A Study to Evaluate the Safety of bb2121 in Subjects With High Risk, Newly Diagnosed Multiple Myeloma (NDMM)

Inclusion Criteria:

Subjects must satisfy all of the following criteria to be enrolled in the study:

1. Subject is newly diagnosed and has symptomatic Multiple Myeloma (MM) prior to initiating induction anti-myeloma therapy
2. Subject is ≥ 18 years of age at the time of initial diagnosis of MM
3. Subject has measurable disease at initial diagnosis by

   * M-protein and/or
   * Light chain MM without measurable disease in the serum or urine
4. Subject has high-risk MM at the time of initial diagnosis of MM per R-ISS Stage III as defined by IMWG:

   * ISS Stage III and cytogenetic abnormalities with t(4; 14) and/or del(17p); and/or t(14:16) by iFISH; or;
   * ISS Stage III and serum LDH \> ULN
5. Subject has Eastern Cooperative Oncology Group performance ≤ 1
6. Subjects has received ≤ to 3 cycles of the following induction anti-myeloma therapy prior to enrollment:

   * Cycle 1: one of the following regimens (RVd, KRd, CyBorD, D-RVd and D-KRd)
   * Cycle 2 to Cycle 3: either KRd or RVd (Cycle 3 must be without dexamethasone)

Exclusion Criteria:

The presence of any of the following will exclude a subject from enrollment: The presence of any of the following will exclude a subject from enrollment:

At initial diagnosis, screening and prior to initiation of induction therapy for MM:

1. Subject has non-secretory MM

   During Screening:
2. Subject received any treatments for MM other than up to 3 cycles of induction therapy per protocol
3. Subject has any of the following laboratory abnormalities:

   1. Absolute neutrophil count \< 1,000/μL
   2. Platelet count \< 50,000 mm3
   3. Hemoglobin \< 8 g/dL (\< 4.9 mmol/L)
   4. Serum creatinine clearance \< 45 mL/min
   5. Corrected serum calcium \> 13.5 mg/dL (\> 3.4 mmol/L)
   6. Serum aspartate aminotransferase or alanine aminotransferase \> 2.5 × upper limit of normal
   7. Serum total bilirubin \> 1.5 × ULN or \> 3.0 mg/dL for subjects with documented Gilbert's syndrome
   8. INR or aPTT \> 1.5 × ULN
4. Subject has history or presence of clinically significant CNS pathology
5. Subjects has high risk for developing deep vein thrombosis or pulmonary embolus and are unable or unwilling to undergo anti-thrombotic therapy
6. Subject has peripheral neuropathy of \> Grade 2 severity according to the NCI CTCAE Version 4.03 with bortezomib based induction regimen
7. Subjects has moderate or severe pulmonary hypertension
8. Subject has intolerance to components of induction regimen (KRd or RVd) or has any contraindication to one or the other drug
9. Subject has not recovered from induction therapy-related toxicities (non-hematologic) to \< grade 1 CTCAE at the time of screening
10. Subject has prior history of deep vein thrombosis or pulmonary embolus (PE) within 6 months of starting study treatment
11. Subject has cardiac conditions such as:

    1. Echocardiogram or multi gated acquisition assessment of left ventricular ejection fraction \< 45%
    2. Subject has a history of clinically significant cardiovascular disease or clinically significant ECG abnormalities
12. Subject has Pulmonary conditions such as:

    1. Subject has known chronic obstructive pulmonary with a forced expiratory vol in 1 sec 50% of predicted normal.
    2. Inadequate pulmonary function defined as oxygen saturation \< 92 % on room air
13. Subject needs ongoing treatment with chronic immunosuppressants
14. Subject has history of primary immunodeficiency
15. Subject is seropositive for human immunodeficiency virus, chronic or active hepatitis B or active hepatitis A or C