Arzneimittelforschung 2012; 62(01): 14-17
DOI: 10.1055/s-0031-1295430
Original Article
© Georg Thieme Verlag KG Stuttgart · New York

IRL-1620, an Endothelin-B Receptor Agonist, Enhanced Radiation Induced Reduction in Tumor Volume in Dalton’s Lymphoma Ascites Tumor Model

A. Gulati
1   Department of Pharmaceutical Sciences, Chicago College of Pharmacy, Midwestern University, USA
E. S. Sunila
2   Department of Immunology, Amala Cancer Research Center, Thrissur, Kerala, India
G. Kuttan
2   Department of Immunology, Amala Cancer Research Center, Thrissur, Kerala, India
› Author Affiliations
Further Information

Publication History

received 20 September 2011

accepted 24 October 2011

Publication Date:
10 January 2012 (online)


ETB receptor agonist, IRL-1620 (or SPI-1620) presently in US Phase 1 clinical trial, has been demonstrated to selectively and transiently increase tumor blood flow. The present study was conducted to determine the effect of IRL-1620 on radiation therapy in tumor bearing mice inoculated with Dalton’s Lymphoma Ascites cells. Tumors were allowed to grow for 30 days to a size of 1.10–1.29 cm3 before starting the treatment. The animals with or without IRL-1620 treatment were exposed to radiation (4 Gy/dose) on every alternate day for a total of 5 doses. Tumor volume was determined twice every week till the end of study. Radiation alone did not affect the tumor volume; however, animals treated with IRL-1620 followed by radiation produced a significant (64%) reduction in tumor volume. Survival of mice improved from 0/10 at 56 days after tumor inoculation in vehicle plus radiation group to 6/10 at 70 days in IRL-1620 (9 nmol/kg) plus radiation group. It is concluded that IRL-1620 improves the efficacy of radiation treatment in tumor bearing mice. (These findings have been earlier presented as an abstract [1]).

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