A preclinical survey on the efficacy of NSC-290205 in combination with doxorubicin (ADR) in Lewis lung carcinoma (LLC)

Abstract

17131 Background: NSC-290205 (A) is a hybrid synthetic antitumor ester, which combines a D-lactam derivative of androsterone and nitrogen mustard. Studies on modified steroidal esters of carboxylic derivatives of N,N-bis(2-chloroethyl)aniline, have shown that they exhibit reduced toxicity and increased antitumor activity and specificity. In this study we investigated the antitumor activity of compound A in combination with ADR (AHOP) in comparison with standard CHOP regimen. Methods: C57Bl mice were used for the antitumor evaluation of AHOP/CHOP. Experiments were initiated by implanting the tumor. LLC cells (purchased by NCI, Bethesda, USA) were implanted intramuscularly into the right hind leg as a suspension of 7 × 106 cells in 0.1 ml. The antitumor activity was assessed from the inhibition of tumor growth by volume in cm3 and the oncostatic parameter T/C % according to the protocol of experimental evaluation of antitumor drugs of the NCI, USA. Treatments were given as a single dose (D) on day 1, intermitted dose (D/2 × 3) on days 1, 5, 9 or consecutive dose (D/4 × 9) on days 1 through 9. Results: Treatment with A or cyclophosphamide produced almost equal borderline activity. Moreover, both CHOP and AHOP regimens showed significant and comparable antitumor effect (p < 0.05 by the Wilkoxon test). AHOP caused the maximum effect inhibiting the tumor growth by 67.7% and T/C values of 270%. CHOP was less effective producing 54.8% tumor inhibition and T/C values of 238%. Conclusions: It is very likely that the D-lactamic steroid (androstan) alkylator for A, containing the -NHCO group, combined with ADR, which intercalates between base-pairs, is the explanation for higher activity of AHOP vs. CHOP. This significant effect of NSC-290205 with the anthracycline adriamycin on LLC adds to NSC-290205 advantage for further clinical development. No significant financial relationships to disclose.