Study of Dalantercept and Axitinib in Patients With Advanced Renal Cell Carcinoma

Key Inclusion Criteria:

- Histologically confirmed, advanced, predominantly clear cell renal cell carcinoma
(RCC).

- Part 1: Progression of disease following up to three lines of prior therapy, including
at least one approved VEGF receptor tyrosine kinase inhibitor for RCC. Adjuvant
therapy is permitted as one line of prior therapy.

- Part 2: Progression of disease following one VEGF pathway inhibitor for RCC (e.g.
sunitinib, pazopanib, sorafenib, bevacizumab, tivozanib, or cabozantinib) inclusive of
adjuvant therapy if there was documented disease progression during treatment.
Patients may have received one additional line of an approved mTOR kinase inhibitor
(e.g. everolimus, temsirolimus). Prior exposure to investigational and/or approved
anticancer immune therapies is permitted.

- A minimum of 1 week since the last dose of prior therapy (a minimum of 4 weeks since
anticancer immune therapy or bevacizumab +/- interferon).

- Measurable disease that is evaluable by Response Evaluation Criteria in Solid Tumors
(RECIST) v1.1.

- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.

- Life expectancy of at least 12 weeks.

- Clinical laboratory values within acceptable ranges within 72 hours prior to study day
1.

Key Exclusion Criteria:

- Clinically significant organ/system disease unrelated to RCC that in the judgment of
the investigator should preclude treatment with dalantercept or axitinib.

- Clinically significant cardiovascular risk.

- Known CNS metastases or leptomeningeal disease:

For Part 1, patients with CNS metastases treated with whole brain radiotherapy, gamma
knife, and/or surgery who are considered stable by CNS imaging and are not being treated
with corticosteroids 6 weeks prior to study day 1 may be enrolled.

For Part 2, patients with CNS metastases treated stereotactic radio-surgery (SRS), and/or
surgery who are considered stable by CNS imaging for at least 2 months prior to enrollment
and are not being treated with corticosteroids 6 weeks prior to study day 1 may be
enrolled.

- Any active malignancy, other than RCC, for which chemotherapy or other anti-cancer
therapy is indicated. Patients with adequately treated non-melanoma skin cancer, in
situ cancer, or other cancer from which the subject has been disease-free for at least
3 years will be permitted.

- Any lesion invading or having encasement ≥ 180 degrees around the wall of a major
blood vessel as assessed by computed tomography (CT) scan and/or magnetic resonance
imaging (MRI).

- Radiotherapy within 2 weeks prior to study day 1.

- Lack of recovery from toxic effects of previous treatment for RCC ≤ grade 1 with the
exception of alopecia, unless stabilized under adequate medical control.

- Patients undergoing renal dialysis.

- Major surgery within 4 weeks prior to study day 1 (patients must have recovered
completely from any previous surgery prior to study day 1).

- Any active infection requiring antibiotic therapy within 2 weeks of study day 1.

- Anti-coagulation therapy. Aspirin, other anti-platelet agents, and low molecular
weight heparin are permitted unless the investigator deems the patient is at a
significant risk for bleeding.

- Current use or anticipated inability to avoid potent CYP3A4/5 inhibitors or inducers
(please refer to the Inlyta® [axitinib] prescribing information) during participation
in the study.

- Peripheral edema requiring medical intervention within 2 weeks prior to study day 1.

- Bleeding diathesis including clinically significant platelet disorders or active
hemoptysis (defined as bright red blood of ≥ 1/2 teaspoon [2.5 mL] in any 24 hour
period) within 6 months prior to study day 1. For clinically significant epistaxis
within 4 weeks prior to study day 1, no risk of further bleeding must be clearly
documented.

- Known history of hereditary hemorrhagic telangiectasia (HHT).

- Known active hepatitis B virus (HBV) or hepatitis C virus (HCV) infections or positive
human immunodeficiency virus (HIV) antibody results. Patients with sustained virologic
response to HCV treatment or immunity to HBV from prior infection without cirrhosis
may be included.

- History of severe (defined as ≥ grade 3, using the National Cancer Institute Common
Toxicity Criteria for Adverse Events, version 4.0 [NCI-CTCAE] v4 current active minor
version) allergic or anaphylactic reaction or hypersensitivity to recombinant proteins
or excipients (10 mM Tris buffered saline) in the investigational agent.

- Any prior treatment with dalantercept or any other agent targeting ALK1 pathway.

- Any prior treatment with axitinib.

- A morbidity (per the prescribing information) that would require starting a patient at
a reduced dose of axitinib.

- Treatment with another investigational drug (with the exception of anticancer immune
therapy) or device, or approved therapy for investigational use, within 5 times the
half-life of the drug or within 3 weeks prior to study day 1 if the half life is not
known.

- Pregnant or lactating female patients.