Inclusion Criteria

- INCLUSION CRITERIA:

- Age greater than or equal to 18 years.

- Diagnosis of metastatic malignant melanoma or metastatic renal cell cancer confirmed
by the Laboratory of Pathology, NCI.

- Patients must have metastatic malignant melanoma or metastatic renal cell cancer
(AJCC stage IV [M1] or equivalent disease). Metastatic renal cell cancer patients
must either have refused treatment with, have been unable to tolerate or have
experienced progressive disease after treatment with sorafenib or sunitinib, and
temsirolimus.

- Patients must have measurable disease.

- DLCO/VA and FEV-1.0 greater than 50% of predicted on pulmonary function tests.

- AST and ALT less than 3 times the upper limit of normal.

- Absolute neutrophil count greater than or equal to 1,500/mm(3).

- Platelets greater than or equal to 75,000/mm(3).

- PT/PTT within 1.5 times upper limit of normal. Patients with a history of DVT and who
are on anticoagulation therapy may be eligible, provided their DVT was at least 8
weeks prior to enrollment and they have had no further complications.

- Karnofsky performance status greater than or equal to 70% (ECOG less than or equal to
1)

- Serum creatinine of less than or equal to 1.5 times the upper limit of normal.

- CNS metastases: Patients who remain asymptomatic after successful definitive
treatment of brain metastases (i.e., surgical resection, curative whole brain
irradiation, stereotactic radiation therapy, or a combination of these) demonstrating
stable or improved radiographic appearance on MRI scan greater than or equal to 3
months after completion of treatment and no signs of cerebral edema are eligible.

EXCLUSION CRITERIA:

- Patients must not have received any systemic corticosteroid therapy for 3 weeks prior
to the start of therapy with the exception of physiological replacement doses of
cortisone acetate or equivalent.

- Patients must not have received any cytotoxic therapy, immunotherapy, antitumor
vaccines or monoclonal antibodies in the 4 weeks prior to the start of the study.

- History of any hematopoietic malignancy.

- Life expectancy of less than 3 months.

- Presence of serum antibodies to IL-15.

- Patients must not have a marked baseline prolongation of QT/QTc interval (e.g.,
demonstration of a QTc interval greater than 500 milliseconds (ms)).

- Documented HIV, active or chronic hepatitis B, hepatitis C or HTLV-I infection.

- A positive hepatitis B serology indicative of previous immunization (i.e., HBsAb
positive and HBc Ab negative), or a fully resolved acute HBV infection is not an
exclusion criterion.

- A positive hepatitis C serology is an exclusion criterion.

- Concurrent anticancer therapy (Including other investigational agents).

- History of severe asthma, presently on chronic medications (a history of mild asthma
not requiring therapy is eligible).

- History of autoimmune disease, with the exception of an autoimmune event associated
with prior ipilimumab (anti-CTLA-4) therapy that has completely resolved for a period
of more than 4 weeks.

- Inability or refusal to practice effective contraception during therapy or the
presence of pregnancy or active breastfeeding (Men and women of childbearing
potential must use an effective method of birth control or abstinence during
treatment and for four months after completion of treatment).

- History of medical or psychiatric disease, active substance abuse or social
circumstances which in the view of the Principal Investigator, would preclude safe
treatment.

- Patients with cognitive impairment or likely to develop cognitive impairment while on
study.

- Inability to give informed consent.