Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Semin Oncol. 2011 Apr;38 Suppl 1:S10-9. doi: 10.1053/j.seminoncol.2011.01.018.
During the past decade, tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of gastrointestinal stromal tumors (GIST), providing new treatment options with unprecedented clinical benefit. Recognition of the key role played by the receptor tyrosine kinases KIT and platelet-derived growth factor receptor alpha (PDGFRα) in the pathogenesis of GIST led to the development of imatinib, the first TKI for this indication and the current first-line standard of care for unresectable or metastatic GIST. However, the clinical efficacy of imatinib is limited by two concerns: the rare patient-specific intolerance to the drug, and the fact that the majority of patients will eventually develop treatment-refractory disease that is resistant to this selective TKI. Although sunitinib has been approved worldwide as second-line therapy for GIST following failure of imatinib, the benefits of sunitinib in treating GIST following imatinib failure are most often more limited than first-line therapy, with emergence of treatment-resistant disease in less than 1 year. Other TKIs studied in clinical trials for GIST include a wide range of different agents, such as sorafenib, dasatinib, pazopanib, regorafenib, masitinib, and nilotinib. Each agent differs in its selectivity for individual tyrosine kinases, conferring each with distinct properties that determine clinical safety and efficacy. No agent has yet reached regulatory approval for management of GIST following the failure of both imatinib and sunitinib. This review highlights relevant differences and similarities in the structures and functions, including kinase selectivity and mechanisms of binding, of the currently approved TKIs and certain others in development for the treatment of advanced GIST. In addition, the ability of some TKIs to inhibit alternative targets with potency similar to or greater than their intended primary target (pleiotropic effects) is also discussed.
在过去的十年中,酪氨酸激酶抑制剂 (TKI) 彻底改变了胃肠道间质瘤 (GIST) 的治疗方法,为这种疾病提供了具有前所未有的临床获益的新治疗选择。对受体酪氨酸激酶 KIT 和血小板衍生生长因子受体 α (PDGFRα) 在 GIST 发病机制中所起的关键作用的认识,导致了伊马替尼的开发,这是该适应证的第一种 TKI,也是目前不可切除或转移性 GIST 的一线标准治疗方法。然而,伊马替尼的临床疗效受到两个问题的限制:一是极少数患者对药物不耐受,二是大多数患者最终会发展为对这种选择性 TKI 耐药的治疗抵抗性疾病。虽然舒尼替尼已在全球范围内被批准用于伊马替尼治疗失败后的 GIST 二线治疗,但舒尼替尼在伊马替尼治疗失败后的 GIST 中的疗效通常不如一线治疗,不到 1 年内就会出现治疗抵抗性疾病。在临床试验中研究用于 GIST 的其他 TKI 包括广泛的不同药物,如索拉非尼、达沙替尼、帕唑帕尼、瑞戈非尼、马替尼和尼洛替尼。每种药物在其对个别酪氨酸激酶的选择性方面存在差异,这使每种药物都具有独特的特性,决定了其临床安全性和疗效。在伊马替尼和舒尼替尼治疗失败后,还没有一种药物获得监管部门批准用于 GIST 的治疗。本文重点介绍了目前批准的 TKI 以及某些其他用于治疗晚期 GIST 的在研药物的结构和功能(包括激酶选择性和结合机制)方面的相关差异和相似性。此外,还讨论了一些 TKI 抑制与其主要靶标具有相似或更高效力的替代靶标的能力(多效性效应)。