Therapeutic Potential of Sc-47 in Comparison to Lu-177 and Y-90: Preclinical Investigations

• Targeted radionuclide therapy with Lu-177- and Y-90-labeled radioconjugates is a clinically-established treatment modality for metastasized cancer. Sc-47 is a therapeutic radionuclide that decays with a half-life of 3.35 days and emits medium-energy beta(-)particles. In this study, Sc-47 was investigated, in combination with a DOTA-folate conjugate, and compared to the therapeutic properties of Lu-17-folate and Y-90-folate, respectively. In vitro, Sc-47-folate demonstrated effective reduction of folate receptor-positive ovarian tumor cell viability similar to Lu-177-folate, but Y-90-folate was more potent at equal activities due to the higher energy of emitted beta(-)particles. Comparable tumor growth inhibition was observed in mice that obtained the same estimated absorbed tumor dose (similar to 21 Gy) when treated with Sc-47-folate (12.5 MBq), Lu-177-folate (10 MBq), and Y-90-folate (5 MBq), respectively. The treatment resulted in increased median survival of 39, 43, and 41 days, respectively, as compared to 26 days in untreated controls. There were no statistically significant differences among the therapeutic effects observed in treated groups. Histological assessment revealed no severe side effects two weeks after application of the radiofolates, even at double the activity used for therapy. Based on the decay properties and our results, Sc-47 is likely to be comparable to Lu-177 when employed for targeted radionuclide therapy. It may, therefore, have potential for clinical translation and be of particular interest in tandem with Sc-44 or Sc-43 as a diagnostic match, enabling the realization of radiotheragnostics in future.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Radiologi och bildbehandling (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Radiology, Nuclear Medicine and Medical Imaging (hsv//eng)

Keyword

Sc-47

Lu-177

Y-90

radionuclide therapy

SPECT

folate receptor

DOTA-folate

IGROV-1 tumor

receptor radionuclide therapy

tumor-therapy

in-vitro

vivo

y-90-dotatoc

toxicity

growth

beta

Pharmacology & Pharmacy

Publication and Content Type

ref (subject category)

art (subject category)