A Phase 1b-2, Open-Label Study of JNJ-68284528, a Chimeric Antigen Receptor T-Cell (CAR-T) Therapy Directed Against BCMA in Subjects with Relapsed or Refractory Multiple Myeloma

The purpose of the study is to characterize safety of JNJ-68284528 and establish the
recommended Phase 2 dose (RP2D) (Phase 1b) and to evaluate the efficacy of JNJ-68284528
(Phase 2).

Inclusion Criteria:

- Have documented diagnosis of multiple myeloma according to International Myeloma
Working Group (IMWG) diagnostic criteria

- Have measurable disease at Screening as defined by any of the following a) Serum
monoclonal paraprotein (M-protein) level more than or equal to (>=) 1.0 gram per
deciliter(g/dL) or urine M-protein level >=200 milligram per 24 hours (mg/24hr); or b)
Light chain multiple myeloma without measurable disease in the serum or the urine:
Serum immunoglobulin free light chain 10 mg/dL and abnormal serum immunoglobulin kappa
lambda free light chain ratio

- Have received at least 3 prior multiple myeloma treatment lines of therapy or are
double refractory to an immunomodulatory drug (IMiD) and proteasome inhibitor (PI)
(refractory multiple myeloma as defined by IMWG consensus criteria). Note: induction
with or without hematopoietic stem cell transplant and with or without maintenance
therapy is considered a single lines of therapy a) Undergone at least 1 complete cycle
of treatment for each line of therapy, unless progressive disease (PD) was the best
response to the regimen

- Have received as part of previous therapy a PI, an IMiD, and an anti-CD38 antibody

- Participant must have documented evidence of progressive disease based on
investigator's determination of response by the IMWG criteria on or within 12 months
of their last line of therapy. Confirmation may be from either central or local
testing. Also, participants with documented evidence of progressive disease (as above)
within the previous 6 months and who are refractory or non-responsive to their most
recent line of therapy afterwards are eligible

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

Exclusion Criteria:

- Have received prior treatment with chimeric antigen receptor T (CAR-T) therapy
directed at any target

- Have received any therapy that is targeted to B-cell maturation antigen (BCMA)

- Have 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) less than or equal to (<=) 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)

- Received a cumulative dose of corticosteroids equivalent to >= 70 mg of prednisone
within the 7 days prior to apheresis

- Have received either of the following: a) An allogenic stem cell transplant within 6
months before apheresis. Participants who received an allogeneic transplant must be
off all immunosuppressive medications for 6 weeks without signs of graft-versus-host
disease (GVHD) b) An autologous stem cell transplant less than or equal to (<=) 12
weeks before apheresis

- Have known active, or prior history of central nervous system (CNS) involvement or
exhibits clinical signs of meningeal involvement of multiple myeloma