Inclusion Criteria:

- Relapsed or refractory Multiple Myeloma (MM)

a. Treated with at least 1 prior regimen for myeloma

1. Prior treatment with bortezomib (Velcade) is acceptable with a wash-out of 2
weeks

2. Treatment with prior autologous transplant is permitted

3. If a transplant is used as consolidation following chemotherapy, without
intervening disease progression, it will be considered 1 line of treatment with
the preceding chemotherapy

- Diagnosis of symptomatic MM as defined by the International Myeloma Working Group
(IMWG) :

1. Second line or greater/Refractory/Relapsed, Stage I, Stage II, Stage III

2. Measureable disease as indicated by monoclonal protein in the serum of greater
than or equal to (≥) 1 grams per deciliter (g/dL), monoclonal light chain in the
urine protein electrophoresis of ≥ 200 mg/24 hours, or measurable plasmacytoma

- At least 1 osteolytic bone lesion

- Disease-free of active second/secondary or prior malignancies for equal to or over 5
years with the exception of currently treated basal cell, squamous cell carcinoma of
the skin, or carcinoma "in-situ" of the cervix or breast

- Ambulatory patients greater than or equal to (≥) 30 years of age

- Performance status of 0 or 1 on the Eastern Cooperative Oncology Group (ECOG) scale

- Estimated life expectancy of ≥ 26 weeks

- Adequate organ function including:

1. Hematologic:

1. Absolute neutrophil count (ANC) greater than or equal to (≥)
1000/microliter

2. Platelet (PLT) count ≥ 75,000/microliter

3. Hemoglobin (Hgb) ≥ 8.0 g/dL

2. Acceptable coagulation status:

1. Prothrombin time (PT) and partial thromboplastin time (PTT) ≤ 1.2 x the
upper limit of normal (ULN)

2. International normalized ratio (INR) less than or equal to (≤) 1.6 (unless
receiving anticoagulation therapy)

- If receiving warfarin: INR ≤ 3.0 (and no active bleeding, [i.e., no
bleeding within 14 days prior to first dose of study therapy])

3. Hepatic:

1. Bilirubin ≤ 1.5 x ULN

2. Alanine Transaminase (ALT) and Aspartate Transaminase (AST) ≤ 2.5 x ULN (if
liver metastases are present, then ≤ 5 x ULN is allowed)

3. Creatinine ≤ 1.5 x ULN, and/or a calculated creatinine clearance ≥ 45 mL
using the Cockcroft and Gault Method

- Women of childbearing potential (WCBP) must have a negative serum or urine pregnancy
test within 10 to 14 days and again within 24 hours of starting study drug

1. WCBP must agree to have pregnancy tests monthly (every 14 days for women with
irregular cycles) while on study drug and 4 weeks after the last dose of study
drug

2. Men must also agree to use a condom if their partner is of child bearing
potential, even if they have had a successful vasectomy

3. Males and females with reproductive potential must agree to use medically
approved contraceptive precautions starting 4 weeks prior to initiation of the
therapy and during the trial and for 18 months following the last dose of study
drug

4. Should a woman become pregnant or suspect she is pregnant while participating in
this study, she should inform her treating physician immediately

- Provide written informed consent prior to any study-specific procedures

- Are reliable and willing to make themselves available for the duration of the study
and are willing to follow study procedures

Exclusion Criteria:

- Received treatment with an investigational drug, which has not received regulatory
approval for any indication, within 28 days of study treatment with DKN-01

- Received any experimental non-drug therapy (e.g., donor leukocyte/mononuclear cell
infusions) within 56 days of entry

- Previously treated with an anti-Dickkopf-1 (anti-DKK-1) or antibody therapy, or have
had a significant allergy to a known pharmaceutical therapy that, in the opinion of
the Investigator, poses an increased risk to the patient

- Received radiation therapy, surgery, or chemotherapy within 2 weeks prior to study
entry (6 weeks for nitrosoureas or Mitomycin C)

- Received bisphosphonates (e.g., etidronate, clodronate, tiludronate, pamidronate,
neridronate, olpadronate, alendronate, ibandronate, risedronate, zoledronate) within
2 weeks prior to study entry

- Symptomatic central nervous system (CNS) malignancy or metastasis. Patients with
treated CNS metastases are eligible provided their disease is radiographically
stable, asymptomatic, and they are not currently receiving corticosteroids and/or
anticonvulsants. Screening of asymptomatic patients without a history of CNS
metastases is not required

- Have a history of major organ transplant (for example: heart, lungs, liver, and
kidney)

- Are pregnant or nursing

- Known to be human immunodeficiency virus (HIV) positive, have hepatitis B surface
antigen (HBSAg), or hepatitis C antibodies (HCAb)

- Active, uncontrolled bacterial, viral, or fungal infections, including urinary tract
infection, within 7 days of study entry requiring systemic therapy

- Serious cardiac condition such as myocardial infarction within the past 6 months,
unstable angina, or Class III or IV congestive heart failure as defined by the New
York Heart Association (NYHA); have ECG abnormalities including baseline 12-lead ECG
with Fridericia-corrected QT interval (QTcF) > 470 msec (female) or > 450 msec
(male), a history of congenital long QT syndrome, or any ECG abnormality that, in the
opinion of the Investigator, would preclude safe participation in the study

- History of osteonecrosis of the hip or have evidence of structural bone abnormalities
in the proximal femur on MRI scan that are considered clinically significant or may
have an impact on the interpretation of the scan. Degenerative changes of the hip
joint are not exclusionary

- Known concomitant disease(s) known to influence calcium metabolism including
hyperparathyroidism, hyperthyroidism, Paget's disease of bone, or any other
concurrent severe or uncontrolled concomitant medical condition that, in the opinion
of the Investigator, would preclude participation in this study

- Patients who are currently receiving lithium chloride (LiCl)