Mirvetuximab Soravtansine-Gynx - Targeting Hope in FRα Positive, Platinum-Resistant Cancers

What Is Mirvetuximab Soravtansine-Gynx?

Mirvetuximab soravtansine-gynx is a cancer medicine used to treat certain gynecological cancers.

It is mainly given to adults with:

• Ovarian cancer.

• Fallopian tube cancer.

• Primary peritoneal cancer that has stopped responding to platinum-based chemotherapy.

This medicine is only used when the cancer cells have a protein, folate receptor alpha (FRα) on their surface. It targets cancer cells that express the FRα protein. Once it attaches to these cancer cells, it delivers a cancer-killing substance directly into the cancer cells to slow or stop tumor growth while limiting damage to healthy cells.

Is Mirvetuximab Soravtansine-Gynx FDA-Approved?

Mirvetuximab soravtansine-gynx was approved by the United States Food and Drug Administration (USFDA) on November 14, 2022.

The approval was granted for use in adults with FRα-positive, platinum-resistant ovarian, fallopian tube, or primary peritoneal cancer who have already received previous treatments.

Drug Group:

Mirvetuximab soravtansine-gynx belongs to a group of medicines known as folate receptor alpha-directed antibodies–drug conjugates. It also contains a microtubule inhibitor, which is a type of drug that blocks cancer cells from dividing and multiplying.

Indications:

Mirvetuximab soravtansine-gynx is used to treat adult patients who have:

• Folate receptor-alpha (FRα) positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer. These patients must have already received one to three previous cancer treatments.

• Physicians select individuals for this treatment based on a test (FRα tumor expression) that has FDA approval.

Contraindications:

There are no known contraindications listed for the drug.

Dosage Forms and Available Strengths:

Injection:

• Mirvetuximab soravtansine-gynx is supplied as a single-dose vial.

• The liquid inside the vial is clear to slightly hazy and colorless.

• Each vial contains 5 mg of the drug per 1 ml of solution.

For Patients

What Are the Clinical Uses of Mirvetuximab Soravtansine-Gynx?

Mirvetuximab soravtansine-gynx is used in patients whose ovarian, fallopian tube, or peritoneal cancer has not improved with previous chemotherapy treatments. It is especially helpful for patients whose cancer no longer responds to standard platinum-based drugs.

This medicine belongs to a special group of treatments that recognize specific proteins on cancer cells. Once attached, it delivers a toxic substance directly into the cancer cell, causing the cell to stop growing and eventually die. This targeted approach helps reduce harm to normal, healthy cells.

How Should Mirvetuximab Soravtansine-Gynx Be Used?

• Mirvetuximab soravtansine-gynx is given as an intravenous infusion, meaning it is injected into a vein.

• The infusion is administered by a trained doctor or nurse.

• Treatment is always given in a hospital or clinic setting.

• The medicine comes in liquid form and is diluted before use.

• It is usually given once every three weeks.

• The total number of treatment cycles depends on how well the patient responds and how well the drug is tolerated.

• Before each infusion, patients receive medicines to reduce the risk of allergic reactions, nausea, and vomiting.

• During the infusion, healthcare staff closely monitor the patient for side effects.

• If side effects occur, the infusion may be slowed, paused, or adjusted as needed.

What Are the Side Effects of Mirvetuximab Soravtansine-Gynx?

Some patients may experience side effects while receiving this medicine. Common side effects include:

• Nausea.

• Abdominal pain.

• Tiredness or fatigue.

• Constipation.

• Vomiting.

• Muscle weakness or spasms.

Patients should inform their doctor if any of these side effects become severe or do not improve.

Serious Side Effects

Patients should seek medical help immediately if they experience:

• New or worsening numbness or tingling in the hands or feet.

• Muscle weakness.

• Difficulty breathing.

• Persistent cough.

• Shortness of breath.

• Chest pain.

Other side effects may also occur. Any unusual or unexpected symptoms should be reported to a healthcare provider.

For Doctors

Pharmacodynamics:

• Exposure - Response Relationship:Higher exposure to Mirvetuximab soravtansine-gynx has been linked to better treatment responses. However, increased exposure also raises the risk of side effects such as nerve damage and moderate eye problems.

• Cardiac Electrophysiology:At the recommended dose, Mirvetuximab soravtansine-gynx does not cause significant changes in the QTc interval, indicating no major effect on heart rhythm.

Mechanism of Action:

• Mirvetuximab soravtansine-gynx is an antibody–drug conjugate (ADC).

• It consists of two main parts:

  • An antibody

  • A chemotherapy agent called DM4 (Dolastatin 10 derivative).

• The antibody binds specifically to folate receptor alpha (FRα).

• FRα is commonly found in high amounts on certain cancer cells.

• DM4 interferes with microtubules, which are structures that cancer cells need to divide.

• Once the antibody binds to FRα, the drug is taken into the cancer cell.

• Inside the cell, DM4 is released and damages the microtubule system.

• This stops cell division and leads to cancer cell death.

Pharmacokinetics:

Pharmacokinetics describes how the drug moves through the body.

• Exposure: The highest plasma levels of Mirvetuximab soravtansine-gynx were observed during the infusion after patients received the prescribed dose of six mg/kg (milligrams per kilogram) adjusted ideal body weight (AIBW). Later, on the second and third days, the highest concentrations of its breakdown products, unconjugated DM4 and S-methyl-DM4, were detected. The amounts of these drugs reached a stable state after one treatment cycle, and continued doses only slightly increased it.

• Distribution: The body distributes Mirvetuximab soravtansine-gynx, which has an average volume comparable to a few large soda bottles. The majority of the breakdown products, S-methyl DM4 and DM4, are attached to blood proteins.

• Elimination: Mirvetuximab soravtansine-gynx and its breakdown products are removed from the body through the kidneys. It takes about 4.8 days for Mirvetuximab soravtansine-gynx, 2.8 days for DM4, and 5.0 days for S-methyl-DM4 for half of the medicine to be eliminated from the body.

• Metabolism: The body breaks down Mirvetuximab soravtansine-gynx into smaller pieces, whereas CYP3A4 (Cytochrome P450 3A4) is responsible for processing DM4 and S-methyl-DM4. Although they make up a minor portion of the overall drug levels in the blood, these breakdown products are the principal forms present.

• Excretion: Within 24 hours of infusion, the breakdown product S-methyl-DM4 and another metabolite were discovered in urine, indicating that the body primarily excretes them through urine.

What Is the Dosage and Method of Administration For Mirvetuximab Soravtansine-Gynx?

• Selection of Patients: As suggested for platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer, patients should be chosen for Mirvetuximab soravtansine-gynx treatment based on the presence of FRα tumor expression.

• Recommended Dosage: The recommended intravenous infusion dose of Mirvetuximab soravtansine-gynx is six mg/kg adjusted ideal body weight (AIBW), administered once every three weeks (21-day cycle) until the condition progresses or the level of toxicity is unacceptable.

• Prescription Drugs and Necessary Eye Care:

  • Premedications should be given to patients before each Mirvetuximab soravtansine-gynx infusion in order to lower the frequency and intensity of infusion-related reactions (IRRs), nausea, and vomiting.

  • Eye assessments, such as slit lamp and visual acuity tests, should be performed before starting therapy, every other cycle during the first 8 cycles, and as directed by a physician. It is important to use lubricating eye drops and ophthalmic topical steroids as prescribed.

  • The dose of Mirvetuximab soravtansine-gynx can be reduced or discontinued if adverse effects occur. The initial dose is 6 mg/kg AIBW; if necessary, it can be reduced to 5 mg/kg and eventually to 4 mg/kg.

  • Patients who are unable to tolerate the lowest dose should be permanently removed from treatment. Depending on the severity of the reaction, different dosage adjustments are made to address adverse reactions.

  • These adjustments may include holding, reducing, or permanently stopping treatment. With these adjustments, the goal is to minimize side effects while maximizing treatment effectiveness and keeping a regular three-week gap between doses.

Preparation:

• Handle with care, as it is a potent drug.

• The dose should be calculated based on patient weight.

• Allow the vial to reach room temperature.

• Inspect for particles or discoloration.

• Gently mix; do not shake.

• Discard unused medication.

Dilution:

• Dilute only with 5% Dextrose Injection, USP (United States Pharmacopeia).

• Do not mix with other drugs.

• Calculate how much five percent USP Dextrose Injection is required to combine with Mirvetuximab soravtansine-gynx.

• Gently turn the bag to gradually combine the diluted medication. Do not shake it.

• The mixture can be kept for a brief period at room temperature or in the refrigerator if it is not used right away. Make sure to utilize it within the allotted time.

Administration:

• Inspect the diluted solution before use.

• Administer premedications first.

• Infuse using a 0.2 or 0.22 µm in-line filter.

• Start infusion slowly and increase gradually.

• Flush IV line with 5% Dextrose after infusion.

Storage and Handling:

• When it is time to prepare, keep the vials upright in the original carton and refrigerate between two degrees Celsius and eight degrees Celsius (36 degrees Fahrenheit and 46 degrees Fahrenheit).

• Keep them away from light. Avoid shaking or freezing.

Clinical Studies:

In a study of 106 patients with platinum-resistant ovarian cancer. Several therapies, including Bevacizumab, had already been administered to these patients. Every three weeks, an IV infusion of Mirvetuximab soravtansine-gynx was administered until the cancer either spread or the adverse effects were intolerable. The investigation discovered that:

• About 32% showed tumor response.

• 5% had a complete response.

• 27% had a partial response.

• Median response duration was 6.9 months.

Drug Interactions:

Strong CYP3A4 Inhibitors:

• The compound DM4 found in Mirvetuximab soravtansine-gynx is impacted by the liver enzyme CYP3A4.

• Taking drugs that block CYP3A4 may cause the body's levels of DM4 to rise.

• This may increase the possibility of having negative reactions to Mirvetuximab soravtansine-gynx.

• When using Mirvetuximab soravtansine-gynx with CYP3A4 inhibitors, it is critical to closely monitor patients for potential adverse effects.

Warnings and Precautions:

• Ocular Abnormalities: Mirvetuximab soravtansine-gynx treatment could result in serious eye issues such as uveitis, dry eyes, photophobia, corneal abnormalities, and vision impairment. These side effects affected about 61 percent of individuals with ovarian cancer, with nine percent being categorized as severe (grade 3).

• Pneumonitis: 10 percent of individuals receiving Mirvetuximab soravtansine-gynx experienced pneumonia, a potentially fatal lung ailment. Hypoxia, coughing, dyspnea, and abnormal radiological exam results are possible symptoms.

• Peripheral Neuropathy: After receiving Mirvetuximab soravtansine-gynx therapy, 36 percent of patients developed peripheral neuropathy, with two percent having severe cases. Tingling, burning feelings, weakness, or discomfort in the limbs are possible symptoms.

• Embryo-Fetal Toxicity: Taking the medicine during pregnancy carries a risk of harming the fetus. To minimize any harm to the fetus, effective contraception is indicated during therapy and for a brief period following the final dose.

Use in Specific Populations:

• Pregnancy: Mirvetuximab soravtansine-gynx contains a substance that might influence the growing fetus's cells. There is no particular data on its effects on pregnant women. Nevertheless, it is crucial to talk about possible dangers with the physician if one intends to get pregnant while taking the drug.

• Lactation: No information is available regarding the effects of Mirvetuximab soravtansine-gynx on the nursing infant or whether it is excreted in breast milk. It is recommended not to breastfeed while on the drug and for one month following the last dose due to the possibility of injury.

• Reproductive Potential: Before beginning therapy, it is important to determine whether or not a fetus is developing because the drug can harm the developing fetus. Effective contraception should be used by women who are fertile both during the treatment and for seven months following the last dosage.

• Pediatric Use: There is no proof of Mirvetuximab soravtansine-gynx’s safety or efficacy in kids.

• Geriatric Use: Research indicates that Mirvetuximab soravtansine-gynx’s safety and efficacy are not greatly impacted by age. The results for older and younger individuals did not differ significantly.

• Renal Impairment: Patients with mild to severe renal impairment do not require a dosage change. Severe renal failure and its consequences are uncertain.

• Hepatic Impairment: Individuals with mild to moderate liver disease should not use Mirvetuximab soravtansine-gynx. However, dosage adjustments are not required for people with moderate liver problems.