PRINCETON, N.J., April 5 /PRNewswire-FirstCall/ -- Cytogen Corporation today announced that data from a preclinical study with QUADRAMET(R) (samarium Sm-153 lexidronam injection) was presented at the 97th Annual Meeting of the American Association for Cancer Research (AACR) in Washington, D.C. Preclinical data on QUADRAMET, currently marketed for the relief of pain associated with cancer progression to bone in a variety of tumor types, suggests that a novel method of administration of the product may increase local targeted exposure to the osteosarcoma tumor in a single limb and minimize systemic exposure to radioactivity.
“Because it very specifically targets bone, QUADRAMET is ideally suited for treatment of a disease like osteosarcoma,” said Pete Anderson, M.D., Ph.D., Professor with the University of Texas MD Anderson Cancer Center and one of the authors of the study. “However, because osteosarcoma is sometimes relatively resistant to radiation, the large doses needed to control a tumor can be associated with bone marrow toxicity. This novel administration technique for QUADRAMET appears to facilitate delivery of large doses of radiation to the limb containing the primary tumor while largely sparing the rest of the body.”
Research findings presented in AACR abstract #5194 and in a poster titled “Targeted internal radiotherapy for osteosarcoma: Isolated limb perfusion using a bone seeking radiopharmaceutical (153Sm-EDTMP),” demonstrate that isolated limb perfusion (ILP) can specifically target QUADRAMET to limbs of dogs with spontaneously occurring osteosarcomas. With this technique, limb perfusion using an infant heart-lung oxygenation bypass device was performed for one hour, followed by washout from the circuit prior to re-establishing normal blood flow. Gamma camera imaging and scintigraphy were performed immediately after re-establishing limb blood flow. Quantitative scintigraphy estimates of radioactivity in the tissues of the isolated limb versus the contralateral non-perfused limb were calculated. Isolated limb blood, peripheral blood and urine were analyzed for radioactivity to determine relative gamma counts.
Histopathology showed no damage to muscle or bone of the isolated limb. Function of the limb after the procedure was excellent in all dogs. Gamma camera pictures showed a “bone-only” deposition pattern. Mean systemic blood and urine gamma counts were 0.5 counts per minute, whereas mean gamma counts for the isolated limb blood were 8.3 counts per minute throughout the one hour perfusion. There was 14-fold more QUADRAMET in the isolated limb as compared to the contralateral limb.
The results demonstrate ILP using QUADRAMET can be performed with minimal systemic or local normal tissue toxicity. The effect of ILP using QUADRAMET is currently being assessed in pet dogs with spontaneously occurring osteosarcoma. If successful these studies will provide the basis for future human clinical studies.
“We are encouraged by the data presented by collaborating researchers from Colorado State University and The University of Texas MD Anderson Cancer Center demonstrating that novel administration methods for QUADRAMET could improve tumor targeting and reduce the risk of systemic toxicity in the treatment of osteosarcoma,” stated Michael D. Becker, president and chief executive officer of Cytogen.
About Osteosarcoma
Osteogenic sarcoma, or osteosarcoma, is the most common primary malignancy of the bone in the United States. Osteosarcoma is slightly more common in males than in females. Teenagers are the most commonly affected age group, but it can occur at any age.
About QUADRAMET
QUADRAMET is indicated for the relief of pain in patients with confirmed osteoblastic metastatic bone lesions that enhance on radionuclide bone scan. This press release describes clinical applications that differ from that reported in the QUADRAMET package insert.
QUADRAMET is an oncology product indicated for pain relief that pairs the targeting ability of a small molecule, bone-seeking phosphonate (EDTMP) with the therapeutic potential of radiation (samarium Sm-153). Skeletal invasion by prostate, breast, multiple myeloma, and other cancers often creates an imbalance between the normal process of bone destruction and formation. QUADRAMET selectively targets such sites of imbalance, thereby delivering radioactivity to areas of the skeleton that have been invaded by metastatic tumor.
QUADRAMET has demonstrated a range of characteristics that may be advantageous for the treatment of pain arising from metastatic bone disease, including early onset of pain relief (patients may experience pain relief within the first week with maximal relief generally occurring at three to four weeks after injection), predictable and reversible bone marrow toxicity or myelosuppression that tends to return to pretreatment levels after eight weeks, ease of administration, and length of pain relief, lasting an average of four months in responding patients. QUADRAMET is administered as a single intravenous injection, usually on an outpatient basis, and exhibits selective uptake in areas of bone formation with little or no detectable accumulation in soft tissue.
QUADRAMET Safety Profile
QUADRAMET causes bone marrow suppression. In clinical trials, white blood cell counts and platelet counts decreased to a nadir of approximately 40% to 50% of baseline in 123 (95%) of patients within 3 to 5 weeks after QUADRAMET, and tended to return to pretreatment levels by 8 weeks. Because of the unknown potential for additive effects on bone marrow, QUADRAMET should not be given concurrently with chemotherapy or external beam radiation therapy unless the clinical benefits outweigh the risks. Blood counts should be monitored weekly for at least 8 weeks, or until recovery of adequate bone marrow function. Non-hematologic adverse events that occurred in 5% or more of patients and greater than placebo were plain flare (7%), diarrhea (6%), infection (7%), spinal cord compression (6.5%), arrhythmias (5%), and hematuria (5%). Patients who receive QUADRAMET should be advised that for several hours following administration, radioactivity will be present in excreted urine. To help protect themselves and others in their environment, precautions need to be taken for 12 hours following administration.
A copy of the full prescribing information for QUADRAMET, including warnings, precautions, adverse events and other safety information, may be obtained in the U.S. from Cytogen Corporation by calling toll-free 800-833- 3533 or by visiting the Web site at http://www.cytogen.com , which is not part of this press release.
About Cytogen Corporation
Founded in 1980, Cytogen Corporation of Princeton, NJ is a biopharmaceutical company dedicated to improving the lives of patients with cancer by acquiring, developing and commercializing innovative molecules targeting the sites and stages of cancer progression. Cytogen’s marketed products include QUADRAMET(R) (samarium Sm-153 lexidronam injection) and PROSTASCINT(R) (capromab pendetide) kit for the preparation of Indium In-111 capromab pendetide in the United States. Cytogen also has exclusive United States marketing rights to COMBIDEX(R) (ferumoxtran-10) for all applications, and the exclusive right to market and sell ferumoxytol (previously Code 7228) for oncology applications in the United States. Cytogen’s development pipeline consists of therapeutics targeting prostate-specific membrane antigen (PSMA), a protein highly expressed on the surface of prostate cancer cells and the neovasculature of solid tumors. Full prescribing information for the Company’s products is available at www.cytogen.com or by calling 800-833-3533. For more information, please visit the Company’s website at http://www.cytogen.com , which is not part of this press release.
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Cytogen Corporation
CONTACT: Jonathan Fassberg of The Trout Group for Cytogen Corporation,+1-212-477-9007, ext. 16
Web site: http://www.cytogen.com/
