HER2低表达乳腺癌的靶向治疗研究进展
郭晴, 张剑
中国癌症杂志
2023, 33 ( 2):
181-190.
DOI: 10.19401/j.cnki.1007-3639.2023.02.012
乳腺癌是全球女性的第一大恶性肿瘤,发病率在逐年增加。人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)在乳腺癌的生物学行为及发病机制中起着重要作用。乳腺癌HER2低表达是指HER2免疫组织化学染色1+或2+且原位杂交(in situ hybridization,ISH)阴性,占全部类型的45% ~ 55%。尽管在目前的临床实践中,HER2低表达大多数仍被报告为HER2阴性或三阴性乳腺癌,但HER2低表达与HER2未检出乳腺癌不仅在HER2蛋白表达水平上不同,在雌激素受体(estrogen receptor,ER)状态、原发肿瘤体积、淋巴结受累情况、新辅助治疗后的病理学完全缓解率(pathologic complete response,pCR)以及无病生存期(disease-free survival,DFS)等方面也存在差异。在针对早期HER2低表达乳腺癌靶向治疗的临床试验中,NSABP B-31及N9831试验表现出乳腺癌患者受益于曲妥珠单抗辅助治疗的可能性,然而,在Ⅲ期前瞻性随机对照研究NSABP B-47中,曲妥珠单抗并未改变HER2低表达乳腺癌患者的无浸润性肿瘤复发生存期(invasive disease-free survival,iDFS)、5年无远处复发间期及总生存期(overall survival,OS)。近年来针对晚期HER2低表达乳腺癌靶向治疗开展的临床试验层出不穷,主要围绕曲妥珠单抗、拉帕替尼、恩美曲妥珠单抗(trastuzumab emtansine,T-DM1)、DS-8201(又名trastuzumab deruxtecan, T-DXd, Enhertu)及SYD985等新型抗体-药物偶联物(antibody-drug conjugate,ADC)类药物。Ⅲ期临床试验CALGB9840表明曲妥珠单抗对HER2非过度表达的乳腺癌缺乏治疗效果,改变鲁妥珠单抗剂量后仍无法克服治疗窗口窄的问题。两项随机Ⅲ期试验(EGF30001和EGF100151)均发现接受拉帕替尼并未改善HER2低表达乳腺癌患者的无进展生存期(progression-free survival,PFS)。单臂Ⅱ期研究4258g及4374g初步发现HER2低表达乳腺癌患者对T-DM1的敏感性,但由于患者数量较少,结论尚不明确。Ⅲ期临床研究DESTINY-Breast04证实了DS-8201(5.4 mg/kg)与医师选择方案(2∶1随机分配)在HER2低表达转移性乳腺癌中的安全性和有效性。针对SYD985的Ⅰ期临床试验显示了其治疗HER2低表达乳腺癌的效果和安全性(1.2 mg/ kg)。除此之外,以新型ADC药物(RC48-ADC、ARX788、A166等)、双特异性抗体(KN026、ZW25、ertumaxomab等)及乳腺癌疫苗(nelipepimut-S、GP2、AE37等)为代表的一系列新型抗HER2治疗手段的临床研究也正在进行中。本文将对近年HER2低表达乳腺癌靶向治疗药物的主要临床试验进行综述。
Drug | Clinical trials | Phase | Inclusion criteria | Primary outcome | Results | ADC | | | | | | RC48-ADC | NCT04400695 | Ⅲ | Participants with HER2-low, unresectable, locally advanced, or metastatic breast cancer who had previously been treated with an anthracycline and received 1 or 2 systemic chemotherapy regimens after relapse or metastasis | PFS | Ongoing | ARX788 | NCT05018676 | Ⅱ | Unresectable and/or metastatic HER2-low breast cancer. Patients with recurrent or metastatic disease should receive≥2 lines of systemic chemotherapy regimens; Hormone receptor-positive objects need to have received ≥2-line endocrine therapy±targeted therapy (including neoadjuvant/adjuvant therapy) | ORR | Ongoing | A166 | CTR20181301 | Ⅰ | Patients with HER2-expressing locally advanced or metastatic solid tumors (51 HER2-positive (3+ or 2+/ISH+), 6 HER2-low (1+ or 2+/ISH-) | ORR | The efficacy of 36 HER2-positive breast cancer patients with measurable disease was evaluated; the best ORR was 59.1% (13/22) and 71.4% (10/14) in the 4.8 and 6.0 mg/kg cohorts, respectively. Corneal epitheliopathy (73.7%), blurred vision (59.6%), peripheral sensory neuropathy (26.3%), dry eye (21.1%), anemia (19.3%), and hyponatremia (19.3%) were the most common TRAEs. Corneal epitheliopathy (17.5%), hypophosphatemia (5.3%), and dry eye (5.3%) were the most common grade 3 TRAEs | Bispecific antibody | | | | | | KN026 | NCT04165993 | Ⅱ | Patients with HER2-low and hormone receptor positive MBC failed standard chemotherapy and hormone therapy; patients with HER2-low and hormone receptor negative/weak positive MBC failed standard chemotherapy | ORR; DOR | Ongoing | ZW25 | NCT02892123 | Ⅰ | Patients with HER2-expressing cancer that was locally advanced (unresectable) or metastatic | DLTs | Ongoing | Ertumaxomab | NCT00522457 | Ⅱ | Enrolled patients had advanced breast cancer that was ER and/or PgR positive with low HER2 expression (IHC 1+ or 2+ and FISH negative). Patients were required to have PD after hormonal therapy that included at least one aromatase inhibitor, but no prior chemotherapy for advanced disease | ORR | The evaluable population's median TTP was 65.5 days (95% CI: 43-98). Pyrexia (74.1%), headache (40.7%), chill (33.3%), and vomitting (29.6%) were the most frequently observed AEs. The majority (73.8%) of AEs were mild or moderate in severity and resolved within one day | Vaccine | | | | | | Nelipepimut-S | NCT01479244 | Ⅲ | Patients with HER2/neu-positive, node-positive, or high-risk node-negative breast cancer | Disease recurrence | At the interim analysis with the median follow-up (16.8 months), there was no discernible between-arms difference in DFS events. Imaging identified 54.1% of recurrence episodes in NP-S participants as opposed to 29.2% in the placebo group (P = 0.069). Injection-related erythema (84.3%), induration (55.8%), and pruritus (54.9%) were the most prevalent | GP2 | NCT00524277 | Ⅱ | Breast cancer patients with tumors expressing HER2 (IHC 1-3+) who were clinically disease-free, node-positive, and high-risk node-negative were enrolled | Disease recurrence | The 5-year DFS rate in the ITT analysis was 88% (95% CI: 78%-94%) in the vaccine-eligible patients versus 81% (95% CI: 69%-89%) (P = 0.43), in the control group | AE37 | NCT00524277 | Ⅱ | Patients with tumors expressing any level of HER2 (IHC 1-3+) who were node-positive and high-risk node-negative for breast cancer and were clinically disease-free | Disease recurrence | Relative risk decreased 12%, HR = 0.885, 95% CI: 0.472-1.659, P = 0.70; recurrence rate in the immunized group was 12.4% against 13.8% in the control group. Vaccinated patients had a 5-year DFS rate of 80.8%, compared to 79.5% for control patients. The 5-year DFS was 77.2% in patients who received the vaccine (n = 76) compared to 65.7% in those who received a placebo (n = 78) in planned subset analyses of patients with IHC 1+/2+ HER2-expressing tumors (P = 0.21). DFS was 77.7% in the vaccinated patients (n = 25) against 49.0% in the control patients (n = 25) in patients with TNBC (HER2 IHC 1+/2+ and hormone receptor negative) (P = 0.12) |
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表1
抗HER2药物及HER2低表达乳腺癌相关临床试验概览
正文中引用本图/表的段落
乳腺癌是全球女性的第一大恶性肿瘤,发病率在逐年增加。人表皮生长因子受体2(human epidermal growth factor receptor 2,HER2)在乳腺癌的生物学行为及发病机制中起着重要作用。乳腺癌HER2低表达是指HER2免疫组织化学染色1+或2+且原位杂交(in situ hybridization,ISH)阴性,占全部类型的45% ~ 55%。尽管在目前的临床实践中,HER2低表达大多数仍被报告为HER2阴性或三阴性乳腺癌,但HER2低表达与HER2未检出乳腺癌不仅在HER2蛋白表达水平上不同,在雌激素受体(estrogen receptor,ER)状态、原发肿瘤体积、淋巴结受累情况、新辅助治疗后的病理学完全缓解率(pathologic complete response,pCR)以及无病生存期(disease-free survival,DFS)等方面也存在差异。在针对早期HER2低表达乳腺癌靶向治疗的临床试验中,NSABP B-31及N9831试验表现出乳腺癌患者受益于曲妥珠单抗辅助治疗的可能性,然而,在Ⅲ期前瞻性随机对照研究NSABP B-47中,曲妥珠单抗并未改变HER2低表达乳腺癌患者的无浸润性肿瘤复发生存期(invasive disease-free survival,iDFS)、5年无远处复发间期及总生存期(overall survival,OS)。近年来针对晚期HER2低表达乳腺癌靶向治疗开展的临床试验层出不穷,主要围绕曲妥珠单抗、拉帕替尼、恩美曲妥珠单抗(trastuzumab emtansine,T-DM1)、DS-8201(又名trastuzumab deruxtecan, T-DXd, Enhertu)及SYD985等新型抗体-药物偶联物(antibody-drug conjugate,ADC)类药物。Ⅲ期临床试验CALGB9840表明曲妥珠单抗对HER2非过度表达的乳腺癌缺乏治疗效果,改变鲁妥珠单抗剂量后仍无法克服治疗窗口窄的问题。两项随机Ⅲ期试验(EGF30001和EGF100151)均发现接受拉帕替尼并未改善HER2低表达乳腺癌患者的无进展生存期(progression-free survival,PFS)。单臂Ⅱ期研究4258g及4374g初步发现HER2低表达乳腺癌患者对T-DM1的敏感性,但由于患者数量较少,结论尚不明确。Ⅲ期临床研究DESTINY-Breast04证实了DS-8201(5.4 mg/kg)与医师选择方案(2∶1随机分配)在HER2低表达转移性乳腺癌中的安全性和有效性。针对SYD985的Ⅰ期临床试验显示了其治疗HER2低表达乳腺癌的效果和安全性(1.2 mg/ kg)。除此之外,以新型ADC药物(RC48-ADC、ARX788、A166等)、双特异性抗体(KN026、ZW25、ertumaxomab等)及乳腺癌疫苗(nelipepimut-S、GP2、AE37等)为代表的一系列新型抗HER2治疗手段的临床研究也正在进行中。本文将对近年HER2低表达乳腺癌靶向治疗药物的主要临床试验进行综述。
本文回顾了近年HER2低表达乳腺癌靶向治疗药物如曲妥珠单抗、拉帕替尼、T-DM1、DS-8201(又名trastuzumab deruxtecan, T-DXd, Enhertu)、SYD985等的主要临床试验相关研究。
然而,在NSABP B-47研究中,曲妥珠单抗不能使非IHC 3+或FISH阳性的乳腺癌患者受益。NSABP B-47是一项Ⅲ期前瞻性随机对照研究,目的是确定在辅助化疗中加入曲妥珠单抗是否可以改善HER2阴性乳腺癌患者的无浸润性肿瘤复发生存期(invasive disease-free survival,iDFS)。3 270例高危原发性浸润性乳腺癌且IHC 1+或2+、FISH<2.0的患者被随机分配到接受或不接受曲妥珠单抗1年的辅助化疗组中,中位随访时间为46个月。结果显示,辅助化疗联合曲妥珠单抗并未改善iDFS(5年iDFS:辅助化疗联合曲妥珠单抗组为89.8%,辅助化疗组为89.2%;HR = 0.98,95% CI:0.76 ~ 1.25,P = 0.85),且在HER2 IHC表达水平,淋巴结受累或激素受体状态方面差异无统计学意义。两组的5年无远处复发间期及总生存期(overall survival,OS)差异亦无统计学意义(HR = 1.10,95% CI:0.81 ~ 1.50,P = 0.550;HR = 1.33,95% CI:0.90 ~ 1.95,P = 0.150),但辅助化疗中添加曲妥珠单抗的毒性明显 [8]。一项研究汇总了4项前瞻性新辅助临床试验(GeparSepto,NCT01583426;GeparOcto,NCT02125344;GeparX,NCT02682693;Gain-2新辅助治疗,NCT01690702)中接受新辅助化疗的1 098例HER2低表达和1 212例HER2阴性原发性乳腺癌患者的DFS和OS数据,中位随访时间为46.6个月,四分位距(interquartile range,IQR)为(35.0 ~ 52.3)。结果显示,HER2低表达肿瘤的pCR显著低于HER2阴性肿瘤(29.2% vs 39.0%,P = 0.000 2),但OS明显长于HER2阴性患者(3年DFS:83.4% vs 76.1%,P = 0.008 4;3年OS:91.6% vs 85.8%,P = 0.001 6) [3]。
拉帕替尼是一种口服活性小分子,可抑制酪氨酸激酶如HER2和表皮生长因子受体(epidermal growth factor receptor,EGFR)1型 [20-21]。ErbB-2的过量表达导致EGFR系统的信号转导增强,从而抑制了其本身和EGFR的下调 [22]。研究者对两项随机Ⅲ期试验(EGF30001和EGF100151)的生物标志物进行了分析,以优化拉帕替尼治疗的患者选择。EGF30001(Clinicaltrials.gov注册号:NCT00075270)是一项随机、多中心、双盲、安慰剂对照、双臂、Ⅲ期临床试验,比较了579例患有局部HER2阴性(IHC 0或1+或2+/FISH阴性)或未接受过转移性疾病治疗的妇女的临床结果,其中有408例患者检测为HER2阴性。患者接受拉帕替尼与紫杉醇或紫杉醇加安慰剂治疗。EGF100151(Clinicaltrials.gov注册号:NCT00078572)是一项随机、多中心、双臂、Ⅲ期临床试验,比较了399例既往接受过蒽环类药物和曲妥珠单抗治疗的HER2阳性(IHC 3+或2+/FISH阳性)女性乳腺癌患者对卡培他滨-拉帕替尼治疗的临床结果,HER2阴性患者55例。HER2阴性状态定义为FISH<2或IHC 2+、1+或0(如果FISH未知)。对乳腺癌FISH阴性、IHC阳性(IHC>0)女性患者的无进展生存期(progression-free survival,PFS)进行分析结果显示:在患有HER2 FISH检测结果阴性、IHC阳性的女性乳腺癌患者中,接受拉帕替尼化疗的71例患者(HR = 0.97,P = 0.88)和单独接受化疗的72例患者的PFS差异无统计学意义。对FISH阴性、IHC阴性(IHC 0)的患者,化疗联合拉帕替尼治疗(n = 123例)与单独接受化疗(n = 114)相比,其PFS差异无统计学意义(HR = 1.13,P = 0.426 1) [23]。
TDM4258g研究为一项单臂Ⅱ期临床试验,评估静脉注射T-DM1(3.6 mg/kg,每3周1次,持续1年)对HER2阳性MBC患者的疗效和安全性,这些患者在之前接受HER2靶向治疗后肿瘤出现进展,并且接受过化疗。HER2阳性被定义为IHC 3+(10%的肿瘤细胞有强而完整的膜染色)和(或)FISH的HER2/CEP17比率为2.0。在112例接受治疗的患者中,21例患者为HER2正常的肿瘤,随访时间≥12个月。主要终点是ORR。在确认为HER2正常肿瘤的患者中,ORR为4.8%(95% CI:1.0% ~ 21.8%),中位PFS为2.6个月(95% CI:1.4 ~ 3.9个月) [28]。4374g是一项单臂Ⅱ期研究,给予既往接受过曲妥珠单抗、拉帕替尼、蒽环类药物和卡培他滨治疗的MBC患者T-DM1 3.6 mg/kg(静脉注射),HER2阳性标准为IHC 3+或FISH 阳性。共纳入110例患者,其中15例(15.8%)HER2正常(HER2 FISH比率<2.0及IHC≤2+),随访中位时间为17.4个月,主要研究终点是ORR。结果显示,HER2正常患者的ORR为20%(95% CI:5.7% ~ 44.9%),中位PFS 2.8个月(95% CI:1.3个月 ~ N/E)。这一观察结果表明,HER2表达低于目前使用的临床阈值可能足以赋予对T-DM1的敏感性,也有可能是肿瘤的HER2状态随时间变化(即治疗时的肿瘤HER2状态与存档的肿瘤样本不同)。但由于患者数量较少,不能得出明确的结论,需要对该问题进行进一步研究 [29]。
DS8201-A-J101是一项开放标签的剂量递增Ⅰ期试验,在日本的两个研究地点进行。符合条件者为患有乳腺癌、胃癌或胃食管癌,标准疗法难治,无论HER2状态。参与者接受DS-8201的初始静脉注射剂量为0.8 ~ 8.0 mg/kg。结果显示,在23例可评估的患者中,包括13例以前接受过T-DM1治疗的患者和6例HER2低表达的肿瘤患者(定义为IHC1+/FISH阴性、IHC1+/FISH未检测或IHC2+/FISH阴性),10例(95% CI:23.2 ~ 65.5)获得了ORR(10例部分反应者,包括3例未确认的总体缓解)。在这个小规模、重度预处理的研究人群中,DS-8201显示了抗肿瘤活性,甚至在低HER2表达的肿瘤中 [33]。NCT02564900是一项首次进行的Ⅰ期非随机、开放标签、多剂量研究,在美国的8个地点和日本的6个地点进行。这项研究报道了DS-8201在HER2低表达(IHC1+或2+/ISH-)乳腺癌患者中以推荐剂量进行扩增(recommended doses for expansion,RDE)的结果。HER2低表达被定义为IHC 2+/ISH2,IHC 1+/ISH2,或IHC 1+/ISH未检测。有54例晚期HER2低表达乳腺癌患者入选并接受5.4(21例)或6.4 mg/kg(33例)的DS-8201≥1个剂量的治疗。54例受试者既往中位治疗线数为7.5线,83.3%既往经历≥5线治疗,5例(9.3%)患者的HER2表达为IHC 0,30例(55.6%)为IHC 1+,14例(25.9%)为IHC 2+。经独立中心审查确认,ORR为37.0%(95% CI:24.3% ~ 51.3%),中位反应时间为10.4个月(95% CI:8.8个月 ~ 无法评估)。DS-8201在HER2低表达乳腺癌患者中表现出初步抗肿瘤活性。大多数毒性是消化道或血液不良反应。间质性肺疾病是一个重要的识别风险,应密切监测并积极管理 [34]。DAISY是一项多中心、开放标签的Ⅱ期临床试验,评估了5.4 mg/kg剂量的单药DS-8201在HER2过表达(IHC3+或IHC 2+/ISH+,n = 72)、HER2低表达(IHC2+/ISH-或IHC1+,n = 74)和HER2未检出(IHC0+,n = 40)且接受过≥1次化疗方案的MBC患者的疗效,并进行生物标志物分析。主要终点是研究者评估的最佳疗效(best of response,BOR),次要终点为中心评估的BOR、临床获益率(clinical benefit rate,CBR)、疗效持续时间(duration of response,DoR)、PFS及OS。中位随访15.6个月后,HER2低表达队列研究者评估的BOR为37.5%(27/72),中位DoR为7.6个月(95% CI:4.2个月~9.2个月),中位PFS为6.7个月(95% CI:4.4个月~8.3个月);HER2未检出队列的BOR为29.7%(11/37),中位DoR为6.8个月(95% CI:2.8个月 ~ 无法评估),中位PFS为4.2个月(95% CI:2.0个月 ~ 5.7个月)。安全性方面,共有173例患者(96.6%)发生了至少1次治疗相关的不良事件(treatment-related adverse event,TRAE)。13例患者因治疗相关的不良事件而中止治疗(5例患者为间质性肺病) [35]。
抗体-药物偶联物SYD985对HER2低表达乳腺癌患者显示出良好疗效(无论是否有激素受体表达)。一项Ⅰ期临床试验(ClinicalTrials.gov注册号:NCT02277717)评估了SYD985对HER2低表达MBC患者的安全性和疗效。HER2低表达定义为IHC1+/2+/ISH-。该研究共纳入HER2低表达乳腺癌受试者49例,包括激素受体阳性型乳腺癌(32例)和三阴性乳腺癌(17例)。患者每3周接受1.2 mg/kg SYD985静脉注射治疗。结果显示,ORR分别为27%和40%,安全可控。最常见的药物不良反应是疲劳、眼睛干燥、结膜炎。≥3级药物不良反应中最常见中性粒细胞减少(6%)和结膜炎(4%) [39]。
除了前述靶向HER2的单克隆抗体、小分子抑制剂以及初步取得可喜结果的DS-8201等ADC药物,全世界的研究者们也将目光投向其他新型ADC药物(RC48-ADC、ARX788、A166 [40]等)、双特异性抗体(KN026、ZW25、ertumaxomab [41]等)和乳腺癌疫苗(nelipepimut-S [42]、GP2 [43]、AE37 [44]等),并在此基础上开展了相关的临床试验,以期为早期或晚期HER2低表达乳腺癌患者提供新希望。部分正在开展或已取得结果的抗HER2药物及临床试验的信息见表1。
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