News is expected on Monday!!!
90Y-radiogel was designed to provide the highest possible
therapeutic index for treating nonresectable or radiationresistant solid tumors in vivo. PET/CT imaging showed that 90Y-radiogel could be administered without significant outmigration of 90Y-particles to normal organs and tissues. PET/CT confirmed that injected 90Y(YPO4) particles perfused tumor tissue in a manner that provided a homogenous
radiation dose to most of the tumor mass. The authors’ experience confirmed that 90Y-radiogel can be prepared and administered safely for therapy of nonresectable solid tumors in man and animals, including deeply seated tumors accessible via needle as well as tumors at or near skin surfaces. Feline vaccine-associated sarcoma and canine softtissue sarcoma serve as excellent models for testing 90Yradiogel properties, safety, and clinical efficacy. Microscopic extension of sarcomas or metastatic migration into surrounding tissues may limit this model, as the therapy is mainly designed to treat gross disease; microscopic disease extension was likely the reason for edge-of-field recurrence
in the first dog, which was later retreated.
Performance of the 90Y-radiogel met or exceeded design
expectations. After injection, the 90Y- hydrogel composite
solution gelled within interstitial spaces upon reaching body
temperatures to contain the 90Y activity intratumorally. 90Yphosphate particles remained in treated tumor tissue through
complete decay without migrating vascularly to any normal
organ or tissue Treated cats and dogs experienced no radiation-related
illness associated with interstitially placed 90Y-radiogel
therapy. The authors observed no adverse tissue reactions in
any adjacent or distal normal organ or tissue beyond adjacent skin. With subcutaneous tumor tissue receiving an
absorbed dose of about 320 Gy or less, they observed only
mild skin erythema (reddening) with tumors in close contact
with skin, and minor skin irritation in a few cases, partly due
to brief surface contamination (easily removed with an alcohol wipe). In one dog, the draining tract healed completely within 6 weeks. In another dog, the nonhealing
wound persisted for 4 months, after which surgical debulking was advised.
As seen on histopathology, tumor tissues responded well
to treatment, with strong evidence of tumor cell killing associated with localized radiation dose. Animal subjects recovered quickly from the injection procedure. With uniform
placement at high dose, the authors achieved complete remission or stable disease (at 1–2 months posttreatment).
These results confirm the substantial opportunity for using
90Y-polymer composite (radiogel) to treat solid tumors in
both human and veterinary patients.
