Iopofosine I-131

Demonstrated Favorable Safety Pro Preliminary Clinical Activity in Relapsed/Refractory Multiple Myeloma Publication Supports Continued Development of Iopofosine I 131 as a Novel Targeted Radiotherapeutic Across Multiple B-Cell Malignancies FLORHAM PARK, N.J., July 15, 2026 (GLOBE NEWSWIRE) -- Cellectar Biosciences, Inc. (NASDAQ: CLRB), a late-stage clinical biopharmaceutical company focused on the discovery and development of drugs for the treatment of cancer, today announced the publication of results from a Phase 1 dose-escalation study evaluating iopofosine I 131 in combination with low-dose dexamethasone in 31 patients with heavily pretreated relapsed/refractory multiple myeloma (r/r MM). The manuscript, titled “A Phase I Trial of Iopofosine I 131 and Dexamethasone in Patients with Relapsed/Refractory Multiple Myeloma,” was published in the peer-reviewed journal, Cancers . “Iopofosine I 131 represents a differentiated therapeutic approach for patients with relapsed or refractory multiple myeloma who have limited remaining treatment options,” said Sikander Ailawadhi, M.D., professor of medicine, division of hematology/oncology, Mayo Clinic, Jacksonville, Florida and lead author of the publication. “The study demonstrated manageable toxicity with adverse events being essentially limited to cytopenias, encouraging disease control, and evidence of antitumor activity in a heavily pretreated population, supporting the potential of this novel targeted radiotherapeutic in these most fragile patients. The predictability and recovery of the cytopenias support its potential for repeat dosing strategies in future clinical development.” Highlights of the Data: The study evaluated both single-dose and fractionated-dose regimens of iopofosine I 131 in 31 heavily pretreated r/r MM patients, many of whom had exhausted available treatment options. Among 26 efficacy-evaluable patients: Clinical activity appeared more pronounced in patients receiving higher total administered doses 84.6% achieved stable disease or better following treatment 30% overall response rate observed among evaluable patients (n=10) receiving at least 60 mCi of iopofosine I 131 The overall response rate was 15.4%, with four patients achieving partial responses Investigators reported a favorable and manageable safety profile, with adverse events primarily consisting of predictable and reversible hematologic toxicities No new safety signals were identified, and non-hematologic adverse events were generally low grade “Publication of these data in Cancers further validate the potential of iopofosine as a differentiated targeted radiopharmaceutical and underscore the promise of our phospholipid drug conjugate platform as a novel targeted radiotherapeutic platform,” said Jarrod Longcor, Cellectar’s chief operating officer and co-author of the publication. “Importantly, the mechanism of action is not dependent on a single target or mutation, creating the opportunity to address a broad range of B-cell-mediated malignancies. We believe iopofosine has the potential to serve patients across multiple indications, including Waldenström macroglobulinemia, multiple myeloma, diffuse large B-cell lymphoma and other difficult-to-treat hematologic cancers where new therapeutic options remain urgently needed.” The authors further noted that iopofosine’s limited impact on renal and hepatic function, coupled with its predictable and manageable safety profile, may make it particularly attractive for older, frail, or heavily pretreated patients who may not be candidates for more intensive therapies. The study also demonstrated recovery of treatment-related cytopenias over time, supporting the potential for repeat dosing strategies in future clinical development. The full article can be accessed here . About the Phase 1 Study The Phase 1 dose escalation and safety study was conducted as an open-label, multi-center trial, which enrolled 31 patients with relapsed or refractory multiple myeloma who had received a median of four prior lines of therapy. Patients received either a single dose or fractionated doses of iopofosine I 131 plus low-dose dexamethasone. The study established 31.25 mCi/m² as the maximum tolerated single dose and identified 20 mCi/m² administered twice, one week apart, as the highest evaluated fractionated dose regimen. The authors recommended a fractionated Phase 2 regimen of 15 mCi/m² administered on days 1 and 7 in combination with weekly low-dose dexamethasone. About Cellectar Biosciences, Inc. Cellectar Biosciences is a late-stage clinical biopharmaceutical company focused on the discovery and development of proprietary drugs for the treatment of cancer, independently and through research and development collaborations. The company’s core objective is to leverage its proprietary Phospholipid Drug Conjugate™ (PDC) delivery platform to develop the next-generation of cancer cell-targeting treatments, delivering improved efficacy and better safety as a result of fewer off-target effects. The company’s product pipeline includes iopofosine I 131, which is a PDC designed to provide targeted delivery of iodine-131 (radioisotope). Iopofosine I 131 has been tested in Phase 2b trials as a treatment for relapsed or refractory Waldenström Macroglobulinemia (WM), in relapsed or refractory multiple myeloma (MM) and central nervous system (CNS) lymphoma. The CLOVER-2 Phase 1b study is evaluating iopofosine I 131 in pediatric patients with high-grade gliomas, for which Cellectar is eligible to receive a Pediatric Review Voucher from the FDA upon approval. The FDA has granted iopofosine I 131 Breakthrough, six Orphan Drug, four Rare Pediatric Drug and two Fast Track Designations for various cancer indications, and the EMA has granted iopofosine I 131 PRIority MEdicines (PRIME) designation. Cellectar is also developing CLR 121125 (CLR 125), an iodine-125 Auger-emitting program targeted for solid tumors, such as triple negative breast (TNBC), lung, and colorectal cancer, and is currently being evaluated in a Phase 1b study for TNBC, which will determine the recommended dose for the subsequent Phase 2 trial. CLR 125 has been well tolerated in vivo and has demonstrated strong preclinical data showing reduction or inhibition of solid tumor growth. In addition to these assets, the Cellectar team is developing CLR 121225 (CLR 225), an actinium-225 based program targeting solid tumors in indications with significant unmet need, such as pancreatic cancer, as well as proprietary preclinical PDC chemotherapeutic programs and multiple partnered PDC assets. For more information, please visit or join the conversation by liking and following us on the company’s social media channels: X , LinkedIn , and Facebook . Forward Looking Statements Disclaimer This news release contains forward-looking statements. You can identify these statements by our use of words such as "may," "expect," "believe," "anticipate," "intend," "could," "estimate," "continue," "plans," or their negatives or cognates. These statements are only estimates and predictions and are subject to known and unknown risks and uncertainties that may cause actual future experience and results to differ materially from the statements made. These statements are based on our current beliefs and expectations as to such future outcomes. Drug discovery and development involve a high degree of risk. Factors that might cause such a material difference include, among others, uncertainties related to the ability to identify suitable collaborators, partners, licensees or purchasers for our product candidates and, if we are able to do so, to enter into binding agreements with regard to any of the foregoing, or to raise additional capital to support our operations, or our ability to fund our operations if we are unsuccessful with any of the foregoing. A complete description of risks and uncertainties related to our business is contained in our periodic reports filed with the Securities and Exchange Commission including our Form 10-K for the year ended December 31, 2026, and our Form 10-Q for the quarterly period ended March 31, 2026. These forward-looking statements are made only as of the date hereof, and we disclaim any obligation to update any such forward-looking statements. INVESTORS: Anne Marie Fields Precision AQ 212-362-1200 annemarie.fields@precisionaq.com

编者按：偶联药物通过将抗体、多肽、小分子或其他靶向配体与功能性载荷连接，实现向特定细胞、组织或疾病微环境递送治疗载荷的效果。2026年第二季度，偶联药物领域延续了快速发展的态势。多款抗体偶联药物（ADC）取得重要监管进展，进一步走向一线治疗、早期疾病管理和罕见肿瘤治疗场景。首款双特异性ADC获批上市，并在三阴性乳腺癌和食管鳞状细胞癌等适应症中取得后期临床积极结果，显示双抗原识别策略正在进入更成熟的临床开发阶段。与此同时，围绕新型载荷、连接子、双载荷ADC和抗体偶联降解剂（DAC）的并购与合作持续活跃，放射性核素偶联药物（RDC）融资也在升温，提示偶联药物的创新正在从传统ADC进一步扩展到更广泛的靶向递送平台。 在这一过程中，连接子与载荷是决定ADC能否从分子构想走向可开发候选药物的关键因素之一。药明康德研发化学服务部（Research Chemistry Services，RCS）构建了覆盖连接子与载荷合成、分析及纯化的一体化技术平台，为ADC关键小分子组件开发提供系统化支持。依托超过10年的项目经验、580余名专业化学家团队，以及包含1000余种连接子、30多类抗体连接位点和超过30种新型载荷及其类似物的可定制化体系，RCS能够帮助合作伙伴高效推进ADC连接子与载荷开发，加速创新偶联疗法从早期研究迈向可开发阶段。 ADC走向一线治疗和早期疾病管理 2026年第二季度，多款ADC进一步进入一线治疗和早期治疗场景。5月，美国FDA批准阿斯利康（AstraZeneca）和第一三共（Daiichi Sankyo）联合开发的Datroway（datopotamab deruxtecan）用于治疗不可切除或转移性三阴性乳腺癌（TNBC）成人患者，这些患者不适合接受PD-1/PD-L1抑制剂治疗。Datroway是一款TROP2靶向ADC。 仅一个月后，另一款靶向TROP2的ADC也在一线TNBC治疗中取得重要监管进展。6月，美国FDA批准Trodelvy（sacituzumab govitecan）用于两项TNBC一线适应症：一是作为单药用于不适合接受PD-1/PD-L1抑制剂治疗的不可切除局部晚期或转移性TNBC成人患者；二是与Keytruda（pembrolizumab）或Keytruda Qlex联用，用于肿瘤PD-L1表达CPS≥10、适合接受免疫治疗的不可切除局部晚期或转移性TNBC成人患者。临床试验数据显示，在ASCENT-03研究中，Trodelvy单药组中位无进展生存期（PFS）为9.7个月，对照化疗组为6.9个月；在ASCENT-04/KEYNOTE-D19研究中，Trodelvy联合Keytruda组中位PFS为11.2个月，对照组为7.8个月。 Datroway和Trodelvy先后成为TNBC一线治疗选择，显示ADC不再只是多线治疗后的补充选择，而正在与化疗、免疫治疗等标准方案共同影响一线治疗决策。尤其是Trodelvy联合Keytruda的获批，也提示ADC与免疫检查点抑制剂的联合治疗正在成为重要开发方向。ADC可通过靶向递送细胞毒性载荷诱导肿瘤细胞死亡，而免疫治疗则可激活抗肿瘤免疫反应，两者联用有望为部分患者带来更深、更持久的疾病控制。 除了用于晚期癌症一线治疗外，ADC也在向早期疾病管理拓展。5月，Enhertu（trastuzumab deruxtecan）获得美国FDA批准，用于HER2阳性早期乳腺癌的两个新适应症，包括作为新辅助疗法和辅助疗法，治疗不同类型的早期HER2阳性乳腺癌患者。 这一进展具有重要意义。长期以来，ADC主要用于晚期、复发或难治性肿瘤患者；而当ADC进入新辅助和辅助治疗场景，它的价值就不只是延缓晚期疾病进展，还可能参与早期疾病的根治性治疗策略。 在罕见血液肿瘤领域，ADC也取得监管进展。5月，美国FDA批准艾伯维（AbbVie）开发的Decnupaz（pivekimab sunirine）用于治疗成人母细胞性浆细胞样树突状细胞肿瘤（BPDCN）。Decnupaz是一款CD123靶向抗体偶联药物。 双特异性ADC首次获得监管批准，临床管线加速扩展 在ADC走向更广泛临床应用的同时，双特异性ADC也在2026年第二季度迎来重要进展。6月，中国国家药品监督管理局（NMPA）批准百利天恒开发的伦康依隆妥单抗（izalontamab brengitecan）上市，用于治疗复发或转移性鼻咽癌患者。伦康依隆妥单抗同时靶向EGFR和HER3，是首款获得监管机构批准上市的双特异性ADC。百时美施贵宝（Bristol Myers Squibb）已与百利天恒子公司SystImmune达成合作，共同开发这款药物。 在2026年美国临床肿瘤学会（ASCO）年会上，百时美施贵宝与百利天恒公布了iza-bren两项3期临床试验的积极结果。在既往接受治疗的不可切除局部晚期或转移性TNBC患者中，PANKU-Breast02研究显示，iza-bren较医生选择化疗显著改善总生存期（OS）和PFS；在复发或转移性食管鳞状细胞癌患者中，PANKU-Esophagus01研究也显示，iza-bren达到OS和PFS双重主要终点。 双特异性ADC不再只依赖单一抗原识别肿瘤细胞，而是通过同时识别两个肿瘤相关抗原，试图更好地应对肿瘤异质性、靶点表达差异和内吞效率不足等挑战。近日发表于Cancer Cell的综述指出，双特异性ADC可同时结合两种不同细胞表面抗原，一方面扩大潜在患者覆盖范围并应对肿瘤内异质性，另一方面也可通过要求两个靶点共表达来提高肿瘤选择性，从而有望减少对正常组织的影响。该综述还指出，近年来已有超过40款双特异性ADC进入临床开发，其中EGFR/HER3和EGFR/cMET是具有代表性的靶点组合。 ▲常见的双特异性ADC靶点对和进入临床开发阶段的双特异性ADC（图片来源：参考资料[1]） 在融资方面，双特异性ADC也正在吸引资本支持。Sidewinder Therapeutics在4月完成1.37亿美元B轮融资，用于推进下一代双特异性ADC进入临床开发。Sidewinder专注于开发靶向受体共复合物（receptor co-complexes）的双特异性ADC疗法。这类疗法通过工程化双特异性抗体识别由致癌驱动受体和内吞受体组成的肿瘤特异性共复合物，从而实现更精准的肿瘤细胞识别与内吞，提高药物递送至癌细胞的效率，同时减少对正常细胞的影响。这一融资事件显示，双特异性ADC不仅已经有上市和后期临床案例，也正在成为早期平台公司重点布局的方向之一。 载荷和连接子创新，推动ADC从“递送毒素”走向系统设计 下一代ADC的创新并不只发生在靶点端，也发生在载荷和连接子上。传统ADC的载荷主要集中在微管抑制剂和拓扑异构酶I抑制剂等细胞毒性药物，而随着耐药性、肿瘤异质性和安全性挑战日益受到关注，创新者正在探索更丰富的载荷类型、更稳定且可控的连接子系统，以及更均一的偶联方式。 例如，吉利德科学（Gilead Sciences）在2026年5月完成了对Tubulis的收购，获得其靶向NaPi2b的抗体偶联药物TUB-040，以及经过临床验证的Tubutecan连接子-载荷系统。该系统将拓扑异构酶I抑制剂exatecan通过基于P5偶联技术的可裂解连接子系统与抗体连接，并实现均一的高药物抗体比（DAR）。 今年4月，礼来（Eli Lilly and Company）宣布收购CrossBridge Bio，布局双载荷ADC技术。CrossBridge Bio专注于开发同时递送两种作用机制不同载荷的ADC，以期覆盖更多肿瘤细胞状态并降低潜在耐药风险。 同月，罗氏（Roche）与C4 Therapeutics围绕抗体偶联降解剂达成合作。根据协议，C4 Therapeutics将利用其TORPEDO平台设计降解剂载荷，罗氏负责选择和设计抗体，并将抗体与降解剂载荷偶联。DAC将抗体的特异性靶向递送能力与降解剂载荷的催化作用机制相结合，有望将蛋白降解作用更精准地引导至特定肿瘤细胞或组织中，并为高活性降解剂载荷提供更具选择性的递送方式。 从产业化开发角度看，连接子、载荷和偶联相关小分子模块的设计与制备，是ADC能否从分子构想走向可开发候选药物的关键基础。随着ADC结构日益复杂，研发端不仅需要更多可选择的连接子和载荷类型，也需要能够支持快速合成、结构确证、纯化放大和高活性载荷安全处理的一体化平台。 药明康德研发化学服务部构建了覆盖连接子与载荷合成、分析及纯化的一体化技术平台，为ADC关键小分子组件开发提供系统化支持。依托超过10年的项目经验与580余名专业化学家团队，RCS已累计交付超过27000种相关化合物，在多类型连接子合成方面积累了丰富实践经验。平台采用模块化设计理念，建立了包含1000余种连接子、30多类抗体连接位点及超过30种新型载荷及其类似物的可定制化体系。 在载荷与构建模块方面，RCS覆盖多类主流细胞毒性分子体系，包括camptothecin类、auristatin类、maytansinoid类、PBD及duocarmycin类等，并建立了完善的构建模块库与快速物料调用体系，实现从仓储到实验室小于4小时的高效响应。同时，平台支持毫克级至百克级的灵活合成规模，可满足不同阶段项目需求。配套的先进分析与分离能力涵盖LC-MS/HPLC、CAD/ELSD检测、高场核磁（400/500 MHz）、Prep-HPLC-MS及Prep-SFC-MS等技术，可针对稳定性差、紫外响应弱或分离困难的连接子及载荷分子开发专用纯化方案，确保结构确证与高回收率。 此外，RCS配备符合规范的高活性化合物操作实验室，通过隔离器系统、严格去污染流程及完善的人员防护与废弃物管理体系，实现高毒性载荷的安全合规处理。通过将模块化化学设计、规模化合成能力与高标准安全体系相结合，RCS能够帮助合作伙伴高效推进ADC连接子与载荷开发，加速创新偶联疗法从早期研究迈向可开发阶段。 放射性核素偶联药物融资活跃 ADC之外，放射性核素偶联药物也成为2026年第二季度偶联药物融资中的重要亮点。辐联科技（Full-Life Technologies）在5月完成1.5亿美元融资，包括约1.1亿美元D轮股权融资和4000万美元债权融资。公司表示，资金将用于推进临床阶段放射性治疗项目，包括针对前列腺癌的潜在“best-in-class”药物[225Ac]Ac-FL-020，以及针对多种实体瘤适应症的潜在“first-in-class”药物[225Ac]Ac-FL-261，并支持GMP级别锕-225制造能力建设。 NUCLIDIUM在5月完成2600万瑞士法郎B轮扩展融资，使B轮融资总额达到1.05亿瑞士法郎，融资将支持NU101和NU201等铜同位素诊疗一体化项目的临床开发。晶核生物（Bivision Pharmaceuticals）也在5月完成近4亿元人民币B轮融资，继续推进诊疗一体化靶向放射性药物开发。 Cellectar Biosciences在5月宣布完成最高1.4亿美元融资，用于支持iopofosine I 131等项目推进。Cellectar Biosciences利用其专有的磷脂药物偶联物（phospholipid drug conjugate）递送平台，开发下一代靶向癌细胞的治疗方法，通过减少脱靶效应实现更优疗效和更佳安全性。其在研疗法iopofosine I 131旨在实现碘-131的靶向递送。Iopofosine I 131正在2b期试验中接受评估，用于治疗复发或难治性华氏巨球蛋白血症、复发或难治性多发性骨髓瘤和中枢神经系统淋巴瘤。FDA已授予iopofosine I 131突破性疗法认定、6项孤儿药资格、4项罕见儿科疾病认定和2项快速通道资格，覆盖多种癌症适应症。 从ADC走向一线治疗，到双特异性ADC、双载荷ADC和RDC加速布局，偶联药物正在进入一个更加复杂也更具想象力的新阶段。未来，这一领域的发展不仅取决于靶点和载荷选择，也取决于能否把发现、设计、偶联、DMPK、生物分析和CMC开发整合为高效协同的开发体系。药明康德将持续依托其一体化、端到端的CRDMO平台，助力全球合作伙伴加速推进更多创新偶联药物，为患者带来更精准、更有效的治疗选择。 Q2 2026 Review of Conjugated Therapeutics Conjugated therapeutics are designed by linking antibodies, peptides, small molecules, or other targeting ligands with functional payloads, enabling therapeutic agents to be delivered to specific cells, tissues, or disease microenvironments. In the second quarter of 2026, the field continued to advance rapidly. Multiple antibody-drug conjugates (ADCs) achieved important regulatory milestones, further expanding into first-line treatment, early disease management, and rare tumor settings. The first bispecific ADC was approved and delivered positive late-stage clinical results in indications including triple-negative breast cancer and esophageal squamous cell carcinoma, suggesting that dual-antigen recognition strategies are entering a more mature stage of clinical development. At the same time, mergers, acquisitions, and collaborations around novel payloads, linkers, dual-payload ADCs, and degrader-antibody conjugates (DACs) remained active, while financing for radionuclide drug conjugates (RDCs) also gained momentum. Together, these developments show that innovation in conjugated therapeutics is expanding beyond traditional ADCs toward a broader range of targeted delivery platforms. In this evolution, linkers and payloads are among the key factors that determine whether an ADC can progress from molecular concept to developable drug candidate. WuXi AppTec Research Chemistry Services (RCS) has established a comprehensive ADC linker-payload synthesis platform, designed to support the growing demand for highly specialized cytotoxic conjugation components in next-generation targeted therapies. With more than 10 years of project experience, a team of more than 580 professional chemists, and a customizable system that includes more than 1,000 linkers, more than 30 types of antibody conjugation sites, and more than 30 novel payloads and their analogs, RCS can help partners efficiently advance ADC linker and payload development and accelerate the creation of innovative conjugate therapeutics with enhanced efficiency and confidence. ADCs Move Toward First-Line Treatment and Early Disease Management In the second quarter of 2026, multiple ADCs continued to move into first-line and earlier treatment settings. In May, the U.S. FDA approved Datroway (datopotamab deruxtecan), jointly developed by AstraZeneca and Daiichi Sankyo, for the treatment of adults with unresectable or metastatic triple-negative breast cancer (TNBC) who are not candidates for PD-1/PD-L1 inhibitor therapy. Datroway is a TROP2-directed ADC. Only one month later, another TROP2-directed ADC achieved important regulatory progress in first-line TNBC. In June, the U.S. FDA approved Trodelvy (sacituzumab govitecan) for two first-line TNBC indications: as monotherapy for adults with unresectable locally advanced or metastatic TNBC who are not candidates for PD-1/PD-L1 inhibitor therapy; and in combination with Keytruda (pembrolizumab) or Keytruda Qlex for adults with unresectable locally advanced or metastatic TNBC whose tumors express PD-L1 with CPS≥10 and who are eligible for immunotherapy. Clinical trial data showed that in the ASCENT-03 study, median progression-free survival (PFS) was 9.7 months in the Trodelvy monotherapy group and 6.9 months in the chemotherapy control group. In the ASCENT-04/KEYNOTE-D19 study, median PFS was 11.2 months in the Trodelvy plus Keytruda group and 7.8 months in the control group. The regulatory progress of Datroway and Trodelvy in first-line TNBC shows that ADCs are no longer only supplemental options after multiple lines of therapy. Instead, they are beginning to influence first-line treatment decisions alongside chemotherapy, immunotherapy, and other standard approaches. In particular, the approval of Trodelvy in combination with Keytruda highlights the growing importance of ADC and immune checkpoint inhibitor combinations. ADCs can induce tumor cell death by delivering cytotoxic payloads in a targeted manner, while immunotherapy can activate antitumor immune responses. Together, these complementary mechanisms may bring deeper and more durable disease control to some patients. Beyond first-line treatment for advanced cancer, ADCs are also expanding into early disease management. In May, Enhertu (trastuzumab deruxtecan) received U.S. FDA approval for two new indications in HER2-positive early breast cancer, including use as neoadjuvant and adjuvant therapy for different types of early HER2-positive breast cancer. This progress is highly significant. For many years, ADCs were used primarily in patients with advanced, recurrent, or refractory tumors. As ADCs enter neoadjuvant and adjuvant treatment settings, their value is no longer limited to delaying disease progression in advanced cancer. They may also play a role in curative-intent treatment strategies for early-stage disease. ADCs also made regulatory progress in rare hematologic malignancies. In May, the U.S. FDA approved Decnupaz (pivekimab sunirine), developed by AbbVie, for the treatment of adult patients with blastic plasmacytoid dendritic cell neoplasm (BPDCN). Decnupaz is a CD123-directed antibody-drug conjugate. Bispecific ADCs Receive Their First Regulatory Approval, with Clinical Pipelines Accelerating As ADCs move into broader clinical applications, bispecific ADCs also achieved important progress in the second quarter of 2026. In June, China’s National Medical Products Administration (NMPA) approved izalontamab brengitecan, developed by Baili Tianheng, for the treatment of patients with recurrent or metastatic nasopharyngeal carcinoma. Izalontamab brengitecan simultaneously targets EGFR and HER3 and is the first bispecific ADC to receive regulatory approval. Bristol Myers Squibb has entered into a collaboration with SystImmune, a subsidiary of Baili Tianheng, to jointly develop this drug. At the 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, Bristol Myers Squibb and Baili Tianheng announced positive results from two Phase 3 clinical trials of iza-bren. In patients with previously treated unresectable locally advanced or metastatic TNBC, the PANKU-Breast02 study showed that iza-bren significantly improved overall survival (OS) and PFS compared with physician’s choice of chemotherapy. In patients with recurrent or metastatic esophageal squamous cell carcinoma, the PANKU-Esophagus01 study also showed that iza-bren met the dual primary endpoints of OS and PFS. The rationale for bispecific ADCs is increasingly clear: they do not rely on a single antigen to recognize tumor cells. Instead, by recognizing two tumor-associated antigens simultaneously, they are designed to better address challenges such as tumor heterogeneity, variable target expression, and insufficient internalization efficiency. A recent review published in Cancer Cell noted that bispecific ADCs can bind two different cell-surface antigens at the same time. On one hand, this may broaden the potential patient population and help address intratumoral heterogeneity. On the other hand, by requiring co-expression of two targets, bispecific ADCs may improve tumor selectivity and potentially reduce effects on normal tissues. The review also noted that more than 40 bispecific ADCs have entered clinical development in recent years, with EGFR/HER3 and EGFR/cMET representing notable target combinations. ▲Common bispecific ADC target pairs and bispecific ADCs that have entered clinical development (Image source: Reference [1]) Investor interest is also building around bispecific ADCs. In April, Sidewinder Therapeutics completed a $137 million Series B financing to advance next-generation bispecific ADCs into clinical development. Sidewinder focuses on bispecific ADC therapies that target receptor co-complexes. These therapies use engineered bispecific antibodies to recognize tumor-specific co-complexes composed of oncogenic driver receptors and internalizing receptors, enabling more precise tumor cell recognition and internalization, improving drug delivery to cancer cells while reducing effects on normal cells. This financing event shows that bispecific ADCs not only have regulatory and late-stage clinical examples, but are also becoming an important area of focus for early-stage platform companies. Payload and Linker Innovation Drives ADCs from “Toxin Delivery” Toward Systematic Design Innovation in next-generation ADCs is taking place not only at the target level, but also in payloads and linkers. Traditional ADC payloads have mainly focused on cytotoxic agents such as microtubule inhibitors and topoisomerase I inhibitors. As drug resistance, tumor heterogeneity, and safety challenges attract increasing attention, innovators are exploring a broader range of payload types, more stable and controllable linker systems, and more homogeneous conjugation methods. One example is Gilead Sciences’ acquisition of Tubulis in May 2026. Through the acquisition, Gilead obtained TUB-040, a NaPi2b-targeted ADC, as well as Tubutecan, a clinically validated linker-payload system. This system connects the topoisomerase I inhibitor exatecan to antibodies through a cleavable linker system based on P5 conjugation technology and achieves a homogeneous high drug-to-antibody ratio (DAR). In April, Eli Lilly and Company announced its acquisition of CrossBridge Bio to expand into dual-payload ADC technology. CrossBridge Bio focuses on developing ADCs that deliver two payloads with different mechanisms of action simultaneously, with the goal of covering more tumor cell states and reducing potential resistance risk. In the same month, Roche and C4 Therapeutics entered into a collaboration around antibody-degrader conjugates. Under the agreement, C4 Therapeutics will use its TORPEDO platform to design degrader payloads, while Roche will be responsible for selecting and designing antibodies and conjugating them with degrader payloads. DACs combine the targeted delivery capability of antibodies with the catalytic mechanism of degrader payloads, potentially directing protein degradation more precisely to specific tumor cells or tissues and providing a more selective delivery approach for highly active degrader payloads. From an industrial development perspective, the design and preparation of linkers, payloads, and conjugation-related small-molecule modules are critical foundations for advancing ADCs from molecular concept to developable drug candidates. As ADC structures become increasingly complex, R&D teams need not only more linker and payload options, but also an integrated platform that can support rapid synthesis, structural confirmation, purification and scale-up, and safe handling of highly active payloads. WuXi AppTec Research Chemistry Services (RCS) has established a comprehensive antibody–drug conjugate (ADC) linker-payload synthesis platform, designed to support the growing demand for highly specialized cytotoxic conjugation components in next-generation targeted therapies. Built upon more than a decade of experience in complex small-molecule and high-potency chemistry, the platform integrates customized linker-payload synthesis, analytical characterization, and safe handling capabilities into a flexible and scalable workflow. Supported by a team of over 580 experienced chemists, RCS has delivered more than 27,000 compounds and accumulated extensive expertise across diverse linker-payload chemistries, enabling partners to efficiently advance ADC programs from early discovery through development. The platform provides access to a highly modular linker–payload toolbox comprising over 1,000 linkers, more than 30 antibody attachment sites, and over 30 novel payloads and analogs.  RCS supports a broad spectrum of cytotoxic payload classes, including camptothecins, auristatins, maytansinoids, pyrrolobenzodiazepines (PBD), and duocarmycins, alongside a well-established modular building-block warehousing system featuring hundreds of linker and payload intermediates. This infrastructure allows rapid material supply, often transferring compounds from warehouse to laboratory within 4 hours. Meanwhile, the RCS platform support synthesis scales ranging from milligrams to hundreds of grams, facilitated by advanced analytical and purification capabilities, including LC-MS/HPLC, CAD/ELSD detection, high-field NMR, Prep-HPLC-MS, and Prep-SFC-MS. These tools enable efficient impurity identification, challenging separations, and precise structural validation, particularly for unstable or weakly UV-active linker-payload molecules.  Complementing technical expertise, RCS has dedicated high-potency laboratories equipped with isolators, strict containment protocols, and comprehensive personnel protection procedures to ensure safe and compliant handling of cytotoxic compounds. By combining modular chemistry design, scalable synthesis, advanced analytics, and robust safety infrastructure, WuXi AppTec RCS provides partners with an integrated and reliable solution for ADC linker-payload development, accelerating the creation of innovative conjugate therapeutics with enhanced efficiency and confidence. Financing for Radionuclide Drug Conjugates Remains Active Beyond ADCs, radionuclide drug conjugates also attracted significant investor interests in the second quarter of 2026. Full-Life Technologies completed $150 million in financing in May, including approximately $109 million in Series D equity financing and $41 million in debt financing. The company said the funds will be used to advance clinical-stage radiotherapeutic programs, including [225Ac]Ac-FL-020, a potential “best-in-class” drug for prostate cancer, and [225Ac]Ac-FL-261, a potential “first-in-class” drug for multiple solid tumor indications, while also supporting GMP-grade actinium-225 manufacturing capabilities. NUCLIDIUM completed a CHF 26 million Series B extension in May, bringing the total Series B financing to CHF 105 million. The financing will support the clinical development of copper isotope  radiotheranostics programs such as NU101 and NU201. Bivision Pharmaceuticals also completed a nearly RMB 400 million Series B financing in May to continue advancing the development of targeted radiopharmaceuticals for integrated diagnosis and treatment. Cellectar Biosciences announced in May that it had completed financing of up to $140 million to support the advancement of programs such as iopofosine I 131. Cellectar Biosciences uses its proprietary phospholipid drug conjugate delivery platform to develop next-generation therapies targeting cancer cells, with the goal of achieving improved efficacy and safety by reducing off-target effects. Its investigational therapy iopofosine I 131 is designed to enable targeted delivery of iodine-131. Iopofosine I 131 is being evaluated in a Phase 2b trial for the treatment of relapsed or refractory Waldenström macroglobulinemia, relapsed or refractory multiple myeloma, and central nervous system lymphoma. The FDA has granted iopofosine I 131 breakthrough therapy designation, 6 orphan drug designations, 4 rare pediatric disease designations, and 2 fast track designations across multiple cancer indications. From ADCs moving into first-line treatment, to the accelerated development of bispecific ADCs, dual-payload ADCs, and RDCs, conjugated therapeutics are entering a new stage that is both more complex and more expansive. In the future, the development of this field will depend not only on target and payload selection, but also on whether discovery, design, conjugation, DMPK, bioanalysis, and CMC development can be integrated into an efficient and coordinated development system. WuXi AppTec will continue to leverage its integrated, end-to-end CRDMO platform to help global partners accelerate the development of more innovative conjugated therapeutics and bring more precise and effective therapies to patients. 参考资料： [1] Pistilli et al., (2026). Antibody-drug conjugates in precision oncology. 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