For elderly or comorbid patients, the high toxicity of powerful, time-limited combination therapies can outweigh their efficacy. A less harsh, continuous monotherapy is often preferable as it better preserves quality of life, even if it doesn't offer a treatment-free interval or a theoretical "100% life back."

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.

Despite impressive data supporting HMA/Venetoclax, its application in younger, fit patients must be cautious. The pivotal VIALE-A trial excluded key subgroups like FLT3, core binding factor, and certain NPM1 patients, for whom intensive chemotherapy remains the standard.

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.

Current oral BTK/BCL-2 inhibitor combinations for CLL have hit an MRD clearance "wall" of 35-50%. By upgrading the BCL-2 inhibitor to the more potent somatoclax, combined with zanubrutinib, MRD clearance rates nearly double to 98%, demonstrating that improving the BCL-2 component is key to achieving deeper remissions.

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.

Initial studies combining menin inhibitors with venetoclax/azacitidine showed high remission rates but also high mortality. Using each agent at its full, 28-day dose caused severe, fatal myelosuppression, forcing protocol amendments to shorten drug exposure to manage toxicity.

Eikon's strategy for its PARP inhibitor wasn't just to create a better version of an existing drug class, but one with superior combinability. By selectively targeting PARP1, they minimized the hematologic toxicity that prevented older PARP inhibitors from being used with chemotherapies like taxanes, opening up earlier lines of treatment.

While adding a menin inhibitor to the azacitidine/venetoclax doublet for older/unfit AML patients increases response rates, it leaves little reserve for marrow function. This can lead to increased risk of early, fatal complications like infection or bleeding, requiring careful dose management.