When selecting an ADC dose for pivotal trials, the highest response rate is not the sole driver. Developers prioritize the best balance of efficacy and toxicity, often choosing a dose with slightly lower response but significantly fewer serious adverse events, discontinuations, and specific risks like ILD.
The classification of platinum-resistant ovarian cancer is evolving. Clinicians argue it's not a rigid biological state but often a function of imaging timing. They recognize platinum can still be effective in this population, challenging the strict definition used for trial eligibility and treatment decisions.
The pace of new drug approvals in oncology means that established clinical trial control arms, often using older chemotherapies, may no longer represent the true standard of care. This discrepancy can deter patient enrollment and challenges trial designers to remain nimble and current.
Beyond outdated control arms, practical barriers often prevent patients from joining clinical trials. Inflexible criteria, like a GFR of 60 versus 52, and slow turnaround for tissue analysis create delays and anxiety, leading to patient drop-off before a trial can even begin.
In the absence of definitive data, a practical strategy is emerging to alternate ADC payloads, such as switching from a microtubule toxin to a topoisomerase inhibitor. This approach aims to avoid compounding toxicities like neuropathy and potentially circumvent drug resistance mechanisms.
Clinicians are cautioned against oversimplifying ADCs. Factors like linker chemistry, cleavability, and drug-antibody ratio are critical variables. Even with the same target and payload class, these biochemical nuances can lead to profoundly different efficacy and toxicity profiles.
Physicians face a dilemma: using an ADC off-label for a patient with a weak biomarker (e.g., HER2 1+), as permitted by NCCN compendium listings, may provide some benefit. However, this prior exposure can disqualify the patient from future clinical trials for potentially more effective ADCs.
The arrival of multiple effective ADCs and targeted therapies means clinicians can no longer just focus on the next best treatment. They must think "five plays ahead," strategically sequencing therapies to maximize longevity. Today's treatment choice is now heavily influenced by the need to preserve future options.
A key principle for managing ADC side effects is that the toxicity profile is largely determined by the linker-payload combination, not the antibody's target. For example, drugs with a deruxtecan payload will have similar GI toxicities regardless of the target, allowing clinicians to anticipate AEs across a class.
With ADCs carrying a risk of interstitial lung disease (ILD), a critical safety measure is to act on radiological findings alone. Even if a patient is completely asymptomatic, new ground-glass opacities on a CT scan require an immediate treatment hold to prevent potentially rapid and severe pneumonitis.
The modern oncologist-patient relationship involves highly informed patients who actively research their condition. They bring specific clinical trial papers to appointments, questioning physicians about median PFS data and control arms, requiring a more collaborative and data-driven discussion about their care.