Combination of drugs with protein-binding prodrugs

Abstract

The present invention relates to a composition and a combination comprising at least one first drug and at least one protein-binding prodrug, wherein the protein-binding prodrug comprises a protein-binding group, a second drug, and a linker that can be cleaved hydrolytically, enzymatically, or in a pH-dependent manner in the body, as well as to a kit and a pharmaceutical composition comprising said composition or combination.

Claims

1. A composition comprising doxorubicin and 6-maleimidocaproyl (hydrazone) of doxorubicin (DOXO-EMCH), wherein a molar ratio of the DOXO-EMCH to the doxorubicin ranges from 3:1 to 5:1.

2. The composition according to claim 1, further comprising a pharmaceutically acceptable carrier and/or a pharmaceutically acceptable adjuvant and/or diluent.

3. A kit comprising the composition of claim 1 and optional pharmaceutically acceptable carrier and/or a pharmaceutically acceptable adjuvant and/or diluent.

4. The kit according to claim 3, further comprising the pharmaceutically acceptable carrier and/or the pharmaceutically acceptable adjuvant and/or the diluent.

Description

(1) The FIGS. show:

(2) FIG. 1: Chemical structure of doxorubicin (A) and the prodrug DOXO-EMCH (B) which is a 6-maleimidocaproyl(hydrazone) derivative of doxorubicin.

(3) FIG. 2: Curves depicting tumor growth inhibition of subcutaneously growing A2780 xenografts under therapy with doxorubicin, DOXO-EMCH, and the combination of doxorubicin with DOXO-EMCH.

(4) FIG. 3: Curves depicting body weight change (BWC in %) of mice with subcutaneously growing A2780 xenografts under therapy with doxorubicin, DOXO-EMCH, and the combination of doxorubicin with DOXO-EMCH.

(5) The compositions of the present invention surprisingly and advantageously produce an improved efficacy and in vivo tolerability than either the first drug or the protein-binding prodrug alone. Accordingly, it is advantageously possible to efficiently treat a great variety of diseases by combining a protein-binding prodrug with a free drug of the same or a different type, whereby the advantageous properties of said drugs can be improved beyond the properties of the prodrug and the free drug alone.

(6) The present invention will now be further illustrated in the following example without being limited thereto. Many further combinations according to the present invention can be realized as outlined above.

EXAMPLE

Example: Antitumor Efficacy of the Combination of Doxorubicin with the Prodruq DOXO-EMCH

(7) The antitumor efficacy of the clinically established doxorubicin (FIG. 1 A), the 6-maleimidocaproyl(hydrazone) derivative of doxorubicin (DOXO-EMCH; FIG. 1 B), and a combination of doxorubicin and DOXO-EMCH was assessed in the ovarian carcinoma A2780 xenograft model. DOXO-EMCH is an albumin-binding prodrug of doxorubicin that binds rapidly to the cysteine-34 position of circulating albumin and is taken up by solid tumors due to the enhanced permeation and retention effect (EPR effect). Following tumor uptake, DOXO-EMCH is cleaved in the acid environment of tumor tissue, either extra- or intracellularly.

(8) DOXO-EMCH has a maximum tolerated dose (MTD) of 324 mg/kg body weight doxorubicin equivalents in nude mice and has shown superior efficacy over free doxorubicin in a number of xenograft and orthotopic tumor models. MTD of doxorubicin is 28 mg/kg body weight in nude mice models and higher doses, e.g. 212 mg/kg body weight, lead to unacceptable toxicity and mortality.

(9) In order to evaluate the in vivo antitumor efficacy of a combination of doxorubicin with DOXO-EMCH in tumor-bearing mice, a direct comparison was made with a group treated with doxorubicin (28 mg/kg body weight) or DOXO-EMCH (324 mg/kg body weight doxorubicin equivalents) at their respective MTDs. For the combination, a lower dose of doxorubicin (34 mg/kg body weight) was combined with a lower dose of DOXO-EMCH (312 mg/kg body weight doxorubicin equivalents) wherein the DOXO-EMCH was administered 6 h prior to doxorubicin on the respective days of administration (cf. Table 1). The results of this experiment in the ovarian carcinoma A2780 xenograft model are shown in Table 1 and FIGS. 2 and 3.

(10) With respect to antitumor efficacy, doxorubicin at its optimal dose of 28 mg/kg body weight only showed moderate antitumor efficacy up to day 30, after which the mice of this group had to be killed because of unacceptably high tumor burden. In contrast, treatment with DOXO-EMCH at 324 mg/kg body weight produced a pronounced antitumor effect which was statistically significant to the doxorubicin-treated group with tumor remissions for up to 37 days (cf. FIG. 2), after which some of the animals of this group died or were killed due to considerable body weight loss of over 30% (cf. FIG. 3). In contrast, the group treated with the combination of DOXO-EMCH (312 mg/kg body weight doxorubicin equivalents) and doxorubicin (34 mg/kg body weight) produced excellent antitumor effects which were statistically significant to the doxorubicin-treated group with stable tumor remissions for more than 40 days (cf. FIG. 3). Also, compared to the doxorubicin or DOXO-EMCH treated animals, significantly less body weight change (BWC) was observed (12% at the end of the experiment) clearly indicating better tolerability (cf. FIG. 3). Thus, the treatment combining DOXO-EMCH with doxorubicin has a distinct advantage over treatment with doxorubicin or DOXO-EMCH alone with respect to antitumor efficacy and tolerability.

(11) TABLE-US-00001 TABLE 1 Comparison of doses, mortality, relative tumor volumes, body weight change of doxorubicin, DOXO-EMCH, and the combination of DOXO-EMCH with doxorubicin against human ovarian cancer xenografts (A2780). Schedule Dose (i.v.) toxic RTV RTV Mice Compounds [days] [mg/kg/inject.] death BWC [%] day 20 day 30 8 Buffer 6, 13, 20 0 2 50.3 8 Doxorubicin 6, 13 8 0 21 (d26) 7.4 23.9 8 DOXO-EMCH 6, 13, 20 24 0 31 (d37) 0.2 0.1* 8 Doxorubicin + 6, 13, 20 4 + 12 0 12 (d41) 0.2 0.1* DOXO-EMCH Ovar. Ca. A2780, 10E7 cells s.c., day 0, NMRI: nu/nu mice, female RTV: relative tumor volume, BWC: body weight change *significant to Doxorubicin

(12) Experimental Procedure. In vivo efficacy studies were carried out with doxorubicin, the 6-maleimidocaproyl(hydrazone) derivative of doxorubicin (DOXO-EMCH), and a combination of doxorubicin with DOXO-EMCH in the ovarian carcinoma A2780 xenograft model. For in vivo testing, female NMRI: nu/nu mice (Taconic, Denmark) were used. The mice were held in individually ventilaged cages (IVC) under sterile and standardized environmental conditions (252 C. room temperature, 5010% relative humidity, 12 hour light-dark-rhythm). They received autoclaved food and bedding (ssniff, Soest, Germany) and acidified (pH 4.0) drinking water ad libitum. A2780 tumor fragments were transplanted subcutaneously (s.c.) into the left flank region of anaesthetized mice (40 mg/kg i.p. Radenarkon, Asta Medica, Frankfurt, Germany) on day 0. Mice were randomly distributed to the experimental groups (8 mice per group). When the tumors were grown to a palpable size, treatment was initiated. Mice were treated intravenously (i.v.) with either glucose phosphate buffer (10 mM sodium phosphate, 5% D-(+)-glucose, pH 5.8), doxorubicin (28 mg/kg body weight), or DOXO-EMCH (324 mg/kg body weight doxorubicin equivalents), or a combination of DOXO-EMCH (312 mg/kg body weight doxorubicin equivalents) and doxorubicin (34 mg/kg body weight) with a 6 hour interval on the day of administration. DOXO-EMCH was dissolved in 10 mM sodium phosphate, 5% D-(+)-glucose, pH 5.8. The compounds were injected intravenously at weekly intervals on days 6 and 13 and on days 6, 13 and 20 for the remaining compounds. The injection volume was 0.2 ml/20 g body weight. Tumor size was measured twice weekly with a caliper-like instrument in two dimensions. Individual tumor volumes (V) were calculated by the formula V=(length[width]2)/2 and related to the values on the first day of treatment (relative tumor volume, RTV). Statistical analysis was performed with the U-test (Mann and Whitney) with p<0.05. The body weight of mice was determined every 3 to 4 days.