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Treatment Name: Venetoclax (Venclexta)

Venetoclax (Venclexta) is a Treatment Regimen for Chronic Lymphocytic Leukemia (CLL)

How does Venetoclax (Venclexta®) work?
Venetoclax (Venclexta®, ABT-199) is designed to kill cancerous B-lymphocytes that cause the disease known as CLL. Venetoclax does this by binding to and inhibiting a protein in cancerous lymphocytes known as “BCL-2,” which prevents the cell from dying and also makes it resistant to certain chemotherapy regimens.

What are the venetoclax goals of therapy?
Venetoclax is taken to shrink swollen lymph nodes due to CLL and kill CLL cells in the blood and bone marrow. By killing cancerous lymphocytes, Venetoclax is commonly given with the goal of extending survival as long as possible. It is also known as targeted therapy.


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Venetoclax is given according to a weekly ramp-up schedule over 5 weeks to the recommended daily dose of 400 mg as shown here:

  • Usual Venetoclax (Venclexta®) starting dose: 20 mg oral tablet by mouth once daily on Days 1 - 7, with a meal and a glass of water
  • then increase to 50 mg daily on Days 8 - 14,
  • then increase to 100 mg daily on Days 15 - 21,
  • then increase to 200 mg (two 100 mg tabs) daily on Days 22 - 28,
  • then increase to a maximum dose of 400 mg (four 100 mg tabs) daily and on, beginning Day 29

NOTE for patients with a large tumor burden as determined by your doctor, to monitor for Tumor Lysis Syndrome: After taking the first 20 mg dose, labs (blood tests) may be needed 6 - 8 hours later, then again 24 hours later. Likewise, after taking the first 50 mg dose, labs (blood tests) may be needed 6 - 8 hours later, then again 24 hours later.

Dose adjustments due to side effects were required in roughly one out of every ten patients.

Venetoclax may be taken at home, in an infusion center, or in the hospital depending upon the risk level.

Risk levels for patients with CLL taking venetoclax include: low risk, medium risk, or high risk.

Typical duration of therapy is usually until venetoclax no longer works, or unacceptable side effects are experienced.

Venclexta starter pack dosing can be found here.


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Side Effects

In clinical studies, the most commonly reported side effects with Venetoclax are shown here:

  • Diarrhea (52%)
  • Upper respiratory tract infection [such as sinusitis or sore throat] (48%)
  • Nausea (47%)
  • Neutropenia [low “good” white blood cells known as neutrophils] (45%)
  • Fatigue (40%)
  • Cough (30%)
  • Fever (26%)
  • Anemia [low red blood cells] (25%)
  • Headache (24%)
  • Constipation (21%)
  • Increased risk of bleeding [low platelet count] (21%)
  • Joint pain (18%)
  • Vomiting (18%)
  • Swelling or water retention (16%)
  • High blood sugar (15%)
  • Neutropenic fever (6%)
  • Pneumonia (4%)
  • Severe tumor lysis syndrome (3%)
  • Prostate cancer (2%)

Serious reactions were reported in roughly 4 out of 10 patients who took Venetoclax. These included: pneumonia, neutropenic fever, fever without neutropenia, anemia, and tumor lysis syndrome.

Roughly 8% of patients discontinued Venetoclax therapy due to unacceptable side effects or abnormal blood tests, such as low platelet count and low red blood cell count.

Side effect videos Side Effect Videos
Neutropenic FeverNeutropenic FeverDiarrheaDiarrheaNausea and VomitingNausea and VomitingAnemiaAnemiaBleedingBleedingFatigue Fatigue PainPain


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How often is venetoclax monitoring needed?
Labs (blood tests) will be checked before treatment, and as frequently as every 6 – 8 hours if the ramp-up phase occurs in the hospital. As lymph nodes shrink and the number of CLL cells in the blood decrease, the frequency of lab tests will likely decrease.

Monitoring may occur in the hospital or in an outpatient clinic, depending upon whether someone is considered, low, medium, or high risk for tumor lysis syndrome, and whenever a higher dose is used during the first 4-week ramp-up phase.

Monitoring during and after the Venclexta 5-week ramp-up will depend upon response to therapy, side effects experienced, and whether Venetoclax needs to be discontinued if not tolerated. Labs often include: Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), uric acid, Lactate Dehydrogenase (LDH), blood magnesium, calcium, and phosphorous, plus any others your doctor may order. A bone marrow biopsy may be considered to monitor for minimal residual disease.

How often is imaging needed?
Imaging may be checked before Venclexta™ treatment, at Week 6, then Week 12 or 16, then Week 24, then every 12 weeks thereafter, until stable. Imaging may include: X-rays, computerized tomography (CT scan), and any others your doctor may order.

How might blood test results/imaging affect venetoclax treatment?
Depending upon the results, your doctor may advise to continue Venetoclax as planned, reduce the dose, delay or switch therapy, or discontinue this drug.


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ChemoExperts Tips

  • Drink 6 to 8 glasses of water each day starting two days prior to the first dose, and each time the dose is increased, to help reduce the chance of getting tumor lysis syndrome
  • If Venetoclax therapy is stopped for more than one week during the initial 5-week ramp-up phase due to side effects, abnormal blood tests, or infection, or stopped for more than two weeks after taking the 400 mg dose, the dose may again need to be reduced when restarting. Once restarted it will be increased slowly to avoid tumor lysis syndrome
  • Venetoclax interacts with medications commonly taken for other reasons. A pharmacist should ALWAYS review your medication list BEFORE starting Venetoclax to ensure that drug interactions are prevented or managed appropriately. On occasion, medications that you were taking regularly before Venetoclax may need to be switched or discontinued in order to safely take Venetoclax. Ask a pharmacist before starting ANY new medication if you are already taking Venetoclax
  • If neutropenia occurs (a condition where the level of certain white blood cells known as “neutrophils" becomes too low), antibiotics or neutrophil growth factor medications, such as filgrastim, may be prescribed by your doctor
  • Clinical trials may exist for CLL. Ask your doctor if any studies are currently enrolling in your area. If not, go to to search for other centers offering study medications

Patient Assistance & Co-payment Coverage

Patients under the age of 65 years, or those with private insurance plans:
If you have insurance and are looking for patient assistance or copay assistance for Venetoclax (Venclexta), we have provided links that may help.

Visit our Patient Assistance page and click the links to various patient assistance programs for help paying for Venetoclax (Venclexta). Depending upon your income, they may be able to help cover the cost of:

  • Venetoclax

For Branded medications (may be available for generic medications too), check with the manufacturer to determine if a co-pay card is offered and if it could reduce your monthly copay.

  • If you are uninsured, check with the manufacturer to determine if you are eligible to receive medication at no cost.

Medicare and Medicaid patients (Patients 65 years or older):
The clinic providing treatment will likely pre-authorize medications and immune therapies such as Venetoclax (Venclexta) and are the best source to help you understand drug cost.

  • Ask to speak with a patient assistance technician or financial counselor at the clinic or hospital administering this therapy.

Emotional Wellness

What is Emotional Wellness?
Emotional wellness is having a positive outlook balanced with a realistic understanding of current life events. This requires both an awareness and acceptance of your emotions. It is with this knowledge that you can develop a plan to take the necessary actions to positively impact your life.

Emotional wellness uses an ongoing process to continually reflect on the stressors of life in a constructive manner to move forward and create happiness.

Because emotional wellness is deeply connected with physical, social, and spiritual wellness, pursuing it often becomes particularly difficult in times of major illness. Despite this difficulty, working toward emotional wellness has been connected to improved treatment outcomes and a higher likelihood of achieving goals of therapy.

Learn more about pursuing emotional wellness while receiving treatment with Venetoclax (Venclexta)

Individual Drug Label Information

Venetoclax (Venclexta®)

  • Venetoclax is an oral tablet, available in the following doses: 10 mg, 50 mg, 100 mg 
  • Tumor Lysis Syndrome is expected. Patients at high risk for tumor lysis may need to be hospitalized for the first several doses to receive adequate IV fluids, plus electrolyte and kidney function monitoring 
  • Neutropenia is common. Antibiotics may be needed to prevent or treat infections 
  • Live attenuated vaccines should not be administered before, during, or after treatment with venetoclax as they have not been studied and it is unknown if they are safe to use. Ask your pharmacist if you are not sure which vaccines are safe to use 
  • Venetoclax may make certain vaccines less effective. Repeat vaccination may be required at a later time 
  • Take with food and a large glass of water around the same time of day, each day. Do NOT crush, break, or chew tablets. If your dose is 200 mg or 400 mg, multiple tablets will need to be taken at the same time. Do NOT split up dosing during a day as this may change how the medication works or the incidence of certain side effects 
  • Drug interactions may be severe. Certain medications should NOT be taken together with venetoclax. Ask a pharmacist if your home medications are safe to use 
  • It is recommended to take with food to help with absorption 
  • Avoid grapefruit, grapefruit juice, Seville oranges, marmalade and star fruit as these may increase the amount of venetoclax that is in your body leading to unwanted side effects 
  • If you miss a dose, take venetoclax within 8 hours of the normal time you take it, and resume the normal schedule the next day. If a dose is missed and more than 8 hours has past since you usually take it, skip the dose and resume the next day at your usual time 
  • If vomiting occurs, no dose should be taken until the next scheduled dose on the following day. Do NOT make up for missed doses. 
  • Stored at or below 86 degrees Fahrenheit  
  • Dosage adjustments may be required kidney or liver problems 
  • May interact with antifungal medications ending in “azole,” such as voriconazole or posaconazole. These medications MUST NOT be used during the first 5 weeks of venetoclax therapy 
  • May interact with common medications such as ciprofloxacin, fluconazole, diltiazem, verapamil, amiodarone, St. John’s wort, digoxin, warfarin, vitamins, herbal supplements, and many others. Alternative medications should be considered, or the doses greatly reduced (for example, by 50% or more) 
  • Drug interactions with venetoclax may lead to severe side effects. Certain medications should NOT be taken together. Ask a pharmacist if your home medications are safe with this drug
  • May cause fetal harm, avoid this drug during pregnancy and breastfeeding. Females of child-bearing potential should take a pregnancy test before starting venetoclax and use effective contraceptive during therapy and for at least 30 days after the last dose
  • Males may consider sperm banking as venetoclax may cause infertility 
General Venetoclax (Venclexta) Side Effects 
  • Neutropenia [increased infection risk] 
  • Neutropenic fever [medical emergency requiring IV antibiotics immediately] 
  • Diarrhea 
  • Nausea 
  • Anemia [low red blood cells] 
  • Upper respiratory tract infections such as sinus infection, or sore throat 
  • Low platelet count [increased risk of bleeding] 
  • Fatigue 
  • Vomiting 
  • Constipation 
  • Swelling or water retention 
  • Back pain 
  • Headache 
  • Cough 
  • Venetoclax is NOT expected to cause hair loss 
  • Click on the venetoclax (Venclexta) package insert below for reported side effects and possible drug interactions

Side Effect Videos
Nausea and VomitingNausea and VomitingDiarrheaDiarrheaFatigue Fatigue BleedingBleedingPainPainAnemiaAnemiaNeutropenic FeverNeutropenic Fever

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Roberts AW, Davids MS, Pagel JM, et al. Targeting BCL2 with venetoclax in relapsed chronic lymphocytic leukemia. N Engl J Med. 2016;374:311-322.

Created: April 12, 2016 Updated: December 6, 2019

What is Chronic Lymphocytic Leukemia (CLL)?

Chronic Lymphocytic Leukemia (CLL) is the most common type of leukemia diagnosed in adults. It is a cancer of the B-lymphocyte. In rare cases, CLL may be hereditary, but most causes are unknown. The stage of CLL can vary at diagnosis and throughout treatment. Stages of CLL include Rai stage 0, I, II, III, or IV. Many therapies are not curative, however, newer therapies are able to suppress the cancer for many months or even years.

As depicted in the picture, CLL may affect lymph nodes, the spleen, bone marrow, and the blood.

CLL may affect lymph nodes, the spleen, bone marrow, and the blood

Medications for CLL may include intravenous infusions, oral tablets or capsules, or a combination of IV and oral medications. Patients may be diagnosed with CLL without having any symptoms. Others may go to their doctor with symptoms of fatigue, a large spleen, or decreased appetite. The effectiveness of the treatment may depend upon the stage at diagnosis.

NOTE: Treatment Options listed below are not all-inclusive. Other treatments may be available. ChemoExperts provides drug information and does not recommend any one treatment over another. Only your Doctor can choose which therapy is appropriate for you.

What is a "17p deletion"?

A blood test is used to detect the mutation known as a “17p deletion.”

The genetic material which makes up the small arm (also known as “p” for petit) of Chromosome 17, is where the gene known as “the guardian of the genome” lives. When this gene is missing on 17p, this condition is often referred to as a 17p deletion. If this deletion is detected, the leukemia may behave more aggressively. Click for more information on mutation testing.

What does “low risk” mean?

Low risk patients can usually be managed in an outpatient clinic. These are patients who have small lymph nodes (less than 5 cm or about 2 inches), and few CLL cells in the blood (less than 25 thousand per microliter).

Patients with “low risk” CLL should still receive IV hydration when starting venetoclax, as well as an oral medication known as allopurinol to protect the kidneys.

What does “medium risk” mean?

Medium risk patients can usually be managed in an outpatient clinic. These are patients who have slightly larger lymph nodes (between 5 - 10 cm, or about 2 - 4 inches), or many CLL cells in the blood (more than 25 thousand per microliter), but not both.

Patients with “medium risk” CLL should receive IV hydration when starting venetoclax, as well as an oral medication known as allopurinol to protect the kidneys. Patients with kidney problems, or elderly patients may need to be hospitalized for the first day or two when starting the 20 mg or 50 mg doses.

What does “high risk” mean?

High risk patients SHOULD be managed in the hospital for the first day or two when starting the 20 mg or 50 mg doses. These are patients who have a large lymph node (greater than 10 cm, or about 4 inches), or many CLL cells in the blood (more than 25 thousand per microliter), plus a slightly larger lymph node (greater than 5 cm, or about 2 inches).

Patients with “high risk” CLL should receive IV hydration when starting venetoclax, as well as an oral medication known as allopurinol to protect the kidneys, and sometimes an IV medication known as rasburicase to further protect the kidneys.

Starter Pack Dosing

The Venetoclax Starter Pack includes the following:

Week 1: Venetoclax 20 mg (two 10 mg tabs) by mouth once daily = fourteen 10 mg tablets
Week 2: Venetoclax 50 mg by mouth once daily = seven 50 mg tablets
Week 3: Venetoclax 100 mg by mouth once daily = seven 100 mg tablets
Week 4: Venetoclax 200 mg (two 100 mg tabs) by mouth once daily = fourteen 100 mg tablets

Of note: Week 5 and beyond: 400 mg (four 100 mg tabs) by mouth once daily are dispensed as a separate prescription as a one month supply

Important: Tablets should be kept in their original container until use.

What is a CBC?

A Complete Blood Count (CBC) is a frequently ordered blood test that tells clinicians the status of your: 1) White blood cell count, 2) Hemoglobin, and 3) Platelet count at the time the test was taken.

Common uses:
1) White blood cell count (WBC): is used to determine infection risk, or response to chemotherapy. Certain chemotherapy agents may harm our good infection-fighting cells. Sometimes chemotherapy may need to be delayed to allow these cells to recover.

2) Hemoglobin: is used to determine if someone is anemic. Anytime the hemoglobin is below 12 g/dL, the person is said to be anemic. Red blood cell transfusions, and sometimes iron can be given to restore the hemoglobin level, but anemia treatment should always aim at treating the underlying cause or condition.

3) Platelet count: is used to determine if the risk of bleeding is increased or if a platelet transfusion is required to prevent bleeding. Certain medications that increase bleeding risk, such as: aspirin, certain chemotherapy agents, and blood thinners, may need to be stopped temporarily until the platelet count is within a safe range.

What is a CMP?

A Comprehensive Metabolic Panel (CMP) is a frequently ordered blood test that tells clinicians the status of your: 1) Electrolytes & Acid/Base status2) Kidney function, 3) Liver function, 4) Blood sugar, and 5) Calcium at the time the test was taken. It is commonly used to monitor liver and kidney function when beginning new medications such as chemotherapy. A total of 14 tests are run simultaneously and are shown below.

Electrolytes & Acid/Base status:
1) Sodium, 2) Potassium, 3) Carbon dioxide, 4) Chloride

Kidney Function:
5) BUN (blood urea nitrogen), 6) Serum creatinine (Scr)

Liver Function:
7) AST, 8) ALT, 9) Total bilirubin, 10) Alk Phos, 11) Albumin, 12) Total protein

Blood sugar:
13) Serum glucose

14) Serum calcium

What is Tumor Lysis Syndrome?

Tumor lysis syndrome occurs when many cancer cells die quickly and release their contents into the bloodstream. Many times the body has the ability to flush these substances out through the kidneys or metabolize them via the liver. However, sometimes the body needs medicines to help eliminate these substances and to prevent organ damage.

These medicines may include: IV hydration, oral allopurinol, IV rasburicase, plus others