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【2021 ASCO解读】刘晟骅:Abstract 4541:阿替唑珠单抗治疗卡介苗无反应非肌层浸润性膀胱癌的II期试验(4541)

2021年08月08日
作者:刘晟骅
医院:上海市第十人民医院

 

               
刘晟骅
主治医师

上海市第十人民医院泌尿外科主治医师,外科学博士,毕业于复旦大学上海医学院临床医学八年制,导师国内著名泌尿外科专家丁强教授,目前为上海市第十人民医院泌尿外科医师,中国抗癌协会会员,擅长泌尿系统肿瘤,结石,前列腺增生等疾病的诊断和治疗,尤其从事膀胱肿瘤临床和基础研究,曾获得上海市优秀毕业生,复旦大学优秀住院医生等荣誉称号。近5年以第一/共一/通讯作者身份发表SCI论文10篇。其中1篇论文连续被2016-2020年欧洲泌尿外科指南(EAU)引用。荣获2019年同济大学青年教师讲课比赛一等奖。获得同济大学优秀青年培育计划,上海市第十人民医院攀登人才计划,入选2020年上海市青年科技英才扬帆计划项目。

Phase II trial of atezolizumab in BCG-unresponsive non-muscle invasive bladder cancer: SWOG S1605 (NCT #02844816). First Author: Peter C. Black, Vancouver Prostate Centre, University of British Columbia, Vancouver, BC, Canada

Background

Radical cystectomy (RC) is the standard of care for patients with BCG-unresponsive high risk non-muscle invasive bladder cancer (NMIBC), but many patients are unfit for surgery or elect bladder preservation. This trial was designed to evaluate the activity of atezolizumab in BCG-unresponsive high risk NMIBC.

Methods

This single arm phase II registration trial testing systemic atezolizumab (1200 mg IV) every 3 weeks for one year aimed to enroll 135 (70 CIS and 65 non-CIS) eligible patients with histologically proven BCG-unresponsive high risk NMIBC who were unfit for or declined RC. Here we report the 18 month results for all eligible patients who received at least one protocol treatment. The co-primary endpoints were pathological complete response (CR) rate at 6 months in patients with CIS (reported at ASCO 2020), and event-free survival (EFS) in all patients at 18 months using Kaplan-Meier methods (KM), conditional on a positive CIS response rate. A sample size of 135 evaluable patients provided 93% statistical power for detecting a 30% 18-month EFS rate versus 20% using a one-sided alpha = 0.05. EFS in the subset with Ta/T1 disease and duration of response in CIS patients were secondary endpoints.

Results

172 patients were enrolled, 166 received at least one dose of atezolizumab and are included in the safety analysis, and, of those, 128 were eligible and included in the efficacy analysis. As previously reported, 20 (27%) out of 74 patients with CIS attained a pathologic CR at 6 months. The KM estimate of 12 month (actual 11.9 mo) duration of response after 6 month CR for CIS patients was 54% (95% CI 30%, 78%) and the median duration of response was 16.5 months. The KM EFS rate at 18 months in 74 patients with CIS was 17% (90% CI 9%, 25%). The 18 month KM EFS rate in the overall population of 128 patients with Ta, T1 and CIS was 29% (90% CI 22%, 36%). The 18 month actuarial EFS rate in 54 patients with Ta/T1 disease was 45% (90% CI 34, 57%). Any possibly or probably treatment-related adverse event (TRAE) was observed in 142 out of 166 (86%) patients who received any atezolizumab regardless of eligibilty. The most frequent TRAEs were fatigue 72 (43%), diarrhea 34 (20%), and anemia 38 (23%). Grade 3-5 TRAEs occurred in 28 (17%) patients, including rash in 4 (2%), hyponatremia in 4 (2%), hypertension in 3 (2%) and elevated liver function tests in 3 (2%). There were two treatment-related deaths (sepsis and respiratory failure due to myasthenia gravis). 

Conclusions

The observed response of atezolizumab at 6 and 18 months in patients with BCG-unresponsive CIS suggests that this could be a valuable treatment to address a critical unmet need in this patient population. The 18 month EFS in patients with Ta/T1 disease suggests activity in this patient subset. This trial provided no new safety concerns. Funding: NIH/ NCI grants: CA180888, CA180819, CA180820, CA180821, CA180863 and in part by Genentech. Clinical trial information: NCT02844816. Research Sponsor: U.S. National Institutes of Health, Pharmaceutical/Biotech Company

Abstract 4541:阿替唑珠单抗治疗卡介苗无反应非肌层浸润性膀胱癌的II期试验:SWOG S1605(NCT#02844816)

背景

根治性膀胱切除术(RC)是BCG无反应的高危非肌层浸润性膀胱癌(NMIBC)患者的标准治疗,但许多患者不适合手术或选择保留膀胱。本试验旨在评估阿替唑珠单抗对卡介苗无反应的高危NMIBC的疗效。

方法

这项单臂II期注册临床试验研究了每3周静脉使用阿替利珠单抗的疗效,持续1年。研究招募了135名符合条件的患者,包括70名合并原位癌(CIS)和65名不合并CIS的Ta/T1期患者。这些患者都是组织学证实为卡介苗无反应的高危NMIBC,不适合或拒绝接受RC治疗。研究报道了18个月的随访结果。主要终点是CIS患者6个月时的病理完全缓解(CR)率(ASCO 2020报告),以及所有患者18个月时的无事件生存率(EFS)(事件指高级别肿瘤复发或死亡)。次要终点为Ta/T1组的EFS和CIS患者的持续反应时间。

结果

研究共计招募了172例患者,安全性分析纳入了其中166例接受了至少一剂阿替唑珠单抗治疗,其中128例符合条件的患者进一步纳入疗效分析。如前所述,74例CIS患者中有20例(27%)在6个月时获得CR。对于6个月时达到CR的CIS患者,估计持续12个月(实际11.9个月)缓解的比例为54%(95%CI ,30%-78%),中位持续缓解期为16.5个月。74例CIS患者18个月时EFS为17%(90%CI,9%-25%)。在所有128例患者中,18个月EFS为29%(90%CI , 22%-36%)。54例Ta/T1疾病患者18个月的EFS为45%(90%CI,34%-57%)。安全性分析方面,在166例(86%)接受阿替唑珠单抗治疗的患者中,有142例(86%)观察到治疗相关的不良事件(TRAE)。最常见的TRAEs是疲劳72例(43%),腹泻34例(20%),贫血38例(23%)。发生3~5级TRAE 28例(17%),其中皮疹4例(2%),低钠血症4例(2%),高血压3例(2%),肝功能增高3例(2%)。有两例治疗相关死亡(败血症和重症肌无力引起的呼吸衰竭)。

结论

阿替唑珠单抗在卡介苗无反应的CIS患者6个月和18个月时的疗效数据仍有一定的价值,对于卡介苗无反应,而有保膀胱需求的患者,不失为一种治疗选择。Ta/T1亚组患者18个月EFS数据表明阿替唑珠单抗对不合并CIS的患者疗效更好。这次试验没有提出新的安全问题。

解读

本研究是阿替利珠单抗开拓尿路上皮癌适应症的研究之一。近年阿替利珠单抗在尿路上皮癌中的研究不时传出阴性结果,IMvigor 010研究在肌层浸润膀胱癌(MIBC)辅助治疗中与安慰剂相比得到了无差异的DFS1。而IMvigor211研究(在顺铂失效后的局部晚期或转移性尿路上皮癌中与二线化疗比较)的阴性结果则直接导致FDA撤销了其适应症2。本研究是阿替利珠单抗首个非肌层浸润膀胱癌(NMIBC)的单臂II期临床研究,瞄准的是NMIBC中保膀胱治疗的最后一道“防线”:卡介苗治疗无反应的非肌层浸润膀胱癌,若能成功拿下此适应症,则可为高危NMIBC保膀胱治疗提供新的希望。


研究共纳入128名TURBt病理诊断为Ta/T1期且满足后续疗效分析条件的患者,其中74名合并原位癌(CIS),54名未发现CIS。在术后6月行膀胱镜活检并进行疗效判断。在2020年ASCO-GC会议上公布了第一个主要终点,即6个月的CR数据为26%,今年补充数据后更新为27%,与其竞争对手帕博利珠单抗的单臂,II期,卡介苗无反应的NMIBC研究(Keynote-057)的数据相比,大体相似4。在持续应答时间上,12个月的持续应答率为48.9%,而Keynote-057研究为46.2%。2021年的摘要还公布另一主要终点结果,即18个月的EFS。合并CIS的患者仅为14%,但不合并CIS的患者可达到47%,提示阿替立珠单抗似乎对于无CIS的乳头状肿瘤患者疗效更好,这项数据是Keynote-052研究无法提供的,Keynote-052研究仅纳入了CIS患者。但在安全性方面,3-5级的TRAE的数据似乎略高(17% vs 13%),并出现2例治疗相关的死亡。对本研究安全性的担忧以及主要终点事件未达到预定的统计学差异,导致了研究过早的关闭3

WX20210808-202858.png

表1 SWOG S1605(本研究)与Keynote-057研究的对比。

#未报道,此数据根据KM曲线估计;

*Keynote-057研究报道的是3个月达到CR的患者的持续应答率,本研究报道的是3个月达到CR的患者的持续应答率;


此类研究为卡介苗无反应的NMIBC提供了新的用药思路,以往卡介苗无反应的NMIBC的患者需要接受全膀胱切除,对于卡介苗失效后还有什么保膀胱办法?一直是困扰泌尿肿瘤界的难题,主要开展的临床试验有灌注化疗,灌注免疫治疗,系统性免疫治疗,靶向治疗等几种办法,本研究属于系统性免疫治疗。Chevalier等人5发现卡介苗的使用导致尿液中PD-L1调节蛋白水平升高,这为ICI药物在卡介苗难治性膀胱癌的应用提供了可能的理论基础。早前公布的帕博利珠单抗Keynote-057研究因数据较好,在2020年1月获得FDA批准,成为首款治疗NMIBC的PD-1(L1)疗法。虽然随后的阿替利珠单抗的同类研究似乎折戟沉沙,但未来此类相关研究还有帕博利珠单抗(Keynote-676)和纳武单抗(NCT04149574)两项III期临床可以期待,预计结果在2022年下半年公布。


参考文献

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2、Powles T, Durán I, van der Heijden MS, et al. Atezolizumab versus chemotherapy in patients with platinum-treated locally advanced or metastatic urothelial carcinoma (IMvigor211): a multicentre, open-label, phase 3 randomised controlled trial. Lancet. 2018 Feb 24;391(10122):748-757. doi: 10.1016/S0140-6736(17)33297-X. Epub 2017 Dec 18. Erratum in: Lancet. 2018 Oct 20;392(10156):1402. PMID: 29268948.

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