Peripheral Neuropathy In Multiple Myeloma Patients Treated with Lenalidomide
Authors: Castaneda Carmen , Weiss Lilia , Minton Neil A. , Kim Alex , Freeman John , Yu Zhinuan , Knight Robert 
Published: October 2019

Abstract
Abstract 5024

Background:
Lenalidomide is an oral IMiD® immunomodulatory compound with a dual mechanism of action, namely tumoricidal and immunomodulatory activity. As demonstrated by 2 randomized, double-blind, placebo-controlled pivotal phase III registration trials, lenalidomide plus dexamethasone (Len/Dex) was well tolerated and achieved significant clinical efficacy and survival outcomes vs placebo plus Dex (PBO/Dex) in patients (pts) with relapsed/refractory multiple myeloma (MM) (Weber 2007; Dimopoulos 2007). In MM, the rate of symptomatic peripheral neuropathy (PN) is 3–13%, although the rate of subclinical neuropathy detected by electrophysiological studies or histopathological evaluation is estimated to be much higher (40-60%; Kwan 2007). Published incidence of PN has been notable with thalidomide (Thal) ranging from 0 to 90%, depending on pt characteristics, concomitant treatments, dose/exposure duration, and techniques for identifying PN. We present the result of our analysis of PN adverse events (AEs) reported with Len.

Methods:
Reports of PN from the 2 registration studies (MM-009, MM-010; data cutoff June and August 2005, respectively), and postmarketing safety reports (Dec 2005 to Dec 2009) were retrieved from Celgene clinical and safety databases utilizing the Preferred Terms for PN AEs within the PN Standardized MedDRA (v13.0) Query (SMQ) to obtain all possible cases. Severity grades were according to the NCI CTCAE (V3).

Results:

Clinical Studies
703 pts (353 Len/Dex; 350 PBO/Dex) from the 2 registration studies were included in this analysis. The proportion of pts with ≥1 Grade (G) 1–4 PN AEs and ≥1 serious adverse event (SAE) was similar between the Len/Dex and PBO/Dex arm (45.6% vs 44.9% and 1.1% vs 1.1%, respectively). However, the proportion of pts with ≥1 G3/4 PN was slightly higher with Len/Dex vs PBO/Dex (9.3% vs 5.1%). Among the Len/Dex pts with PN AEs, prior Thal or vincristine was reported in 39.1% and 60.9% of pts, respectively and 24.8% of pts had history of PN. Among the PBO/Dex pts with PN AEs, prior Thal or vincristine was reported in 46.5% and 58.0% of pts, respectively and 29.3% of pts had a history of PN. Within this SMQ analysis, the PN AEs reported in ≥5% of the pts were peripheral neuropathy, hypoaesthesia, paraesthesia, and muscle weakness in both treatment arms. 98.3% of PN AEs were not SAEs and 83.2% were G1/2 in the Len/Dex arm. Among pts in the Len/Dex arm and with PN AEs, PN resolved in 61.5% and study drug was continued in 78.9% of pts. Study drug was reduced due to PN in 12.4% and interrupted in 5.0% of pts in the Len/Dex arm. The median time to onset of PN event was longer in the Len/Dex arm compared with the PBO/Dex arm (41 vs 31 days).

Postmarketing
A total of 2857 PN AEs were reported in 2329 of an estimated 73,592 MM pts. The reporting rate of PN AEs is 3.2% in the MM indication. Within this SMQ analysis, the PN AEs reported in ≥0.5% of the pts were peripheral neuropathy, hypoaesthesia, and paraesthesia. 93.8% of PN AEs were not SAEs. Most pts were males and elderly with a median age of 66 yrs (range: 29–95). Among MM pts with PN AEs and available information, 13% had prior Thal, 5% had prior bortezomib, and 11% had a history of PN. In the majority of reports, outcome was unknown and Len was continued. The median time to onset of PN event was 60 days (range: 1–1460).

Conclusion:
In 2 pivotal phase III registration trials, the incidence rate of peripheral neuropathy adverse events was similar between the Len/Dex and PBO/Dex arms. Most pts had prior anti-myeloma therapies associated with PN and a quarter of the pts had a history of PN. Limited information in postmarketing reports on prior therapies and medical history may have underestimated pre-existing PN and exposure to prior anti-myeloma therapies associated with PN. PN AEs occurred within a median of 60 days of starting Len. In conclusion, peripheral neuropathy adverse events in MM pts treated with Len are generally not SAEs and did not commonly require dose modification or interruption.
References
Dimopoulos et al. NEJM 2007;357(21):2123-2132.
Kwan JY. Neurol Clin 2007;25(1):47-69.
Weber et al. NEJM 2007;357(21):2133-2142.

Disclosures:
Castaneda: Celgene: Employment. Weiss:Celgene: Employment. Minton:Celgene: Employment. Kim:Celgene: Employment. Freeman:Celgene: Employment. Yu:Celgene: Employment. Knight:Celgene: Employment.