Lenalidomide

Lenalidomide is an oral immunomodulatory medicine used to treat selected blood cancers and bone marrow disorders. It belongs to a class of medicines related to thalidomide and has effects on immune activity, cancer cell survival, and the bone marrow environment. Lenalidomide binds to a protein called cereblon, part of an E3 ubiquitin ligase complex, altering the breakdown of specific proteins involved in the growth and survival of malignant cells. It can also influence immune cells and reduce support for abnormal blood cell growth. The medicine is supplied as capsules and is commonly used in multiple myeloma, certain myelodysplastic syndromes associated with deletion 5q, and selected lymphomas, depending on the approved indication in each country. It may be given alone or in combination with other medicines, including dexamethasone, bortezomib, melphalan, prednisone, or rituximab. The dose and schedule depend on the disease, combination regimen, kidney function, and blood counts. Lenalidomide can cause significant reductions in blood cells, blood clots, and serious harm to an unborn baby. Careful patient selection, laboratory monitoring, pregnancy-prevention measures, and specialist supervision are essential throughout treatment.

Lenalidomide was developed as an immunomodulatory derivative of thalidomide for the treatment of selected haematological malignancies and bone marrow disorders. Its activity involves cereblon-mediated changes in protein degradation, immune modulation, and effects on malignant cell growth. The United States Food and Drug Administration (FDA) first approved lenalidomide in 2005 for transfusion-dependent anaemia associated with lower-risk myelodysplastic syndromes with a deletion 5q abnormality. Its indications were subsequently expanded to include multiple myeloma and selected lymphomas. The European Commission granted marketing authorisation for Revlimid on 14 June 2007. European approvals have included maintenance treatment for multiple myeloma after autologous stem cell transplantation, combination treatment for newly diagnosed or previously treated multiple myeloma, selected deletion 5q-associated myelodysplastic syndromes, relapsed or refractory mantle cell lymphoma, and previously treated follicular lymphoma in combination with rituximab. The exact approved indications vary by country and product. Clinical development included trials evaluating response, progression-free survival, and maintenance treatment outcomes in multiple myeloma, as well as haematological response and transfusion requirements in myelodysplastic syndromes.

Lenalidomide is used for several approved indications involving blood cancers and bone marrow disorders. In multiple myeloma, it may be prescribed as maintenance treatment after autologous stem cell transplantation, for newly diagnosed disease in patients who are not eligible for transplantation, or for previously treated disease. Depending on the treatment setting, it may be combined with dexamethasone, bortezomib and dexamethasone, or melphalan and prednisone. In selected patients with myelodysplastic syndromes, lenalidomide is used to treat transfusion-dependent anaemia associated with an isolated deletion 5q chromosomal abnormality. It is also approved for certain patients with relapsed or refractory mantle cell lymphoma and, in combination with rituximab, previously treated follicular lymphoma in jurisdictions where these indications are authorised. Treatment selection depends on the diagnosis, disease stage, genetic or cytogenetic findings, previous therapy, kidney function, and applicable local approval. Lenalidomide may be used alone or in combination, according to the specific indication and treatment plan.

Lenalidomide is taken orally as capsules, generally once daily on a defined treatment schedule. In multiple myeloma, a commonly used adult regimen is 25 mg daily on days 1–21 of a 28-day cycle when combined with dexamethasone, although maintenance and other combination regimens use different doses and schedules. For deletion 5q-associated myelodysplastic syndromes, the usual starting dose is commonly 10 mg daily, with adjustments based on blood counts and tolerability. Dosing for mantle cell lymphoma and follicular lymphoma follows the relevant approved regimen and may involve treatment cycles and combination medicines. Kidney function is particularly important because lenalidomide is primarily eliminated through the kidneys, and dose adjustment may be required in renal impairment. Capsules should be swallowed according to the product instructions and should not be opened, crushed, or chewed. Treatment duration depends on the indication, response, adverse effects, and clinical guidance. Patients should follow their prescribed schedule and seek advice about missed doses rather than taking extra capsules.

Common side effects of lenalidomide include low white blood cell counts, low platelet counts, anaemia, fatigue, constipation, diarrhoea, nausea, rash, muscle cramps, and swelling of the limbs. Some patients experience reduced appetite, respiratory infections, or changes in kidney or liver-related laboratory results. The frequency and severity of adverse effects vary according to the underlying disease, dose, treatment duration, and other medicines used in combination. Low blood counts may increase the risk of infection, bruising, or bleeding. Patients should report persistent fever, unusual bruising, bleeding, worsening fatigue, or symptoms of infection promptly. Supportive care, blood tests, treatment interruptions, or clinician-directed dose reductions may help manage some adverse effects. Patients should not alter or discontinue treatment without guidance from their treating specialist unless emergency medical advice directs otherwise.

Lenalidomide can cause serious or life-threatening adverse effects, including severe reductions in blood cell counts, venous and arterial blood clots, severe skin reactions, liver injury, and serious infections. It can cause severe birth defects or fetal death, so pregnancy prevention requirements must be followed strictly; pregnancy testing and controlled dispensing procedures apply according to local regulations. The risk of blood clots may be increased in patients with multiple myeloma, particularly when lenalidomide is combined with dexamethasone or other anticancer medicines. The healthcare team may recommend preventive anticoagulation based on individual risk. Rare but important risks include tumour lysis syndrome and second primary malignancies. Patients should seek urgent medical assessment for chest pain, sudden breathlessness, one-sided leg swelling, severe rash, facial swelling, persistent fever, or unusual bleeding. Treatment may need to be interrupted, reduced, or discontinued depending on the nature and severity of the adverse event. Close supervision is particularly important during early treatment and when combination regimens are used.

Before treatment begins, clinicians should assess complete blood counts, kidney function, liver-related laboratory results, pregnancy status where relevant, and individual risks for blood clots or bleeding. Blood counts should be monitored regularly because neutropenia and thrombocytopenia may require dose modification. Kidney impairment can increase lenalidomide exposure, making appropriate dose adjustment important. Pregnancy-prevention requirements must be explained to patients and followed throughout treatment and for the specified period after the last dose. Lenalidomide should not be used during pregnancy, and breastfeeding should be avoided or discussed according to the applicable product information. Concomitant medicines require review, particularly anticoagulants, antiplatelet medicines, erythropoiesis-stimulating agents, and medicines that may increase thrombotic or bleeding risks. Digoxin levels may require monitoring in some patients. Live vaccines and other vaccination decisions should be discussed with the treating team, especially in patients with compromised immunity. Patients should inform healthcare professionals about prescription medicines, over-the-counter products, and supplements before starting or changing treatment.

Confirm the precise indication, treatment regimen, kidney function, baseline blood counts, and pregnancy-prevention requirements before prescribing or dispensing lenalidomide. Verify that the dose and treatment-cycle schedule match the approved regimen, particularly when it is combined with dexamethasone, bortezomib, melphalan, prednisone, or rituximab. Establish a schedule for monitoring blood counts and kidney function, with additional testing when clinically indicated. Assess thrombotic risk and determine whether preventive anticoagulation is appropriate. Counsel patients about infection symptoms, bleeding, signs of blood clots, severe skin reactions, and the importance of pregnancy-prevention measures. Reinforce safe capsule handling and adherence to the prescribed schedule. Review concomitant medicines for bleeding, clotting, and other relevant risks, and coordinate dose adjustments with the oncology or haematology team. Patients should understand how to obtain advice for missed doses, suspected adverse reactions, or changes in their health during treatment.