Download PDF

- Emiltatug ledadotin observed to be generally well tolerated with differentiated safety and tolerability profile

-观察到Emiltatug-ledadotin通常耐受性良好，具有不同的安全性和耐受性

- Promising clinical activity observed in patients with triple-negative breast cancer (TNBC) previously treated with topoisomerase-1 inhibitor (topo-1) ADCs; confirmed responses observed across all enrolled tumor types

-在先前用拓扑异构酶-1抑制剂（topo-1）ADC治疗的三阴性乳腺癌（TNBC）患者中观察到有希望的临床活性；在所有登记的肿瘤类型中观察到确认的反应

- First expansion cohort initiated in patients with TNBC previously treated with at least one topo-1 ADC; dose exploration efforts ongoing

-首次扩展队列始于先前接受至少一种topo-1 ADC治疗的TNBC患者；剂量探索工作正在进行中

- Company announces expected 2025 milestones and areas of focus

-公司宣布预计2025年里程碑和重点领域

- Conference call today at 8:30 a.m. ET

-美国东部时间今天上午8:30召开电话会议

CAMBRIDGE, Mass., Jan. 10, 2025 (GLOBE NEWSWIRE) -- Mersana Therapeutics, Inc. (NASDAQ: MRSN), a clinical-stage biopharmaceutical company focused on discovering and developing a pipeline of antibody-drug conjugates (ADCs) targeting cancers in areas of high unmet medical need, today announced positive initial clinical data from the Phase 1 dose escalation and backfill cohorts for emiltatug ledadotin (Emi-Le; XMT-1660), Mersana’s lead Dolasynthen ADC candidate targeting B7-H4..

马萨诸塞州剑桥市，2025年1月10日（环球通讯社）--Mersana Therapeutics，Inc.（纳斯达克：MRSN），一家临床阶段的生物制药公司，专注于发现和开发针对高度未满足医疗需求地区癌症的抗体-药物偶联物（ADC）管道，今天宣布了针对emiltatug-ledadotin（Emi-Le；XMT-1660）的第一阶段剂量递增和回填队列的积极初步临床数据，Mersana的主要Dolasynthen ADC候选靶向B7-H4。。

“We believe the initial safety, tolerability and efficacy data for Emi-Le demonstrate a profile that is exciting and differentiated within both the B7-H4 field and the broader ADC landscape,” said Martin Huber, M.D., President and Chief Executive Officer of Mersana Therapeutics. “We have observed clinical activity across tumors, including in heavily pre-treated patients with TNBC.

Mersana Therapeutics总裁兼首席执行官Martin Huber医学博士说：“我们相信Emi Le的初始安全性，耐受性和有效性数据显示出在B7-H4领域和更广泛的ADC领域都令人兴奋和有区别的概况。”。。

These clinical data have led us to initiate expansion in patients with TNBC who have previously been treated with at least one topo-1 ADC, a population with very high unmet need.”.

这些临床数据使我们开始扩大TNBC患者的范围，这些患者以前至少接受过一种topo-1 ADC治疗，这是一种未满足需求的人群。”。

As of a December 13, 2024 data cutoff, the dose escalation portion of the Emi-Le Phase 1 clinical trial enrolled a total of 130 patients with advanced/metastatic TNBC; hormone-receptor-positive, human epidermal growth factor receptor 2 negative breast cancer; ovarian cancer; endometrial cancer and adenoid cystic carcinoma type 1.

截至2024年12月13日的数据截止日期，Emi Le 1期临床试验的剂量递增部分共招募了130名晚期/转移性TNBC患者；激素受体阳性，人表皮生长因子受体2阴性乳腺癌；卵巢癌；子宫内膜癌和腺样囊性癌1型。

The enrolled patient population was heavily pretreated, with patients receiving up to 15 and a median of 4.5 prior lines of therapy, and approximately 92% of enrolled patients with TNBC had been previously treated with at least one topo-1 ADC. Among the 103 patients with known B7-H4 tumor expression, approximately 44% had a tumor proportion score of 70% or higher, which Mersana has preliminarily characterized as “B7-H4 high.”.

登记的患者人群经过了严重的预处理，患者接受了多达15次的治疗，中位数为4.5次治疗，大约92%的TNBC登记患者先前曾接受过至少一次topo-1 ADC治疗。在103例已知B7-H4肿瘤表达的患者中，约44%的肿瘤比例评分为70%或更高，Mersana初步将其表征为“B7-H4高”。

Emi-Le was observed to be generally well tolerated, with no Grade 4 or 5 treatment-related adverse events (TRAEs) reported. The most common TRAEs of any grade across the entire patient population were transient aspartate aminotransferase (AST) increase (38% of patients), generally asymptomatic and reversible proteinuria (31%), generally low-grade nausea (29%) and low-grade fatigue (28%).

观察到Emi-Le通常耐受性良好，没有报告4级或5级治疗相关不良事件（TRAEs）。在整个患者人群中，任何级别最常见的TRAE是瞬时天冬氨酸转氨酶（AST）升高（38%的患者），一般无症状和可逆性蛋白尿（31%），一般低度恶心（29%）和低度疲劳（28%）。

The only Grade 3 TRAEs in ≥5% or more of all patients were AST increase (14%) and proteinuria (9%). Across the entire enrolled patient population, TRAEs leading to discontinuation, dose reduction and dose delay were observed in 2.3%, 9.2% and 12.3% of patients, respectively. No dose-limiting treatment-related neutropenia, neuropathy, ocular toxicity, interstitial lung disease or thrombocytopenia were reported, which the company believes differentiates Emi-Le from many other approved and clinical-stage ADCs..

。在整个登记的患者人群中，分别有2.3%，9.2%和12.3%的患者观察到导致停药，剂量减少和剂量延迟的TRAE。没有报道剂量限制性治疗相关的中性粒细胞减少症，神经病，眼部毒性，间质性肺病或血小板减少症，该公司认为这将Emi Le与许多其他批准的和临床阶段的ADC区分开。。

At intermediate doses in the trial (38.1 mg/m

试验中的中等剂量（38.1 mg/m

2

2

to 67.4 mg/m

至67.4毫克/米

2

2

), the confirmed objective response rate (ORR) among evaluable patients (those with measurable disease at baseline and at least one post-baseline scan) was 23% (6 of 26 patients) across all B7-H4 high tumors and 23% (3 of 13 patients) with B7-H4 high TNBC, all of whom had previously been treated with at least one topo-1 ADC..

)，在所有B7-H4高肿瘤中，可评估患者（基线时有可测量疾病且至少有一次基线后扫描的患者）的确诊客观缓解率（ORR）为23%（26名患者中的6名），23%（13名患者中的3名）患有B7-H4高TNBC，所有患者之前都接受过至少一次topo-1 ADC治疗。。

In the ASCENT Phase 3 clinical trial of sacituzumab govitecan, a topo-1 ADC, the ORR with standard-of-care single-agent chemotherapy in relapsed/refractory TNBC was approximately 5% with progression free survival of approximately seven weeks. Based on these encouraging Emi-Le data at intermediate doses, Mersana has advanced a dose of 67.4 mg/m.

在topo-1 ADC sacituzumab-govitecan的ASCENT 3期临床试验中，复发/难治性TNBC标准治疗单药化疗的ORR约为5%，无进展生存期约为7周。基于这些令人鼓舞的中等剂量Emi Le数据，Mersana将剂量提高了67.4 mg/m。

2

2

every four weeks (Q4W) into an expansion cohort in patients with TNBC who have received one to four prior treatment lines, including at least one prior topo-1 ADC.

每四周（Q4W）进入TNBC患者的扩展队列，这些患者接受了一到四个先前的治疗线，包括至少一个先前的topo-1 ADC。

“In terms of both tolerability and clinical activity, these Emi-Le data are encouraging,” Erika Hamilton, M.D., Director Breast Cancer Research, Sarah Cannon Research Institute in Nashville, Tennessee, said. “It is notable that all the TNBC patients who responded to Emi-Le had previously been treated with at least one topo-1 ADC.

田纳西州纳什维尔莎拉·坎农研究所乳腺癌研究主任埃里卡·汉密尔顿医学博士说：“就耐受性和临床活动而言，这些Emi-Le数据令人鼓舞。”。“值得注意的是，所有对Emi Le有反应的TNBC患者以前都接受过至少一种topo-1 ADC治疗。

The results indicate that Emi-Le may help address an already substantial and growing need among topo-1 experienced breast cancer patients for new treatments.”.

结果表明，Emi-Le可能有助于解决topo-1经验丰富的乳腺癌患者对新疗法的已经相当大且不断增长的需求。”。

At high doses above 76 mg/m

高剂量超过76毫克/米

2

2

, the confirmed ORR among evaluable patients was 22% (2 of 9 patients) across all B7-H4 high tumors. Additionally, 78% (7 of 9 patients) had ≥30% tumor reduction in target lesions. At these high dose levels, objective responses in multiple evaluable patients with B7-H4 high tumors were not confirmed after protocol-mandated dose delays for proteinuria.

，在所有B7-H4高肿瘤中，可评估患者中确诊的ORR为22%（9名患者中的2名）。此外，78%（9例患者中有7例）的靶病变肿瘤减少≥30%。在这些高剂量水平下，在方案规定的蛋白尿剂量延迟后，未确认多个可评估的B7-H4高肿瘤患者的客观反应。

Mersana is implementing proteinuria mitigation efforts and continues to explore higher doses in dose escalation and backfill cohorts to identify a second dose for the expansion portion of the trial..

Mersana正在实施蛋白尿缓解工作，并继续在剂量递增和回填队列中探索更高剂量，以确定试验扩展部分的第二剂量。。

Mersana’s Expected 2025 Milestones and Areas of Focus

梅萨纳2025年的预期里程碑和重点领域

Emi-Le

Emi Le公司

1H2025: Continue enrollment in expansion at a dose of 67.4 mg/m

1H2025：继续以67.4 mg/m的剂量进行扩张

2

2

Q4W in patients with TNBC who have previously received at least one prior topo-1 ADC

先前至少接受过一次topo-1 ADC的TNBC患者的Q4W

2025: Initiate enrollment in expansion at a second dose in patients with TNBC who have previously received at least one prior topo-1 ADC

2025年：对先前至少接受过一次topo-1 ADC的TNBC患者开始第二次剂量的扩容

2025: Present additional Phase 1 clinical data from dose escalation and backfill cohorts

2025年：提供来自剂量递增和回填队列的额外1期临床数据

XMT-2056, Mersana’s lead Immunosynthen ADC targeting a novel HER2 epitope

XMT-2056，Mersana针对新型HER2表位的铅免疫合成ADC

2025: Present initial clinical pharmacodynamic STING activation data

2025年：目前初步的临床药效学STING激活数据

Pipeline

管道

Continue to support internal pipeline and existing collaborations with Johnson & Johnson and Merck KGaA, Darmstadt, Germany

继续支持内部渠道以及与强生和默克KGaA（德国达姆施塔特）的现有合作

Conference Call Information

电话会议信息

Mersana will host a conference call today at 8:30 a.m. ET to discuss the initial clinical data from its Phase 1 clinical trial of Emi-Le. To access the call, please dial 833-255-2826 (domestic) or 412-317-0689 (international). A live webcast that includes the data presentation will be available on the Investors & Media section of the Mersana website at .

Mersana将于美国东部时间今天上午8:30召开电话会议，讨论Emi Le第一阶段临床试验的初步临床数据。要拨打电话，请拨打833-255-2826（国内）或412-317-0689（国际）。Mersana网站的投资者和媒体部分将提供包括数据演示在内的在线直播。

www.mersana.com

www.mersana.com

, and a replay of the webcast will be available in the same location following the conference call for approximately 90 days.

，网络广播的重播将在电话会议后的大约90天内在同一地点提供。

About Mersana Therapeutics

关于Mersana Therapeutics

Mersana Therapeutics is a clinical-stage biopharmaceutical company focused on the development of novel antibody-drug conjugates (ADCs) and driven by the knowledge that patients are waiting for new treatment options. The company has developed proprietary cytotoxic (Dolasynthen) and immunostimulatory (Immunosynthen) ADC platforms that are generating a pipeline of wholly-owned and partnered product candidates with the potential to treat a range of cancers.

Mersana Therapeutics是一家临床阶段的生物制药公司，专注于开发新型抗体-药物偶联物（ADC），并受到患者等待新治疗选择的知识的驱动。该公司开发了专有的细胞毒性（Dolasynthen）和免疫刺激（Immunosynthin）ADC平台，这些平台正在产生一系列全资和合作的候选产品，有可能治疗一系列癌症。

Its pipeline includes Emi-Le (emiltatug ledadotin; XMT-1660), a Dolasynthen ADC targeting B7-H4, and XMT-2056, an Immunosynthen ADC targeting a novel epitope of human epidermal growth factor receptor 2 (HER2). Mersana routinely posts information that may be useful to investors on the “Investors & Media” section of its website at .

其管道包括Emi-Le（emiltatug-ledadotin；XMT-1660），一种靶向B7-H4的Dolasynthen ADC和XMT-2056，一种靶向人表皮生长因子受体2（HER2）新表位的免疫合成ADC。Mersana经常在其网站的“投资者与媒体”部分发布可能对投资者有用的信息。

www.mersana.com

www.mersana.com

.

.

Forward-Looking Statements

前瞻性声明

This press release contains “forward-looking” statements and information within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be identified by words such as “aims,” “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “may,” “plans,” “possible,” “potential,” “seeks,” “will” and variations of these words or similar expressions, although not all forward-looking statements contain these words.

本新闻稿包含1995年《私人证券诉讼改革法案》所指的“前瞻性”声明和信息。这些陈述可以用“目标”、“预期”、“相信”、“可能”、“估计”、“预期”、“预测”、“目标”、“打算”、“可能”、“计划”、“可能”、“潜在”、“寻求”、“将”等词语以及这些词语或类似表达的变体来识别，尽管并非所有前瞻性陈述都包含这些词语。

Forward-looking statements in this press release include, but are not limited to, statements concerning Mersana’s plans regarding the clinical development of Emi-Le and XMT-2056, including with respect to the progress and design of the clinical trials of these product candidates; the potential clinical benefits of Emi-Le; Mersana’s efforts to identify an additional dose for investigation in the expansion portion of its Phase 1 clinical trial of Emi-Le; Mersana’s planned data presentations, including with respect to its Phase 1 clinical trial of Emi-Le and to clinical pharmacodynamic STING activation data related to XMT-2056; Mersana’s collaborations with third parties; and the development and potential of Mersana’s product candidates, platforms, technology and pipeline of ADC candidates.

本新闻稿中的前瞻性声明包括但不限于关于Mersana关于Emi Le和XMT-2056临床开发计划的声明，包括关于这些候选产品临床试验的进展和设计；Emi-Le的潜在临床益处；Mersana努力在其Emi Le 1期临床试验的扩大部分确定额外剂量进行调查；Mersana计划的数据介绍，包括其Emi-Le的1期临床试验以及与XMT-2056相关的临床药效学STING激活数据；Mersana与第三方的合作；以及Mersana候选产品、ADC候选平台、技术和管道的发展和潜力。

Mersana may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in these forward-looking statements as a result of various factors, including, among other things, uncertainties inherent in research and development, in the advancement, progression and completion of clinical trials and in th.

梅萨纳可能无法实际实现这些前瞻性声明中披露的计划、意图或期望，您不应过度依赖这些前瞻性声明。由于各种因素的影响，实际结果或事件可能与这些前瞻性声明中披露的计划，意图和期望存在重大差异，其中包括研究和开发，临床试验的进展，进展和完成以及临床试验中固有的不确定性。

Contact:

联系人：

Jason Fredette

杰森·弗雷德特

617-498-0020

617-498-0020

jason.fredette@mersana.com

jason.fredette@mersana.com