Daratumumab (Darzalex, Darzalex Faspro)

Medicine at a glance

• Generic medicine: daratumumab, a monoclonal antibody targeting a protein called CD38.
• Intravenous formulation: Darzalex, diluted and given through a drip into a vein.
• Subcutaneous formulation: Darzalex Faspro in the US contains daratumumab and hyaluronidase-fihj. European Darzalex injection also contains hyaluronidase. It is injected under abdominal skin.
• Treatment visits usually become less frequent over time, but the timetable depends on your complete regimen.
• Important precautions include reactions around a dose, infections, reduced blood counts and interference with blood compatibility testing.
• Carry your treatment information and tell any hospital that you receive, or previously received, daratumumab.

What daratumumab is and how it works

A monoclonal antibody is a laboratory-made protein designed to recognise a particular target. Daratumumab attaches to CD38, which is found at high levels on many abnormal plasma cells. Plasma cells are immune cells that normally make antibodies. Binding to CD38 can help immune cells and other immune defences destroy the abnormal cells; it can also trigger cell death through other mechanisms.

Daratumumab is a targeted therapy with immune-mediated actions. It is different from conventional chemotherapy and from checkpoint-inhibitor immunotherapy. The word “targeted” does not mean that healthy cells are unaffected. CD38 is present on other cells too, and treatment can weaken protection against infection.

The hyaluronidase in the subcutaneous formulation temporarily helps the medicine spread through the tissue under the skin so it can be absorbed. It is not a second anti-cancer antibody. The two routes use different preparations and doses; they must not be substituted by simply changing the route of an existing vial.

How the team decides whether it is suitable

Your specialist considers your diagnosis, laboratory and bone-marrow findings where relevant, previous treatments, other illnesses, and the prescribing information for the proposed product and combination. They explain the intended benefit and how response will be assessed. CD38 is the medicine’s target, but this does not mean everyone needs a separate CD38 companion test before treatment.

Previous serious allergy to daratumumab or a formulation ingredient matters. For the injection, this includes hyaluronidase. Tell the team about heart or lung disease, ongoing infection, hepatitis B, and any earlier treatment reaction. Both European formulations contain sorbitol. Tell the team if you have hereditary fructose intolerance, a rare inherited condition distinct from ordinary food intolerance: the injection should not be given, and the intravenous product should only be used if strictly necessary.

If you have AL amyloidosis, abnormal protein deposits can affect organs, including the heart. This matters particularly when assessing the safety of a daratumumab-containing plan. Very advanced amyloid heart disease needs particular caution: US Faspro instructions advise against use outside controlled trials for specified severe cardiac stages. Your specialist checks which category applies; results from less advanced heart involvement cannot simply be applied to everyone.

Before treatment starts

Blood tests and medical history

The team checks blood counts and usually kidney and liver function, alongside tests relevant to your disease. Tell them about recurrent infections, breathing problems, diabetes and all medicines or supplements. A baseline weight helps with intravenous dosing. Pregnancy testing and prevention arrangements depend on the whole regimen.

Hepatitis B screening is important even if you feel well or an infection was many years ago. A previously controlled virus can become active during treatment. A positive test does not automatically exclude daratumumab: it prompts a prevention and monitoring plan, sometimes with a liver or infection specialist.

Prepare for possible blood transfusions

Before your first dose, the blood bank should have a blood-group and antibody-screening sample. Further red-cell typing may be arranged. Daratumumab can interfere with later antibody-screening and cross-matching tests used to choose compatible donor blood. Baseline information helps the laboratory work around this.

Keep your alert card or treatment record with you, including the medicine name and last treatment date. Share it with emergency staff and surgeons, not just your usual oncology clinic. This interference does not mean your blood group changes or that you cannot receive a transfusion.

Plan the first visit

Allow time for blood results, preventive medicines, treatment and observation. Arrange transport if an antihistamine makes you sleepy. Save your own hospital’s urgent advice number and check what to do if symptoms develop after you leave. Bring the current schedule for any tablets taken at home.

How treatment is given

Intravenous Darzalex

A nurse gives the diluted medicine through a cannula or suitable central line. The usual dose is 16 mg per kilogram of actual body weight. The first dose may be split across two consecutive days. Infusion speed is increased gradually when tolerated.

The first full infusion can occupy much of the day. In studies, typical median infusion times were approximately seven hours initially, four hours for the second infusion and three hours subsequently. These are planning examples, not guaranteed appointment lengths; reactions or local protocols change the time needed. Tell the nurse immediately about pain, burning, leakage or swelling around the line.

Subcutaneous Darzalex or Darzalex Faspro

The standard injection contains 1,800 mg daratumumab in 15 mL; the US product also specifies 30,000 units of hyaluronidase. A healthcare professional gives it into abdominal tissue over about three to five minutes, away from the navel. They rotate sites and avoid bruised, tender, red, hardened or scarred skin. Tell them if the injection hurts so they can pause or adjust delivery.

The injection time is much shorter than the complete appointment. You still need assessment, preventive medicines and monitoring, particularly with the first and second doses. Some services observe patients for several hours after the first treatment. Your centre specifies the observation period; the label does not establish one universal discharge time for everyone. These products are not intended for self-injection.

Timetables, delays and missed appointments

A common schedule is weekly treatment for eight weeks, then every two weeks through week 24, then every four weeks. Other regimens have different weekly phases, three-week intervals or planned treatment breaks. Some courses have a defined end; others continue while beneficial and tolerable. Follow your written calendar.

If an appointment is missed, contact the unit promptly. The team generally rearranges the dose as soon as possible and adjusts later dates to preserve the required interval. Daratumumab dose reductions are not normally recommended: low blood counts or other problems may instead require a delay. Accompanying medicines can have separate dose changes.

Medicines before and after treatment

A corticosteroid, antihistamine and paracetamol are usually given one to three hours beforehand to reduce reactions. An additional medicine such as montelukast may be selected for particular regimens to help prevent reactions. Do not duplicate steroid tablets: sometimes the steroid already in your regimen provides the required premedication.

Steroid doses after treatment reduce delayed reactions. The exact plan differs for daratumumab alone versus combinations. After three well-tolerated subcutaneous doses, the clinician may stop additional post-injection steroids; this does not mean stopping steroids that form part of your anti-cancer regimen. People with chronic obstructive pulmonary disease may need inhalers around early doses. Never stop these medicines independently.

Antiviral medicine is commonly prescribed to prevent shingles. US labels specify starting within one week of daratumumab and continuing for three months after treatment ends; European information recommends considering antiviral prevention without the same fixed timetable. Follow the plan written for you.

Monitoring and checking whether treatment is working

Blood counts are checked periodically, with timing tailored to the accompanying treatments and previous results. Low neutrophils, the white cells that fight infection, or low platelets may mean postponing treatment. Kidney function, liver tests and other blood chemistry are assessed as appropriate. Tell the team about new symptoms even when the latest results were satisfactory.

During treatment visits, staff assess symptoms and watch for reactions. Where heart involvement or another cardiac risk is present, additional assessment may include heart tests and closer fluid monitoring. Patients with positive hepatitis B tests need monitoring during treatment and for at least six months afterwards under European product guidance.

Disease assessment may include abnormal antibody levels, free light chains, scans or bone-marrow tests, according to your situation. Daratumumab itself is an IgG-kappa antibody and can appear on some protein tests. This can make a small laboratory band difficult to distinguish from disease protein. The laboratory can use specialist methods to help clarify the result; an unexpected band does not automatically mean treatment has failed.

Common side effects and practical management

Side effects vary with the route, the disease and other medicines. Symptoms reported during a combination cannot all be attributed to daratumumab alone. Keep a brief record of their timing, severity and impact on eating, sleep or daily activities.

Tiredness and anaemia

Fatigue may fluctuate between appointments. Alternate manageable activity with rest and ask for help with demanding tasks. Anaemia means too few red blood cells and can cause pallor, dizziness or breathlessness. Report a clear deterioration: infection, anaemia and other treatable problems can resemble ordinary treatment fatigue. Sudden or severe breathlessness needs urgent assessment.

Diarrhoea, constipation and nausea

Take prescribed anti-sickness medicine as directed. Smaller meals and regular drinks may be easier to manage. The team can recommend treatment for diarrhoea or constipation after considering the cause and your other medicines.

Seek prompt advice if diarrhoea persists, you cannot keep fluids down, you pass little urine or feel faint. Severe abdominal pain or vomiting with a swollen abdomen also needs urgent assessment. If you have heart or kidney problems, follow your agreed fluid allowance rather than forcing large quantities of water.

Skin and injection-site symptoms

A small area of redness, itching or soreness can develop after the injection. Show the team if it is worsening, spreading or not settling. Report generalised rash, especially with swelling, dizziness or breathing symptoms, immediately because it may represent a reaction affecting the whole body. Gentle skin care and an unperfumed moisturiser can help dry skin.

Tingling, pain, swelling and sleep changes

Tingling or numbness in hands and feet can occur during treatment combinations. Report difficulty with buttons, walking or balance early; a partner medicine may need adjustment. Muscle, joint or back pain should also be discussed so that suitable pain relief can be chosen.

Ankle swelling, sleep disturbance and changes in blood sugar can occur. Steroids in the treatment plan may contribute. Report new swelling, excessive thirst or frequent urination. Do not assume swelling accompanied by breathlessness is a minor side effect. If you have diabetes, ask how to monitor glucose around steroid days.

Important side effects requiring prompt attention

Reactions during or after a dose

Reactions may include a blocked or runny nose, cough, throat irritation, chills, nausea, rash or dizziness. More serious reactions can affect breathing, blood pressure or the heart. They are most likely around early doses, but can occur later. Subcutaneous reactions can begin after you have left the unit; the US label records onset up to several days after administration.

Tell staff immediately during treatment. They will interrupt an infusion for a reaction and treat symptoms; whether treatment restarts depends on the reaction. Anaphylaxis or a life-threatening reaction requires emergency treatment and permanent discontinuation. At home, follow the urgent-help advice rather than waiting until the next appointment.

Serious infection and viral reactivation

Daratumumab can be associated with serious, sometimes fatal infections, including pneumonia and sepsis. Low white-cell counts increase risk, but infection is possible without a known low count. Fever, chills, new cough, painful urination or suddenly feeling very unwell need immediate advice.

Report painful blistering skin promptly because it may be shingles. Hepatitis B reactivation may first appear in blood tests, or cause jaundice, dark urine, abdominal discomfort or unusual exhaustion. Contact the team urgently if these occur. If reactivation develops, treatment is suspended while the infection is managed; restarting requires specialist assessment.

Bleeding and heart or eye symptoms

Reduced platelets can cause easy bruising, nosebleeds, bleeding gums or small red-purple spots. Report these promptly. Heavy bleeding, blood in vomit, black stools or a severe new headache need urgent medical assessment.

Serious cardiac events have been reported with the subcutaneous combination used in AL amyloidosis, particularly where the heart is already affected. This is a specific high-risk context, not a risk percentage that should be applied to every patient. New palpitations, fainting, worsening swelling or breathlessness require prompt assessment.

Eye reactions have been reported that can cause sudden blurred vision, eye pain or increased pressure inside the eye. Seek immediate assessment. The treatment team should interrupt daratumumab and arrange urgent eye-specialist review before considering further treatment.

Other medicines, supplements and vaccinations

Give the pharmacist a complete list of prescribed medicines, non-prescription products and supplements. Daratumumab is not handled like many oral medicines that rely on liver drug-metabolising enzymes, but your accompanying treatments can have important interactions. Check before adding painkillers, herbal products or “immune-boosting” supplements.

Do not stop prescribed antiviral or other infection-prevention treatment just because you feel well. Some regimens also require prevention of blood clots or other infections. These decisions depend on your whole treatment and personal risks.

Discuss flu, COVID-19 and other non-live vaccines with your team. Protection may be weaker during immune-suppressing treatment, so timing matters. Avoid live vaccines while your immune system is weakened unless your specialist explicitly advises otherwise; the safe interval after treatment is individual. Shingles vaccination does not automatically replace prescribed antiviral tablets.

Everyday life during treatment

You do not need to fast specifically for daratumumab. Follow instructions for any accompanying medicine or procedure. Eat what you can tolerate, follow sensible food hygiene and ask for dietary help if weight loss continues. Drink according to the plan for your kidney and heart health.

Plan work and travel around treatment and recovery. Gentle activity can help maintain stamina, but adjust it to fatigue, neuropathy and bone-health advice. Wash hands regularly and avoid close contact with people who are clearly unwell. Tell the team promptly after a significant infection exposure rather than waiting for symptoms.

Do not drive if sleepy after an antihistamine, dizzy, unusually tired or visually impaired. Arrange someone to accompany you for early appointments if possible. For travel, carry a medicine list, treatment summary and blood-bank alert information, and identify where you could obtain urgent help.

Tell your dentist and other clinicians about the complete treatment plan before procedures. Low blood counts, infection risk or accompanying bone-strengthening medicines may affect arrangements. If fatigue, anxiety or altered body confidence affects relationships or sex, your team can offer practical support; pregnancy prevention remains important even when fertility seems reduced.

Fertility, contraception, pregnancy and breastfeeding

Daratumumab can harm a developing baby. If you could become pregnant, use effective contraception during treatment and for three months after the last dose. Discuss the method before starting. Pregnancy-testing requirements are particularly strict with some accompanying medicines. Contact the team immediately if pregnancy occurs or is suspected.

Lenalidomide, pomalidomide and thalidomide have their own pregnancy-prevention requirements, including precautions for male patients and partners. Follow every requirement of the complete regimen and any longer interval; the daratumumab three-month interval does not replace them. Daratumumab labels do not supply a separate universal male contraception interval.

The effect of daratumumab on future fertility is not known. Discuss sperm or egg preservation before treatment if relevant, allowing for the possible effects of partner medicines. Reduced fertility does not reliably prevent pregnancy.

Do not breastfeed during treatment without an agreed specialist plan. US patient information advises against breastfeeding during treatment; European information calls for a decision between breastfeeding and treatment after weighing benefit and risk. No fixed daratumumab-only interval for restarting breastfeeding is established in these labels. Obtain advice for the entire regimen before restarting. If exposure occurred during pregnancy, tell the baby’s clinicians. Live vaccines for the baby should be delayed until a blood specialist has assessed them.

After treatment finishes

Keep follow-up appointments and report persistent or new symptoms. Continue antiviral prophylaxis and other supportive medicines for the prescribed period; do not assume they all finish with the last injection. Patients with previous hepatitis B may require monitoring for at least six months and sometimes longer according to specialist advice.

Continue to tell healthcare staff about daratumumab because blood compatibility tests can be affected for up to six months after the last dose. Keep the treatment record beyond this period as part of your medical history. Follow the contraception plan and obtain advice about vaccinations and breastfeeding. Recovery and infection risk depend partly on other treatment received.

Frequently asked questions