Safety and Efficacy of Anti-Bcma CAR-T Cells for Relapsed/Refractory Multiple Myeloma: A Systematic Review of Literature
Authors: Khan Israr , Rafae Abdul , Javaid Anum , Ahmed Zahoor , Qadeer Haifza Abeera , Khan Sana Irfan , Dar Abdul Jabbar , Khurshid Qasim , Jaan Ali , Khalid Farhan , Aijaz Zobia , Hashmi Mydah Sajid , Malik Mustafa Nadeem , Anwer Faiz 
Published: November 2020

Background:
Multiple myeloma (MM) is a plasma cell disorder and demonstrates overexpression of B cell maturation antigen (BCMA). Our objective is to evaluate the safety and efficacy of chimeric antigen receptor T cells (CAR-T) against BCMA in patients with relapsed/refractory multiple myeloma (RRMM).
Methods:
We conducted a systematic literature search using PubMed, Cochrane, Clinicaltrials.gov, and Embase databases. We also searched for data from society meetings. A total of 935 articles were identified, and 610 were screened for relevance.
Results:
Data from thirty-one original studies with a total of 871 patients (pts) were included based on defined eligibility criteria, see Table 1. Hu et al. reported an overall response rate (ORR) of 100% in 33 pts treated with BCMA CAR-T cells including 21 complete response (CR), 7 very good partial response (VGPR), 4 partial response (PR). Moreover, 32 pts achieved minimal residual disease (MRD) negative status. Chen et al. reported ORR of 88%, 14% CR, 6% VGPR, and 82% MRD negative status with BCMA CAR-T therapy in 17 RRMM pts. In another clinical trial by Han et al. BCMA CAR-T therapy demonstrated an ORR of 100% among 7 evaluable pts with 43% pts having ≥ CR and 14% VGPR. An ORR of 100% with 64% stringent CR (sCR) and 36% VGPR was reported with novel anti-BCMA CART cells (CT103A). Similarly, Li et al. reported ORR of 87.5%, sCR of 50%, VGPR 12.5%, and PR 25% in 16 pts. BCMA targeting agent, JNJ-4528, showed ORR of 91%, including 4sCR, 2CR, 10MRD, and 7VGPR.
CAR-T- bb2121 demonstrated ORR of 85%, sCR 36%, CR 9%, VGPR 57%, and MRD negativity of 100% (among 16 responsive pts). GSK2857916, a BCMA targeting CAR-T cells yielded ORR of 60% in both clinical trials. Three studies utilizing bispecific CART cells targeting both BCMA & CD38 (LCARB38M) reported by Zhao et al., Wang et al., and Fan et al. showed ORR of 88%, 88%, & 100% respectively. Topp et al. reported ORR of 31% along with 5 ≥CR and 5 MRD negative status in 42 pts treated with Bi T-cells Engager BiTE® Ab BCMA targeting antigen (AMG420). One clinical trial presented AUTO2 CART cells therapy against BCMA with an ORR of 43%, VGPR of 14%, and PR of 28%. CT053CAR-BCMA showed 14sCR and 5CR with a collective ORR of 87.5% and MRD negative status of 85% in 24 and 20 evaluable pts, respectively. Likewise, Mikkilineni et al. reported an ORR of 83%, sCR of 16.7%, and VGPR & PR of 25% and 41% in 12 pts treated with FHVH-BCMA T cells. Similar results are also reported in other clinical trials of BCMA targeting CART therapy (Table 1). The most common adverse effects exhibited were grade 1-3 hematologic (cytopenia) and cytokine release syndrome (CRS) (mostly reversible with tocilizumab).
Conclusion:
Initial data from ongoing clinical trials using BCMA targeting CAR-T therapy have yielded promising results both in terms of improved outcome and tolerable toxicity profiles. Although two phase 3 trails are ongoing, additional data is warranted to further ensure the safety and efficacy of anti-BCMA CAR-T cells therapy in pts with RRMM for future use.

Disclosures
Anwer: Incyte, Seattle Genetics, Acetylon Pharmaceuticals, AbbVie Pharma, Astellas Pharma, Celegene, Millennium Pharmaceuticals.: Honoraria, Research Funding, Speakers Bureau.