Background Lenalidomide was authorised in 2007 by EMA for the treatment of multiple myeloma (MM). It is also used off-label for myelodysplastic syndrome (MS). The drug is given orally at 25 mg on days 1:21 (28-day therapeutic cycle) associated with dexamethasone. Dose modifications or cessation of treatment may be necessary in the event of haematological adverse events (HAEs).

Purpose To evaluate lenalidomide dose modifications in MM and MS patients due to haematological toxicity, as recommended in the EMA’s drug specifications.

Materials and Methods Retrospective observational study involving 16 patients who started treatment with lenalidomide between May 2008 and September 2010. Information was collected from the clinical and pharmacotherapeutic history. If neutropenia or thrombocytopenia arose, modifications made in treatment were analysed.

Results 16 patients were found, 14 treated for MM and 2 for MS. Male/female ratio was 8/8 and median age was 68.3 years (CI95%: 63.1–73.4).

Median number of cycles per patient was 6 (2–21). Considering all cycles, 98 were studied.

Pre-cycle neutropenia and thrombocytopenia were the main dose-restricting toxicities. Platelet counts <30 × 10⁹/L were found in 9 cycles; the dose was reduced in 2 patients, spaced out in 1 and both adjustments in another patient.

Neutrophil counts <0.5 ×10⁹/L were found in 12 cycles; the dose was reduced in 4 patients and spaced out in 3. No modifications were made in 55% and 41.6% of thrombocytopenic and neutropenic patients, respectively. No records were kept about support measures such as platelet pools or granulocyte-stimulating colony-growth factors.

Conclusions Lenalidomide’s haematological toxicity is dose-related and often made worse by the basal bone marrow damage due to the haematological disease. Despite this certainty, hardly half of the patients with platelet or neutrophil damage had their dose or schedule adjusted. At this point, the patients could benefit from hospital pharmaceutical care. Important limitations of our study were lack of data about support measures and the small number of cases.

No conflict of interest.