Efficacy of Lenalidomide Based Three Drug Versus Two Drug Regimen for Relapsed Multiple Myeloma: A Systematic Review and Meta-Analysis of Randomized Trials
Authors: Usman Muhammad , Faridi Warda , Fraz Muhammad Asad , Tariq Muhammad Junaid , Malik Saad Ullah , Sagar Fnu , Ijaz Awais , Hussain Abid , Ahmad Malik Qistas , Khalil Muhammad Jahanzeb , Khalid Amna , Lakhani Midhat , Durer Ceren , Durer Seren , Anwer Faiz 
Published: October 2019

Abstract
Introduction:
Survival of patients with multiple myeloma (MM) has improved over the last decade, mainly due to advent of newer drugs, three drug based induction, high dose chemotherapy consolidation and routine use of maintenance therapy for eligible patients. Despite advances in therapy, many cases of MM ultimately relapse and there is need to summarize evidence comparing efficacy and clinical outcome of combination regimens used in relapsed or refractory MM (RRMM) treatment. We performed a systematic review and meta-analysis of randomized controlled trials to compare the efficacy of lenalidomide based three drug regimens versus two drug regimens among relapsed and refractory myeloma (RRMM) patients.
Methods:
We conducted a literature search on PubMed, Embase, Wiley Cochrane Library, Web of Science and ClinicalTrials.gov which was completed on March 26, 2018. We used keywords like "relapsed multiple myeloma", "revlimid", "dexamethasone", "elotuzumab", "carfilzomib", "bortezomib", "ixazomib", "daratumumab", "doxorubicin", "pembrolizumab", "thalidomide", "cyclophosphamide" along with MeSH and Emtree terms. The primary meta-analytic approach was a random effects model using the Mantel-Haenszel method. It was used to calculate pooled risk ratio of objective response rates with 95% confidence interval. Cochrane Collaboration's tool was used for quality assessment of included studies. Systematic reviews, meta-analyses, combination regimen without lenalidomide, newly diagnosed MM patients, and other plasma cell dyscrasias were excluded.
Results:
Literature search retrieved 11,362 titles. Following initial screening, 72 articles were considered for full text review. Of these only five studies with 2844 patients met inclusion criteria and two studies qualified for meta-analysis. The study arm used daratumumab (Dara), ixazomib, carfilzomib, or elotuzumab in combination with lenalidomide (Len) and dexamethasone (Dex). The control arm used combination of Len and Dex (LenD). There was no difference in overall response rate (ORR) between ixazomib-Len-Dex regimen versus LenD (RR=1.33, 95% CI = 0.83 to 2.17, p= 0.236). However significantly higher complete response (CR) was observed in ixazomib-Len-Dex group compared to LenD (RR = 1.82, 95% CI = 1.14 to 2.93, p = 0.013). An absolute increase in ORR among carfilzomib-Len-Dex, elotuzumab-Len-Dex, and daratumumab-Len-Dex versus LenD was 20.4% (87.1% vs. 66.7%, p <0.001), 13% (79% vs 66%, p <0.001) and 16.5% (92.9% vs. 76.4%, p <0.001) respectively.
Conclusion:
Daratumumab and carfilzomib in Len based three drug regimens have better clinical efficacy when compared to lenalidomide and dexamethasone based two drug regimens among relapsed and refractory multiple myeloma patients. There was no difference between the ORR of ixazomib based combination regimen and LenD but higher number of patients achieved deeper responses.

Disclosures
No relevant conflicts of interest to declare.