STRO-004 demonstrates robust and consistent antitumor activity across multiple TF-expressing

STRO-004在多个表达TF的肿瘤中显示出强大且一致的抗肿瘤活性。

solid tumor PDX models, with improved efficacy versus benchmark ADCs

实体瘤PDX模型，相较于基准ADCs疗效更佳

STRO-006 and STRO-227 show meaningful, dose-dependent antitumor activity across solid tumor models

STRO-006 和 STRO-227 在实体瘤模型中显示出显著的、剂量依赖性的抗肿瘤活性。

Presentation of TROP2-targeted immunostimulatory ADC program partnered with Astellas highlights the potential of Sutro’s platform for developing dual-payload ADCs

与Astellas合作的TROP2靶向免疫刺激ADC项目展示了Sutro平台开发双载荷ADC的潜力。

SOUTH SAN FRANCISCO, Calif., April 19, 2026 (GLOBE NEWSWIRE) -- Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), a clinical-stage oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), today announced promising preclinical data across its pipeline of next- generation ADCs in five posters and one oral presentation at the American Association for Cancer Research (AACR) Annual Meeting 2026.

南旧金山，加利福尼亚州，2026年4月19日（环球新闻社）——Sutro Biopharma, Inc.（Sutro或公司）（纳斯达克股票代码：STRO），一家处于临床阶段的肿瘤学公司，专注于开创位点特异性和新型抗体药物偶联物（ADC），今天在美国癌症研究协会（AACR）2026年年会上，通过五张海报展示和一场口头报告，宣布了其下一代ADC管线中令人鼓舞的临床前数据。

Of note, results from a preclinical study of STRO-004, its DAR8 Topo1 ADC targeting Tissue Factor (TF), were reviewed today in an oral presentation titled “STRO-004, an exatecan-based next-generation tissue factor (TF)-targeted ADC, demonstrates superior efficacy across TF-expressing solid tumors in a comprehensive single-mouse PDX trial.”.

值得注意的是，今天在一场题为“STRO-004，一种基于exatecan的下一代靶向组织因子（TF）的ADC，在全面的单鼠PDX试验中展示了对表达TF的实体瘤的卓越疗效”的口头报告中，审查了其DAR8 Topo1 ADC靶向组织因子（TF）的STRO-004的临床前研究结果。

In the preclinical study, STRO-004 demonstrated robust and consistent antitumor activity across a broad range of TF-expressing solid tumor patient-derived xenograft (PDX) models, with improved efficacy compared to benchmark ADCs. At a single, clinically relevant dose of 5 mg/kg, STRO-004 achieved remarkable disease control and tumor reduction across multiple tumor types.

在临床前研究中，STRO-004 在广泛的表达组织因子 (TF) 的实体瘤患者来源的异种移植 (PDX) 模型中展示了强大且一致的抗肿瘤活性，其疗效优于基准抗体药物偶联物 (ADC)。在 5 mg/kg 的单次临床相关剂量下，STRO-004 在多种肿瘤类型中实现了显著的疾病控制和肿瘤缩小。

STRO-004’s favorable tolerability, with a highest non-severely toxic dose (HNSTD) of 50 mg/kg, and pharmacokinetic profile are expected to enable increased drug exposure and payload delivery, supporting the Company’s belief that STRO-004 will demonstrate superior depth and durability of response in the clinic.

STRO-004的良好耐受性，最高非严重毒性剂量（HNSTD）为50 mg/kg，以及药代动力学特征，预计将实现更高的药物暴露和有效载荷递送，支持公司相信STRO-004将在临床中展示出更优的反应深度和持久性。

Exploratory biomarker analyses provide preliminary insight into STRO-004's mechanism of action, suggesting potential for combination studies addressing specific indications in either early or late lines of treatment..

探索性生物标志物分析提供了关于STRO-004作用机制的初步见解，表明其在早期或晚期治疗中针对特定适应症进行联合研究的潜力。

“The STRO-004 preclinical data presented today underscore the potential of our next-generation ADCs to drive meaningful activity across multiple solid tumors,” said Jane Chung, Sutro’s Chief Executive Officer. “As STRO-004 advances in the clinic – with initial results from our Phase 1 study expected in mid-2026 – these preclinical data further strengthen our confidence in its potential across indications.

“今天展示的STRO-004临床前数据突显了我们下一代ADC在多种实体瘤中推动显著活性的潜力，”Sutro首席执行官Jane Chung表示。“随着STRO-004在临床中的推进——我们预计1期研究的初步结果将在2026年年中公布——这些临床前数据进一步增强了我们对其在各个适应症中潜力的信心。”

More broadly, they underscore the versatility of our platform to generate differentiated ADCs across many targets and payloads, supporting a pipeline designed to address significant unmet need in cancer.”.

更广泛地说，它们突显了我们平台的多功能性，能够针对多种靶点和载荷生成差异化的ADC，支持一条旨在满足癌症领域重大未满足需求的研发管线。

In addition to the oral presentation, Sutro will present multiple posters highlighting advances across its ADC pipeline and discovery platforms, the full details of which are included below.

除了口头报告，Sutro 还将展示多张海报，重点介绍其 ADC 管线和发现平台的进展，详细信息如下。

Select Poster Highlights:

选择海报亮点：

Full Poster Presentation Details:

完整海报展示详情：

In addition to these presentations, Sutro’s strategic partner, Astellas Pharma, also reviewed preclinical results from its TROP2-targeted iADC program at AACR today. The oral presentation, titled “ASP2998, a TROP2-targeted immunostimulatory antibody-drug conjugate (iADC) with dual payloads, demonstrates potent efficacy and a favorable safety profile in nonclinical models,” highlighted the company’s progress in the development of next-generation iADCs leveraging Sutro’s cell-free protein synthesis platform.

除了这些展示之外，Sutro的战略合作伙伴安斯泰来制药今天也在AACR上审查了其针对TROP2的iADC项目的临床前结果。题为“ASP2998，一种具有双重有效载荷的TROP2靶向免疫刺激抗体药物偶联物（iADC），在非临床模型中显示出强大的疗效和良好的安全性”的口头报告强调了该公司在利用Sutro无细胞蛋白合成平台开发下一代iADC方面的进展。

ASP2998 is a first-in-class iADC that combines cytotoxic and immune-stimulatory mechanisms to enhance antitumor efficacy. Inclusion of a STING agonist augments the antitumor efficacy, immune activation and durable tumor immunity of ASP2998, supporting its superior activity over toxin-only anti-TROP2 ADCs.

ASP2998 是一种首创的免疫刺激抗体偶联药物 (iADC)，结合了细胞毒性和免疫刺激机制以增强抗肿瘤效果。加入 STING 激动剂进一步提升了 ASP2998 的抗肿瘤效力、免疫激活和持久的肿瘤免疫能力，证明其在疗效上优于仅含毒素的抗 TROP2 抗体偶联药物 (ADC)。

Preclinically, ASP2998 demonstrated a favorable safety profile, supporting a promising therapeutic index. ASP2998 entered the clinic earlier this year and is actively dosing patients..

临床前研究中，ASP2998展示了良好的安全性，支持其具有前景的治疗指数。ASP2998于今年早些时候进入临床阶段，并正在积极给患者用药。

Following the congress, the Company’s presentations will be made available in the Scientific Publications section of Sutro Biopharma’s website at www.sutrobio.com.

会议结束后，公司的演讲将在Sutro Biopharma网站的科学出版物部分提供，网址为www.sutrobio.com。

About Sutro Biopharma

关于Sutro Biopharma

Sutro Biopharma, Inc. is a clinical-stage biotechnology company advancing a next-generation antibody-drug conjugate (ADC) platform designed to deliver single- and dual-payload ADCs that enable meaningful breakthroughs for patients with cancer. By fully optimizing the antibody, linker, and payload, Sutro’s cell-free platform produces ADCs that are engineered to improve drug exposure, reduce side effects, and expand the range of treatable tumor types.

Sutro Biopharma, Inc. 是一家处于临床阶段的生物技术公司，致力于推进下一代抗体药物偶联物 (ADC) 平台，该平台旨在提供单载荷和双载荷 ADC，为癌症患者带来有意义的突破。通过全面优化抗体、连接子和载荷，Sutro 的无细胞平台生产的 ADC 旨在改善药物暴露、减少副作用，并扩大可治疗的肿瘤类型范围。

With unique capabilities in dual-payload ADCs, Sutro aims to overcome treatment resistance and redefine what’s possible in cancer therapy. The Company’s pipeline of single- and dual-payload ADCs targets large oncology markets with limited treatment options and significant need for improved therapies..

凭借在双载荷ADC领域的独特能力，Sutro旨在克服治疗耐药性，并重新定义癌症治疗的可能性。公司单载荷和双载荷ADC的研发管线针对的是治疗选择有限且对改进疗法需求巨大的大型肿瘤市场。

For more information, follow Sutro on social media @Sutrobio or visit

欲了解更多信息，请在社交媒体上关注 Sutro @Sutrobio 或访问

www.sutrobio.com

www.sutrobio.com

.

。

Forward-Looking Statements

前瞻性声明

This press release contains forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995, including, but not limited to, statements regarding the therapeutic potential and anticipated clinical benefits of STRO-004, STRO-006, STRO-227, and other ADC product candidates; Astellas’ development of ASP2998; anticipated preclinical and clinical development activities; timing of announcements of IND submissions, trial initiation, clinical results, and other regulatory filings; outcome of discussions with regulatory authorities; potential benefits of the Company’s product candidates and platform; potential business development and partnering transactions; and potential market opportunities for the Company’s product candidates; the timing and receipt of anticipated future milestone payments.

本新闻稿包含1995年《私人证券诉讼改革法案》“安全港”条款意义上的前瞻性声明，包括但不限于关于STRO-004、STRO-006、STRO-227和其他ADC候选产品的治疗潜力及预期临床益处的声明；安斯泰来对ASP2998的开发；预期的临床前和临床开发活动；IND递交、试验启动、临床结果及其他监管文件的时间安排和公告；与监管机构讨论的结果；公司候选产品及其平台的潜在益处；潜在的业务发展和合作交易；公司候选产品的潜在市场机会；以及预期未来里程碑付款的时间和收取。

All statements other than statements of historical fact are statements that could be deemed forward-looking statements. Although the Company believes that the expectations reflected in such forward-looking statements are reasonable, the Company cannot guarantee future events, results, actions, levels of activity, performance or achievements, and the timing and results of biotechnology development and potential regulatory approval is inherently uncertain.

所有非历史事实的陈述均可能被视为前瞻性陈述。尽管公司认为这些前瞻性陈述中反映的预期是合理的，但公司无法保证未来的事件、结果、行动、活动水平、表现或成就，且生物技术开发和潜在监管批准的时间与结果本质上存在不确定性。

Forward-looking statements are subject to risks and uncertainties that may cause the Company’s actual activities or results to differ significantly from those expressed in any forward-looking statement, including risks and uncertainties related to the Company’s ability to advance its product candidates, the receipt and timing of potential regulatory designations, approvals and commercialization of product candidates, the market size for the Company’s product candidates b.

前瞻性声明受到风险和不确定性的约束，可能导致公司的实际活动或结果与任何前瞻性声明中表达的内容存在显著差异，包括与公司推进其产品候选者能力相关的风险和不确定性、潜在监管认定、批准和产品候选者商业化的时机和收据、公司产品候选者的市场大小等。

Investor Contact

投资者联系

Emily White

艾米丽·怀特

Sutro Biopharma

苏特罗生物制药

(650) 823-7681

(650) 823-7681

ewhite@sutrobio.com

ewhite@sutrobio.com

Media Contact

媒体联系人

Amy Bonanno

艾米·博纳诺

Lyra Strategic Advisory

天琴座战略咨询公司

abonanno@lyraadvisory.com

abonanno@lyraadvisory.com

Released April 19, 2026

发布于2026年4月19日