Combinations with a backbone-cyclized peptide

Abstract

A novel combination comprising a β-hairpin peptidomimetic of the formula cyclo(-Thr-Trp-Ile-Dab-Orn-.sup.DDab-Dab-Trp-Dab-Dab-Ala-Ser-.sup.DPro-Pro) (I), and a compound of the glycylcycline class, especially tigecycline, that enable therapeutic control of specific bacterial infections in human or animals at doses of the individual compounds lower than either of the compounds administered alone. The combination can be used as a medicament to treat e.g. skin or soft tissue infections; eye, ear, blood stream, or intra-abdominal infections; infections related to respiratory diseases, to bone diseases, to cardiovascular diseases, to genitourinal diseases, or to gastrointestinal diseases.

Claims

1. A combination comprising: a β-hairpin peptidomimetic of the formula cyclo(-Thr-Trp-Ile-Dab-Orn-DDab-Dab-Trp-Dab-Dab-Ala-Ser-DPro-Pro) (I), wherein Dab is (S)-2,4-diaminobutanoic acid, DDab is (R)-2,4-diaminobutanoic acid, and Orn is (S)-2,5-diaminopentanoic acid; and a compound of the glycylcycline class, or pharmaceutically acceptable salts.

2. A combination according to claim 1 wherein the compound of the glycylcycline class is tigecycline or a pharmaceutically acceptable salt thereof.

3. A pharmaceutical composition comprising a combination according to claim 1 and at least one pharmaceutically inert carrier.

4. A pharmaceutical composition according to claim 3 in a form suitable for oral, topical, transdermal, injection, infusion, buccal, transmucosal, rectal, vaginal, pulmonary or inhalation administration, especially in the form of tablets, dragees, capsules, solutions, liquids, gels, plaster, creams, ointments, syrup, slurries, powders, suspensions, spray, nebulizer or suppositories.

5. A kit comprising a part containing a β-hairpin peptidomimetic of the formula (I) according to claim 1, or a pharmaceutically acceptable salt thereof and a part containing a compound of the glycylcycline class or a pharmaceutically acceptable salt thereof.

6. A kit according to claim 5 wherein the compound of the glycylcycline class is tigecycline or a pharmaceutically acceptable salt thereof.

7. A method of treating a bacterial infection or disease related to such infection in human or animals comprising administering to a subject in need thereof an adequate amount of a combination according to claim 1.

8. A method of treating a bacterial infection or disease related to such infection in human or animals comprising a kit according to claim 5.

9. A method of manufacturing a pharmaceutical composition comprising the step of combining the combination according to claim 1 with at least one pharmaceutically inert carrier.

10. A method of treating a bacterial infection or disease related to such infection in human or animals comprising administering to a subject in need thereof a therapeutically acceptable amount of a pharmaceutical composition according to claim 3.

Description

EXAMPLES

(1) In Vivo Efficacy Test

(2) Efficacy in Murine Pneumonia Model Against Pseudomonas aeruginosa PAX11045 and Estimation of ED.sub.50

(3) Reference 1:

(4) The efficacy and ED.sub.50 of the compound of formula (I) (“compound 1”) was determined against Pseudomonas aeruginosa clinical isolate PAX11045 in a pneumonia model in mice. Colony counts in lung and spleen were determined at 20 hours post treatment.

(5) Infection of Mice

(6) Fresh overnight colonies of PAX11045 from a 5% Horse Blood Agar plate were suspended in 0.9% sterile saline to approximately 10.sup.8 CFU/ml and further diluted to approximately 5×10.sup.7 CFU/ml. Female mice (DBA/2, outbred, 18-22 g, Charles River) were anesthetized with 0.08 ml of Zoletil (tiletamine+zolazepam) and inoculated via the nose with a pipette with 0.05 ml of the bacteria suspension containing approximately 10.sup.6 CFU. 4 hours after inoculation, the mice were treated orally with 45 μl neurophen (20 mg ibuprofen/ml corresponding to approximately 30 mg/kg) as pain relief.

(7) Treatment of Mice with Compound 1

(8) Two vials containing 10 mg of active compound 1 were dissolved in 2.25 ml 0.9% sterile saline each to a concentration of 4.5 mg/ml. One vial was further 2-fold diluted with saline to 2.25, 1.125, 0.56 and 0.28 mg/ml. The mice were treated subcutaneously with 0.2 ml in the neck region with a single dose at 4 hours post infection with a dose calculation based on a mean animal weight of 20 g. As positive control Ciprofloxacin was used in the same manner with a fixed dose of 19 mg/kg.

(9) Sampling

(10) Colony counts were determined post inoculation at 4 hours (untreated mice) and 24 hours (treated and vehicle-only treated mice). Immediately after the mice were sacrificed, the lungs and spleens were collected and frozen at −20° C. After thawing, the organs were homogenized in 1 ml 0.9% saline. Each sample was then 10-fold diluted in saline and 20 μl spots were applied on blood agar plates. All agar plates were incubated 18-48 hours at 35° C. in ambient air.

(11) CFU Counts

(12) The CFU/ml in the inoculum was determined to 7.92 log.sub.10 CFU/ml corresponding to 6.62 log.sub.10 CFU/mouse.

(13) At 4 hours after infection the mean log.sub.10 CFU/lung was 5.28 and the CFU level remained at a similar level after 24 hours in the vehicle-only group. Analog baseline data were collected for the spleen with a mean log.sub.10 CFU/spleen of 1.96 at 4 hours, which increased to 2.60 after 24 hours in the vehicle-only group.

(14) Treatment with compound 1 resulted in both organs in a concentration dependent significant reduction of the CFU levels compared to vehicle treatment (p<0.001 for the higher concentrations). Also Ciprofloxacin (19 mg/kg) had a potent effect on reducing the bacterial loads (p<0.001).

(15) Evaluation of the dose-response curve for ED.sub.50 of compound 1 against PAX11045 in murine lungs using a sigmoidal dose-response model (variable slope) revealed an estimation of 4.33 mg/kg. Table 1 below summarizes the relevant efficacy values.

EXAMPLE 1

(16) The efficacy and ED.sub.50 of the compound of formula (I) (“compound 1”) in combination with tigecycline was determined against Pseudomonas aeruginosa clinical isolate PAX11045 in a pneumonia model in mice. Colony counts in lung were determined at 20 hours post treatment.

(17) Infection of Mice

(18) Fresh overnight colonies of PAX11045 from a 5% Horse Blood Agar plate were suspended in 0.9% sterile saline to approximately 10.sup.8 CFU/ml and further diluted to approximately 5×10.sup.7 CFU/ml. Female mice (DBA/2, outbred, 18-22 g, Chales River) were anesthetized with 0.08 ml of Zoletil and inoculated via the nose with a pipette with 0.1 ml of the bacteria suspension containing approximately 10.sup.6 CFU. 4 hours after inoculation, the mice were treated orally with 45 μl neurophen (20 mg ibuprofen/ml corresponding to approximately 30 mg/kg) as pain relief.

(19) Treatment of Mice with Tigecycline

(20) 53 mg of tigecycline (Tygacil, Wyeth) was dissolved in 5.3 ml 0.9% sterile saline to a concentration of 10 mg/ml and further diluted with saline to 1.25 mg/ml. The mice were treated subcutaneously with 0.2 ml in the neck region with a single dose at 3 hours post infection corresponding to 12.5 mg/kg on the basis of a mean animal weight of 20 g.

(21) Treatment of Mice with Compound 1

(22) Two vials containing 5 mg of active compound 1 were dissolved in 2.5 ml 0.9% sterile saline each to a concentration of 2 mg/ml. One vial was further 2-fold diluted with saline to 1.1, 0.55, 0.275 and 0.137 mg/ml. The mice were treated subcutaneously with 0.2 ml in the neck region with a single dose at 4 hours post infection with a dose calculation based on a mean animal weight of 20 g. As positive control Ciprofloxacin was used in the same manner with a fixed dose of 20 mg/kg.

(23) Sampling

(24) Colony counts were determined post inoculation at 4 hours (untreated mice) and 24 hours (treated and vehicle-only treated mice). Immediately after the mice were sacrificed, the lungs were collected and frozen at −20° C. After thawing, the organs were homogenized in 1 ml 0.9% saline. Each sample was then 10 fold diluted in saline and 20 μl spots were applied on blood agar plates. All agar plates were incubated 18-24 hours at 35° C. in ambient air.

(25) CFU Counts

(26) The CFU/ml in the inoculum was determined to 7.6 log.sub.10 CFU/ml corresponding to 6.3 log.sub.10 CFU/mouse.

(27) At 4 hours after infection the mean log.sub.10 CFU/lung was 6.13 and the CFU level remained at a similar level after 24 hours in the vehicle-only group.

(28) Treatment with a combination of compound 1 and tigecycline resulted in a concentration dependent significant reduction of the CFU levels compared to vehicle treatment (p<0.001). Also Ciprofloxacin (20 mg/kg) had a potent effect on reducing the bacterial loads (p<0.001).

(29) Treatment with tigecycline (12.5 mg/kg) alone had no effect on the bacterial loads.

(30) Evaluation of the dose-response curve for ED.sub.50 of compound 1 in presence of a fixed dose of tigecycline (12.5 mg/kg) against PAX11045 in murine lungs using a sigmoidal dose-response model (variable slope) revealed an estimation of 1.33 mg/kg. The following table summarizes the relevant efficacy values.

(31) TABLE-US-00003 TABLE 1 Efficacy values of compound 1 compound 1 in presence compound 1 of 12.5 mg/kg tigecycline Top level 1.3 log.sub.10 CFU/ml 0.13 log.sub.10 CFU/ml Bottom level −2.2 log.sub.10 CFU/ml −2.37 log.sub.10 CFU/ml E.sub.max 3.5 log.sub.10 CFU/ml 2.5 log.sub.10 CFU/ml ED.sub.50 4.33 mg/kg 1.33 mg/kg Static dose 1.55 mg/kg 0.74 mg/kg 1 log killing dose 8.1 mg/kg 1.2 mg/kg 2 log killing dose 20 mg/kg 2.1 mg/kg R.sup.2 0.55-0.75 0.77