A Safety Study of SGN-CD352A for Patients With Relapsed/Refractory Multiple Myeloma

The study will have 2 parts. In the first part, different doses of SGN-CD352A will be given
to different patients (each individual patient will get the same dose for all treatments).
The doses will be very low at the start of the trial, and will increase only when the lower
dose levels are proven safe.

In the second part of the study, up to 2 dose levels that are both safe and show promising
activity against MM will be given to more patients

Inclusion Criteria:

- Diagnosis of MM requiring systemic therapy (per the International Myeloma Working
Group [IMWG] ).

- Age 18 years or older.

- An Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1.

- Life expectancy greater than 3 months.

- Received at least 2 prior lines of therapy for MM including an immunomodulatory drug
and a proteasome inhibitor.

- Measurable disease, as defined by at least one of the following: Serum M protein 0.5
g/dL or higher, Urine M protein 200 mg/24 hr or higher, Serum free light chain (SFLC)
10 mg/dL or higher, and Abnormal SFLC ratio.

- Adequate hematologic, renal, and hepatic function

- A negative pregnancy test (for females of childbearing potential).

- Patients must provide written informed consent.

Exclusion Criteria:

- Other invasive malignancy within the past 3 years.

- Active cerebral/meningeal disease related to the underlying malignancy.

- Active Grade 3 or higher infection.

- Known to be positive for HIV or known to have active hepatitis B or C.

- Previous allogeneic stem cell transplant.

- Idiopathic interstitial pneumonia or impaired diffusion capacity of the lung for
carbon monoxide (DLCO).

- Cerebrovascular or cardiovascular event, or congestive heart failure within the last 6
months.

- Females who are pregnant or breastfeeding.