The study was terminated early due to a strategic realignment of the sponsor's business plan, not related to safety, efficacy, or data integrity concerns.

The purpose of this study is to evaluate the efficacy and safety of LCAR-B38M chimeric antigen receptor T (CAR-T) cells.

Inclusion Criteria:

• Documented initial diagnosis of multiple myeloma according to International Myeloma Working Group (IMWG) diagnostic criteria

• Measurable disease at Screening

• Received at least 3 prior lines of treatment for multiple myeloma

  a) Undergone at least 1 complete cycle of treatment for each line, unless progressive disease (PD) was documented by IMWG criteria as the best response to the regimen

• Received a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD)

• Participant must have documented evidence of progressive disease based on investigator's determination of response consistent with IMWG criteria on or within 12 months of their last regimen. Non-responsive disease is defined as either failure to achieve minimal response or development of progressive disease (PD) while on therapy. Also, participants with documented evidence of PD disease (as above) within the previous 6 months and who are refractory or non-responsive to their most recent line of treatment afterwards are eligible

• Eastern Cooperative Oncology Group (ECOG) Performance Status grade of 0 or 1

Exclusion Criteria:

• Prior treatment with chimeric antigen receptor T (cells) CAR-T therapy directed at any target

• Any therapy that is targeted to B-cell maturation antigen (BCMA)

• The following cardiac conditions: a) New York Heart Association (NYHA) stage III or IV congestive heart failure b) Myocardial infarction or coronary artery bypass graft (CABG) 6 months prior to enrollment c) History of clinically significant ventricular arrhythmia or unexplained syncope, not believed to be vasovagal in nature or due to dehydration d) History of severe non-ischemic cardiomyopathy e) Impaired cardiac function (left ventricular ejection fraction [LVEF] less than [<]45%) as assessed by echocardiogram or multiple-gated acquisition (MUGA) scan (performed less than or equal to (<=) 8 weeks of apheresis)

• Have received a cumulative dose of corticosteroids equivalent to greater than or equal to(>=)70 milligram (mg) of prednisone within 7 days prior to apheresis

• Diagnosed or treated for invasive malignancy other than multiple myeloma, except:

  1. Malignancy treated with curative intent and with no known active disease present for greater than or equal to (>=) 2 years before enrollment; or
  2. Adequately treated non-melanoma skin cancer without evidence of disease

• Prior antitumor therapy with insufficient washout period

• Toxicity from previous anticancer therapy must resolve to baseline levels or to Grade 1 or less except for alopecia or peripheral neuropathy

• Received either of the following:

  1. An allogeneic stem cell transplant for multiple myeloma
  2. An autologous stem cell transplant less than or equal to (<=) 12 weeks before apheresis

• Known active, or prior history of, central nervous system (CNS) involvement or exhibits clinical signs of meningeal involvement of multiple myeloma