Elahere Side Effects: What to Expect and When to Call Your Doctor

Elahere (mirvetuximab soravtansine-gynx) has a distinct side effect profile compared to traditional chemotherapy. Many patients find that its effects are more manageable than standard regimens — no hair loss, and often less severe nausea and bone marrow suppression. However, it carries a unique set of side effects — particularly involving the eyes and nerves — that require careful monitoring. Here's what patients should know before starting treatment.

Boxed Warning: Ocular Toxicity

Elahere carries a boxed warning — the FDA's most serious drug warning — for ocular (eye) toxicity. This is the most important safety concern unique to Elahere and requires proactive management. Eye side effects occur because folate receptor alpha (FRα) is also expressed in ocular tissues.

In the MIRASOL trial, ocular side effects were among the most common:

Blurred vision: 45% of patients (9% Grade 3 or higher)

Keratopathy (cornea damage): 37% of patients (11% Grade 3 or higher)

Dry eye: 29% of patients

Cataract: 16% of patients (3% Grade 3 or higher)

Photophobia (light sensitivity): 18% of patients

What you must do: Get a complete eye exam before your first Elahere dose, then every other cycle for the first 8 cycles. Use the prescribed lubricating eye drops and steroid eye drops every day as directed. Do not wear contact lenses during treatment unless your provider specifically tells you it's okay.

The good news: clinicians report that most eye problems can be managed with steroid eye drops. Permanent eye damage is rare, and many patients can continue treatment once eye symptoms improve.

Most Common Side Effects (Occurring in 10%+ of Patients)

In addition to eye effects, the MIRASOL trial identified these common side effects:

Fatigue: 47% (3% Grade 3/4) — the most common overall side effect. Rest when you can; tell your care team if fatigue is affecting your daily activities.

Peripheral neuropathy (nerve pain/numbness in hands and feet): 37% (4% Grade 3/4) — report new or worsening tingling, burning, or numbness promptly.

Abdominal pain: 34% (3% Grade 3/4)

Musculoskeletal pain: 31%

Diarrhea: 29% — stay well hydrated; contact your provider if it's severe.

Nausea: 27% — premedication before infusion helps reduce this; anti-nausea medications may be prescribed for home use.

Constipation: 27%

Vomiting: 18%

Reduced appetite: 18%

Headache: 14%

Pneumonitis (lung inflammation): 10%

Serious Side Effects: When to Get Help Right Away

Call your oncology team immediately or go to the emergency room for any of these symptoms:

Breathing problems: Shortness of breath, new or worsening cough, fever — these can signal pneumonitis (lung inflammation), which can be life-threatening.

Severe vision changes: Sudden worsening of vision, new eye pain, or visual disturbances that appear quickly.

Infusion reactions: Chest pain, difficulty breathing, hives, flushing, or dizziness during or shortly after infusion — tell the infusion team immediately.

Liver problems: Yellowing of skin or eyes, right upper belly pain, dark urine.

Pregnancy: Elahere can harm an unborn baby. Use effective contraception during treatment and for 7 months after your last dose.

Side Effects Elahere Does NOT Usually Cause

One reason patients and oncologists often prefer Elahere over traditional chemotherapy in PROC is its more favorable toxicity profile in several areas:

Hair loss (alopecia): Not a common side effect of Elahere, unlike paclitaxel.

Severe bone marrow suppression: Much less severe than traditional cytotoxic chemotherapy, with fewer dangerously low blood cell counts.

For information on medications that can interact with Elahere and increase side effect risks, see: Elahere Drug Interactions: What to Avoid and What to Tell Your Doctor.

Need help finding an infusion center near you? medfinder can help locate facilities in your area that administer Elahere.