Personalized Treatment with low doses of Lenalidomide and Dexamethasone for Relapsed Multiple Myeloma in frail or Elderly Patients
Authors: Ruedas Angel , Guisado Pablo , Aguado Beatriz , Perez Ricardo , Martinez Joaquin , Garcia-Gutierrez J Valentin , Blanchard M. Jesús , Bravo Pilar , Montalban Carlos 
Published: October 2019

Abstract
Abstract 5049

Background.
Treatment of frail or elderly patients with relapsing symptomatic/active Multiple Myeloma (MM) is very difficult due to concomitant diseases, impaired bone marrow reserve, systemic toxicity, relatively decreased renal function and general problems of old age. Dexamethasone and new agents (thalidomide, lenalidomide, bortezomib and bendamustine) have been used in this setting, in most cases with doses adapted to the clinical situation.

Aims.
To retrospectively analyze the management of frail and/or very elderly MM patients with relapsed and active disease treated with reduced doses of the aforementioned agents in five hospitals in Madrid, Spain.

Methods.
The files of this group of MM patients were studied. The most common treatment has been the combination of low doses of lenalidomide (len) and of dexamethasone (dex), whereas treatment with reduced doses of other agents has been anecdotal; therefore we analyzed the results of len/dex combinations. Len and dex have been used in lower than standard doses, adapted to the individual initial situation of the patients and tailored according to effect and toxicity throughout treatment. There was no specific protocol and the management of the patients has depended exclusively on the practice and criteria of the treating physicians. Patient risk was stratified following the Salmon and Durie (S&D) score and the International Staging System (ISS). Response was assessed with the IMWG criteria. The study has been approved by the Ethics Committee of Hospital Ramon y Cajal, as coordinating center.

Results.
38 patients were included in the study. Mean age was 79 years (range 68–90). 30 pts (79%) were older than 75 years and 10 pts had over 85 years. More than half of the patients (21) had two or more comorbidities. Patients had previously received 1 to 5 (m=1. 8) different treatment modalities, including steroids, melphalan (25), bortezomib (20), thalidomide (6) (or their combinations), and others or even APBSCT (3). 23 pts (60%) had IgG (m=4087 mg/dl, range 868–13000); 13 (34%) IgA (m=2115, range 355–4930) and 2 (5%) only light chains. 22 had κ and 15 λ light chains. 19 (50%) had BJ proteinuria. Mean Hemoglobin level was 10. 7 gr/dl (7. 5–14. 1) and mean creatinine level 1. 3 mg/dl (0. 4–12. 9); 28 (74%) had bone disease. 3 pts had S&D stage I, 22 stage II, and another 13 stage III. 13 pts had ISS stage I, 17 had stage II and 7 stage III. Patients received between 1 and 30 cycles of len/dex (m= 8). Median initial Len dose was 10 mg, the majority between 5 and 15mg, although 4 received 25 mg that were rapidly reduced. Mean initial dex dose was 20mg/day for 4 days. 4 pts (10. 5%) achieved Complete Remission (CR) (3 with negative IF), 27 (71%) Partial Remission (PR) (5 with VGPR) and 2 (5%) a significant, but lesser than 50%, reduction of the M-component (Stable Disease, Std). Altogether, overall response (CR+PR+Std) occurred in 33 pts (86%). The best response occurred after 2 to 9 cycles (m=4) of len/dex. Treatment was stopped in 15 patients due to neurological (4) or hematological (1) toxicity, pulmonary embolism (1), unrelated causes (4) and after achieving a plateau response (5). Time to next treatment was 1–30 months, (m=8 mo). 7 pts relapsed after 3–21 months (m=7). 10 patients died, 5 of related (disease progression, cardiac amyloidosis, renal progression to ESRF) and 5 of unrelated (cancer, sepsis, myocardial infarction, congestive heart failure) causes. Grade III-IV bone marrow toxicity occurred in 9 pts and neurological toxicity (PNP) in 5 (all of them had previously been treated with bortezomib or thalidomide).

Conclusions.
Personalized low doses of len/dex have been the most common treatment for frail/very elderly patients with relapsed MM in our centers and it is an active and tolerable option in this setting. The haematological toxicity was expectable and manageable, but prior treatments with bortezomib or thalidomide were associated with limiting neurotoxicity.

Disclosures:
No relevant conflicts of interest to declare.