Lenalidomide Therapy in Nine Patients with POEMS Syndrome.
Authors: Jaccard Arnaud , Abraham Julie , Recher Christian , Dulery Remy , Guichard Isabelle , Haroche Julien , Asli Bouchra , Amoura Zahir , Brissaud Jean Marie , Musset Lucille , Facon Thierry , Leblond Veronique , Moreau Philippe , Fermand Jean-Paul , Bordessoule Dominique 
Published: October 2019

Abstract
Abstract 3872
Poster Board III-808

Introduction
POEMS syndrome is a rare disease characterized by peripheral neuropathy, organomegaly, endocrinopathy, monoclonal plasma cells, skin changes, papilledema, volume overload, sclerotic bone lesions, thrombocytosis, and high serum VEGF level. Efficient treatments consist in irradiation for patients with localized solitary plasmocytoma and high-dose chemotherapy with autologous stem cell transplantation for appropriate candidates without a focal lesion. Conventional myeloma chemotherapy can only control the disease in a limited number of patients. Results of monoclonal anti-VEGF antibodies, which seem to be attractive due to the role of VEGF in this disease, are controversy with efficacy in 3 patients but treatment related deaths in 2 other patients. Thalidomide effectiveness has been reported in Japanese patients but enthusiasm for its use is tempered by the high incidence of thalidomide-induced peripheral neuropathy. Lenalidomide, which efficacy has been described in one observation (Dispenzieri, Blood 2007 110: 1075-1076), has the advantage of being anti-angiogenic, cytotoxic to malignant plasma cells and with a much lower risk of peripheral neuropathy. We reported here a multicentric French experience with this drug in POEMS syndrome.

Patients and Methods
There were 3 women and 6 men treated with Lenalidomide in 7 French centres. Median age was 60 (41-76). All patients had sensitive polyneuropathy with motor deficiency in 5 patients. A monoclonal component was present in all cases (IgA lambda in 7 patients, IgG lambda and lambda light chain only in 1 patient each). Other manifestations of POEMS syndrome included sclerotic bone lesions in 6 patients, endocrinopathies in 7 patients, skin changes in 8 patients, oedema in 7 patients, organomegaly in 5 patients, papilledema in 5 patients, thrombocytosis in 3 patients. VEGF serum level was elevated in 4 among 5 patients with a dosage. Previous treatments were high-dose chemotherapy with autologous stem cell transplantation in 3 patients, Melphalan-Prednisone in 3 patients because of advanced age, and prolonged steroid treatment in 2 patients. One patient received Lenalidomide as primary treatment before high-dose therapy. Lenalidomide was given during 21 days each month and sequentially associated with dexamethasone, 5 patients received 25 mg/day and 4 patients received 10 or 15 mg, for a median of 5 cycles (1 to 11).

Results
Serious side effects were noted in 3 patients with 2 hematologic toxicities (grade III and IV) and a cutaneous allergy. Six patients could be evaluated for hematologic response and all responded, complete response in 3 patients and partial in 3 (>25%). Clinical responses occurred early, before 3 months of treatment, in 6 cases among 8 (1 patient is not yet evaluable), with a marked improvement in performance and in neurological syndrome. Other manifestations of POEMS syndrome improved, especially oedema in 5 cases among 6. VEGF level (normal value < 500 pg/ml) could be serially measured in 4 patients with a normalization in 1 patient and a significant decrease in 3 patients, median 7100 pg/ml (2100-10100) before treatment to 887 pg/ml (304-3270). In 1 of these 3 patients VEGF level increased to initial value while he was still taking Lenalidomide. A second patient experimented a relapse 5 months after ending Lenalidomide, he is still in good response after Lenalidomide reintroduction. With a median follow-up of 12 months (1-26) all patients are alive.

Conclusion
Lenalidomide seems to be a very promising therapy in POEMS syndrome. It should be tested in larger studies in patients with a systemic disease, who are not able to receive high dose therapy, in relapsing patients and before high dose treatment to avoid transplant related morbidity, particularly engraftment syndrome.

Disclosures:
Jaccard: Celgene: Membership on an entity's Board of Directors or advisory committees. Facon:Celgene: Membership on an entity's Board of Directors or advisory committees and Speakers Bureau. Moreau:Celgene: Membership on an entity's Board of Directors or advisory committees. Fermand:Celgene: Speakers Bureau.