There were many tests. For the one that showed a 72% tumor regression result, approximately 15 rats were in each of 6 treatment groups ( 3 concentrations of Targretin, 2 concentrations of Tamoxifen, and a control). The 72% at the highest Targretin concentration refers to the effect on the primary tumor. For 10, 30 and 100 mg of Targretin, the complete regression frequencies were 10%, 28%, and 72%. For 150 and 800 ug of Tamoxifen, the frequencies were 7% and 33%. For the control group the frequency was 0%. In addition to the complete regression (tumors disappeared), additional primary tumors showed a partial regression. These numbers were taken after 6 weeks of treatment. At the highest concentrations, Targretin cause complete regression of all tumors in 46% of the animals compared to 20% for Tamoxifen treated rats. Most of the rats had secondary tumors.
This was not a clinical trial. All of the rats were treated by Ligand scientists. The 72.2% was a complete response. Another 16.7% showed a partial response. 11.1% of the tumors continued to progress. For Tamoxifen, the numbers (for the highest concentration) were 33.3% complete regression, 33.3% partial regression, 4.8% static, and 28.6% progressed. |
