Cytogen Corporation, an oncology-focused biopharmaceutical company, has announced the presentation of new data relating to its lead therapeutic product Quadramet (samarium Sm-153 lexidronam injection) during the 36th Congress of the International Society of Paediatric Oncology (SIOP).

The data were reported by independent investigators at the Mayo Clinic who are evaluating the use of high dose Quadramet in conjunction with chemotherapy for the treatment of acute myeloid leukaemia (AML).

"While Quadramet is currently available as a non-opioid alternative for rapid and long-acting pain relief from metastatic bone disease associated with various cancers, the investigational data presented further demonstrate how Quadramet's novel mechanism of action may enhance anticancer activity when used in combination with melphalan and other therapeutic agents," Michael D Becker, Cytogen's president and CEO said adding, "Supplemented by both ongoing and additional clinical studies, we believe that Quadramet could prove to be an important bone-seeking therapy for cancer patients."

Four high-risk AML patients (age range 15 to 20 years) received a significantly higher dose of Quadramet than used for palliative indications prior to preparative chemotherapy conditioning regimens with melphalan (n = 3) or busulfan/cyclophosphamide (n = 1) and hematopoietic stem cell transplantation. High-risk features included secondary AML and a chromosomal defect known as monosomy 7 (n = 1), chemotherapy induction failure (n = 1), and AML in relapse (n = 2). The dose of Quadramet administered to the patients was 19 mCi/kg (n = 1) and 30 mCi/kg (n = 3), compared to the approved 1 mCi/kg dose used in the palliative setting.

"As a result of its highly specific targeting to bone, Quadramet provides a novel method for delivering radiation, and our results in AML patients indicates that, even at much higher doses than are typically administered, the treatment was well tolerated," said Peter Anderson, a paediatric oncologist at the Mayo Clinic and lead investigator in the study. He added, "Moreover, the positive clinical responses observed in this group of high-risk patients indicate that further evaluation of this therapeutic approach is warranted."

"The group at the Mayo Clinic has pioneered investigations into the use of high dose Quadramet in the treatment of hematologic malignancies," said William Goeckeler, senior vice president of Operations at Cytogen. "These results are exciting not only for the positive clinical responses reported but also because they add to the growing body of data on the lack of renal and other non-hematologic toxicity associated with the use of these very high doses of Quadramet," he concluded.