Pirtobrutinib is a novel Bruton’s Tyrosine Kinase (BTK) inhibitor. It has been approved for the treatment of relapsed/refractory mantle cell lymphoma (MCL) in patients who have received at least 2 lines of systemic therapy (including a BTK inhibitor), as well as chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in patients who have previously received treatment with a BTK inhibitor and a BCL-2 inhibitor.

Side Effects of Pirtobrutinib

Common Adverse Reactions

Hematological abnormalities: Neutropenia (46%), hemoglobin decrease (39%), lymphopenia (31%), thrombocytopenia (29%).

General symptoms: Fatigue (32%), musculoskeletal pain (30%).

Gastrointestinal reactions: Diarrhea (24%).

Infection-related: COVID-19 (22%).

Other reactions: Contusions (21%), cough (20%).

In Patients with Mantle Cell Lymphoma (n=128)

Incidence of serious adverse events: 38%.

Adverse reactions leading to treatment interruption: 32%.

Adverse reactions leading to permanent treatment discontinuation: 9%.

In Patients with Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma (n=110)

Incidence of serious adverse events: 56%.

Adverse reactions leading to treatment interruption: 42%.

Severe Side Effects of Pirtobrutinib

Risk of Severe Infections

Overall infection status: 24% of patients developed grade 3 or higher infections.

Fatal infections: 4.4% of patients experienced fatal infections.

Specific infection types: Pneumonia (14%), sepsis (6%), febrile neutropenia (4%).

Bleeding Events

Incidence of major bleeding: 3% (defined as grade 3 or higher bleeding or any central nervous system bleeding).

Overall bleeding rate: 17% (excluding contusions and petechiae).

Fatal bleeding: 0.3%.

Risk of Concomitant Use with Antithrombotic Drugs

Patients not using antithrombotic drugs: 2.3%.

Patients using antithrombotic drugs concurrently: 0.7%.

Precautions for Pirtobrutinib

Patient Selection Criteria

Indication confirmation: Relevant mutations must be confirmed through genetic testing.

Exclusion criteria: Active central nervous system lymphoma, major cardiovascular diseases, major bleeding events, etc.

Routine Monitoring Items

Hematological monitoring: Regular monitoring of complete blood count.

Liver function monitoring: Assessment of bilirubin and transaminases before and during treatment.

Cardiac function monitoring: Attention to symptoms related to arrhythmias.

Management of Drug Interactions

Strong CYP3A inhibitors: Avoid concomitant use; reduce the dose if necessary.

Strong or moderate CYP3A inducers: Avoid concomitant use; increase the dose if necessary.