Background Pomalidomide is a new oral antineoplastic that has a similar structure to thalidomide. It provides a last line in the treatment of multiple myeloma (MM), after thalidomide, bortezomib and lenalidomide.
Purpose To estimate the tolerance and efficiency of pomalidomide after a period of one year of use under the status of Temporary Use Authorisation (TUA), and on a cohort of patients with MM who have relapsed.
Materials and methods The analysis was conducted retrospectively from August 2012 to September 2013. The therapeutic use protocol provided by the manufacturer requires that the level of polymorphonuclear neutrophils (PMN) and platelets should be monitored. On one hand, biological tolerance was estimated from the patient’s complete blood count (CBC) (1/month), and on the other hand, clinical tolerance was estimated from the clinical and therapeutic data existing in the medical files. Efficiency was calculated from the rate of complete Ig on serum protein electrophoresis (SPE) or incomplete Ig i.e. free light chains (FLC) measured by immunofixation.
Results Five patients, 2 men/3 women (P1, P2, P3, P4, P5) were treated with pomalidomide on 6th and even 8th line treatment. 3/5 patients presented MM with complete immunoglobulins (Ig) and 2/5 had MM with FLC. The initial dose of pomalidomide complied with the recommended regimen (4 mg/day for 21 days/28) associated with an antithrombotic. In terms of biological tolerance, 5/5 patients presented neutropenia (2 grade III/3 grade IV) and thrombocytopenia (3 grade 0/2 grade IV) during the first month. 4/5 patients again developed neutropenia (3 grade III/1 grade IV) and 3/5 patients thrombocytopenia (1 grade I/2 grade II) during the second month of treatment. In terms of clinical tolerance, adverse effects identified were: neuropathy of lower limbs grade III, paresthesias grade I, faintness, dizziness, episodes of daytime sweating, bronchospasm, coughs, intermittent diarrhoea, infections, peeling.
In terms of efficiency, the SPE of 3/5 patients shows a decrease in the amount of complete Ig (P1: 49.2 to 4.7 g/l, P2: 16.4 to 4.8 g/l, P3: 42.4 to 35.7 g/l) within one year. The FLC rate decreased for P4 (1204 to 670 mg/l) and increased for P5 (850 to 1600 mg/l) within one year too. All in all, P1 and P4 have been able to continue treatment, P2 has benefited from an allograft of hematopoietic stem cells (HSCs), P3 has died and P5 is in remission.
Conclusions 5/5 patients presented at least one serious adverse effect during the treatment. Adjusting the dose improves haematological tolerance but the Ig or FLC levels deteriorate, hence the need to increase the posology under cover of G-CSF. Pomalidomide demonstrated its efficiency and obtained its Marketing Authorisation (MA) in August, 2013 for use in 3rd-line treatment.
No conflict of interest.
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