Valorphin (Valorphin TFAsalt) has opioid analgesic activity, binds to rat mu-opioid receptor, with an IC50 of 14 nM.

μ opioid:14 nM

In vivo model (female BLRB mice with subcutaneously inoculated syngeneic mammary carcinoma), simultaneous treatment with 25 mg/m(2) epirubicin and 1 mg/kg valorphin resulted in 42% of tumor growth inhibition, as compared with the negative control group and 22% inhibition as compared with the epirubcin-treated group (at 20th day of treatment). Survival was significantly improved (69% compared to 39% in the group treated with epirubicin only) at day 26 after the treatment beginning[1].

49 mice were randomized in 4 groups: two groups (12 animals each) corresponding to the negative control, the reference group (13 animals) and the experimental group (12 animals). The control and the reference group were treated as in preliminary experiment, the experimental group were injected with the mixture of valorphin (1 mg/kg) and epirubicin (25 mg/m^2), dissolved in 0.9% NaCl solution in distilled water. Three injections (volume 0.2 ml) were made with 6-day intervals. Since no reliable difference in tumor size or lifespan of animals in the two negative control groups were observed, the data obtained in these groups were pooled. At day 20 after the first injection, the size of the tumors were determined as described above. Tumor volumes were calculated using for- mula, inhibition of tumor growth was determined using formula . Percentages of survival were determined for 1-26 days of treatment. The observation was quitted after the total death of the animals in the negative control group[1].