Pomalidomide-Dexamethasone in the Management of Heavily Pretreated Multiple Myeloma

Background: Pomalidomide is a new generation IMID, with a very good compliance, thanks to oral administration, which can be used also in heavily pretreated patients, in a domestic setting. Aims: In this retrospective observational trial, It has been evaluated efficacy and tolerance of pomalidomide plus dexamethasone (PD) as salvage regimen in heavily pretreated patients with relapsed and refractory MM (rrMM), whose prognosis is particularly severe. Methods: 33 patients (19 M/14 F), with rrMM, median age at diagnosis 69 years (r. 52-84), and median age at start of treatment 76 years (r.56-89) treated with several lines of treatments (median 7, r. 2-11), every refractory to all the drugs previously received (also Bortezomib, Thalidomide and Lenalidomide), received Pomalidomide-Dexamethasone (Pomalidomide 4 mg for 21 days, Dexamethasone 40 mg days 1,8,15,22, pegfilgrastim day +8) every 28 days, until progression. ISS was equally distributed, and cytogenetic was evaluable in 14 patients, and in particular three del13q and one t(11;14) were present. All the patients had previously been treated with schedule containing bortezomib and IMIDs. 60% (20/33) of them had undergone at least to a single ASCT. All patients were relapsed and refractory to last therapies received before PD. Results: Pomalidomide was well tolerated, with grade 3 anemia in 51% (17/33) of patients, 36.3% (12/33) grade 3 neutropenia (pegfilgrastim in primary prophylaxis was given, no hospitalization was required, no septic shocks were observed), 30.3% (10/33) grade 3-4 thrombocytopenia without hemorrhagic events and transfusion-dependence. No severe extra-hematologic toxicity was observed. According to IMWG, ORR1 (≥PR) was 45.4% (15/33: 4 CR, 5 VGPR, 6 PR), but, considering that we are evaluating a cohort of heavily pretreated patients without any other alternative treatment, with really poor prognosis, another parameter should be considered, ORR2 (≥SD), considering stable disease as a successful result in progressive MM. ORR2 was 78.7% (26/33: 4 CR, 5 VGPR, 6 PR, 11 SD). These can be considered as impressive result in this subset of patients. Oral treatment gives a really good compliance, in frail and unfit patients, and response, when present, is always really fast (median time to response: 2 months (r.1-6)), median OS from diagnosis was 92 months (range 21-234), median OS from start of pomalidomide was 9 months (range 1-25). Conclusions: Pomalidomide-dexamethasone has shown significant effic