A key principle for clinicians is that an antibody-drug conjugate's adverse events are primarily dictated by its linker-payload (e.g., deruxtecan, vedotin), not its specific antibody target. This allows for anticipating toxicities like neuropathy or GI issues based on the payload class, creating a predictable framework for management across different ADCs.
Clinicians identify outdated control arms—like single-agent chemotherapy without newer targeted agents—as a major deterrent for patient trial participation. Patients are unwilling to be randomized to a therapy that doesn't reflect the current, more effective standard of care. This pressure is forcing sponsors and the FDA to design trials with more realistic comparator arms.
In the REJOYCE ovarian-1 trial for RDXD, the 5.6 mg/kg dose was selected to move forward over a 6.4 mg/kg dose that showed a higher response rate (57%). The lower dose had significantly fewer serious adverse events and a lower rate of interstitial lung disease (ILD), demonstrating a crucial trade-off where safety and tolerability outweigh peak efficacy in late-stage development.
With multiple ADCs available, an emerging sequencing strategy is to alternate between different mechanisms of action, such as following a microtubule toxin-based ADC with a topoisomerase-1 inhibitor payload. This approach aims to avoid compounding specific toxicities, like neuropathy, and potentially circumvent resistance, though it is a strategy born from logic rather than clinical trial data.
Unlike some immunotherapy guidelines, experts recommend immediate steroid treatment for even Grade 1 (asymptomatic) ADC-induced pneumonitis or interstitial lung disease (ILD) found on scans. This aggressive, proactive approach is considered necessary due to the risk of rapid clinical deterioration, prioritizing safety and the ability to resume cancer therapy.
Clinicians face a strategic dilemma where using an ADC off-label for a patient with a low-expressing biomarker (e.g., TDXD for HER2 1+) could provide benefit but also render that patient ineligible for a future clinical trial of a potentially more effective ADC. This highlights a tension between immediate access and optimizing long-term treatment sequencing.
The traditional definition of platinum-resistant ovarian cancer based on a six-month recurrence interval is becoming less rigid. Clinicians recognize this timeframe can be an arbitrary surrogate for tumor biology, influenced by imaging schedules. The paradigm is shifting, especially post-PARP inhibitor therapy, where the value of re-challenging with platinum is being reconsidered despite shorter intervals.
Despite enthusiasm for chemo-free regimens, experts are skeptical that ADCs can replace platinum-taxane combinations in the first-line setting for ovarian or endometrial cancer. The standard chemotherapy backbone has a response rate exceeding 50%, a high bar for any new agent to clear. ADCs are therefore being developed more as maintenance or add-on therapies.
The modern pipeline of antibody-drug conjugates in solid tumors has largely moved away from older microtubule toxin payloads (like DM4 or MMAE). The majority of ADCs currently in development, and the focus of clinical excitement, utilize camptothecin-based payloads, specifically topoisomerase-1 inhibitors like deruxtecan, reflecting a major technological evolution in the field.
Despite targeting the same protein (Trope-2), different ADCs like sacituzumab govitecan (SG) and sacituzumab tirumotecan (sac-TMT) exhibit unique toxicity profiles due to their different linker-payloads. Clinicians must be prepared for diarrhea with SG versus oral mucositis with sac-TMT, requiring distinct mitigation strategies for drugs that otherwise seem very similar.
The arrival of multiple effective, biomarker-linked therapies for diseases like ovarian cancer creates a new, complex challenge for oncologists. No longer a matter of choosing the single best next option, treatment has become a strategic game of sequencing, requiring physicians to think "five plays ahead" to maximize the benefit of all available drugs over the patient's lifetime.
Strict, and sometimes arbitrary, clinical trial eligibility criteria are a key barrier to enrollment. A patient with a GFR of 52 being excluded from a trial requiring a GFR of 60 illustrates how minor, clinically insignificant differences can prevent patients from accessing novel therapies. This highlights a need for more pragmatic and flexible trial inclusion criteria.