High-Risk Disease Management and Biomarker-Guided Decisions

Dr. Lipsky separates high-risk biomarkers conceptually, emphasizing TP53 aberrations and IGHV unmutated status should be considered distinctly rather than aggregated. TP53 aberrations—encompassing del(17p) and/or TP53 mutation—represent the highest-risk adverse predictive biomarkers across all CLL treatment strategies.

For TP53-aberrant patients (approximately 8% frontline, up to 40% in later lines) receiving venetoclax-obinutuzumab, CLL14 data show median PFS approximately 4 years compared to 6 years in the overall population. With zanubrutinib monotherapy, the adverse predictive impact of TP53 aberrations doesn't become apparent until year 6. This translates to a strong preference for continuous BTK inhibitor monotherapy for TP53-aberrant patients outside clinical trials, though absolute contraindications to BTK inhibitors (anticoagulation requirements, severe bleeding history) may necessitate fixed-duration alternatives.

IGHV unmutated status represents a different consideration and not a truly high-risk contraindication to fixed-duration therapy but rather a predictor of shorter PFS on venetoclax-based combinations (approximately 5 years) compared to IGHV-mutated patients (approximately 9 years). IGHV-unmutated patients remain excellent candidates for time-limited therapy given retreatment options, though clinicians should counsel realistic PFS expectations.

Dr. Coombs highlights a critical clinical distinction: patients progressing on continuous BTK inhibitors often progress rapidly and symptomatically, requiring immediate bridging to alternative therapy, with no option for same-class rechallenge. In contrast, patients progressing on venetoclax-obinutuzumab frequently experience asymptomatic progression with a median gap of approximately 1 to 2 years before IWCLL treatment indications develop. Dr. Shadman discusses incorporating SEQUOIA Arm D MRD data into clinical practice, extending zanubrutinib-venetoclax beyond 1 year for TP53-aberrant or IGHV-unmutated patients who maintain detectable MRD, extrapolating from demonstrated undetectable MRD rate improvements between years 1 and 2.