Adding adjuvant drugs from distinct breast cancer trials

Area of Science:

• Oncology
• Clinical Trials
• Breast Cancer Research

Background:

• Perioperative treatment options for early-stage operable breast cancer have expanded.
• Multiple therapies may be available for the same patient, creating treatment selection challenges.
• Concurrent or sequential administration of therapies is suggested by guidelines, but combining independently tested strategies can be problematic.

Purpose of the Study:

• To highlight the dilemma of combining perioperative therapies in early-stage breast cancer.
• To question the net benefit and toxicity of combined or sequential therapies versus monotherapy in phase 3 trials.
• To advocate for a cautious, evidence-driven approach and regulatory enforcement for combination trials.

Main Methods:

• Review of clinical scenarios involving combination therapies in early-stage breast cancer.
• Analysis of potential benefits and risks of combining agents like pembrolizumab plus olaparib or olaparib plus CDK4/6 inhibitors.
• Discussion of the extrapolation from monotherapy data to combination therapy efficacy.

Main Results:

• Individual therapies show efficacy, but the net gain of combined/sequential use in the perioperative setting is unproven in phase 3 trials.
• Potential for no additional benefit if the same patient subset benefits from each therapy individually.
• Short- and long-term toxicities of combinations have not been assessed in phase 3 trials, and their impact on dose reductions and overall outcomes is unknown.

Conclusions:

• The combination or sequential use of perioperative therapies requires a cautious, evidence-based approach.
• Regulatory enforcement for combination trials is needed, rather than extrapolating from monotherapy data.
• This dilemma extends beyond breast cancer, impacting neoadjuvant and adjuvant therapies across various cancers.