Investigating Resistance Mechanisms to Non-covalent Bruton's Tyrosine Kinase Inhibitors and Therapeutic Approaches to Overcome Resistance for Patients with B-Cell Malignancies

项目摘要 B细胞恶性肿瘤，如慢性淋巴细胞白血病（CLL）和其他形式的非霍奇金淋巴瘤 淋巴瘤（NHL）是通常发生在成人中的常见血液恶性肿瘤。这些恶性肿瘤 由功能失调的成熟B细胞引起B细胞受体（BCR）通路的不规则信号传导可导致 B细胞恶性肿瘤的增殖和存活使得布鲁顿酪氨酸（BTK），一种BCR早期的激酶 这是一个有吸引力的癌症治疗靶点。虽然现有的治疗方法可以导致疾病缓解， 几乎所有的患者都会复发，导致CLL仍然被认为是不治之症的共识。 BTK的共价（不可逆）小分子抑制剂，如伊曲替尼，已经改变了治疗方法。 CLL、套细胞淋巴瘤（MCL）和Waldenström巨球蛋白血症（WM）。共价BTK抑制剂 在多种B细胞恶性肿瘤中有效，然而由于耐药性和不耐受性，许多患者 停止这些代理。为了克服这些问题，高度选择性和可逆的非共价BTK 已经开发了抑制剂。它们目前正在临床试验中进行测试，显示出安全性和前景 在多种B细胞肿瘤中的疗效，包括预先大量治疗的CLL、MCL、WM和滤泡性淋巴瘤， 证明非共价BTK抑制剂可能解决替代疗法日益增长的未满足需求 对于这些患者。尽管吡托替尼具有有益的特征，并且在研究中观察到较高的总体缓解率， I期研究中，一些既往接受过治疗的CLL和B细胞恶性肿瘤患者对 治疗或对单药治疗初始应答后复发。 基于BTK、PLCG 2和其他反复突变基因的下一代突变分析 在CLL中，在非共价BTK抑制剂治疗之前和治疗进展时，我们现在 鉴定了仅在治疗后可检测到的新型BTK和PLCG 2变体。鉴于这些初步 研究结果，我假设BTK或B细胞受体信号通路（如 作为PLCG 2突变）导致对非共价BTK抑制的抗性，并且组合BTK 抑制剂与其它靶向CLL的药物将避免所述耐药性。目前，没有任何报告 对非共价BTK抑制剂的耐药机制。该提案将确定 通过该方法，细胞产生对非共价BTK抑制的抗性，并用另外的抗BTK抗体攻击该抗性。 目标1：确定新BTK突变的潜在机制 在对非共价BTK抑制的获得性抗性中观察到。目标2：测试联合疗法以克服 B细胞淋巴瘤对BTK抑制剂的耐药性。对治疗替代品的需求呈指数级增长， 获得性耐药患者的发病率增加。这项研究的结果将产生重大影响 用于各种B细胞恶性肿瘤患者。此外，这些发现将为发展提供信息， 与非共价BTK抑制剂的合理组合疗法。

PROJECT SUMMARY B-cell malignancies such as chronic lymphocytic leukemia (CLL) and other forms of Non-Hodgkin lymphomas (NHL) are common hematologic malignancies typically occurring in adults. These malignancies arise from dysfunctional, mature B-cells. Irregular signaling of the B-Cell receptor (BCR) pathway can lead to proliferation and survival of B-cell malignancies making Bruton’s tyrosine (BTK), a kinase early in the BCR pathway, an attractive target for cancer therapy. While available treatments can lead to disease remission, nearly all patients relapse, leading to the consensus that CLL remains to be considered an incurable disease. Covalent (irreversible) small molecule inhibitors of BTK, such as ibrutinib, have transformed the management of CLL, mantle cell lymphoma (MCL), and Waldenström’s Macroglobulinemia (WM). Covalent BTK inhibitors are efficacious in multiple B-cell malignancies, however due to resistance and intolerance, many patients discontinue these agents. To overcome these problems, highly selective and reversible non-covalent BTK inhibitors have been developed. They are currently being tested in clinical trials showing safety and promising efficacy in multiple B-cell neoplasms, including heavily pre-treated CLL, MCL, WM, and follicular lymphoma, demonstrating that non-covalent BTK inhibitors might address a growing unmet need for alternative therapies for these patients. Despite the beneficial features of pirtobrutinib and a high overall response rate seen in the Phase 1 studies, some patients with previously treated CLL and B-cell malignancies did not respond to treatment or relapsed after initial response to monotherapy. Based on next-generation mutational analysis of BTK, PLCG2, and additional genes recurrently mutated in CLL prior to non-covalent BTK inhibitor therapy and at the time of on treatment progression, we have now identified novel BTK and PLCG2 variants that were only detectable post-treatment. Given these preliminary findings, I hypothesize that on-target mutations within BTK or the B-cell receptor signaling pathway (such as PLCG2 mutations) result in resistance to non-covalent BTK inhibition and that combining BTK inhibitors with other CLL targeting drugs will circumvent said resistance. Currently, there are no reports of resistance mechanisms to non-covalent BTK inhibitors in patients. This proposal will identify the mechanisms by which cells develop resistance to non-covalent BTK inhibition and challenge that resistance with additional targeted therapies in the following aims: Aim 1: Identify the mechanism underlying novel BTK mutations observed in acquired resistance to non-covalent BTK inhibition. Aim 2: Test combination therapies to overcome resistance to BTK inhibitors in B-cell lymphoma. There is an exponential need for therapeutic alternatives due to an increased incidence of patients with acquired resistance. The results of this study will have a major impact for patients with a variety of B-cell malignancies. Additionally, these findings will inform the development of rational combination therapies with non-covalent BTK inhibitors.