Active Ingredient: Mirvetuximab soravtansine
Mirvetuximab soravtansine as monotherapy is indicated for the treatment of adult patients with folate receptor-alpha (FRα) positive, platinum-resistant high grade serous epithelial ovarian, fallopian tube, or primary peritoneal cancer who have received one to three prior systemic treatment regimens.
For this indication, competent medicine agencies globally authorize below treatments:
For:
Intravenous, 6 milligrams mirvetuximab soravtansine per kilogram of body weight, once every 3 weeks.
Eligible patients should have FRα tumour status defined as ≥75% viable tumour cells demonstrating moderate (2+) and/or strong (3+) membrane staining by immunohistochemistry (IHC), assessed by a CE-marked in vitro diagnostic (IVD) with the corresponding intended purpose. If a CE-marked IVD is not available, an alternative validated test should be used.
The recommended dose of mirvetuximab soravtansine is 6 mg/kg adjusted ideal body weight (AIBW) administered once every 3 weeks (21-day cycle) as an intravenous infusion until disease progression or unacceptable toxicity. Dosing based on AIBW reduces exposure variability for patients who are either underweight or overweight.
The total dose of mirvetuximab soravtansine is calculated based on each patient’s AIBW using the following formula:
AIBW = Ideal Body Weight (IBW [kg]) + 0.4*(Actual weight [kg] – IBW)
Female IBW [kg] = 0.9*height [cm] – 92
For a female patient who is 165 cm in height and 80 kg in weight:
| First, calculate IBW: | IBW = 0.9 * 165 – 92 = 56.5 kg |
| Then calculate AIBW: | AIBW = 56.5 + 0.4 * (80 – 56.5) = 65.9 kg |
Administer the pre-medications in Table 1 prior to each infusion of mirvetuximab soravtansine to reduce the incidence and severity of IRRs, nausea, and vomiting.
Table 1. Pre-medication prior to each mirvetuximab soravtansine infusion:
| Pre-medication | Route of administration | Examples (or equivalent) | Administration time prior to mirvetuximab soravtansine infusion |
|---|---|---|---|
| Corticosteroid | intravenous | dexamethasone 10 mg | at least 30 minutes prior |
| Antihistamine | oral or intravenous | diphenhydramine 25 mg to 50 mg | |
| Antipyretic | oral or intravenous | acetaminophen or paracetamol 325 mg to 650 mg | |
| Antiemetic | oral or intravenous | 5-HT3 serotonin receptor antagonist or appropriate alternatives | before each dose and following the administration of other premedication |
For patients experiencing nausea and/or vomiting, additional antiemetics may be considered thereafter as needed.
For patients who experience an IRR Grade ≥2, additional pre-medication with dexamethasone 8 mg two times a day (BID) (or equivalent) the day before mirvetuximab soravtansine administration should be considered.
Ophthalmic exam: An ophthalmic exam including visual acuity and slit lamp exam should be conducted before the initiation of mirvetuximab soravtansine and if a patient develops any new or worsening ocular symptoms prior to the next dose. In patients with ≥ Grade 2 ocular adverse reactions, additional ophthalmic exams should be conducted at a minimum of every other cycle and as clinically indicated until resolution or return to baseline.
Ophthalmic topical steroids: For patients found to have signs of ≥ Grade 2 corneal adverse reactions (keratopathy) on slit lamp examination, secondary prophylaxis with ophthalmic topical steroids is recommended for subsequent cycles of mirvetuximab soravtansine, unless the patient’s eye care professional determines that the risks outweigh the benefits of such therapy.
During treatment with ophthalmic topical steroids the measurement of intraocular pressure and an examination with slit lamp should be carried out regularly.
Lubricating eye drops: It is recommended to instruct patients to use lubricating eye drops throughout treatment with mirvetuximab soravtansine.
Before the start of each cycle, the patient should be advised to report any new or worsening symptoms to the treating physician or qualified individual.
In patients who develop new or worsening ocular symptoms, an ophthalmic exam should be conducted before dosing. The treating physician should review the patient’s ophthalmic examination report before dosing and determine the dose of mirvetuximab soravtansine based on the severity of findings in the most severely affected eye.
Table 2 provides dose reductions and modifications for adverse reactions. The schedule of administration should be maintained at a 3-week interval between the doses.
Table 2. Dose reduction schedule:
| Mirvetuximab soravtansine dose levels | |
|---|---|
| Starting dose | 6 mg/kg AIBW |
| First dose reduction | 5 mg/kg AIBW |
| Second dose reduction | 4 mg/kg AIBW* |
* Permanently discontinue in patients who cannot tolerate 4 mg/kg AIBW.
Mirvetuximab soravtansine is for intravenous infusion at a rate of 1 mg/min. If well tolerated after 30 minutes, the infusion rate can be increased to 3 mg/min. If well tolerated after 30 minutes at 3 mg/min, the infusion rate can be increased to 5 mg/min.
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