Treatment Duration, Maintenance Concepts, and Development of New ADC Targets in Breast

This section explores the evolving discussion around duration of ADC therapy and the possibility of maintenance treatment once patients reach maximal response. Dr Mouabbi explains that many patients discontinue ADC therapy because of toxicity rather than disease progression. This observation has led to interest in structured maintenance approaches that preserve treatment benefit while reducing cumulative exposure to the payload.

The experts describe how clinicians determine the point of best response. They note that repeated imaging helps confirm whether the disease has reached maximal regression. Once confirmed, a transition to maintenance therapy with a lower intensity schedule or reduced dose may lessen toxicity while maintaining disease control. They emphasize the importance of early detection of side effects such as fatigue, gastrointestinal symptoms, and pulmonary changes. This approach may support longer treatment durations and improved quality of life.

The conversation expands to emerging trials evaluating maintenance strategies in HER2 positive and HER2 low disease. These studies aim to determine whether maintenance preserves response and whether reintroduction of the full ADC at progression can recapture activity.

The speakers then review new ADC targets under development. HER3, B7 H3, and LIV1 are highlighted as promising candidates. These targets appear in tumors that have limited treatment options and may broaden ADC applicability in hormone receptor positive disease, residual disease after prior ADC exposure, and other clinically challenging settings. They note that early phase results show encouraging activity across multiple targets.

The section concludes by stressing the importance of advancing both treatment duration strategies and new biologic targets. As ADC use expands, clinicians will need to balance efficacy with long term tolerability and incorporate new agents into evolving treatment pathways.