Pronunciation: laz-kluez
Generic name: lazertinib
Dosage form: tablets (80 mg, 240 mg)
Drug class: EGFR inhibitors

Medically reviewed by Carmen Pope, Senior Medical Editor, B. Pharm. Last updated on July 30, 2026.

What is Lazcluze?

Lazcluze (lazertinib) is used to treat certain types of EGFR-mutated non-small cell lung cancer (NSCLC) in adults. Lazcluze is taken once daily with food and is always taken together with amivantamab (Rybrevant), a medicine given by infusion, so that treatment targets EGFR in two different ways at once.

In the MARIPOSA clinical trial (NCT04487080), Lazcluze plus Rybrevant delayed the cancer from growing or spreading and helped people live longer compared to osimertinib on its own.

Lazcluze (lazertinib) received FDA approval on August 19, 2024.

What is Lazcluze used for?

Lazcluze is a targeted treatment, called a kinase inhibitor, used with Rybrevant as a first-line, FDA-approved treatment for adults with NSCLC that is locally advanced or metastatic, meaning it has spread to other parts of the body or cannot be removed by surgery. It is not chemotherapy.

The cancer must have one of two changes in the epidermal growth factor receptor (EGFR) gene: an exon 19 deletion or an exon 21 L858R substitution. An FDA-approved test confirms this, using either a tumor sample or a blood (plasma) sample. If the mutation is not found in blood, tumor tissue is tested.

Lazcluze side effects

Common side effects

The most common side effects of Lazcluze given with amivantamab are:

• rash
• infected skin around the nail
• infusion-related reaction (from amivantamab)
• muscle and joint pain
• swelling of hands, ankles, feet, face, or all of your body (edema)
• sores in the mouth
• unusual feeling in the skin, such as tingling or crawling (paresthesia)
• feeling very tired
• diarrhea
• constipation
• COVID-19
• bleeding
• decreased appetite
• itchy skin
• feeling sick (nausea).

Changes in blood test results were also common. The most common severe (Grade 3 or 4) changes were decreased albumin, decreased sodium, increased ALT, decreased potassium, decreased hemoglobin, increased AST, increased GGT, and increased magnesium.

Lazcluze may cause fertility problems in males and females, which may affect your ability to have children. Talk to your healthcare provider if this is a concern for you.

Your healthcare provider may temporarily stop your treatment, lower your dose, or stop treatment completely if you have serious side effects.

Serious Lazcluze side effects

Lazcluze may cause the following serious side effects:

• blood clot problems. Blood clots in the veins of your legs (deep vein thrombosis) or lungs (pulmonary embolism) are serious, but common, and may lead to death. Your healthcare provider will start you on medicine to reduce the risk of blood clots for the first four months of treatment. Tell your healthcare provider right away if you have any signs and symptoms of blood clots, including swelling, pain or tenderness in the leg, sudden unexplained chest pain, or shortness of breath.
• lung problems. Lazcluze may cause lung problems that may lead to death. Symptoms may be similar to those symptoms from lung cancer. Tell your healthcare provider right away if you get any new or worsening lung symptoms, including shortness of breath, cough, or fever.
• skin problems. Lazcluze may cause severe rash including redness, raised acne-like bumps, itching, and dry skin. Tell your healthcare provider right away if you get any skin reactions. Your healthcare provider may start you on an antibiotic for the first 3 months of treatment followed by an antibiotic lotion for your scalp for the next 9 months. During treatment with Lazcluze, you should apply a non-comedogenic (does not clog pores) skin moisturizer (ceramide-based or other types of moisturizers that provide long-lasting skin hydration and does not include drying ingredients) on your face and whole body (except scalp) and wash your hands and feet every day with 4% chlorhexidine solution. Your healthcare provider may treat you with a medicine(s) or send you to see a skin specialist (dermatologist) if you get skin reactions during treatment with Lazcluze. See "What should I avoid while taking Lazcluze?"
• liver problems (hepatotoxicity). Lazcluze may cause severe liver problems, including increased liver function tests. Your healthcare provider will do blood tests to check your liver before you start and during treatment with Lazcluze. Tell your healthcare provider right away if you get any symptoms of liver problems, including pain on the right side of your stomach area (abdomen), dark or brown (tea colored) urine, or yellowing of your skin or the white part of your eyes.
• eye problems. Lazcluze may cause eye problems such as inflamed cornea (front part of your eye). Tell your healthcare provider right away if you get symptoms such as eye redness, eye pain, new or worsening problems with vision, and sensitivity to light. Your healthcare provider may send you to see an eye specialist (ophthalmologist) if you get eye problems during treatment with Lazcluze. You should not use contact lenses until your eye symptoms are checked by a healthcare provider.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

How effective is Lazcluze?

MARIPOSA was a randomized, active-controlled, multicenter trial in 858 people with previously untreated locally advanced or metastatic EGFR-mutated NSCLC. Participants received either Lazcluze plus amivantamab or osimertinib on its own.

• Cancer growth was delayed longer with Lazcluze plus amivantamab than osimertinib (23.7 versus 16.6 months), and people lived longer, with a 25% reduction in the risk of death.
• Overall response rate was 78% with Lazcluze plus amivantamab and 73% with osimertinib. Responses lasted a median of 25.8 months compared with 16.7 months.

How does Lazcluze work?

Epidermal growth factor receptor (EGFR) is a protein on the surface of cells that signals how quickly the cell should grow and divide. In some lung cancers, a mutation in the EGFR gene leaves that signal permanently switched on, so the cells keep multiplying.

Lazertinib works by blocking the enzyme that carries the signal, switching it off and slowing the cancer down. It acts more strongly on the mutated receptor than on the normal one.

Before taking this medicine

Before taking Lazcluze, tell your healthcare provider about all of your medical conditions, including if you:

• have a history of lung or breathing problems
• are pregnant or plan to become pregnant. Lazcluze can harm your unborn baby.
• are breastfeeding or plan to breastfeed.

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Pregnancy

Females who can become pregnant:

• Your healthcare provider should do a pregnancy test before you start treatment with Lazcluze.
• You should use effective birth control (contraception) during treatment and for 3 weeks after your last dose of Lazcluze.
• Tell your healthcare provider right away if you become pregnant or think you might be pregnant during treatment with Lazcluze.

Males who have female partners who can become pregnant:

• You should use effective birth control during treatment and for 3 weeks after your last dose of Lazcluze.

Breastfeeding

It is not known if Lazcluze passes into your breast milk. Do not breastfeed during treatment and for 3 weeks after your last dose of Lazcluze.

How should I take this medicine?

• Take Lazcluze exactly as your healthcare provider tells you to take it.
• Take Lazcluze tablets once daily, with or without food.
• Swallow the tablets whole. Do not crush, cut, split, or chew them.
• On the day you receive Rybrevant (amivantamab), take your Lazcluze tablets any time before the Rybrevant infusion.
• Your healthcare provider may give you other medicines alongside Lazcluze to reduce the risk and severity of skin and nail reactions, and to reduce the risk of blood clots.
• Lazcluze may be given in combination with other anti-cancer medicines. If you have any questions about these medicines, ask your healthcare provider.

Related/similar drugs

Lazcluze dosing information

• The recommended Lazcluze dosage is 240 mg orally once daily, with or without food, given in combination with amivantamab.
• Continue treatment until the disease progresses or side effects become unacceptable.

Take Lazcluze any time before amivantamab when both are given on the same day. Refer to the amivantamab prescribing information for amivantamab dosing.

Preventive medicines are given alongside Lazcluze:

• Anticoagulant prophylaxis to reduce the risk of venous thromboembolic events for the first four months of treatment. If there are no signs or symptoms of a blood clot during those four months, your healthcare provider may consider stopping it.
• An oral antibiotic (doxycycline or minocycline 100 mg twice daily) from Day 1 for the first 12 weeks, then antibiotic lotion to the scalp (clindamycin 1% once daily) for the next 9 months, along with a non-comedogenic moisturizer and daily washing of hands and feet with 4% chlorhexidine solution.

Liver function tests, including ALT, AST, and total bilirubin, are done before starting Lazcluze and during treatment as needed.

The dose may be lowered because of side effects. Recommended dose reductions are:

What should I do if I miss a dose?

If you miss a dose of Lazcluze and:

• it has been less than 12 hours, take the missed dose.
• it has been more than 12 hours, skip the dose and take your next dose at your regularly scheduled time.

If you vomit a dose of Lazcluze, do not take an extra dose. Take your next dose at your regularly scheduled time.

What to avoid

Lazcluze can cause skin reactions. You should limit your time in the sun during treatment and for 2 months after your treatment with Lazcluze. Wear protective clothing and use a broad-spectrum UVA/UVB sunscreen during treatment.

What other drugs affect Lazcluze?

Tell your healthcare provider about all of the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Lazcluze and other medicines may affect each other, causing side effects. Know the medicines you take. Keep a list of them to show your healthcare provider or pharmacist when you get a new medicine.

You should not start or stop any medicine before you talk with the healthcare provider who prescribed Lazcluze.

• Strong and moderate CYP3A4 inducers, such as rifampin and efavirenz should not be taken with Lazcluze. They lower the amount of lazertinib in your body, which may make it work less well. Your healthcare provider may switch you to an alternative medicine.

Not all possible drug interactions are listed here. See the Lazcluze Prescribing Information for more details.

Storage

Store at room temperature between 68°F and 77°F (20°C and 25°C). Short excursions between 59°F and 86°F (15°C and 30°C) are permitted.

Keep Lazcluze and all medicines out of the reach of children.

Ingredients

Active ingredient: lazertinib mesylate

Inactive ingredients: croscarmellose sodium, magnesium stearate, mannitol, microcrystalline cellulose, and silica hydrophobic colloidal. The tablet coating consists of glycerol monocaprylocaprate type I, iron oxide black (in 240 mg strength tablets), iron oxide red (in 240 mg strength tablets), iron oxide yellow (in 80 mg strength tablets), macrogol (PEG) polyvinyl alcohol graft copolymer, polyvinyl alcohol-partially hydrolyzed, talc, and titanium dioxide.

Company

Lazcluze (lazertinib mesylate) is manufactured for Janssen Biotech, Inc., Horsham, PA 19044, USA.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Medical Disclaimer