A long-term favorable response and effective control of neutropenia obtained by low-dose pomalidomide treatment in a patient with relapsed refractory multiple myeloma: a case report

In June 2011, a 66-year-old woman was diagnosed as multiple myeloma (IgG-k type). In July 2011, she received bortezomib and dexamethasone therapy with a 5-week cycle. After the third treatment cycle, the patient showed disease progression to secondary plasma cell leukemia. In September 2011, lenalidomide and dexamethasone therapy was initiated with a 4-week cycle; however, the patient remained refractory to treatment. In October 2011, the therapy regimen was switched to vincristine/doxorubicin/dexamethasone with a 3-week cycle. Partial response (PR) was achieved after the first cycle. In December 2011 and April 2012, autologous peripheral blood stem cell transplantations were performed. Stringent complete remission was achieved in December 2011 and was sustained for about 3 years. Disease relapse occurred in January 2015. There was a temporary response to melphalan and prednisolone (MP) therapy; however, the patient eventually developed progressive disease. In September 2015, MP therapy was switched to pomalidomide 4 mg q.d. plus dexamethasone 40 mg once weekly. Because neutropenia developed, the dose of pomalidomide was reduced in stages to 1 mg on alternate days followed by a 7-day washout period from day 22 to day 28. Despite this being below the recommended minimum dose, there was a favorable response: the total leukocyte count and neutrophil count were maintained at ≥1000/μL and ≥500/μL, respectively, obviating the need for continued administration of granulocyte-colony stimulating factor. As of late December 2015, PR was maintained while the patient received a third cycle of alternate-day treatment with 1 mg pomalidomide.