Antibody-drug conjugates move from niche therapy to central strategy in gynaecologic cancer
Antibody-drug conjugates have moved well beyond proof of concept in gynaecologic oncology. In ovarian, endometrial and cervical cancers, three agents are already approved for previously treated disease: mirvetuximab soravtansine for folate receptor-α-positive ovarian cancer, trastuzumab deruxtecan for solid tumours expressing HER2 at a staining intensity of 3+ on immunohistochemistry, and tisotumab vedotin for cervical cancer independent of tissue factor expression. The clinical message is straightforward: targeted delivery of highly potent payloads is no longer experimental in this disease group, and the class is beginning to define treatment choices after standard chemotherapy has failed.
The appeal of these agents comes from their architecture. An ADC links an antibody that recognizes a tumour-associated antigen to a cytotoxic payload, allowing drug delivery with greater selectivity than conventional chemotherapy. In practice, the biology is not fully contained within the cell that binds the antibody. Payload release, internalization, bystander effects, and antigen density all influence activity, which helps explain why two patients with the same diagnosis can respond very differently depending on target expression and tumour biology.
Biomarker selection is now the gatekeeper for access to treatment
Target choice is no longer a theoretical exercise. It is the first clinical filter that determines whether a patient can receive one of these drugs at all. Folate receptor-α, HER2, tissue factor and mesothelin all appear in the development pipeline, and the review places strong emphasis on the fact that target selection and target expression thresholds vary from agent to agent. In some settings, a biomarker is a formal requirement; in others, the drug can be used without a companion diagnostic threshold tied to expression.
This creates real-world complexity for pathology labs and treatment teams. Biomarker development is complicated by assay reproducibility, spatial heterogeneity and temporal stability. A tumour sample taken from one metastatic site may not represent the biology of another lesion, and antigen expression can shift over time under therapeutic pressure. For clinicians, the implication is direct: a negative or borderline result does not always mean the target is biologically absent, but it may still determine whether treatment is available under the current approval framework.
The review also makes clear that target expression thresholds are not interchangeable across agents. HER2, for example, is operationalized differently here than in other disease settings, and the details of staining intensity matter. Precision oncology depends on these distinctions because the antibody can only do its work if the tumour presents the relevant antigen in a usable form.
Toxicity patterns differ by drug, payload and target
ADC toxicities do not follow a single template. The review separates off-target effects from on-target and off-tumour effects, a useful distinction because both can affect treatment continuity. Ocular toxicity, stomatitis and interstitial lung disease emerge as adverse events clinicians need to recognize early and manage proactively. Different agents carry distinct safety profiles, and the monitoring strategy has to be matched to the specific drug rather than treated as a class-wide checklist.
One short sentence captures the bedside reality: toxicity can determine whether an otherwise active ADC remains usable.
Because payloads are highly potent, even a well-engineered conjugate can produce clinically meaningful injury in normal tissues. Ocular toxicity is especially relevant when corneal or visual symptoms threaten adherence. Stomatitis can reduce oral intake and worsen quality of life. Interstitial lung disease demands vigilance because delays in recognition can turn a manageable adverse event into a life-threatening one. The review’s safety focus reflects a simple clinical fact: efficacy is only part of the equation when a drug is being considered for repeated administration in a patient with recurrent cancer.
Resistance and sequencing are becoming the next major bottlenecks
The most important unanswered questions now sit downstream of approval. Resistance mechanisms are a central concern, and they are unlikely to be explained by a single pathway. Tumours may alter antigen expression, change internalization behavior, or evolve resistance to the payload itself. Once a cancer has been exposed to one ADC, the next choice may depend on whether a second agent uses the same target or a similar payload class.
Sequencing remains unresolved. Can tumours be retreated with ADCs aimed at the same antigen? Does switching to a different target improve the odds, or is payload biology more important than antigen choice? The review identifies these as active development questions rather than settled practice. The answer will matter in gynaecologic cancers because many patients receive multiple lines of therapy and may encounter ADCs more than once over the course of their disease.
A second short sentence matters here: cross-resistance may not respect the boundaries of individual drug labels.
Combination strategies are extending the reach of ADCs
Rational combinations are already broadening the field. The review points to pairing ADCs with immune checkpoint inhibitors as a strategy to amplify antitumour immunity and prolong the durability of response. The biological logic is compelling. ADCs can increase tumour cell death and antigen release, while checkpoint blockade may reduce the immune braking signals that limit a durable response. In combination, the two approaches may turn a transient cytotoxic effect into a deeper and longer-lasting antitumour state.
This is not just a laboratory concept. It reflects a broader shift in gynaecologic oncology toward regimens that combine targeted cell kill with immune activation. If the ADC creates immunogenic debris and the checkpoint inhibitor helps the immune system sustain its response, the partnership may be more powerful than either approach alone. Still, the review does not claim that every combination will work equally well. The burden now is to define which partners, which sequences and which disease contexts yield the best balance of efficacy and toxicity.
Earlier-line and maintenance use will force new questions about duration and quality of life
The development of ADCs is no longer confined to late-line salvage therapy. They are being tested earlier in treatment and in maintenance settings, where the standards are higher and the tolerance for chronic toxicity is lower. In those settings, quality of life, clinical efficacy and duration of therapy become inseparable. A drug that looks attractive in heavily pretreated disease may face a different calculus when used for months or longer in patients who are still trying to preserve function, vision, appetite and daily independence.
That shift also raises practical questions about how long treatment should continue, when to stop, and how to balance cumulative toxicity against disease control. The review frames these as active priorities for the field, not side issues. As the class expands, clinicians will need not only better targets and better combinations, but also a clearer framework for deciding when prolonged exposure is helping and when it is simply accumulating harm.
The review leaves the field at a familiar but clinically important point: the drugs are here, the targets are multiplying, and the next gains will depend on solving resistance, sequencing and toxicity before the class outgrows the evidence needed to use it safely.