While second-generation BTK inhibitors are clinically similar, the next major advance in combination therapy may come from the BCL2 inhibitor component. The newer agent sonrotoclax is potentially more potent and selective than venetoclax, which could lead to superior efficacy and tolerability in future regimens.

When a patient progresses on a covalent BTK inhibitor, using venetoclax next offers a strategic advantage beyond its efficacy. It may reshape the disease's clonal architecture by suppressing BTK-resistant clones, potentially restoring or improving the benefit from a different BTK inhibitor used later in the treatment course.

Adding obinutuzumab to acalabrutinib/venetoclax (triplet therapy) deepens responses but led to higher death rates in trials, partly due to COVID-19. This makes it a high-risk, high-reward strategy that experts reserve for younger, healthier patients with high-risk disease who prioritize coming off therapy.

Adding obinutuzumab later to acalabrutinib/venetoclax therapy—and only for patients with an incomplete response—achieves the same remission rates as upfront administration. This delayed approach improves overall survival by avoiding early, severe infections, particularly COVID-19, associated with the antibody.

To combat the significant myelosuppression from the standard 28-day venetoclax cycle in AML, many clinicians are adopting a strategy of performing a bone marrow biopsy around day 21 and pausing the drug if blast clearance is achieved to allow for hematologic recovery.

Despite strong single-agent trial results, experts believe the field is shifting away from continuous monotherapy. The most significant future impact for pirtobrutinib will likely be as a backbone of fixed-duration combination therapies with drugs like venetoclax, aiming for deeper remissions without indefinite treatment.

In the AMPLIFY trial, the acalabrutinib-venetoclax (AV) arm showed superior overall survival. This was heavily influenced by the COVID-19 pandemic, as regimens containing the anti-CD20 antibody obinutuzumab (AVO and chemo) had significantly more fatal COVID cases, making the antibody a liability during that period.

While the continuous BTK inhibitor zanubrutinib showed longer progression-free survival, this efficacy came with a significant safety trade-off. It led to a 47% rate of serious adverse events compared to 24% for the fixed-duration acalabrutinib-venetoclax combination in the indirect analysis.

An MD Anderson study showed that delaying the addition of obinutuzumab to an acalabrutinib-venetoclax regimen achieved similar deep remission rates (uMRD) as upfront administration. This sequencing strategy significantly reduced severe neutropenia (52% vs 12%) and infections, making the potent combination safer.