全球首个！复宏汉霖PD- L1 ADC破局胸腺癌，HLX43将于美国启动全球多中心临床研究

• 胸腺癌（TC）突破性治疗潜力：HLX43是全球首个布局胸腺癌的PD-L1 ADC，具备突破性治疗潜力，有望填补该罕见高侵袭癌种 ADC治疗的空白；

• 潜在同类最优（FIC）的广谱抗肿瘤ADC：HLX43在非小细胞肺癌（NSCLC）、胸腺鳞癌（TSCC）等实体瘤中皆展现出“高效、低毒”的治疗潜力，广谱抗肿瘤药物价值凸显；

• 领跑PD-L1 ADC全球开发：HLX43是全球首款进入II期临床的PD-L1 ADC，复宏汉霖正高效推进该产品在中、美、日、澳等地的国际多中心临床研究，以缩短HLX43的全球上市周期，加速惠及全球患者。

胸腺癌（Thymic carcinoma）是一种起源于胸腺上皮的罕见恶性肿瘤，约占所有胸腺上皮肿瘤的14%-22%^[1]。该疾病呈现侵袭性特征，如局部浸润、胸内淋巴结和远处转移，且预后较差^[2]。其病理亚型以鳞状细胞癌（squamous cell carcinoma）为主，占比约70%，其次为淋巴上皮癌、未分化癌等^[3]。流行病学研究显示，该疾病中位发病年龄为50-60岁^[1]，全球年发病率稳定在0.15/10万，但近年诊断率呈上升趋势^[2]。对于早期局限性胸腺癌，手术切除是首选治疗方法。对于晚期或复发转移患者，一线治疗主要为联合化疗方案，二线治疗包括化疗、靶向治疗、免疫治疗等系统治疗。但现有治疗方案存在各种局限，如缺少驱动基因、耐药机制复杂、不良反应严重等，且整体疗效有限，亟待更加安全且有效的新型治疗方案^[4-8]。

HLX43是一款靶向程序性死亡-配体1（PD-L1）的广谱抗肿瘤ADC候选药物，由全人源IgG1抗PD-L1抗体与创新连接子-拓扑异构酶抑制剂荷载偶联而成，药物抗体比（drug-to-antibody ratio, DAR）约为8。HLX43兼具毒素精准杀伤（ADC）和肿瘤免疫治疗（IO）的复合功能：其毒素不仅能够藉靶点内吞进入肿瘤细胞后进行释放，并在肿瘤微环境中释放后借助旁观者效应进入肿瘤细胞，阻断DNA复制，从而导致肿瘤细胞凋亡；此外，HLX43的PD-L1靶向抗体可激活免疫调节机制，发挥协同抗肿瘤效应。HLX43的I期临床数据展现出令人鼓舞的初步疗效和安全性，对鳞状/非鳞状NSCLC，有无EGFR突变、有无脑/肝转移、PD-L1阳性/阴性的NSCLC患者都展现了优异的治疗潜力。值得关注的是，HLX43在胸腺鳞状细胞癌（TSCC）患者人群中展现了优异的疗效数据，75%的胸腺鳞状细胞癌患者达到部分缓解（3/4名，ORR = 75%）。该I期研究数据在2025 美国临床肿瘤学会（ASCO）年会上首次发布，并将于2025年世界肺癌大会（WCLC）以壁报形式进行更新，由该研究的主要研究者，中国医学科学院肿瘤医院王洁教授在壁报导览环节发布。

目前公司正在全力推进HLX43临床开发进程，积极探索其在多种实体瘤中的治疗潜力，包括非小细胞肺癌、胸腺鳞癌、肝细胞癌、食管鳞癌、头颈鳞癌、宫颈癌、鼻咽癌等。单药之外，HLX43联用复宏汉霖自研斯鲁利单抗（H药 汉斯状®，抗PD-1单抗）治疗实体瘤的 Ib/II 期临床试验也正在进行中，进一步探索“ADC+IO”的协同抗肿瘤疗效。HLX43不仅可能克服PD-1/L1免疫疗法不响应或耐药问题，并对化疗、TKI治疗失败的患者都具有潜在疗效，有望为更多晚期/转移性实体瘤患者带来新的治疗选择。

未来，复宏汉霖将加速推动HLX43在全球范围内的研发进程，不断夯实更多创新分子的差异化布局，为更多肿瘤患者带来高质量、可负担的创新治疗方案。

Henlius to Initiate a Phase 1 Multicenter Study in US of Its PD-L1 ADC HLX43 for the Treatment of Thymic Carcinoma

• Breakthrough Potential in Thymic Carcinoma (TC):

HLX43, the first PD-L1 ADC demonstrating promising efficacy in thymic carcinoma (TC), is positioned to address the critical gap as ADC therapies for this rare, highly aggressive malignancy

• Potential Best-in-Class Pan-Tumor ADC:

HLX43 exhibits "high efficacy and low toxicity" across solid tumors including NSCLC and thymic squamous cell carcinoma (TSCC), highlighting its broad-spectrum therapeutic potential

• Leading Global Development of PD-L1 ADC:

HLX43 is the first PD-L1 ADC advancing to Phase 2 trials globally. The company is accelerating multicenter studies of HLX43 in China, the U.S., Japan, and Australia to expedite global launch to benefit broader patient populations

Recently, Shanghai Henlius Biotech, Inc. (2696.HK) announced that HLX43 for Injection, the company‘s innovative programmed death-ligand 1 (PD-L1) targeting antibody-drug conjugate (ADC) has been approved by the United States Food and Drug Administration (FDA) to initiate a phase 1 clinical trial incorporating thymic carcinoma (TC) cohort to benefit a broader range of tumor patients globally. Previously, HLX43 has already been approved to conduct phase 2 MRCT in patients with advanced non-small cell lung cancer (NSCLC) in China, U.S., Japan and Australia. To date, no PD-L1 targeting ADC has been approved for marketing globally. HLX43 is the first PD-L1 ADC progressed to phase 2 clinical trial development globally.

Thymic Carcinoma (TC) is a rare malignant neoplasm originating from thymic epithelial cells, accounting for approximately 14%-22% of all thymic epithelial tumors (TETs) ^[1]. TC demonstrates aggressive behavior characterized by local invasion, intrathoracic lymph node metastasis, and distant dissemination, correlating with poor prognosis^[2]. Histopathologically, thymic squamous cell carcinoma (TSCC) constitutes the predominant subtype (∼70%), followed by lymphoepithelial carcinoma and undifferentiated carcinoma^[3]. Epidemiological studies indicate a median age at diagnosis of 50-60 years^[1], with a stable global annual incidence of 0.15 per 100,000 person-years; however, increasing diagnostic rates have been observed in recent years^[2]. For localized early-stage patients, surgical resection remains the primary therapeutic approach, while advanced or recurrent/metastatic cases require first-line platinum-based combination chemotherapy followed by second-line systemic therapies (including chemotherapy, targeted therapies, and immunotherapy). Critical therapeutic limitations persist, including lack of actionable driver mutations, complex drug resistance mechanisms, significant treatment-related toxicities, and suboptimal efficacy, underscoring the urgent unmet medical need for safer and more effective novel treatment strategies^[4-8]. 

HLX43 is a broad-spectrum anti-tumor ADC candidate targeting PD-L1, composed of a fully humanized anti-PD-L1 IgG1 antibody, a novel tripeptide linker and topoisomerase inhibitor payload. The drug-to-antibody ratio (DAR) is around 8. Its mechanisms of action integrate targeted cytotoxic delivery and immune checkpoint activation through PD-L1/PD-1 blockade. Upon binding to tumor cells with PD-L1 expression, the cytotoxic payload of HLX43 will be delivered into tumor cells via dual mechanisms. HLX43 will undergo receptor-mediated endocytosis, releasing the cytotoxic payload intracellularly via linker cleavage, and the payload further diffuses into neighboring tumor cells via bystander effect, thereby blocking DNA replication and triggering tumor cell apoptosis. Meanwhile, the anti-PD-L1 antibody of HLX43 activates immune modulation and blocks immune checkpoints, driving synergistic anti-tumor efficacy. The results from the phase 1 clinical trial of HLX43 has been first released at the 2025 ASCO Annual Meeting, demonstrating manageable safety profile and encouraging efficacy in various solid tumors especially in patients with NSCLC, including squamous and non-squamous NSCLC patients (sqNSCLC and nsqNSCLC), patients with or without EGFR mutation, patients with or without brain/liver metastasis, and PD-L1 positive or negative patients. Notably, encouraging preliminary efficacy was observed in thymic squamous cell carcinoma (TSCC) patients, 75% patients with TSCC achieved partial response (ORR=75%, 3/4). Updated phase 1 clinical data will be presented in the poster tour session by Jie wang from Cancer Hospital Chinese Academy of Medical Sciences, the leading PI（principal investigator) of this study at the upcoming 2025 World Conference on Lung Cancer (WCLC) .

The company is currently accelerating the clinical development of HLX43 and actively exploring its therapeutic potential in various solid tumors, including NSCLC, TSCC, hepatocellular carcinoma (HCC), esophageal squamous cell carcinoma (ESCC), head and neck squamous cell carcinoma (HNSCC), cervical cancer (CC) and nasopharyngeal cancer (NPC). Both monotherapy studies and a phase 1b/2 trial combining HLX43 with serplulimab (Henlius' proprietary anti-PD-1 monoclonal antibody) are ongoing simultaneously to further exploit the synergistic effects of ADC-mediated cytotoxicity and immunotherapy-induced immune activation. HLX43 may benefit more patients with advanced or metastatic solid tumors by providing a novel treatment option for those who are unresponsive or have developed resistance to PD-1/PD-L1-targeted therapies, as well as the patients who have failed prior chemotherapy or TKI therapies.

Looking forward, Henlius will accelerate the global development of HLX43, continuously strengthening the differentiated layout of more innovative molecules to bring high-quality, affordable innovative treatment options to tumor patients worldwide.