clinical milestones has been associated with positive long-term outcomes, nilotinib as initial therapy in patients with CML in chronic phase represents the future in CML treatment. Longer follow-up is necessary to recognize survival advantages.     

达沙替尼治疗伊马替尼耐药的 BCR／ABL阳性白血病

目的评价达沙替尼治疗伊马替尼耐药的BCR/ABL阳性白血病的疗效和安全性。方法对9例伊马替尼耐药的慢性髓系白血病（CML）或Ph阳性急性淋巴细胞白血病（Ph＋ALL）患者,给予达沙替尼100～140 mg·d-1口服治疗,评估疗效和耐受情况。结果 9例伊马替尼耐药的BCR/ABL阳性白血病,2例CML-CP患者均获得CHR,1例达CCyR;5例CML-BC患者中4例获得CHR和PCyR,1例NR;2例Ph＋ALL患者中1例检测到E255V突变,采用达沙替尼治疗达CHR和PCyR,1例诱导缓解时,同时行VDP方案化疗,继发严重感染死亡。结论达沙替尼治疗伊马替尼耐药的BCR/ABL阳性白血病患者可获得血液学甚至细胞遗传学缓解,且耐受性好。     

大剂量伊马替尼、达沙替尼和尼洛替尼治疗慢性髓性白血病的成本效用分析

目的：分析大剂量伊马替尼、达沙替尼和尼洛替尼治疗对标准剂量伊马替尼耐药的慢性髓性白血病患者的成本效用。方法：计算三种治疗方案下患者的效用和花费的成本,在马尔可夫模型（Markov）中以3个月为周期进行5年的模拟并对结果做成本效用比较。结果：尼洛替尼治疗方案累计成本为1 595 289.10元,健康效用为1.276 4质量调整生命年（QALYs）,相比于尼洛替尼,大剂量伊马替尼组的增量成本效用比（ICUR）为-22 759 433.08（￥/QALYs）,达沙替尼组为-30 960 469.51（￥/QALYs）。结论：尼洛替尼方案累计成本最低且获得最多的QALYs,为绝对优势方案。     

Dasatinib for the treatment of Philadelphia chromosome-positive leukaemias

BCR-ABL, a constitutively active tyrosine kinase, causes chronic myeloid leukaemia (CML). Rational development of drugs targeting BCR-ABL has significantly improved the treatment of CML. Imatinib (a BCR-ABL tyrosine kinase inhibitor) produces haematological and cytogenetic remissions across all phases of CML and is the present standard of care. Imatinib resistance occurs in a significant proportion of patients and mechanisms of resistance include BCR-ABL mutations and activation of alternate oncogenic pathways. Dasatinib is a novel, potent, multi-targeted oral kinase inhibitor. Preclinical and clinical investigations demonstrate that dasatinib effectively overcomes imatinib resistance and has further improved the treatment of CML. Dasatinib was recently approved by the FDA for use in Philadelphia-positive leukaemias in patients who are resistant or intolerant to imatinib.     

伊马替尼治疗慢性髓细胞白血病慢性期临床疗效观察

目的：分析甲磺酸伊马替尼（IM）治疗慢性髓系白血病（CML）慢性期的临床疗效及影响疗效的因素。方法随访观察74例 CML 慢性期患者,IM中位治疗剂量为400（200～600）mg·d －1,评估其临床疗效,总生存时间和疾病无进展生存时间,并对相关疗效影响因素进行分析。结果中位随访时间为20（6～72）个月,累积达到血液学缓解（CHR）为98．6％,血液学中位缓解时间1（1～3）月;63例（85．1％）达到主要细胞遗传学缓解（MCyR）,中位达 MCyR 时间为9（5～24）个月;53例（71．6％）达完全细胞遗传学缓解（CCyR）,41例（55．4％）达到主要分子生物学缓解（MMR）;6例（8．1％）达到完全分子生物学缓解（CMR）;初治组及复治组应用 IM治疗后 CHR 及 MCyR 差异无统计学意义,但 CCyR 及 MMR 差异均有统计学意义（P ＜0．016）;由 EUTOS 评分区分的低危组与高危组应用 IM治疗后 CHR 差异无统计学意义,但 MCyR、CCyR 及 MMR 差异均有统计学意义（P ＜0．020）;其中初治组与复治组及 EUTOS 评分低危组与高危组 OS 差异无统计学意义,但其 PFS 差异均有统计学意义（P 分别为0．021和0．004）。结论IM用于 CML 慢性期患者治疗可获得极高的血液学缓解率和较高细胞遗传学缓解率,不良反应少,提高了患者生存质量,延长患者的生存时间;在 CML 确诊早期应用可提高疗效,IM治疗前时间大于6个月或EUTOS 评分高危组可影响 IM疗效。     

Dasatinib as an investigational drug for the treatment of Philadelphia chromosome-positive acute lymphoblastic leukemia in adults

Introduction: Acute lymphoblastic leukemia (ALL) with BCR-ABL1 translocation is an aggressive malignancy that is usually treated with intensive chemotherapy with the possibility of allogeneic stem cell transplantation. The encoded fusion protein may be important for leukemogenesis; clinical studies show that dasatinib has an antileukemic effect in combination with steroids alone or intensive chemotherapy.

Areas covered: Relevant publications were identified through literature searches (the used terms being acute lymphoblastic leukemia plus dasatinib) in the PubMed database. We searched for original articles and reviews describing the pharmacology and clinical use of dasatinib in ALL with BCR-ABL1. The mechanism of action, pharmacology and clinical study findings are examined.

Expert opinion: Dasatinib is associated with a high complete remission rate in ALL when used alone and in combination with steroids or intensive chemotherapy. However, mutations at T315 and F317 are associated with dasatinib resistance. Overall toxicity has been acceptable in these studies and no unexpected toxicity was observed. It is not known whether the antileukemic effect of dasatinib differs between subsets of BCR-ABL1⁺ patients or is attributed to inhibition of the fusion protein alone, or a combined effect on several kinases, and whether dasatinib-containing combination treatment should be preferred in these patients instead of other emerging strategies, e.g. monoclonal antibodies.     

New Bcr-Abl inhibitors in chronic myeloid leukemia: keeping resistance in check

Targeted therapy with the Abl kinase inhibitor imatinib has markedly improved the outlook for patients with chronic myeloid leukemia (CML). Breakpoint cluster region (Bcr)-Abl signaling is reactivated at the time of resistance, predominantly due to mutations in the kinase domain of Bcr-Abl that interfere with drug binding. This discovery prompted the development of new Abl kinase inhibitors, among which nilotinib and dasatinib have gained regulatory approval. Despite excellent results in patients with imatinib-resistant or imatinib-intolerant CML treated with nilotinib or dasatinib, early indications suggest that: the cross-resistant Bcr-Abl^T315I mutant is disproportionately represented among patients who relapse on these therapies; each Abl inhibitor exhibits vulnerabilities to certain kinase domain mutations. We review new inhibitors of Bcr-Abl, including preliminary information on inhibitors of Bcr-Abl^T315I and discuss the potential of combined Abl kinase inhibitor therapy to pre-empt resistance. Improved Abl inhibitor therapies will be useful in achieving maximum disease control but a clinical T315I inhibitor remains a high priority.     

达沙替尼应用于伊马替尼耐药的慢性粒细胞白血病的研究进展

伊马替尼是一种酪氨酸激酶抑制剂(TKI),是第一代用于治疗Ph染色体阳性的CML的分子靶向药物,然而其逐渐出现的耐药情况是治疗的一大难题。第二代靶向治疗药物如达沙替尼等具有更大的抗耐药潜力。本文对此进行综述。     

Targeting survival pathways in chronic myeloid leukaemia stem cells

Chronic myeloid leukaemia (CML) is a clonal myeloproliferative disorder characterized by the presence of a fusion oncogene BCR-ABL, which encodes a protein with constitutive TK activity. The implementation of tyrosine kinase inhibitors (TKIs) marked a major advance in CML therapy; however, there are problems with current treatment. For example, relapse occurs when these drugs are discontinued in the majority of patients who have achieved a complete molecular response on TKI and these agents are less effective in patients with mutations in the BCR-ABL kinase domain. Importantly, TKI can effectively target proliferating mature cells, but do not eradicate quiescent leukaemic stem cells (LSCs), therefore allowing disease persistence despite treatment. It is essential that alternative strategies are used to target the LSC population. BCR-ABL activation is responsible for the modulation of different signalling pathways, which allows the LSC fraction to evade cell death. Several pathways have been shown to be modulated by BCR-ABL, including PI3K/AKT/mTOR, JAK-STAT and autophagy signalling pathways. Targeting components of these survival pathways, alone or in combination with TKI, therefore represents an attractive potential therapeutic approach for targeting the LSC. However, many pathways are also active in normal stem cells. Therefore, potential targets must be validated to effectively eradicate CML stem cells while sparing normal counterparts. This review summarizes the main pathways modulated in CML stem cells, the recent developments and the use of novel drugs to target components in these pathways which may be used to target the LSC population.

Linked Articles

This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8     

血红素加氧酶-1对慢性粒细胞白血病细胞凋亡效应的研究

目的探讨HO-1在慢性粒细胞白血病（以下简称慢粒）中的表达,研究其对抗细胞凋亡的效应,并研究抑制HO-1的表达对细胞凋亡的影响。方法探讨HO-1在慢性粒细胞白血病中的表达,研究其对抗细胞凋亡的效应,并研究抑制HO-1的表达对细胞凋亡的影响。结果RT-PCR结果显示骨髓血中HO-1的表达呈组成性,与对照组相比,诱导K562细胞HO-1的表达促进了细胞的生长（P＆lt;0.05）,并且这种表达成剂量依赖性,而抑制HO-1的表达促进了细胞的凋亡（P＆lt;0.05）,细胞的存活率只有对照组的30%。结论慢粒标本中HO-1的表达呈组成性,HO-1是一种可诱导型分子,并发挥抗凋亡效应,抑制HO-1的表达可能成为治疗慢粒的新方法。     

Benefits and risks of ponatinib versus bosutinib following treatment failure of two prior tyrosine kinase inhibitors in patients with chronic phase chronic myeloid leukemia: a matching-adjusted indirect comparison

Objective: Comparing the benefit–risk profiles of ponatinib vs. bosutinib in third-line (3L) treatment of chronic phase chronic myeloid leukemia (CP-CML) is challenging because their pivotal trials lacked comparator arms. To characterize the overall benefit–risk profile in 3L CP-CML patients treated with bosutinib vs. ponatinib, a matching-adjusted indirect comparison (MAIC) was performed to compare efficacy outcomes and treatment duration after adjusting for trial subjects’ baseline characteristics, and tolerability was assessed with an unadjusted comparison of study-drug discontinuation.

Methods: The MAIC was performed using published data from the pivotal bosutinib trial and the most recent individual-patient-level data on file from the pivotal ponatinib trial.

Results: Responses were more frequent and durable with ponatinib (n?=?70 MAIC-adjusted) than with bosutinib (n?=?119) – complete cytogenetic response (CCyR): 61% vs. 26%; Kaplan–Meier estimate of maintaining CCyR at 4 years: 89% vs. 54%. Median treatment duration was longer with ponatinib than with bosutinib: 38.4 vs. 8.6 months. Only 9% of ponatinib patients (n?=?97 unadjusted) vs. 42% of bosutinib patients discontinued due to death, disease progression or unsatisfactory response; 19% vs. 24% discontinued due to adverse events.

Conclusions: Based on these surrogate measures of patient benefit–risk profiles, ponatinib appears to provide a net overall benefit vs. bosutinib in 3L CP-CML.     

伊马替尼治疗Ph阳性进展期慢性粒细胞白血病

目的:观察伊马替尼治疗Ph阳性进展期慢性粒细胞白血病(CML)的疗效和耐药情况,研究改善伊马替尼耐药的方法。方法:32例Ph阳性进展期CML病人,其中加速期12例,急变期20例,每日口服伊马替尼600或800mg,持续3～9mo。结果:CML加速期病人血液学完全缓解率和总有效率分别为42%和83%,主要细胞遗传学缓解率25%,持续完全血液学缓解病例占25%。CML急变期各类型病人血液学完全缓解率和总有效率分别为20%和55%,主要细胞遗传学缓解率15%,持续完全血液学缓解病例占10%。CML急变期原发耐药和继发耐药分别为45%和20%,联合化疗与暂停伊马替尼对继发耐药可暂时改善其耐药性,但药物有效时间明显缩短。结论:伊马替尼对初治或复治的CML加速期和急变期病人均有效,可作为非移植CML治疗的标准一线方案,伊马替尼治疗CML急变期的原发耐药和继发耐药率较高,联合化疗和暂停伊马替尼可暂时改善其耐药性。     

伊马替尼治疗失败慢性期CML患者及早干预的意义及二代TKIs选择

慢性髓细胞性白血病(CML)应用伊马替尼后,明显改善了预后,但治疗失败的患者则预后不良。为改善这些患者的预后,一方面需要加强细胞遗传学和分子生物学监测,及早发现治疗失败并给予干预。另一方面,对于大多数治疗失败的患者,二代酪氨酸激酶抑制剂(TKIs)是合适的选择,如果就目前临床上两种二代TKIs进行比较,总体看来尼洛替尼好于达沙替尼。     

The safety of Bosutinib for the treatment of chronic myeloid leukemia

Introduction: Tyrosine kinase inhibitors (TKIs) are a potentially lifelong treatment for patients with chronic myeloid leukemia (CML). Adverse events (AEs) associated with TKIs are significant impediments in the daily life of patients that can impact compliance, and efficacy.

Areas covered: This is a review on safety of bosutinib in the treatment of chronic phase CML. Data is extracted from the latest updates of bosutinib phase I/II and III trials.

Expert opinion: Bosutinib is an effective agent against all phases of CML presently approved for the treatment in patients with resistance or intolerance to prior TKI therapy. Bosutinib has a unique toxicity profile characterized by early and transient diarrhea. Otherwise, the AE profile of bosutinib is comparable to other TKIs, with the exception of cardiovascular AEs that are infrequent in bosutinib-treated patients. Similar to other TKIs, the minimum effective dose of bosutinib remains unknown. Better definition of the optimal effective dose may spare, for those patients otherwise benefitting from treatment, unnecessary AEs.     

伊马替尼与干扰素联合治疗慢性粒细胞白血病的疗效分析

目的:探讨伊马替尼与干扰素联合化疗治疗慢性粒细胞白血病(CM L)的疗效。方法:2004年6月—2009年7月新诊断的58例Ph染色体阳性CM L慢性期患者,随机分为伊马替尼组和干扰素联合化疗组,比较两组临床疗效。结果:两组总有效率差异无统计学意义(P>0.05);伊马替尼组完全血液学缓解率,完全细胞遗传学缓解率、完全分子学效应率、5年总生存率均明显高于干扰素联合化疗组(P<0.05)。结论:伊马替尼和干扰素联合化疗都可作为CM L慢性期的有效治疗方法,应依据不同情况实施个体化治疗。     

Roflumilast: the evidence for its clinical potential in the treatment of chronic obstructive pulmonary disease

Introduction:

Chronic obstructive pulmonary disease (COPD), characterized by a progressive deterioration of lung function caused primarily by the inhalation of toxic substances, is a leading cause of morbidity and mortality worldwide. Current treatment options for the management of its symptoms include the use of bronchodilators and glucocorticoid agents that are not universally beneficial and which are associated with limitations. Phosphodiesterase-4 (PDE4) inhibitors are a novel class of antiinflammatory agents being developed for COPD treatment.

Aims:

The purpose of this article is to review the clinical potential of roflumilast, a PDE4 inhibitor currently in phase III clinical trials, in the management of patients with COPD.

Evidence review:

Phase II studies indicate that roflumilast can be given orally once daily. Preliminary evidence from two phase III, randomized, double-blind, placebo-controlled studies suggest that roflumilast improves or stabilizes lung function, as measured by forced expiratory volume in 1 s and 6 s (FEV₁ and FEV₆), forced vital capacity (FVC), and peak expiratory flow (PEF) in patients with COPD. Improvements in COPD exacerbation rate were also reported in these trials. Quality of life, as measured by the St George’s Respiratory Questionnaire, also improved with roflumilast treatment. Clinical studies to date suggest that roflumilast is well tolerated.

Clinical potential:

Current evidence supports the use of roflumilast in the management of COPD as shown by improvements in patients’ symptoms and quality of life, and good tolerability profile. Its once-daily oral dosing regimen is unique among current therapies for COPD. This potential and the place of roflumilast in the stepwise management of the disease need to be confirmed as further evidence is published. Additional evidence will also be welcome to determine if its mechanism of action moderates the progression of lung function deterioration.     

伊马替尼治疗常规化学治疗失败的进展期慢性粒细胞白血病21例

目的:观察伊马替尼治疗常规化学治疗(化疗)失败的进展期慢性粒细胞白血病(CML)的有效性及不良反应。方法:21例病人在常规化疗无效后服用伊马替尼,其中加速期4例,急变期17例,起始剂量400 mg·d~(-1),无明显不良反应后改为600 mg·d~(-1)。结果:所有病人服用伊马替尼后,白细胞、血小板及幼稚细胞均明显下降,与服药前比较差异非常显著(P<0.01)。除1例因败血症死亡,2例病人骨髓部分缓解外,其余病人服药后7～45d均达到血液学完全缓解。伊马替尼对白细胞影响较明显,部分病人出现恶心、呕吐等消化道症状及眼睑水肿、肌痛等不良反应。结论:伊马替尼治疗常规化疗失败的难治性CML有较高的血液学缓解率,服用方便,效果好,不良反应轻。     

Current concerns of undertreatment and overtreatment in chronic myeloid leukemia based on European LeukemiaNet 2013 recommendations

Introduction: The aim of this paper is to indicate optimal tyrosine kinase inhibitor (TKI) administration practices based on European LeukemiaNet (ELN) 2013 recommendations for chronic myeloid leukemia (CML). Likewise, current concerns of undertreatment and overtreatment with TKIs during the long-term clinical course of CML will be outlined.

Areas covered: Currently available TKIs for the management of CML are reviewed. The survival benefit of TKIs (imatinib, dasatinib, nilotinib, bosutinib, ponatinib) for the CML is excellent. The CML and TKI literature search was made in PubMed with particular focus on the clinical trials, recommendations, guidelines and expert opinions, as well as the ELN CML 2013 recommendations.

Expert opinion: Initial TKI treatment for low-risk chronic phase CML is imatinib 400 mg; high-Sokal risk and/or CML patients with complex karyotypic abnormalities would require more powerful second-generation TKIs (dasatinib 100 mg or nilotinib 600 mg). Absence of early molecular response after 6 months, complete cytogenetic response after 12 months and major molecular response after 18 months may require a more powerful TKI switch. If one of the two second-generation TKIs (nilotinib or dasatinib) was used as first-line therapy and failed, the other (dasatinib or nilotinib) could be administered.