Rilzabrutinib

近日，云顶新耀公布新型BTK抑制剂1b/2a期临床结果，针对自身免疫性肾脏疾病。这意味着BTK抑制剂在完成血液肿瘤领域的迭代升级后，正以不可阻挡之势“卷”入自免新战场。  01  迭代加快布鲁顿酪氨酸激酶（BTK）作为B细胞受体（BCR）信号通路的核心枢纽，其异常活化是驱动多种B细胞恶性肿瘤（如CLL、MCL、WM）生长的关键因素。由于BTK在B细胞及部分造血细胞（如巨噬细胞、肥大细胞）中特异性表达，而在T细胞中缺失，使其成为极具潜力的精准靶点。BTK抑制剂正是通过高特异性结合BTK，阻断其自身磷酸化及活化，从而切断致癌信号传导，诱导肿瘤细胞凋亡（图1）。图1.BCR信号是B细胞存活的重要信号通路自2013年第一代抑制剂伊布替尼获批至今，BTK抑制剂的发展呈现出显著的迭代加速特征，其核心驱动力直指临床亟待解决的痛点。伊布替尼的诞生具有里程碑意义，它引领B细胞恶性肿瘤治疗进入“无化疗时代”。然而，其选择性不足导致脱靶抑制（如EGFR、TEC、BMX等），引发皮疹、房颤、腹泻和高血压等显著副作用，成为临床应用的主要掣肘（表1）。表1.全球已上市 BTK 抑制剂这一缺陷迅速催生了第二代BTK抑制剂的密集研发与上市，通过结构优化大幅提升对BTK的选择性，有效减轻脱靶效应，显著改善了治疗安全性。当通过与BTK活性位点的Cys481形成不可逆共价结合的第一、二代共价BTK抑制剂成为CLL/SLL等疾病的标准治疗并展现优于化疗的无进展生存期（PFS）获益时，耐药性问题浮出水面。Cys481位点突变（在MCL和高危CLL/SLL中发生率更高）导致药物结合失效，成为患者疾病进展的主要原因。这一难题直接推动了第三代非共价可逆BTK抑制剂的突破性进展。它们无需依赖Cys481结合，通过可逆方式抑制BTK，成功绕开了共价抑制剂的主要耐药机制，为耐药患者提供了关键解决方案（表1）。图2.全球 BTK 抑制剂销售额（亿美元）（左）BTK 抑制剂全球市场规模（亿美元）（右）此外，市场动态是这一快速迭代最直观的印证。伊布替尼曾长期主导市场，其全球销售额连续四年超80亿美元，但近年已出现连续下滑。与此同时，第二代产品如阿可替尼和泽布替尼展现出强劲增长势头。根据Deutsche Bank Report 2022 数据，BTK抑制剂全球市场仍处于扩张期，预计2026年规模将达204亿美元（图2）。这一此消彼长的格局清晰表明，更安全、更有效的迭代产品正快速赢得临床认可。  02  肿瘤激战当前BTK药物在肿瘤领域竞争已进入白热化阶段。截至目前，全球处于临床阶段的BTK抑制剂候选药物多达40种，但其中仅默沙东的非共价可逆抑制剂Nexitamubtin（奈他布替尼）进展到III期临床（图3）。这种研发火热但临床转化艰难的局面，为现有的六款上市药物巩固市场地位提供了时间，同时也迫使企业寻求差异化策略以建立竞争优势。图3.BTK抑制剂重点药物当前竞争的核心，聚焦于新一代（三代）BTK抑制剂的正面较量。礼来凭借目前唯一上市的三代药物吡托布鲁替尼率先发力。该药采用非共价结合机制，有望克服约30%患者因BTK C481S突变而产生的耐药性问题。礼来正通过一系列积极的头对头III期临床试验发起攻势：在套细胞淋巴瘤（MCL）领域，同时挑战伊布替尼、阿卡替尼和泽布替尼这三款“前辈”；在慢性淋巴细胞白血病/小淋巴细胞淋巴瘤（CLL/SLL）领域，则直接对标伊布替尼。更显雄心的是，礼来还在探索吡托布鲁替尼挑战CD20单抗作为一线治疗的潜力，试图改变现有的治疗模式。另外，默沙东的三代候选药物Nemtabrutinib的II期数据已展现出竞争力：在CLL/SLL患者中客观缓解率（ORR）达到56%，边缘区淋巴瘤（MZL）患者ORR高达64%，MCL联合治疗的ORR也达到64%，为其即将参与的市场争夺打下了基础。正当小分子药物激战正酣之时，百济神州的BTK降解剂BGB-16673凭借全新的作用机制开辟了另一条战线（图4）。这款PROTAC药物通过招募E3泛素连接酶来诱导BTK蛋白降解，从源头上解决耐药蛋白累积的问题。图4.BTK CDAC有望成为cBTKi后同类最佳MOA其早期临床数据令人瞩目：在I期CaDAnCe-101研究中，经过大量前期治疗的CLL患者ORR达到78%，在200mg剂量组更飙升至94%；华氏巨球蛋白血症（WM）患者ORR为90%，边缘区淋巴瘤（MZL）患者ORR更是达到100%。基于这些积极结果，百济神州于2025年5月启动了BGB-16673头对头挑战吡托布鲁替尼的III期研究，随着头对头临床试验数据的陆续揭晓，真正的赢家将逐渐浮出水面。  03  进军自免BTK抑制剂这一在血液肿瘤领域缔造了巨大商业价值的靶向疗法，正强势进军自免这片“兵家必争之地”。目前全球共有33款针对自免的在研BTK抑制剂，其适应症聚焦于多发性硬化症（MS）、慢性自发性荨麻疹（CSU）、系统性红斑狼疮（SLE）及类风湿性关节炎（RA）等核心领域，一场围绕BTK靶点的差异化开发竞赛已然擂鼓喧天。其中，诺华的Remibrutinib作为“先锋”，已在国内提交上市申请，剑指CSU。其关键III期研究（REMIX-1和REMIX-2）数据确证了显著疗效：经治CSU患者接受瑞米布替尼（25mg，每日2次）治疗12周后，关键指标如每周荨麻疹活动度评分（UAS7）、瘙痒严重程度评分（ISS7）和荨麻疹严重程度评分（HSS7）均较安慰剂组显著下降。图5.Remibrutinib治疗难治性CSU的III期临床研究结果更令人鼓舞的是，据《新英格兰医学杂志》公布的III期结果（图5），治疗第1周即可快速减轻瘙痒和荨麻疹症状，至第24周约30%患者症状完全消失，第52周时近半数患者实现无瘙痒和荨麻疹症状。诺华选择CSU这一存在大量抗组胺药应答不佳患者的领域作为突破口，成功开辟了差异化路径。几乎同期，赛诺菲的Rilzabrutinib（图6）在免疫性血小板减少症（ITP）领域取得关键进展。其针对持续性或慢性ITP成年患者的III期LUNA 3研究达到主要终点，与安慰剂组相比，Rilzabrutinib组实现持久血小板应答的患者比例显著更高（23% vs 0%，p<0.0001）。该药已获美国FDA优先审评，国内上市申请亦于2024年12月30日获受理，有望成为首个获批治疗ITP的BTK抑制剂。图6.Rilzabrutinib作用机制除上述临近上市的“排头兵”外，更多药企正依托BTK靶点的广泛适用性，在各自免细分领域进行纵深布局，构建多层次竞争格局。罗氏的口服、可逆、非共价BTK抑制剂Fenebrutinib，凭借其穿透血脑屏障的独特优势，在多发性硬化症（MS）领域展现出潜力。其II期FENopta开放标签扩展研究显示，接受治疗长达1年的复发性MS患者中96%疾病无复发，残疾状况未进展，III期结果预计2025年底公布；而赛诺菲的另一款产品Tolebrutinib同样瞄准MS，其III期HERCULES研究显示对非复发性继发进展型MS（SPMS）患者残疾进展延缓31%，但在复发性MS的两项III期研究中未达显著降低年复发率的主要终点；云顶新耀开发的EVER001则聚焦自身免疫性肾脏疾病，进一步拓宽了BTK抑制剂在自免领域的治疗疆域。  结语  从血液肿瘤到自身免疫疾病，BTK抑制剂通过跨领域“内卷”持续拓展治疗边界，重塑全球药物研发格局。参考资料[1]Cool, Allison et al. “BTK inhibitors: past, present, and future.” Trends in pharmacological sciences vol. 45,8 (2024): 691-707. [2]https://www.nejm.org/doi/pdf/10.1056/NEJMoa2408792[3]平安证券研报[4]财通证券研报[5]各企业官网及各种公开资料等识别微信二维码，添加抗体圈小编，符合条件者即可加入抗体圈微信群！请注明：姓名+研究方向！本公众号所有转载文章系出于传递更多信息之目的，且明确注明来源和作者，不希望被转载的媒体或个人可与我们联系(cbplib@163.com)，我们将立即进行删除处理。所有文章仅代表作者观点，不代表本站立场。

Rilzabrutinib granted orphan drug designation in the US for sickle cell disease Fourth orphan drug designation for rilzabrutinib in rare diseasesUnder regulatory review in the US, the EU, and China in immune thrombocytopenia Paris, June 3, 2025. The US Food and Drug Administration (FDA) has granted orphan drug designation to rilzabrutinib, a novel, advanced, oral, reversible Bruton's tyrosine kinase (BTK) inhibitor that works via multi-immune modulation, to target a reduction in vaso-occlusive crises, which may occur via inflammation, in sickle cell disease. The FDA grants orphan drug designation to investigational therapies addressing rare medical diseases or conditions that affect fewer than 200,000 people in the US. Karin Knobe, MD, PhDGlobal Head of Development, Rare Diseases“Receiving our fourth orphan drug designation for rilzabrutinib reinforces our continued dedication to developing medicines to address the unmet medical needs of people living with rare diseases. People with sickle cell disease often live with severe episodes of pain from vaso-occlusive crises and other complications that can significantly impact both quality of life and life expectancy. There remains a need for novel treatment approaches to address these experiences by modulating the immune system responses that can contribute to sickle cell disease pathogenesis.” In addition to sickle cell disease, rilzabrutinib has received orphan drug designation for immune thrombocytopenia (ITP) in the US, the EU, and Japan, for warm autoimmune hemolytic anemia (wAIHA) in the US and the EU, and for IgG4-related disease (IgG4-RD) in the US. The safety and efficacy of rilzabrutinib have not been determined by any regulatory authority. Rilzabrutinib is currently under regulatory review in the US, the EU, and in China for its potential use in ITP. The target action date for the FDA regulatory decision for ITP, which was granted fast track designation, is August 29, 2025. Sickle cell disease supporting dataPreclinical data on sickle cell disease was presented at ASH 2024 showing that rilzabrutinib helped reduce vaso-occlusion –blockage of blood vessels – and inflammation in transgenic mice with sickle cell disease. About rilzabrutinib Rilzabrutinib is a novel, advanced, oral, reversible Bruton’s tyrosine kinase (BTK) inhibitor that has the potential to be an effective new medicine for several rare immune-mediated or inflammatory diseases by working to restore immune balance via multi-immune modulation. BTK, expressed in B cells, macrophages, and other innate immune cells, plays a critical role in multiple immune-mediated disease processes and inflammatory pathways. With the application of Sanofi’s TAILORED COVALENCY® technology, rilzabrutinib can selectively inhibit the BTK target while potentially reducing the risk of off-target side effects. About sickle cell diseaseSickle cell disease is a group of rare, genetic blood disorders in which red blood cells are misshapen, typically in a sickle or crescent shape, causing them to get stuck in small blood vessels, blocking blood flow. This can lead to episodes of severe pain as well as other health complications including infections, stroke, lung, eye, and kidney disease. Sickle cell disease affects more than 100,000 people in the US, approximately 90% of whom are African American and 3-9% of whom are Hispanic or Latino. Approximately 1 in 365 babies of African American descent born in the US have sickle cell disease, while an estimated 1 in 13 are carriers of the disease. People in the US with sickle cell disease have an estimated life expectancy that is 20 years shorter than average. About Sanofi Sanofi is an R&D driven, AI-powered biopharma company committed to improving people’s lives and creating compelling growth. We apply our deep understanding of the immune system to invent medicines and vaccines that treat and protect millions of people around the world, with an innovative pipeline that could benefit millions more. Our team is guided by one purpose: we chase the miracles of science to improve people’s lives; this inspires us to drive progress and deliver positive impact for our people and the communities we serve, by addressing the most urgent healthcare, environmental, and societal challenges of our time. 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