Combination of Vandetanib, Radiotherapy, and Irinotecan in the LoVo Human Colorectal Cancer Xenograft Model

Phyllis Wachsberger, Randy Burd, Anderson Ryan, Constantine Daskalakis, Adam P. Dicker

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Purpose: The tumor growth kinetics of the human LoVo colorectal xenograft model was assessed in response to vandetanib, an orally available receptor tyrosine kinase inhibitor, radiotherapy (RT), or irinotecan (CPT-11), as single therapies and in combination. Methods and Materials: LoVo cells were injected subcutaneously into the right hind limb (5×106 cells in 100μL phosphate-buffered saline) of athymic NCR NUM mice and tumors were grown to a volume of 200-300 mm3 before treatment. Vandetanib was administered at 50 mg/kg daily orally for 14 days starting on Day 1. RT was given as three fractions (3×3 Gy) on Days 1, 2, and 3. CPT-11 was given at 15 mg/kg intraperitoneally on Days 1 and 3. Tumor volumes were measured on a daily basis and calculated by measuring tumor diameters with digital calipers in two orthogonal dimensions. Results: All three single treatments (vandetanib, CPT-11, and radiation) significantly slowed LoVo colorectal tumor growth. Vandetanib significantly increased the antitumor effects of CPT-11 and radiation when given in combination with either of these treatments. These treatment combinations resulted in a slow tumor growth rate during the 2 weeks of vandetanib administration. The triple combination of vandetanib, CPT-11, and radiation produced the most marked improvement in response as observed by measurable shrinkage of tumors during the first week of treatment. Conclusions: The tumor growth delay kinetics observed in this study of the LoVo colorectal model suggest concurrent and sustained post-sequencing of vandetanib with cytotoxic therapy may be beneficial in tumors of this type.

Original languageEnglish (US)
Pages (from-to)854-861
Number of pages8
JournalInternational Journal of Radiation Oncology Biology Physics
Issue number3
StatePublished - Nov 1 2009


  • Angiogenesis inhibitor
  • CPT-11
  • LoVo colorectal cancer
  • Radiotherapy
  • Vandetanib

ASJC Scopus subject areas

  • Radiation
  • Oncology
  • Radiology Nuclear Medicine and imaging
  • Cancer Research


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