Efficacy and Toxicity Profile of Elotuzumab for Multiple Myeloma: A Systematic Review and Meta-Analysis
Authors: Jamil Faiza , Shafqat Madeeha , Samuel Sharoon , Shah Zunairah , Durer Ceren , Durer Seren , Sadiq Maryam , Tariq Muhammad Junaid , Jose Jemin Aby , Faridi Warda , Bakr Mohamed Mokhtar , Zahid Umar , McBride Ali , Safdar Ahmad , Anwer Faiz 
Published: October 2019

Abstract
Background:
Elotuzumab (elo) is a humanized monoclonal antibody, which has been approved by the FDA for use in combination with lenalidomide (lena) and dexamethasone (dexa) in patients (pts) with relapsed and refractory multiple myeloma (RRMM). Elotuzumab is effective as a single agent, as well as in combination for multiple myeloma treatments, supporting the use of elo in pts with RRMM and newly diagnosed multiple myeloma (NDMM) pts.
Method:
After review of literature using database searches was done on 6/27/18 (Pubmed, Embase, Cochrane Library, Web of Science and Clinical Trials.gov), 9 prospective and 1 retrospective study with 1128 enrolled pts met the inclusion criteria to date in RRMM and 2 clinical trials including 123 pts in NDMM (Table 1). CMA software v.3 was used for meta-analysis. A random-effect model was applied.
Result:
Regimens used in RRMM: Based on pooled analysis (95% CI), an overall response rate (ORR) of 66% (54-76.2) was calculated in 685 evaluable pts treated with elo based regimens in RRMM (Figure 1). Most common grade (G) ≥ 3 hematological adverse events (HAE) and non-hematological adverse events (NHAE) based on regimen were calculated using pooled analysis in RRMM pts (Table 2). Anemia was noted in 12.1% ( 7.7-18.6) in 559 pts, while neutropenia in 14.5% (7.5-26.4) out of 591 pts and thrombocytopenia (tcp) in 11.9% (7.9-17.4) in 198 evaluable pts. Diarrhea 5.5% (3.6-8.3), pyrexia 2.4% (1.5-4), peripheral neuropathy (PN) 8.4% (3.8-17.8) were measured in 626, 668 and 143 pts respectively.
Elotuzumab as monotherapy: 1 study (n=34) evaluated the efficacy of elo as single agent in RRMM. The median age, time from diagnosis and number of prior therapies were 64.5 years (y) (46-87), 4.4 y (0.9-12.8) and 4.5 y (2-10) respectively. It produced an ORR of 1.4% (0.1-19.1 95% CI) in 34 evaluable pts. Adverse events recorded were pyrexia and fatigue in 17.6% and 8.8% pts respectively.
Elotuzumab in two drug regimen: In RRMM, 2 clinical trials (n=49) evaluated the efficacy (95% CI) of elo, ORR of 25% (4.1-72.3) was calculated. The best PFS (progression free survival) produced was in combination of elo 20 mg with bortezumib (bort) 1.3mg/m2 of 9.46 months as compared to 1.8 months when elo10mg/kg + dexamethasone (dexa) 28mg was used. In our analysis for safety, common G≥ 3 HAE calculated were, thrombocytopenia 8.7% (3.3-21.1) n=49, neutropenia 10.7 % (3.5-28.4) n=28 pts and anemia 7.1% (1.8-24.5) n=28 pts. NHAE included diarrhea 1.7% (0.1-22.3), PN 10.7% (3.5-28.4), pyrexia 1.7% (0.1-22.3) in 28 evaluable pts each.
Elotuzumab in three drug regimen: In RRMM, 10 clinical trials including 602 pts evaluated the efficacy of elo as a part of triple drug regimen, producing an ORR of 72.2% (54-76.2). The best results were produced with the combination of elo 10-20mg/kg + lenalidomide (lena) 25mg + dexa 40mg producing a PFS of 32.2 mo and 28.62 mo in its phase I and II cohorts respectively. Based on pooled analysis (95% CI) common HAE calculated were neutropenia 17.5% (7.6-35.4) in n=563, thrombocytopenia 12.7% (8.2-19.4) in n=149 and anemia 13% (8-20.5) in n=531 pts. Common G ≥ 3 NHAE estimated were diarrhea 5.7% (3.7-8.6), PN 6.6% (2-19.2), pyrexia 2.5% (1.5-4.1) in 598, 115 and 640 pts respectively.
Elotuzumab based regimen in NDMM: A currently ongoing clinical trial NCT02272803 has produced promising results in NDMM pts. As a part of three drug regimen with dose of elo 10mg/kg-20mg/kg, lena 25mg, dexa 20mg in 40 pts produced an ORR of 87.5% (73.2-95.8) versus control group of lena 25mg plus dexa 40mg in 42 pts with an ORR of 73.8% (58-86.1). The PFS rate recorded at 1 year was 93% (79-98%) and 91% (73-97%) respectively. The HAE G ≥ 3 included, neutropenia 18% and leukopenia 15%. In another study with 41 pts, elo was used in combination with lena, bort and dexa producing an ORR of 100% and greater than grade 3 adverse events including Tcp 15%, PN 2%.
Conclusion:
Results produced in our study suggest that elotuzumab is highly effective when used in pts with RRMM and NDMM. Combination regimens for elo produces an ORR ranging from 79-83% with elo + lena+ dexa, proving that the best results were produced by three drug regimens. Large prospective studies are required to evaluate efficacy and safety of elotuzumab in combination therapies.

Disclosures
No relevant conflicts of interest to declare.