The use of proteasome inhibitors among patients with POEMS syndrome.

Abstract

e19530 Background: Neuropathy is a universal symptom of patients with POEMS syndrome, which makes the use of bortezomib less appealing. However, proteasome inhibitors (PIs) can provide rapid and deep hematologic responses in plasma cell disorders. Because there is very little data regarding the use PIs in POEMS syndrome, we performed a study of patients with POEMS syndrome treated with PIs. Methods: Among the 167 patients with POEMS syndrome seen at our institution between 2001-2016, we identified 12 patients who received a PI. One patient receiving < 1 cycle of bortezomib because of worsening neuropathy was included but was excluded from response analyses. One patient received 2 different PIs at separate points during the disease course and each course was considered separately. Four response categories were considered: hematologic, PET, VEGF and clinical as previously described (Dispenzieri et. al AJH 2015). Results: Among the 12 patients who received 13 courses of therapy, the median age at PI initiation was 59; 8 patients were male. Median number of prior therapies was 1 (0-4) and median time from diagnosis to initiation of PI was 75 months. Excluding steroids, regimens were as follows: bortezomib, n=3; bortezomib and cyclophosphamide, n=4; carfilzomib, n=1; and ixazomib, n=1. With a median follow-up from PI initiation of 18 months, the median duration of treatment was 7 months (1-18). Three patients achieved a hematologic CR. Of 6 patients with an abnormal baseline VEGF, 3 achieved normalization VEGF levels. Of 5 patients with an abnormal baseline PET, 2 achieved normalization of their PET. Two patients had improvement of their neuropathy, with the rest having stable symptoms. Of 9 patients with fluid overload, 8 improved. Only 2 patients stopped therapy due to worsening neuropathy related to PIs. Median PFS and OS from initiation of PI were 50 months and 53 months, respectively. Conclusions: We show that PI use in patients with POEMS syndrome can be safe and effective. Nearly 75% of patients treated with bortezomib had no exacerbation of their neuropathy. Clinical improvement in severe fluid overload symptoms (edema, ascites, pleural effusions) is almost universal, making PI-based therapy an attractive potential option in these patients.