Campath is used to treat B-cell chronic lymphocytic leukemia in adults.

Lemtrada is used to treat relapsing forms of multiple sclerosis in people 17 years and older (including active secondary progressive disease), after at least two other medicines did not work or have stopped working.

Lemtrada will not cure MS, but it can make relapses occur less often. Lemtrada is not for use in treating clinically isolated syndrome.

Lemtrada may also be used for purposes not listed in this medication guide.

Lemtrada can cause life-threatening side effects, including serious medical problems that may occur months to years after you receive Lemtrada.

Lemtrada is given as an infusion into a vein. A healthcare provider will give you this injection. You will be watched closely for up to 2 hours or longer after the infusion, to make sure you do not have a serious reaction.

Campath is usually given 3 times per week for 12 weeks. Lemtrada is usually given in 2 or more treatment courses, separated by 1 year. Your doctor will determine how long to treat you and the number of courses you need. Lemtrada must be given slowly. The Campath infusion can take 2 hours to complete. The Lemtrada infusion can take 4 hours to complete.

You may be given other medicines to help prevent certain side effects or infections. Use these medicines for the full prescribed length of time.

Lemtrada affects your immune system. You may get infections more easily, even serious or fatal infections. You will need frequent medical tests, and your next dose may be delayed based on the results.

You should have a human papilloma virus (HPV) screening every year if you are a female.

Lemtrada can have long lasting effects on your body. You may need medical tests for up to 2 months after you stop using Campath, or 4 years after you stop using Lemtrada.

You may not be able to use Lemtrada if you are allergic to it, or if you have an active infection, o HIV (human immunodeficiency virus).

Tell your doctor if you have ever had:

• tuberculosis or other infections;

• a thyroid disorder;

• kidney disease;

• bleeding problems, or if you receive blood transfusions; or

• if you have received any vaccine in the past 6 weeks.

Tell your doctor if you have never had chickenpox or if you have never received a varicella vaccine (Varivax). You may need to receive the vaccine and then wait 6 weeks before using Lemtrada.

Lemtrada may increase your risk of developing other types of cancer, such as melanoma, thyroid cancer, lymphoma, or leukemia. Ask your doctor about this risk.

You may need to have a negative pregnancy test before starting this treatment. Lemtrada may harm an unborn baby. Use effective birth control to prevent pregnancy while receiving this medicine, and for at least 3 months after your last dose of Campath and for 4 months after your last dose of Lemtrada. Tell your doctor if you become pregnant.

If you use Campath while you are pregnant, make sure any doctor caring for your new baby knows that you used the medicine during pregnancy. Being exposed to Campath in the womb could affect your baby's vaccination schedule.

Lemtrada may affect fertility (ability to have children) in both men and women. However, women should still use birth control to prevent pregnancy because this medicine can harm an unborn baby.

It may not be safe to breastfeed while using Lemtrada. You should not breastfeed while using Campath, and for at least 3 months after your last dose.

Call your doctor for instructions if you miss an appointment for your Lemtrada.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Do not receive a "live" vaccine while using Lemtrada. The vaccine may not work as well or you could develop a serious infection. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and nasal flu (influenza) vaccine.

While being treated with Lemtrada, avoid foods that may be a source of Listeria infection, or heat them thoroughly before consuming. This includes deli meat, undercooked meat, seafood, poultry, unpasteurized dairy products, or soft cheeses.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Get emergency medical help if you have symptoms of thrombotic thrombocytopenic purpura: purple spots on the skin or in the mouth, jaundice (yellowing of the skin or eyes), tiredness, fever, feeling short of breath, fast heart rate, speech or vision changes, confusion, seizure, dark or blood in your urine, stomach pain, nausea, vomiting, or diarrhea.

Lemtrada may cause a brain infection that can lead to disability or death. Tell your doctor if you have problems with speech, thought, vision, or muscle movement. These symptoms can get worse quickly.

Some side effects may occur during or shortly after the injection. Tell your caregiver if you feel weak, feverish, chilled, dizzy, nauseated, light-headed, or have a rash, wheezing, chest pain, trouble breathing, swelling in your mouth or throat, or fast, slow, or irregular heartbeats.

Lemtrada can cause your immune system to attack cells and organs in your body. This can lead to serious medical problems that may occur months to years after you receive Campath or Lemtrada. Call your doctor at once if you have:

• unusual bleeding or bruising, nosebleeds, bleeding gums, heavy menstrual periods, blood in your urine or stools, coughing up blood, problems with speech, weakness on one side, neck pain, severe headache, drooping of your face;

• a mole that has changed in size or color, cough, wheezing, chest pain, feeling short of breath, coughing up blood;

• an overactive immune system--fever, swollen glands, rash, feeling unsteady or less alert, trouble waking, seizure;

• liver problems--loss of appetite, stomach pain (upper right side), dark urine, jaundice (yellowing of the skin or eyes);

• kidney problems--swelling in your lower legs, weight gain, loss of appetite, sudden pain in your stomach and back, urine that looks pink/brown or foamy;

• signs of infection--fever, chills, sore throat, cough, mouth sores, skin sores or blisters, tingling, burning pain, pale or yellowed skin, pain or burning when you urinate, dark urine, feeling light-headed, cold hands and feet;

• signs of tuberculosis--cough, night sweats, loss of appetite, weight loss, and feeling very tired;

• signs of a stroke or tear in an artery--sudden severe headache, weakness on one side of your body, drooping in your face, slurred speech;

• gallbladder problems--fever, nausea, vomiting, and stomach pain;

• symptoms of Autoimmune encephalitis--personality or mood changes, hallucinations, agitation, confusion, short term memory loss, movement disorders;

• symptoms of Adult onset Still's disease--high fever, pain, stiffness with or without swelling in multiple joints, rash;

• thyroid problems--sweating, feeling cold, fast heartbeats, feeling nervous or tired, eye swelling, weight gain or loss, constipation; or

• symptoms of thyroid cancer--a lump or swelling in your neck or throat, trouble swallowing, hoarse voice, or a new cough (not caused by a cold).

Common side effects of Lemtrada may include:

• reactions to the injection, rash, itching, tingling, hives;

• stomach pain, nausea, vomiting, diarrhea;

• infections (fever, chills, runny or stuffy nose, mouth or throat pain, painful urination);

• chest pain or tightness, coughing up blood;

• dizziness, tiredness, trouble sleeping;

• headache, joint pain, back pain, pain in your arms or legs; or

• thyroid problems, flushing (sudden warmth, redness, or tingly feeling).

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 FDA at 1-800-FDA-1088.

Tell your doctor about all your other medicines, especially drugs that weaken the immune system such as cancer medicine, or medicines to prevent organ transplant rejection.

Other drugs may affect Lemtrada, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.