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HER2阳性乳腺癌占全部乳腺癌的15%~20%,高达30%~50%的HER2阳性晚期乳腺癌患者发生脑转移。虽然立体定向放疗、全脑放疗和手术切除等局部治疗是脑转移标准治疗方法,但是往往于6~12个月内面临颅内复发,这可能由于局部治疗无法清除微转移灶所致。因此,需要为脑转移尤其活动性(尚未治疗或治疗后进展)脑转移研发化疗之外的全身靶向治疗方案。
由于曲妥珠单抗等大分子HER2抗体无法有效穿过血脑屏障,对中枢神经系统活性极低,既往HER2阳性乳腺癌脑转移研究主要集中于小分子HER2酪氨酸激酶抑制剂,包括拉帕替尼、吡咯替尼和奈拉替尼。对于HER2阳性乳腺癌脑转移初次治疗患者,拉帕替尼+卡培他滨的客观缓解率为66%,但是对于经过多线治疗患者,客观缓解率降至21%。对于HER2阳性乳腺癌转移放疗后患者,吡咯替尼+卡培他滨的颅内客观缓解率为42.1%。不过,那些已经对酪氨酸激酶抑制剂耐药的活动性脑转移成为临床难题,急需新的全身治疗方案。
近期研究表明,恩美曲妥珠单抗、德曲妥珠单抗等HER2抗体缀合小分子化疗药物对HER2阳性乳腺癌脑转移有一定疗效。KAMILLA研究HER2阳性乳腺癌脑转移患者事后探索性分析表明,恩美曲妥珠单抗颅内客观缓解率为21.4%。此外,奈拉替尼+恩美曲妥珠单抗治疗HER2阳性活动性脑转移患者6个月时疾病稳定或客观缓解率达38.1%~50.0%。DESTINY-Breast01、02和03研究汇总分析表明,德曲妥珠单抗对HER2阳性乳腺癌活动性脑转移患者中枢神经系统客观缓解率达45.5%。同样,DEBBRAH研究报告该人群颅内客观缓解率达46.2%。DESTINY-Breast12研究证实,德曲妥珠单抗对HER2阳性乳腺癌活动性脑转移患者中枢神经系统客观缓解率达62.3%,使其成为首选治疗方案。值得注意的是,KAMILLA研究59.5%的患者用过HER2酪氨酸激酶抑制剂治疗,而DESTINY-Breast12研究该比例仅约5%。开发新一代抗体缀合药物,并测试其对HER2阳性乳腺癌脑转移的效果,具有较大的临床价值。
新一代抗体缀合药物ARX788将两枚小分子微管蛋白抑制剂通过非天然氨基酸对乙酰苯丙氨酸定点缀合于HER2抗体,能够抑制癌细胞有丝分裂,诱导细胞周期停滞、死亡。ARX788从复旦大学附属肿瘤医院开始一期临床研究,直至三期临床研究ACE-Breast-02,该关键研究由复旦大学附属肿瘤医院胡夕春教授牵头,已经证实ARX788与拉帕替尼+卡培他滨相比,HER2阳性晚期乳腺癌患者中位无进展生存为11.3个月比8.2个月,进展或死亡风险减少36%(风险比:0.64,P=0.0006),突显其治疗潜力。不过,该研究未入组活动性脑转移患者。
2025年10月30日,英国《柳叶刀》旗下《临床医学》在线发表复旦大学附属肿瘤医院李婷①、林明曦①、王碧芸、赵明川、曹君、王磊苹、陶中华、金娟、缪海涛、龚成成、赵燕南、彭文霞、胡夕春✉️、张剑✉️等学者的ACE-Breast-06研究报告,首次前瞻探讨了ARX788对HER2阳性乳腺癌活动性脑转移经过多线治疗患者的有效性和安全性,弥补了ACE-Breast-02研究的缺憾。
ACE-Breast-06 (NCT05018702): ARX788 in HER2-positive Breast Cancer Patients With Brain Metastases
Official Title: A Prospective, Single-arm, Single-center Phase II Clinical Study of Recombinant Humanized Anti-HER2 Monoclonal Antibody-AS269 Conjugate (ARX788) in the Treatment of HER2-positive Breast Cancer Patients With Brain Metastases
该单中心单组二期临床研究于2021年8月至2025年4月入组年龄18至75岁HER2阳性乳腺癌至少存在一个可测量活动性脑转移灶(≥1厘米)患者32例(其中25.0%为二线治疗,40.6%为三线治疗,其余为至少四线治疗;40.6%经过中枢神经系统放疗,6.3%经过脑部手术;全部经过曲妥珠单抗和紫杉类治疗,其中40.6%经过帕妥珠单抗治疗;全部经过酪氨酸激酶抑制剂治疗,其中吡咯替尼占90.6%、拉帕替尼占9.4%)每3周静脉注射ARX788治疗,剂量为1.5mg/kg,直至疾病进展或毒性反应不可耐受。主要终点是中枢神经系统临床获益率(≥24周时完全缓解、部分缓解或疾病稳定的患者比例)。次要终点包括中枢神经系统总体缓解率、中枢神经系统无进展生存、无进展生存、总生存、下次进展部位和安全性。每6周测量肿瘤大小,对ARX788治疗至少一次患者进行有效性和安全性分析。
结果,截至2025年4月,32例患者中位随访15.0个月(范围1.8~42.5个月)
中枢神经系统临床获益率:34.4%(95%置信区间:18.6~53.2%)
中枢神经系统确认总体缓解率:25.0%(95%置信区间:11.5~43.4%)
中枢神经系统中位无进展生存:5.6个月(95%置信区间:3.0~7.4个月)
中位无进展生存:5.5个月(95%置信区间:2.8~7.0个月)
总生存:数据尚不成熟
仅出现颅外进展:8.3%
仅出现颅内进展:70.8%
颅内且颅外进展:20.8%
治疗相关不良事件发生率:
≥3级:12.5%
≥3级视力模糊:9.4%
≥3级肺间质病或肺炎:6.3%
≥3级角膜病变:6.3%
≥3级干眼症:3.1%
≥3级血小板减少:3.1%
≥3级胃肠道毒性:低于1%
5级肺间质病或肺炎:3.1%
因此,ACE-Breast-06二期临床研究结果表明,超过三分之一的HER2阳性乳腺癌活动性脑转移多线治疗失败(全部用过曲妥珠单抗、紫杉类和酪氨酸酶抑制剂)患者经过ARX788治疗脑转移病灶能够实现持续24周以上完全缓解、部分缓解或疾病稳定,四分之一的患者脑部肿瘤显著缩小,为患者争取了接近半年的脑转移无进展生存时间,超过七成患者仅颅内进展,≥3级治疗相关不良事件发生率仅12.5%,血液学毒性和胃肠道毒性发生率相对较低,ARX788有望成为此类患者的潜在治疗选择,未来需要开展包括患者报告结局的多中心大样本随机对照三期临床研究,更全面地评价ARX788对HER2阳性乳腺癌脑转移,尤其经过德曲妥珠单抗治疗患者的临床价值。
eClinicalMedicine. 2025 Oct 30;90:103614. IF: 10.0
Efficacy and safety of ARX788 for individuals with HER2-positive breast cancer and brain metastases (ACE-Breast-06): a single-arm, phase 2 trial in China.
Ting Li, Mingxi Lin, Biyun Wang, Mingchuan Zhao, Jun Cao, Leiping Wang, Zhonghua Tao, Juan Jin, Haitao Miao, Chengcheng Gong, Yannan Zhao, Wenxia Peng, Xichun Hu, Jian Zhang.
Fudan University Shanghai Cancer Center, Shanghai, China; Shanghai Medical College, Fudan University, Shanghai, China.
BACKGROUND: ARX788 is a next-generation antibody-drug conjugate (ADC) in which an anti-HER2 monoclonal antibody is linked to a monomethyl auristatin F (MMAF) payload. This study aimed to investigate the intracranial efficiency of ARX788 in epidermal growth factor receptor 2 (HER2)-positive breast cancer with active brain metastases.
METHODS: This prospective, single-arm, phase 2 trial was conducted at a single centre in Shanghai, China. Eligible participants were patients (aged 18-75 years) with HER2-positive breast cancer who had received trastuzumab, taxane, and tyrosine kinase inhibitor (TKI) treatment, and also had at least one measurable active brain metastatic lesion (≥1 cm). Participants received ARX788 at 1.5 mg/kg via intravenous infusion every 3 weeks until disease progression or unacceptable toxicity. The primary endpoint was clinical benefit rate (CBR) in the central nervous system (CNS), defined as the proportion of patients with complete response (CR)/partial response (PR)/stable disease (SD) at ≥24 weeks as per RANO-BM. Secondary endpoints included CNS overall response rate, CNS progression-free survival (PFS), PFS, overall survival, sites of next progression, and safety. Tumour response was assessed every 6 weeks. Both efficacy and safety analyses included patients who had received at least one dose of ARX788. This study is registered with ClinicalTrials.gov, NCT05018702.
FINDINGS: Between August 2021 and April 2025, 32 patients were included and treated with ARX788. The median follow-up duration was 15.0 months (range, 1.8-42.5), and two patients were still receiving ARX788 treatment at final data cutoff (April 2025). As for the intracranial efficacy, the CNS CBR was 34.4% (95% CI: 18.6-53.2; 11 of 32 patients) and the proportion of patients with confirmed CNS overall response rate was 25.0% (11.5-43.4). Median CNS PFS was 5.6 (95% CI: 3.0-7.4) months and median PFS was 5.5 (95% CI: 2.8-7.0) months. Data on overall survival were immature at the time of data analysis. As for the sites of next progression, 8.3% of participants had extracranial progression alone, 70.8% had intracranial progression alone, and 20.8% had both intracranial and extracranial progression. Grade ≥3 treatment-related adverse events (TRAEs) occurred in four (12.5%) of 32 patients. The most common grade ≥3 TRAEs were blurred vision (9.4%), interstitial lung disease/pneumonitis (6.3%), keratopathy (6.3%), dry eyes (3.1%), and thrombocytopaenia (3.1%). The rate of grade ≥3 gastrointestinal toxicity was less than 1%. A grade 5 ILD/pneumonitis event occurred in one (3.1%) patient.
INTERPRETATION: This phase 2 trial is, to our knowledge, the first study of ARX788 in patients with brain metastases. Whilst acknowledging the limitations of this design, our findings show support for ARX788 as a potential treatment alternative for patients with HER2-positive active brain metastases. Future prospective studies incorporating patient-reported outcomes are needed to better capture the clinical benefit of ARX788.
FUNDING: National Natural Science Foundation of China; National Key Research and Development Program of China; Shanghai Science and Technology Innovation Action Plan; and Beijing Science and Technology Innovation Medical Development Foundation Key Project.
KEYWORDS: HER2-positive, Breast cancer, Brain metastases, ARX788
DOI: 10.1016/j.eclinm.2025.103614
(来源:SIBCS)
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