The failure of an adjuvant trial for the TKI pazopanib was likely caused by a protocol change that reduced the dose to manage transaminitis. While well-intentioned to improve tolerability and adherence, the lower dose was sub-therapeutic. This serves as a critical lesson that managing side effects by compromising dose can nullify a drug's potential efficacy.

The toxicity profile of amivantamab has been transformed by modern management. Data from studies like COCOON (prophylaxis) and PALOMA-3 (subcutaneous formulation) show dramatically lower rates of adverse events and discontinuations compared to the original MARIPOSA trial, rendering early toxicity tables less relevant.

Due to significant ocular toxicity affecting most patients, the approved starting dose for belantumab is likely not optimal long-term. Effective management requires clinicians to proactively hold, delay, and reduce doses at the first sign of side effects, meaning real-world application will differ from the initial protocol.

For patients with significant comorbidities like cardiovascular disease, proactively starting lenvatinib at a reduced dose (e.g., 14mg instead of 20mg) is a practical strategy to mitigate anticipated severe toxicities from the outset.

A critical reason patients stop ADC treatments is the burden of side effects like skin toxicity or GI issues, not just disease progression. This underscores the urgent need to develop ADCs with better safety profiles, enabling patients to stay on effective therapy longer.

New targeted therapies like Zanidatamab and Zolbetuximab show great promise but cause significant side effects like diarrhea and nausea. Their successful clinical adoption hinges on proactive management using detailed guidelines and prophylactic medications, as toxicity can be severe enough to force treatment discontinuation despite the drug's efficacy.

Data on Enfortumab Vedotin suggests that for modern therapies, maintaining patients on treatment longer via a lower, more tolerable starting dose is more important than administering the maximum labeled dose upfront, a concept inherited from the cytotoxic chemotherapy era.

For older, transplant-ineligible myeloma patients, quadruplet regimens are not administered at full strength. Clinicians proactively reduce doses of bortezomib, lenalidomide, and dexamethasone based on patient fitness and renal function to manage toxicity while maintaining efficacy.

Clinicians recommend starting lenvatinib at the full 20mg dose rather than escalating from a lower dose. This ensures therapeutic levels are reached. They then dose-reduce aggressively as needed. Starting low risks falsely concluding the drug is ineffective if the patient tolerates a suboptimal dose without response.