Extension Study of EC145 (Vintafolide) for Subjects Enrolled in a Previous Study With EC145 (MK-8109-010)

Inclusion Criteria: * Must have received prior treatment with EC145 within the context of an Endocyte-sponsored, IRB-approved clinical trial. * Disease (i.e., cancer) that was considered "stable" at the last evaluation while participating in the previous EC145-containing study. "Stable" is defined as not having progression of disease per standard criteria (RECIST, etc). Stable disease may be indicated by previously attained complete or partial tumor shrinkage that has not progressed per standard criteria. * No more than 10 weeks have elapsed since the last evaluation of "stable disease". * Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 * Must have recovered (to baseline/stabilization) from prior EC145-associated acute toxicities. * Adequate bone marrow reserve, hepatic, and renal function. * Negative serum pregnancy test for women of childbearing potential * Willingness to practice contraceptive methods for men and women of childbearing potential. Exclusion Criteria: * Pregnancy. * Development of a secondary malignancy requiring treatment. * Symptomatic central nervous system (CNS) metastasis. * History of receiving any investigational treatment or other systemic therapy directed at controlling cancer since the subject's last dose on the parent EC145 study.