Landmark Real-World Study Will Track a Breakthrough Lung Cancer Drug Across China

A powerful new antibody–drug conjugate that has already reshaped the treatment of a stubborn subset of lung cancer is about to face its most demanding test yet: the messy, unscripted reality of everyday clinical practice. Researchers in China have launched RERUN, a prospective, multicenter, observational cohort study designed to evaluate how trastuzumab deruxtecan, one of the most celebrated cancer drugs of the past decade, performs in Chinese patients with HER2-mutant metastatic non-small cell lung cancer outside the carefully controlled boundaries of a clinical trial. The study protocol, published in the journal Advances in Therapy, describes an effort spanning roughly 30 sites across the country and enrolling approximately 150 adult patients, with the goal of generating the kind of real-world evidence that regulators, physicians, and payers increasingly demand before a therapy can be considered truly established.

Trastuzumab deruxtecan, often abbreviated T-DXd, belongs to a class of therapeutics known as antibody–drug conjugates, which are sometimes described as guided missiles for cancer cells. The molecule combines three engineered components: a monoclonal antibody that binds HER2, a protein found on the surface of certain tumor cells; a cleavable linker that is stable in the bloodstream but degradable inside tumor tissue; and DXd, a potent topoisomerase I inhibitor that damages DNA and kills dividing cells. What sets this conjugate apart from earlier generations is its drug-to-antibody ratio of approximately eight payloads per antibody, a high loading achieved without compromising the drug’s stability, and its so-called bystander effect. Because the linker is cleaved by enzymes abundant in the tumor microenvironment, the released payload can diffuse into neighboring cancer cells that express little or no HER2 themselves, extending the drug’s lethal reach beyond its nominal target.

The clinical significance of this design became clear in a series of pivotal trials. In the DESTINY-Lung01 and DESTINY-Lung02 studies, trastuzumab deruxtecan produced durable responses in patients with metastatic non-small cell lung cancer harboring activating HER2 mutations, a molecular alteration long considered difficult to drug. Earlier attempts to exploit HER2 in lung cancer, including tyrosine kinase inhibitors such as afatinib, dacomitinib, poziotinib, and pyrotinib, had delivered only modest and inconsistent benefits, leaving patients with few options once platinum-based chemotherapy failed. The success of the antibody–drug conjugate approach prompted regulatory approvals in the United States and elsewhere, and the drug was subsequently approved in China for patients with locally advanced or metastatic HER2-mutant non-small cell lung cancer. The Chinese Society of Clinical Oncology has incorporated the therapy into its national treatment guidelines, cementing its place in standard care.

Yet approval and guideline inclusion do not answer every question. Randomized trials enroll selected patients who meet strict eligibility criteria, are treated under protocol-mandated schedules, and are followed with a rigor that everyday medicine rarely matches. Real-world populations are older, more comorbid, more ethnically and geographically diverse, and more likely to deviate from idealized dosing. Chinese patients, in particular, have historically been underrepresented in global oncology trials, and the molecular and clinical characteristics of HER2-mutant lung cancer in Chinese populations may differ in ways that matter for treatment response. This evidence gap is precisely what the RERUN investigators, led by a team spanning major cancer centers from Beijing to Shanghai to Guangzhou, intend to close.

The study’s architecture reflects the practical demands of real-world research. RERUN is explicitly observational: patients receive trastuzumab deruxtecan according to their physicians’ judgment and routine clinical practice, not a fixed protocol, and no treatment assignments are made by the researchers. Eligible participants are adults aged 18 or older with pathologically documented unresectable and/or metastatic non-squamous non-small cell lung cancer carrying any known activating HER2 mutation. Enrollment is underway at approximately 30 sites across China, and the investigators anticipate following patients for roughly six months after the last patient joins, a timeline calculated to achieve approximately 60 percent maturity for the primary endpoint, meaning that by the analysis point about 60 percent of patients are expected to have experienced disease progression or death, providing enough statistical events for a meaningful estimate.

That primary endpoint is real-world progression-free survival, assessed by the treating investigators in patients receiving the drug as second-line or later therapy. Progression-free survival, the length of time a patient lives without their cancer growing or spreading, is a cornerstone measure in lung cancer research because it captures how long a therapy actually controls the disease. Secondary outcomes broaden the picture considerably: the investigators will track time to treatment discontinuation or death, best overall response rate as judged by tumor shrinkage, overall survival, and a comprehensive assessment of safety and tolerability. All data will be collected prospectively, meaning the information is gathered as patients move through treatment rather than reconstructed retrospectively from medical records, and analyzed descriptively, an approach appropriate for a cohort study whose purpose is characterization rather than hypothesis testing against a control group.

The safety component deserves particular attention. Antibody–drug conjugates carry distinctive toxicities, and trastuzumab deruxtecan is no exception. The most closely watched adverse event is interstitial lung disease, an inflammation and scarring of lung tissue that, in rare cases, can be severe or fatal, a concern that is especially charged in a population whose lungs are already compromised by cancer. Other recognized toxicities include nausea, fatigue, and declines in blood cell counts. Clinical trials established a manageable safety profile at the approved doses, but real-world monitoring is essential to detect how these risks manifest in a broader population, particularly in China, where patterns of prior treatment, baseline health, and diagnostic surveillance may differ from the trial settings in which the drug was first characterized.

The scientific rationale for focusing on HER2 mutations in lung cancer is grounded in the molecular epidemiology of the disease. Activating mutations in the ERBB2 gene, which encodes HER2, occur in a small but meaningful fraction of non-small cell lung cancers, and analyses of thousands of advanced cases have mapped the landscape of these alterations, which cluster in specific regions of the kinase domain. Patients whose tumors harbor these mutations have historically fared poorly on conventional chemotherapy and have derived limited benefit from immune checkpoint inhibitors, underscoring the need for targeted approaches. The RERUN protocol situates itself within this context, noting that the study is intended to support treatment decision-making in routine oncology practice and to improve outcomes for Chinese patients with HER2-mutant non-small cell lung cancer across diverse healthcare settings, from elite national cancer centers to provincial hospitals.

The study has been registered as NCT06809764, obtained ethical approval from the Institutional Review Board of the leading site, Shanxi Provincial Cancer Hospital, and from all participating centers, and is being conducted in accordance with the Declaration of Helsinki, with written informed consent required from every patient before any study-related procedures. The research is sponsored by Daiichi Sankyo (China) Holdings, which co-developed the drug with AstraZeneca under a global collaboration agreement, and the sponsor participated in study design, data interpretation, and manuscript review, a funding structure that the published protocol discloses transparently alongside the authors’ conflict of interest statements.

For the oncology community, RERUN represents more than a single drug’s report card. It is part of a broader movement to validate precision oncology in the settings where patients actually live, where doses are adjusted, imaging intervals vary, and comorbidities complicate every decision. If the study confirms that the striking results seen in DESTINY-Lung02 and the China-specific DESTINY-Lung05 trial translate into durable progression-free survival and tolerable toxicity across a nationwide cohort, it will strengthen the case for making trastuzumab deruxtecan a standard of care for HER2-mutant lung cancer in China and provide a template for real-world evidence generation across other markets. If it reveals gaps between trial performance and clinical reality, those findings will be equally valuable, pointing physicians toward the patients, dosing strategies, and monitoring practices that need the most attention. Either way, the results will help determine whether one of modern oncology’s most celebrated weapons can deliver on its promise for the patients who need it most.

Subject of Research: Real-world evaluation of trastuzumab deruxtecan in Chinese patients with HER2-mutant metastatic non-small cell lung cancer

Article Title: Effectiveness and Safety of Trastuzumab Deruxtecan in Chinese Patients with HER2-Mutant Metastatic Non-Small Cell Lung Cancer (RERUN): Study Protocol for a Real-World, Multicenter, Prospective, Observational Study

Article References: Duan, J., Zhuo, M., Su, C., Liu, Y., Wang, L., Yang, N., Cao, B., Hu, M., Jin, S., Li, H., Li, X., Pan, Y., Hu, J., Lu, D., Tang, C., Yang, B., Huang, Y., Jiang, G., Li, W., … Wang, J. (2026). Effectiveness and Safety of Trastuzumab Deruxtecan in Chinese Patients with HER2-Mutant Metastatic Non-Small Cell Lung Cancer (RERUN): Study Protocol for a Real-World, Multicenter, Prospective, Observational Study. Advances in Therapy. https://doi.org/10.1007/s12325-026-03729-7

Image Credits: AI Generated

DOI: 10.1007/s12325-026-03729-7

Keywords: trastuzumab deruxtecan, HER2 mutations, non-small cell lung cancer, antibody-drug conjugate, real-world evidence, observational study, progression-free survival, China, precision oncology, drug safety, DESTINY-Lung trials, clinical research