Gemtuzumab Ozogamicin: A Game-Changer in AML Treatment

Overview

Gemtuzumab ozogamicin is a unique class of medication that combines a protein called an antibody with a chemical used in chemotherapy. The purpose of this mixture is to target and kill certain bodily cells while attempting to spare healthy ones. It is used to treat acute myeloid leukemia (AML), a particular kind of leukemia (a blood cell malignancy) that affects both adults and children. For this treatment to be effective, the cells in this leukemia must have a marker called CD33 (Siglec-3). When AML is first detected or when prior treatments have not worked, Gemtuzumab ozogamicin may be administered. The United States Food and Drug Administration (USFDA) approved the Gemtuzumab ozogamicin injection on September 1, 2017.

Drug Group:

Drugs classified as monoclonal antibodies include Gemtuzumab ozogamicin.

Indications:

Two forms of acute myeloid leukemia (AML) are treated with the medication Gemtuzumab ozogamicin:

• AML With a Recent CD33 Positive Diagnosis: It is intended for adults with recently diagnosed leukemia of this kind.

• AML With Relapse or Refractory to CD33: It is for people with AML who have relapsed after treatment or who have not responded to prior therapy (refractory), including adults and children two years of age and above.

Contraindications:

If a person has previously experienced an adverse reaction to Gemtuzumab ozogamicin or is allergic to any of its ingredients, they should not use it. It should be avoided by those who have previously experienced severe allergic reactions, as they may result in anaphylaxis.

Dosage Forms and Available Strengths:

Gemtuzumab ozogamicin is supplied as a 4.5 mg (milligrams) powder in a single-dose vial for injection. This powder appears off-white to white. It must first be reconstituted, that is, combined with liquid and then further diluted before usage.

For Patients

What Is Acute Myeloid Leukemia?

Cancer is the result of unchecked cell growth in a particular area of the body; different types of cancer affect different organs. Acute myeloid leukemia is one of the various kinds of leukemia, a blood cell malignancy (AML). AML usually starts in the bone marrow and quickly spreads to the bloodstream, brain, spinal cord, testicles, liver, spleen, and lymph nodes, among other possible locations. Though it can also originate from other blood-forming cells, it primarily begins in cells that are intended to become white blood cells. There are other names for AML, including acute myelogenous leukemia and acute myelocytic leukemia.

What Are the Clinical Uses of Gemtuzumab Ozogamicin Injection?

AML is a specific type of cancer that can be treated with a medication called Gemtuzumab ozogamicin injection. It is administered alone or in combination with other chemotherapy medications. Some types of white blood cells are the source of AML. This medication is for newly diagnosed cancer in adults and children older than one month. Additionally, it is intended for adults and children older than two whose cancer worsened following prior chemotherapy treatments. Drugs classified as monoclonal antibodies include Gemtuzumab ozogamicin. It aids in the destruction of cancer cells.

How Should Gemtuzumab Ozogamicin Injection Be Used?

Gemtuzumab ozogamicin injection is administered through a needle or catheter inserted into a vein. It is supplied as a powder that must be combined with liquid. Usually, it is injected gradually over the course of two hours. The regimen is based on how the body reacts to the drug, whether the cancer has been treated in the past, and whether other chemotherapy treatments are being taken.

Serious or potentially fatal responses can occur during an infusion and for up to a day after receiving a Gemtuzumab ozogamicin injection. Gemtuzumab ozogamicin doses will be preceded by certain drugs to assist in preventing a response. A physician or nurse will keep a close eye on the patient both throughout the infusion and in the immediate aftermath to ensure that there are no adverse drug responses. Any of the following symptoms, which could appear during or within 24 hours after the infusion, should be reported right away to the doctor or nurse: rash, fever, chills, fast heartbeat, swelling tongue or throat, shortness of breath, or difficulty breathing.

Depending on the patient's response to the medicine and any side effects, the doctor may reduce the rate of infusion, postpone, cease, or administer additional medications in addition to Gemtuzumab ozogamicin injectable therapy. It is crucial to discuss the feelings with the doctor both during and after the procedure.

What Are the Side Effects of Gemtuzumab Ozogamicin Injection?

Injections of Gemtuzumab ozogamicin may have adverse consequences. If any of these symptoms concern the patient or they persist, let the doctor know:

• Nausea.

• Diarrhea.

• Rash.

• Headache.

• Pain.

• Vomiting.

• Constipation.

Certain adverse effects may be dangerous. If the person has any of the following symptoms, get immediate medical attention or give the doctor a call as soon as possible:

• Unusual or severe bleeding or bruises.

• Signs of infection, fever, chills, or sore throat.

• Rapid heartbeat.

• Cough.

• Shortness of breath or difficulty breathing.

Gemtuzumab ozogamicin injection may result in additional adverse effects. If the person has any odd side effects while taking this medicine, get in touch with the doctor.

What Are the Things to Inform the Doctor Before Taking Gemtuzumab Ozogamicin Injection?

• Patients should let the physician and pharmacist know if they have any allergies before getting Gemtuzumab ozogamicin injection, whether it be to other drugs, the injection itself, or any of its constituent parts. One can ask the pharmacist for a list of the ingredients.

• It is critical to inform the physician and pharmacist about all medications taken, including over-the-counter and prescription medications, vitamins, supplements, and herbal remedies. Patients need to disclose drugs that may interact with Gemtuzumab ozogamicin, such as Fluconazole, Amiodarone, and Chlorpromazine.

• If there is a family history of long QT syndrome or abnormal blood mineral levels, patients should inform the doctor.

• It is best to avoid giving the patient a Gemtuzumab ozogamicin injection if they are expecting a child, are planning a pregnancy, or intend to father one.

• Before beginning therapy, a negative pregnancy test is essential. Birth control should be used both during and after therapy if the patient is male and has a partner who may become pregnant.

• It is crucial to stop breastfeeding the patient during the Gemtuzumab ozogamicin injection and for a time after the last dosage. Furthermore, as Gemtuzumab ozogamicin may impact fertility in both men and women, patients should talk to the doctor about any concerns they may have regarding pregnancy.

Dietary Consideration: Maintain the same diet unless advised otherwise by the doctor.

Missed Dose: If a Gemtuzumab ozogamicin appointment is missed, contacting the doctor's office promptly to reschedule is important. The dosing schedule will be adjusted accordingly.

Overdose: Gemtuzumab ozogamicin is given by a medical professional in a hospital; thus, it is unlikely that someone could take too much of it.

For Doctors

Pharmacodynamics:

The goal of Gemtuzumab ozogamicin treatment is to saturate as many CD33 sites on leukemia cells as feasible in order to maximize its effects. Research indicates that blood CD33 reaches near-maximum saturation at doses of two mg/m2 (milligrams per square meter) and above. However, as the amount of Gemtuzumab ozogamicin in the blood increases, especially in patients who have already received stem cell transplants, there is a larger risk of veno-occlusive disease (VOD) at a higher dosage of nine mg/m2, given in two doses separated by 14 days.

Mechanism of Action:

A medication called Gemtuzumab ozogamicin targets a particular protein called CD33 that is present in some cancer cells. It consists of two components: N-acetyl gamma calicheamicin, a tiny chemical, and an antibody known as hP67.6. The tiny chemical that is coupled to the antibody functions as a potent drug while the antibody detects and binds to the CD33 protein in cancer cells. The tiny molecule is released by the linker into the cancer cell when the medication attaches to it and is absorbed by the cell. The cancer cell eventually dies as a result of this chemical damaging its DNA (deoxyribonucleic acid). Gemtuzumab ozogamicin generally acts on cancer cells within the body by identifying and eliminating them.

Pharmacokinetics:

For the fractionated regimen, no clinical PK (pharmacokinetics) data is available. Gemtuzumab ozogamicin is given in two doses of nine mg/m2, separated by 14 days. In patients who got the first dose, the Cmax (maximum concentration) was 3.0 mg/mL (milligrams per milliliter), and it went up to 3.6 mg/mL after the second dose.

• Distribution: In vitro, human plasma proteins bind 97 percent of N-acetyl gamma calicheamicin dimethyl hydrazide. The overall volume of distribution of hP67.6 antibody in patients, calculated as the sum of V1 [6.31 L] and V2 [15.1 L], was estimated to be around 21.4 L based on population PK analyses.

• Elimination: Following the first dosage, the clearance (CL) value of hP67.6 from plasma was 0.35 L/h (liters per hour), and following the second dose, it was 0.15 L/h, indicating a nearly 60 percent drop. For hP67.6, the terminal plasma half-life (t½) was 90 hours following the second dosage and 62 hours following the first.

• Metabolism: Research conducted in vitro showed that N-acetyl gamma calicheamicin dimethyl hydrazide undergoes a significant amount of metabolism, with the disulfide moiety being reduced mostly by non-enzymes.

• Specific Populations: The pharmacokinetics of Gemtuzumab ozogamicin were not significantly affected by age, race, sex, mild or moderate renal impairment, or minor hepatic impairment. It is unknown how Gemtuzumab ozogamicin is absorbed by patients who have severe hepatic impairment and severe renal impairment.

What Is the Prescribed Dosage and Method of Administration for Gemtuzumab Ozogamicin Injection?

1. Prescription Drugs and Specific Concerns:

• Adults should take 50 mg of intravenous or oral diphenhydramine and 650 mg of Acetaminophen one hour before taking Gemtuzumab ozogamicin. They should also take an equivalent corticosteroid, or one mg/kg (milligrams per kilogram) of Methylprednisolone, within 30 minutes of the infusion. The dosages for kids are changed according to their weight.

• It is advisable to take precautions against tumor lysis syndrome.

• Prior to using Gemtuzumab ozogamicin, patients with hyperleukocytosis or elevated white blood cell counts should have their cell counts lowered.

2. Suggested Dosage:

• Combination Regimen for Newly Diagnosed de Novo CD33-Positive AML:

  • During the induction and consolidation cycles, Gemtuzumab ozogamicin is administered in addition to other medications.

  • On days one, four, and seven of the induction cycle, a dose of three mg/m2 (milligrams per square meter) is advised.

  • The same dosage is used on day one of consolidation cycles.

• Newly Diagnosed CD33-Positive AML (One-Agent Treatment):

  • The suggested dose for the induction cycle is three mg/m2 on day eight and six mg/m2 on day one.

  • The dose for continuing therapy is two mg/m2 every four weeks.

  • Refractory or relapsed CD33-positive AML (treatment with a single agent).

  • On days one, four, and seven, a dose of three mg/m² is advised.

• Adjusting Doses for Toxicities:

  • Frequent monitoring of blood counts and chemistries is recommended.

  • Based on toxicities such as thrombocytopenia, neutropenia, liver issues, or infusion responses, dose modifications can be required.

3. Reconstitution:

• Take care to maintain sterility throughout.

• Give the Gemtuzumab ozogamicin vials five minutes or so to warm up.

• To create a one mg/mL solution, combine each vial with 5 mL of sterile water for injection.

• Gently swirl, without shaking, until it disappears.

• Look for any alterations in color or particles. The presence of tiny white granules is normal.

• Use immediately or store in the refrigerator for up to one hour. Do not freeze it, and keep it out of direct sunlight.

4. Dilution:

• Determine the required amount by considering the patient's dimensions.

• With a syringe, remove the desired amount from the vial or vials. Keep it out of the light and discard any extras.

• Remove the equal volume of injection (0.9 percent sodium chloride) from a bag.

• In an infusion container, combine the saline and Gemtuzumab ozogamicin solution. Keep the light off of it.

• To mix it, gently tip the jar upside down; do not shake.

• Use it immediately or briefly store it in the refrigerator. Store it in the refrigerator for up to 12 hours or at room temperature for up to six hours. Keep it out of the light and avoid freezing it.

5. Administration:

• For the infusion line, use an in-line 0.2-micron polyethersulfone (PES) filter.

• To keep the IV bag dark during the infusion, cover it.

• Slowly infuse the solution over a two-hour period.

• During the infusion, avoid combining Gemtuzumab ozogamicin with other medications.

Storage and Handling: Store Gemtuzumab ozogamicin vials in the original box to protect them from light and keep them chilled between two and eight degrees Celsius (36 and 46 degrees Fahrenheit). Do not freeze them. Being a strong medication, Gemtuzumab ozogamicin must be handled and disposed of appropriately, following prescribed guidelines.

Clinical Studies:

• In Newly-Diagnosed CD33-Positive AML Patients:

  • In patients with newly diagnosed CD33-positive AML, the combination of Gemtuzumab ozogamicin with chemotherapy demonstrated a better event-free survival (EFS) than chemotherapy alone, with a median EFS of 17.3 months versus 9.5 months, respectively, in the study ALFA-0701. With a hazard ratio (HR) of 0.56, there was a noticeable advantage.

  • Study AML-19 found that in older AML patients or those who were hesitant to receive aggressive chemotherapy, Gemtuzumab ozogamicin single-agent therapy increased overall survival (OS) when compared to best supportive care (BSC). With Gemtuzumab ozogamicin, the median OS was 4.9 months, while with BSC, it was 3.6 months. With an HR of 0.69, OS showed a notable improvement.

• Patients With CD33-Positive AML Who Have Relapsed or Are Refractory to Treatment:

  • In the MyloFrance-1 research, Gemtuzumab ozogamicin as a single drug produced complete remission (CR) in 26 percent of patients, with a median survival period of 11.6 months without relapse.

Drug Interactions:

No studies have been done on clinical drug interactions.

Warnings and Precautions:

• Veno-Occlusive Liver Disease and Other Hepatotoxicity: Despite being effective in treating leukemia, Gemtuzumab ozogamicin can cause major problems with the liver, such as the potentially fatal veno-occlusive liver disease (VOD). VOD can occur in certain patients, particularly in those with pre-existing liver issues. Before administering each dose of Gemtuzumab ozogamicin, doctors regularly assess liver function to check for potential problems. They also closely monitor any symptoms that may arise, such as abdominal pain, weight gain that is not explained, and jaundice or yellowing of the skin or eyes. Should any liver issues emerge, the treatment regimen might need to be modified.

• Reactions Associated With Infusion (Including Anaphylaxis): Some people may have severe infusion-related side effects, such as fever, chills, or trouble breathing, during or after receiving Gemtuzumab ozogamicin. Patients are given medications prior to the infusion to reduce the risk of these reactions, and their vital signs are continuously monitored both during and after the procedure. In order to protect patient safety, Gemtuzumab ozogamicin administration may need to be stopped if a serious reaction happens.

• Hemorrhage (Bleeding): A drop in blood cell counts is a possible side effect of Gemtuzumab ozogamicin treatment, and this can result in bleeding, including severe or life-threatening cases. Patients receiving Gemtuzumab ozogamicin have experienced a variety of bleeding events, some of which have been serious. Before every dosage, blood cell counts are checked through routine blood tests, and patients are closely monitored for any signs of bleeding while undergoing treatment. Treatment plan modifications may be necessary in the event of severe bleeding.

• QT Interval Prolongation: Gemtuzumab ozogamicin carries the risk of altering the heart's electrical activity, which could result in irregular heart rhythms. Therefore, doctors perform thorough assessments of heart health prior to initiating treatment, particularly in patients with a history of heart problems or those taking medications that impact heart function.

• Adverse-Risk Cytogenetics Used in AML: It is noteworthy that patients whose leukemia cells have specific genetic abnormalities may not benefit significantly from Gemtuzumab ozogamicin. Based on each patient's particular characteristics and test results, doctors assess the risks and benefits of continuing Gemtuzumab ozogamicin treatment.

• Embryo-Fetal Toxicity: If Gemtuzumab ozogamicin is given to pregnant women, there is a chance that the unborn child could suffer. Therefore, it is recommended that women who are or may become pregnant use effective contraception both during and after receiving Gemtuzumab ozogamicin treatment. Men are also encouraged to use contraception to avoid becoming pregnant through their partners. Notifying the healthcare provider right away for those who become pregnant while undergoing treatment is essential to ensuring proper management.

Use in Specific Populations:

• Pregnancy: If Gemtuzumab ozogamicin is taken while pregnant, a growing fetus may be at risk. Research on its effects on pregnant women is scarce, but studies on animals point to possible harm to the developing fetus. Pregnant women or those intending to get pregnant should, therefore, be aware of these dangers.

• Nursing: There is no information on Gemtuzumab ozogamicin’s effects on breastfed infants or if it enters breast milk. It is not advised to breastfeed an infant while receiving Gemtuzumab ozogamicin treatment or for at least a month following the last dose because of the possibility of adverse reactions.

• Females and Males of Reproductive Potential: Determine whether a woman of reproductive age is pregnant before beginning Gemtuzumab ozogamicin treatment. To avoid pregnancy, effective contraception should be used both during and after treatment. Based on observations made in animal studies, Gemtuzumab ozogamicin may also have an impact on male and female fertility.

• Pediatric Use: There is insufficient data to determine the safety and efficacy of Gemtuzumab ozogamicin in children with specific forms of leukemia. More research is required to fully understand its effects, even though there is little evidence to support its use in pediatric patients with relapsed or refractory leukemia.

• Usage in the Elderly: Gemtuzumab ozogamicin has been investigated in older persons treating specific forms of leukemia in conjunction with other drugs. Studies on older elderly and younger persons revealed comparable safety and efficacy. On the other hand, older people may be more susceptible to some adverse effects, like infections and fever.