Despite subsequent data not confirming an increased bleeding risk compared to other therapies, the initial studies on pacritinib showed a signal for increased bleeding. Consequently, it is still advised that the drug be stopped for several days prior to any major surgical procedure as a safety precaution.

Non-covalent BTK inhibitors like pirtobrutinib are currently approved for use after covalent BTK inhibitors fail. Moving them to the frontline setting, as studied in BRUIN-313, disrupts the established treatment pathway and creates uncertainty for managing relapsed disease, as the standard 'next step' is removed.

BTK inhibitors function as highly potent antiplatelet agents, an 'on-target' effect. Many surgeons are unaware, leading to significant post-operative bleeding if the drug isn't stopped. Patients must be educated to inform their surgical teams and advocate for themselves.

Beyond raising platelet counts, the newly approved BTK inhibitor rilzabrutinib provides dramatic improvements in the fatigue associated with ITP. This unique benefit, likely due to its anti-inflammatory properties, makes it a strong consideration for patients where fatigue is a primary quality of life issue.

Pirtobrutinib is the first BTK inhibitor to show a rate of atrial fibrillation equivalent to a chemoimmunotherapy control arm in a randomized trial. This uniquely safe cardiovascular profile makes it a strong first-line candidate for older Chronic Lymphocytic Leukemia (CLL) patients or those with significant heart-related comorbidities.

Early data from the CLL 314 study shows a progression-free survival benefit for pirtobrutinib over ibrutinib in frontline CLL patients. This finding suggests a potential future shift where non-covalent BTK inhibitors could become the initial standard of care.

Pirtobrutinib's reduced side effects, like atrial fibrillation, stem from its precise targeting of BTK with minimal 'binding promiscuity' to other kinases. This makes it a safer option for patients who have already been on a less-targeted BTK inhibitor.

While pirtobrutinib is effective after covalent BTK inhibitors, the reverse is unproven. Starting with pirtobrutinib frontline raises a critical unanswered question about whether patients will still respond to older covalent inhibitors, complicating sequencing decisions, especially for younger patients.

The LUNA-three trial demonstrated that ITP patients on rilzabrutinib showed improved fatigue. Notably, even patients whose platelet counts did not respond to the drug still had better fatigue outcomes than the placebo group, suggesting a separate anti-inflammatory benefit on quality of life.