A Study of JNJ-68284528, a Chimeric Antigen Receptor T Cell (CAR-T) Therapy Directed Against B-Cell Maturation Antigen (BCMA) in Participants With Relapsed or Refractory Multiple Myeloma

This study will evaluate the safety and efficacy of JNJ-68284528. The study will include two
phases. In Phase1b the study will enroll adults with multiple myeloma with interval
assessments for potential dose escalation or de-escalation in subsequent participants. The
dose selected at the completion of phase 1b will be used in Phase 2. Following consent,
enrolled participants will undergo an apheresis procedure to collect cells for manufacture of
investigational drug product (JNJ-68284528). Following manufacture of the drug product,
participants will undergo lymphodepletion prior to infusion of JNJ-68284528. Participants
will be followed for at least 2 years after study drug infusion, with long-term 15 year
follow-up on a separate study. The study will evaluate safety, biomarkers,
pharmacokinetic/pharmacodynamic evaluations and efficacy.

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 regimens 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 regimen a) Undergone at least 1 complete cycle of
treatment for each regimen, 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

- Have documented disease progression within 12 months of starting the most recent
anti-myeloma therapy

- 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) 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 8 weeks of
apheresis)

- Have systemic corticosteroid therapy of greater than 5 mg/day of prednisone (or
equivalent dose of another corticosteroid) within 2 weeks 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 12 weeks before apheresis

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