The introduction of ADCs into frontline ovarian cancer treatment creates a new challenge: conflicting biomarkers. A patient's tumor might be positive for both HER2 (an ADC target) and a BRCA mutation (a PARP inhibitor target), forcing clinicians to choose between two effective targeted therapies without clear guidance.

A novel strategy involves combining antibody-drug conjugates (ADCs) with PARP inhibitors. This approach could potentially overcome the need for a germline BRCA mutation, significantly broadening the patient population that could benefit from PARP inhibitor therapy in triple-negative breast cancer.

The future of advanced prostate cancer treatment may involve combining ADCs with bispecific T-cell engagers. This strategy could use ADCs for a short duration to deliver a potent hit, followed by immunotherapy to achieve durable remission, potentially reducing toxicity and enabling earlier use.

In a future TNBC landscape with new antibody-drug conjugates (ADCs), Pumitamig is framed as a fundamentally different tool. The expert views ADCs as a form of "chemotherapy," while Pumitamig is an "immunotherapeutic strategy." This conceptual separation suggests a future where these novel agents are used in combination or sequence, not in direct competition.

The Begonia trial showed an ~80% response rate by combining an ADC (Dato-DXD) with immunotherapy (Durvalumab) in first-line metastatic TNBC patients, 87% of whom were PD-L1 negative. This suggests ADCs, through immunogenic cell death, may create an immune-responsive environment, expanding IO benefit beyond the traditional biomarker.

When a patient has a BRCA2 mutation, clinicians on the panel view it as such a dominant predictive biomarker that they would prioritize a PARP inhibitor-based triplet regimen. This single genetic finding often outweighs other clinical factors or even the potential addition of docetaxel in treatment decisions.

For high-risk, HR+ patients with germline BRCA mutations, data suggest they derive less benefit from CDK4/6 inhibitors. A practical approach is to give one year of the PARP inhibitor olaparib first, followed by a CDK4/6 inhibitor, capitalizing on the delayed initiation allowance in major trials.

A nuanced approach to PARP inhibitors involves reserving combinations for BRCA2 patients with clear, aggressive clinical features like high-volume disease or liver metastases. This strategy balances potent efficacy against toxicity for a molecularly defined but clinically heterogeneous group, avoiding overtreatment of those with more indolent disease.

In high-risk, BRCA-positive patients eligible for both, clinicians favor giving a PARP inhibitor first. The rationale is based on established survival data, shorter one-year duration, and emerging biological evidence suggesting BRCA2-mutated tumors may be resistant to CDK4/6 inhibitors due to concurrent RB gene loss.