Systemic therapy of myeloma xenografts by an attenuated measles virus

Conditionally replicating viruses are promising agents for the treatment of malignancy. Here It Is shown that the live attenuated Edmonston-B vaccine strain of measles virus (MV-Edm) replicates selectively In human myeloma ce lls and has potent antitumor activity. In vitro, replication of MV-Edm was restricted in phytohemagglutinin (PHA)-stimulated peripheral blood lymphocy tes (PBLs) but proceeded efficiently in a panel of 6 myeloma cell lines-ARH -77, RPMI 8226, JJN-3, MM1, KAS-6/1, and KMS-11-and In primary myeloma cell s isolated by CD138 sorting from the bone marrow aspirates of 6 patients. M V-Edm infection Induced potent cytopathic effects in these myeloma cells, r esulting in the formation of multinucleated syncytia that eventually became nonviable. In contrast, syncytial formation in PHA-stimulated PBLs was min imal after MV-Edm infection. In vivo, MV-Edm was antitumorigenic and Inhibi ted the establishment of myeloma cells as xenografts in immunocompromised m ice. When Injected directly into ARH-77 myeloma xenografts in the mice, MV- Edm caused complete regression of these xenografts. MV-Edm administered int ravenously Into the tail veins of mice also showed significant antineoplast ic activity against established RPMI 8226 and ARH-77 xenografts. In particu lar, the ARH-77 myeloma xenografts were exquisitely sensitive to MV-Edm the rapy, and tumors In all mice regressed completely. In light of its selectiv ity for myeloma cells and its potent antineoplastic activity against myelom a xenografts; in vivo, MV-Edm merits further development for the treatment of multiple myeloma. (C) 2001 by The American Society of Hematology.