Mirvetuximab soravtansine-gynx

Mirvetuximab soravtansine-gynx (Elahere)

Drug Class

Mechanism of Action

  1. Antibody binds to FRα, highly expressed on certain ovarian cancer cells.
  2. Internalization → lysosomal degradation releases DM4.
  3. DM4 inhibits tubulin polymerization → mitotic arrest → apoptosis.

Indications (FDA-approved)

  • Adults with FRα-positive, platinum-resistant epithelial ovarian, fallopian tube, or primary peritoneal cancer
  • Must have received 1–3 prior systemic treatment regimens
  • Requires FRα expression testing (companion diagnostic).

Administration & Dosing

  • IV infusion every 3 weeks (21-day cycle)
  • Starting dose: 6 mg/kg (adjusted using adjusted ideal body weight [AIBW])
  • Premedication: corticosteroids, antihistamines, antipyretics recommended (to reduce infusion-related reactions)

Adverse Effects

Common:

  • Ocular toxicity (blurred vision, keratopathy, dry eye) → requires baseline and ongoing ophthalmologic exams
  • Fatigue, nausea, diarrhea, abdominal pain
  • Myelosuppression (anemia, thrombocytopenia, neutropenia)
  • Peripheral neuropathy (due to microtubule inhibition)

Serious:

  • Severe ocular disorders (boxed warning)
  • Infusion-related reactions
  • Pneumonitis

Monitoring

  • Ophthalmologic exams: baseline, every other cycle, and as needed
  • CBC: monitor for myelosuppression
  • Liver function tests
  • Signs of pulmonary toxicity

Clinical Notes

  • First targeted ADC approved for platinum-resistant ovarian cancer.
  • Useful in heavily pretreated patients who otherwise have limited options.
  • Avoid use in FRα-negative tumors (no benefit).
  • Requires eye drop prophylaxis (lubricating, corticosteroid, and vasoconstrictor drops) during treatment
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