Venetoclax

Chronic Lymphocytic Leukemia and Small Lymphocytic Lymphoma

Venetoclax is used to treat adults with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). It may be prescribed as a standalone treatment or in combination with other medications.

Acute Myeloid Leukemia

This medication is also used to treat newly diagnosed acute myeloid leukemia (AML) in adults. For this condition, it is used in combination with other drugs, such as azacitidine, decitabine, or low-dose cytarabine. It is typically prescribed for patients who:

• Are 75 years of age or older.
• Have other medical conditions that make them unable to receive standard, intensive chemotherapy.

Targeting Cancer Cell Survival

Venetoclax belongs to a class of medications known as B-cell lymphoma-2 (BCL-2) inhibitors. In certain types of blood cancers, such as chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML), the body produces too much of a protein called BCL-2.

Restoring Natural Cell Death

The BCL-2 protein plays a key role in helping cancer cells survive. It acts like a shield, preventing the cells from undergoing a natural process called apoptosis, or programmed cell death. When cancer cells have high levels of BCL-2, they can live longer than they should and continue to multiply.

Venetoclax works by:

• Binding to the BCL-2 protein: The medication attaches itself directly to the BCL-2 protein inside the cancer cells.
• Blocking the survival signal: By binding to the protein, venetoclax prevents BCL-2 from protecting the cancer cell.
• Triggering cell death: Once the BCL-2 protein is blocked, the cancer cell receives the signal to die, allowing the body to naturally clear away the diseased cells.

Because this medication specifically targets the BCL-2 protein, it is considered a targeted therapy. It is designed to be more selective for cancer cells that rely on this protein for survival.

Common Side Effects

The most frequently reported side effects of venetoclax include:

• Diarrhea, nausea, or vomiting
• Fatigue or unusual tiredness
• Cough and upper respiratory tract infections
• Swelling of the hands, legs, or feet
• Muscle, bone, or joint pain
• Headache

Serious Side Effects

Venetoclax can cause serious complications that require prompt medical evaluation:

• Tumor Lysis Syndrome (TLS): This is a medical emergency caused by the rapid breakdown of cancer cells. Symptoms may include fever, chills, nausea, vomiting, confusion, shortness of breath, or dark or cloudy urine.
• Low Blood Cell Counts: A decrease in white blood cells (neutropenia) is common and can lead to severe infections. It may also cause low red blood cell counts (anemia) and low platelet counts (thrombocytopenia).
• Severe Infections: Patients may be at a higher risk for serious infections such as pneumonia or sepsis.
• Fever: Any fever while taking this medication should be reported to a healthcare provider immediately, as it may be a sign of a serious infection or low white blood cell count.

Tumor Lysis Syndrome

Venetoclax can cause tumor lysis syndrome (TLS), a condition where cancer cells break down quickly, leading to kidney failure or heart problems. This risk is highest when starting treatment or increasing the dose. Healthcare providers typically monitor blood chemistry and may require preventative measures such as increased fluid intake or specific medications to lower uric acid levels.

Neutropenia and Infections

A significant decrease in white blood cells (neutropenia) is a common and serious risk. This condition can make it harder for the body to fight infections. Serious infections, including pneumonia and sepsis, have been reported. Regular blood counts are necessary to monitor for these changes.

Drug Interactions

Certain medications, particularly strong CYP3A inhibitors, can significantly increase the levels of venetoclax in the body, raising the risk of TLS. Healthcare providers may need to adjust the dose or avoid certain combinations.

Vaccinations

Live vaccines should be avoided during and after treatment until the immune system has recovered. The medication may also make other vaccines less effective.

Embryo-Fetal Toxicity

Based on its mechanism of action, venetoclax may cause harm to a developing fetus. Females of reproductive potential are advised to use effective contraception during treatment and for 30 days after the last dose. Breastfeeding is not recommended during treatment.

Pregnancy

Venetoclax can cause harm to an unborn baby. Healthcare providers typically require a pregnancy test before starting this medication for individuals who are able to become pregnant. It is important to use effective birth control during treatment and for at least 30 days after the final dose to prevent pregnancy.

Breastfeeding

It is not known whether venetoclax passes into human breast milk. Because of the potential for serious side effects in a nursing infant, breastfeeding is not recommended during treatment and for at least one week after the last dose.

Fertility

Based on findings from animal studies, venetoclax may affect male fertility. Individuals concerned about how this medication might impact their ability to have children should discuss these risks with a healthcare professional.

Available Forms

Venetoclax is supplied as a tablet to be taken by mouth. It is typically administered once daily with a meal and water.

Starter Materials

For patients beginning therapy, the medication may be provided in a specialized starter pack. This pack is designed to help patients follow the required schedule during the initial phase of treatment when the amount of medication taken changes weekly.

Appearance

The tablets are manufactured in different shapes and colors to distinguish between the various strengths available. Patients should ensure they are taking the specific tablet prescribed by their healthcare provider for their current stage of treatment.

FDA Approval and Indications

Venetoclax is approved by the FDA for the treatment of adults with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL). It may be used alone or in combination with other medications for these conditions.

The medication is also approved for use in combination with azacitidine, decitabine, or low-dose cytarabine for the treatment of newly diagnosed acute myeloid leukemia (AML) in adults who meet specific criteria:

• Patients who are 75 years of age or older.
• Patients who have other medical conditions that prevent the use of standard, intensive chemotherapy.

Regulatory History and Safety Requirements

The FDA initially granted accelerated approval for venetoclax in certain AML cases, which was later converted to a regular approval after clinical trials confirmed the treatment's benefits. While the medication does not have a Boxed Warning, the FDA-approved labeling includes a mandatory dose-escalation (ramp-up) schedule. This regulatory requirement is intended to manage the risk of tumor lysis syndrome, a serious condition caused by the rapid breakdown of cancer cells during the start of treatment.

FDA-Approved Indications

The U.S. Food and Drug Administration (FDA) has approved venetoclax for the following uses:

• Chronic Lymphocytic Leukemia (CLL) and Small Lymphocytic Lymphoma (SLL): Venetoclax is approved for use in adults with CLL or SLL. It may be used alone or in combination with other medications, such as rituximab or obinutuzumab.
• Acute Myeloid Leukemia (AML): Venetoclax is approved for use in combination with azacitidine, decitabine, or low-dose cytarabine for newly diagnosed AML in adults who are 75 years or older, or who have other medical conditions that prevent the use of standard intensive chemotherapy.

Regulatory History

Venetoclax first received accelerated approval in 2016 for certain types of CLL. Since then, the FDA has expanded its approved uses and granted regular approval for several indications based on clinical trial data showing its effectiveness in shrinking tumors and improving progression-free survival. In 2020, the FDA granted regular approval for its use in combination therapies for AML.

Mechanism of Action

Venetoclax is classified as a B-cell lymphoma-2 (BCL-2) inhibitor. It is the first FDA-approved therapy in this class. It works by blocking the BCL-2 protein, which helps cancer cells survive. By inhibiting this protein, the drug helps trigger the natural death of cancer cells.