This will include all prescription drugs, herbal products, vitamins, minerals, and over-the-counter (OTC) medications. Any changes in concomitant medications also will be recorded in the subject’s eCRF. Any concomitant medication deemed necessary for the welfare of the subject during the study may be given at the discretion of the inve stigator, including palliative radiation. Blood transfusions are allowed at any time during the study, except to meet eligibility criteria. x Antineoplastic systemic chemotherapy or biological therapy is prohibited. x Systemic corticosteroids are prohibited for any purpose other than to treat symptoms from an event of clinical interest of su spected immunologic etiology. The use of physiologic doses of corticosteroids may be approved after consultation with the investigator. If in the interest of safety, the investigator must treat the subject immediately. x ,QKDOHGRUWRSLFDOVWHURLGVDQGD GUHQDOUHSODFHPHQWVWHURLGGR VHV 10 mg daily prednisone equivalent, are permitted in the absence of active autoimmune disease. x Subjects already taking erythropoietin at the time of screening for the study may continue, provided they have be en taking it for more than one month at the time study treatment is started. Prophylac tic erythropoietin should not be started during screening or the first two weeks of study treatment but may be started thereafter. x Granulocyte colony stimulating factors should not be used prophylactically during the first two weeks of study treatment. Use of prophylactic colony stimulating factors may be considered thereafter following discussion with the investigator. x Live vaccines within 30 days prior to the first dose of NCI-4650 and while participating in the study are prohibited. Examples of liv e vaccines include but are not limited to the following: measles, mumps, rubella, chic ken pox, yellow fever, rabies, Bacillus Calmette-Guérin, and typhoid (o ral) vaccine. Seasonal influe nza vaccines for injection are generally killed virus vaccines and are allowed. However, intranasal influenza vaccines (e.g., FluMist ®) are live attenuated vaccines, and are prohibited. x Radiation therapy to a symptomatic solitary lesion or to the brain may be considered on an exceptional case-by-case basis after docum ented consultation with the investigator. The subject must have clear measurable disease outside the radiated field. Administration of palliative radiation therapy will be considered clinical progression. Subjects who, in the assessment by the investigator , require the use of any of the aforementioned treatments for clinical management should be removed from the trial.