• Age \> 18 years.

• High-risk SMM with ≤40% plasma cells in the bone marrow and with high-risk criteria defined as having 1 of the following 2 criteria:

∙ High-risk per 20-2-20 Criteria defined as presence of any two of the following:

⁃ Serum M-protein ≥ 2 gm/dL

• Involved to uninvolved free light chain (FLC) ratio≥ 20

• Bone marrow PC% ≥ 20% to \<40%.

• OR total score of 9 using the following scoring system:

∙ FLC Ratio

• \>10-25 = 2

‣ Serum M-protein (g/dL)

• \>1.5-3 = 3

‣ BMPC%

• \>15-20 = 2

‣ FISH abnormality (t(4,14), t(14,16), 1q gain, or del13q = 2

‣ Presence of ≥10% BMPC and at least one of the following:

⁃ Evolving pattern:

∙ eMP (≥10% increase in serum M-protein ) over a 6 month period OR;

‣ Evolving change in hemoglobin (eHb) ≥ 0.5 g/dl decrease over a 12 months period OR;

‣ Progressive Involved light chain increase \>10% over a 6 month period along with a light chain ration \> 8

• Abnormal PC immunophenotype (≥95% of BMPCs are clonal) and reduction of ≥1 uninvolved immunoglobulin isotype. (Only IgG; IgA and IgM will be considered) High risk cytogenetics defined as presence of t(4;14), t(14;16), t(14;20), 17p deletion, TP53 mutation, 1q21 gain

• No evidence of CRAB criteria\* or new criteria of active MM (SLIM-CRAB) which including the following:

‣ Increased calcium levels: Corrected serum calcium \>0.25 mmol/L (\>1mg/dL) above the upper limit of normal or \>2.75 mmol/L (\>11mg/dL);

⁃ Renal insufficiency (attributable to myeloma);

⁃ Anemia (Hgb 2g/dL below the lower limit of normal or \<10g/dL);

⁃ Bone lesions (lytic lesions or generalized osteoporosis with compression fractures)

⁃ No evidence of the following new criteria for active MM including the following:

• Bone marrow plasma cells \>60%

∙ Serum involved/uninvolved FLC ratio ≥100

∙ MRI with more than one focal lesion

‣ Participants with CRAB criteria that are attributable to conditions other than the disease under study may be eligible after discussion with the Sponsor Investigator.

• ECOG Performance Status (PS) 0 or 1 (Appendix 8)

• The following laboratory values obtained \< 28 days prior to registration:

‣ ANC \>1000/mL

⁃ PLT \>75,000/mL

⁃ Total bilirubin ≤ 2.0 mg/dL (If total is elevated check direct and if normal patient is eligible.)

⁃ AST \<2.5 x institutional upper limit of normal (ULN)

⁃ ALT \<2.5 x institutional upper limit of normal (ULN)

⁃ Estimated creatinine clearance CrCl ≥60 mL/min (Cockcroft Gault equation).

• Voluntary written informed consent before performance of any study-related procedure not part of normal medical care, with the understanding that consent may be withdrawn by the subject at any time without prejudice to future medical care.

• Women of childbearing potential must have a negative pregnancy test at screening.

‣ When a woman is of childbearing potential, the following are required:

‣ • Subject must agree to practice a highly effective method of contraception (failure rate of \<1% per year when used consistently and correctly) and agree to remain on a highly effective method of contraception from the time of signing the informed consent form (ICF) until 1 year after receiving a cilta-cel infusion. Examples of highly effective contraceptives include:

∙ user-independent methods: 1) implantable progestogen-only hormone contraception associated with inhibition of ovulation; 2) intrauterine device; intrauterine hormone- releasing system; 3) vasectomized partner.

∙ user-dependent methods: 1) combined (estrogen- and progestogen-containing) hormonal contraception associated with inhibition of ovulation: oral or intravaginal or transdermal; 2) progestogen-only hormone contraception associated with inhibition of ovulation (oral or injectable).

⁃ In addition to the highly effective method of contraception, a man:

• Who is sexually active with a woman of childbearing potential must agree to use a barrier method of contraception (eg, condom with spermicidal foam/gel/film/cream/suppository) from the time of signing the ICF until 1 year after receiving a cilta-cel infusion.

∙ Who is sexually active with a woman who is pregnant must use a condom. Women and men must agree not to donate eggs (ova, oocytes) or sperm, respectively, during the study and for 1 year after the last dose of study treatment.

⁃ Note: Hormonal contraception may be susceptible to interaction with the study treatment, which may reduce the efficacy of the contraceptive method.