Mavacamten

Mavacamten is a prescription medication used for the treatment of obstructive hypertrophic cardiomyopathy. 

• Mavacamten is available under various brand names: Camzyos

Common side effects of Mavacamten include:

• dizziness

Serious side effects of Mavacamten include:

• hives,
• difficulty breathing,
• swelling of the face, lips, tongue, or throat,
• sudden vision loss,
• blurred vision,
• tunnel vision,
• eye pain or swelling,
• seeing halos around lights,
• fast, irregular, or pounding heartbeats,
• fluttering in your chest,
• shortness of breath,
• sudden dizziness,
• lightheadedness,
• fainting,
• severe headache,
• confusion,
• slurred speech,
• arm or leg weakness,
• trouble walking,
• loss of coordination,
• feeling unsteady,
• very stiff muscles,
• high fever,
• profuse sweating, and
• tremor.

Rare side effects of Mavacamten include:

• none

Seek medical care or call 911 at once if you have the following serious side effects:

• Severe headache, confusion, slurred speech, arm or leg weakness, trouble walking, loss of coordination, feeling unsteady, very stiff muscles, high fever, profuse sweating, or tremors;
• Serious eye symptoms such as sudden vision loss, blurred vision, tunnel vision, eye pain or swelling, or seeing halos around lights;
• Serious heart symptoms include fast, irregular, or pounding heartbeats; fluttering in the chest; shortness of breath; sudden dizziness, lightheadedness, or passing out.

This is not a complete list of side effects and other serious side effects or health problems that may occur because of the use of this drug. Call your doctor for medical advice about serious side effects or adverse reactions. You may report side effects or health problems to FDA at 1-800-FDA-1088.

Adult dosage

Capsule

• 2.5 mg
• 5 mg
• 10 mg
• 15 mg

Obstructive Hypertrophic Cardiomyopathy

Adult dosage

• Initiation phase dosing (week 4)
  • Valsalva LVOT gradient less than 20 mmHg: Reduce dose to 2.5 mg/day
  • Valsalva LVOT gradient above 20 mmHg: Maintain at 5 mg/day
• Initiation phase dosing (week 8)
• Taking 2.5 mg/day
  • Valsalva LVOT gradient less than 20 mmHg: Withhold drug and resume at Week 12
  • Valsalva LVOT gradient above 20 mmHg: Maintain at 2.5 mg/day
• Taking 5 mg/day
  • Valsalva LVOT gradient less than 20 mmHg: Reduce dose to 2.5 mg/day
  • Valsalva LVOT gradient above 20 mmHg: Maintain at 5 mg/day
• Initiation phase dosing (week 12)
  • Taking 2.5 mg/dayless than 20 mmHg: Restart on 2.5 mg if LVEF is more than 50% and recheck clinical status and echocardiogram (ECHO) in 4 weeks
  • Maintain same dose for next 8 weeks, unless LVEF is less than 50%
• Taking 5 mg/day
  • Refer to maintenance dosing algorithm
  • Maintenance phase dosing (week 12 and every 12 weeks)
  • LVEF less than 50%: Interrupt treatment
  • Maintain on same dose and follow-up 12 weeks later
  • LVEF 50-55%, regardless of Valsalva LVOT gradient OR,
  • LVEF above 55% and Valsalva LVOT gradient less than 30 mmHg
  • LVEF more than 55% and Valsalva LVOT gradient more than 30 mmHg
  • Up-titration to next higher daily dose level (eg, 2.5 mg to 5 mg; 5 mg to 10 mg; 10 mg to 15 mg)
  • Recheck clinical status and ECHO in 4 weeks and maintain same dose for next 8 weeks unless LVEF less than 50%
  • Further up-titration allowed after 12 weeks of treatment on same dose level
  • Treatment interruption if LVEF <50%
  • LVEF less than 50%
  • Interrupt treatment
  • Recheck ECHO parameters every 4 weeks until LVEF is more than 50%
  • Permanently discontinue if LVEF is less than 50% twice on 2.5 mg/day
  • LVEF is more than 50%
  • Restart at next lower daily dose; if interrupted at 2.5 mg, restart at 2.5 mg
  • Recheck clinical status and ECHO in 4 weeks and maintain the same dose for the next 8 weeks unless LVEF is less than 50%, THEN
  • Follow maintenance phase dosage

Dosage Considerations – Should be Given as Follows: 

• See “Dosages”

If your medical doctor is using this medicine to treat your pain, your doctor or pharmacist may already be aware of any possible drug interactions and may be monitoring you for them. Do not start, stop, or change the dosage of any medicine before checking with your doctor, health care provider, or pharmacist first.

• Mavacamten has severe interactions with any other drugs.
• Mavacamten has serious interactions with at least 33 other drugs.
• Mavacamten has moderate interactions with at least 92 other drugs.
• Mavacamten has minor interactions with no other drugs.

This information does not contain all possible interactions or adverse effects. Visit the RxList Drug Interaction Checker for any drug interactions. Therefore, before using this product, tell your doctor or pharmacist about all your products. Keep a list of all your medications with you and share this information with your doctor and pharmacist. Check with your healthcare professional or doctor for additional medical advice, or if you have health questions or concerns.

Contraindications

• Coadministration with moderate-to-strong CYP2C19 inhibitors or strong CYP3A4 inhibitors
• Coadministration with moderate-to-strong CYP2C19 or CYP3A4 inducers

Effects of drug abuse

• None

Short-Term Effects

• See “What Are Side Effects Associated with Using Mavacamten?”

Long-Term Effects

• See “What Are Side Effects Associated with Using Mavacamten?”

Cautions

• Only available through restricted REMS program requiring certification of prescribers and pharmacies, and enrollment of patients
• Based on animal studies, may cause fetal toxicity when administered to pregnant females; confirm absence of pregnancy in females of reproductive potential before initiating and instruct patient on use of effective contraception
• Heart failure
• Reduces systolic contraction and can cause HF or totally block ventricular function
• Patients who experience a serious intercurrent illness (eg, serious infection) or arrhythmia (eg, atrial fibrillation, other uncontrolled tachyarrhythmia) are at greater risk of developing systolic dysfunction and HF
• Patients should report any signs or symptoms of heart failure immediately to their healthcare provider
• Assess clinical status and LVEF before and regularly during treatment and adjust dose accordingly
• Promptly evaluate new or worsening arrhythmia, dyspnea, chest pain, fatigue, palpitations, leg edema, or elevations in N-terminal pro-B-type natriuretic peptide (NT-proBNP) as these may be signs and symptoms of HF
• Asymptomatic LVEF reduction, intercurrent illnesses, and arrhythmias require additional dosing considerations
• Initiation with LVEF below 55% is not recommended
• Drug interaction overview
  • Primarily metabolized by CYP2C19 and CYP3A4
  • Coadministration with drugs that interact with these enzymes may lead to life-threatening drug interactions (e.g., heart failure) or loss of effectiveness
  • Advise patients of potential drug interactions, including OTC medications (e.g., omeprazole, esomeprazole, or cimetidine)
  • Moderate-to-strong CYP2C19 or strong CYP3A4 inhibitors
• Contraindicated
  • Coadministration with moderate-to-strong CYP2C19 inhibitors or strong CYP3A4 inhibitors increases mavacamten systemic exposure, which may increase risk of HF due to systolic dysfunction
  • Moderate-to-strong CYP2C19 or CYP3A4 inducers
• Contraindicated
  • Coadministration with moderate-to-strong CYP2C19 or CYP3A4 inducers decreases mavacamten systemic exposure, which may reduce efficacy
  • May increase risk of adverse effects
• Hormonal contraceptives
  • Use alternant contraceptive (eg, intrauterine system) not affected by CYP450 induction or add nonhormonal contraception during treatment and for 4 months after last dose
  • Progestin and ethinyl estradiol are CYP3A4 substrates
  • Mavacamten may decrease exposures of ethinyl estradiol and progestin, which may lead to contraceptive failure or increased breakthrough bleeding
  • Weak CYP2C19 or moderate CYP3A4 inhibitors
  • On stable therapy with weak CYP2C19 or moderate CYP3A4 inhibitor: Initiate at recommended 5 mg/day dose
  • Intend to initiate weak CYP2C19 or moderate CYP3A4 inhibitor: Reduce mavacamten dose by 1 level
  • On stable treatment with mavacamten 2.5 mg/day: Avoid initiating weak CYP2C19 or moderate CYP3A4 inhibitor (no lower mavacamten dose available)
  • Drugs that reduce cardiac contractility
• Avoid coadministration
  • Coadministration with disopyramide in combination with verapamil or diltiazem has been associated with left ventricular systolic dysfunction and HF symptoms in patients with obstructive HCM
  • Avoid concomitant use in patients on disopyramide, ranolazine, verapamil with a beta blocker, or diltiazem with a beta blocker as these medications and combinations were excluded from the clinical study

Pregnancy & Lactation

• Based on animal data, may cause fetal harm when administered to pregnant females
• Human data are not available on use during pregnancy to evaluate for drug-associated risk of major birth defects, miscarriage, or other adverse maternal or fetal outcomes
• Confirm absence of pregnancy in females of reproductive potential prior to initiation and use of effective contraception
• Contraception
  • Advise females of reproductive potential to use effective contraception during treatment and for 4 months after last dose
  • Mavacamten may reduce effectiveness of combination hormonal contraceptives; advise using an alternant contraceptive method or add nonhormonal contraception
• Clinical considerations
  • Underlying maternal condition during pregnancy poses risk to mother and fetus
  • Obstructive HCM in pregnancy associated with increased risk for preterm birth
  • Advise pregnant females about potential risk to fetus with maternal exposure to mavacamten during pregnancy
• Lactation
  • Unknown if present in human or animal milk, effects on breastfed infants, and effects milk production
  • Consider developmental and health benefits of breastfeeding along with the mother’s clinical need for mavacamten and any potential adverse effects on the breastfed child from the drug or from the underlying maternal condition