# US 8,772,013 B2 · Methods for targeted in vitro and in vivo drug delivery to mammalian cells via bacterially derived intact minicells

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- Number: US 8,772,013 B2
- Document ID: US8772013B2
- Status: Granted
- Kind: B2
- Application number: 10/588,028
- Filed: 2005-01-27
- Published: 2008-02-28
- Granted: 2014-07-08
- Earliest claimed: 2004-02-02
- Assignees: EnGeneIC Molecular Delivery Pty Ltd
- Applicants: Himanshu Brahmbhatt; Jennifer MacDiarmid
- Inventors: Himanshu Brahmbhatt; Jennifer MacDiarmid
- Web page: https://patentgrep.com/patent/US8772013B2

## CPC

- A61K 9/5068: {Cell membranes or bacterial membranes enclosing drugs (liposomes with additional exogenous lipids A61K9/127)}
- A61K 9/0019: {Injectable compositions; Intramuscular, intravenous, arterial, subcutaneous administration; Compositions to be administered through the skin in an invasive manner (non-active ingredients are additionally classified in A61K47/00)}
- A61K 9/5073: {having two or more different coatings optionally including drug-containing subcoatings}
- A61K 31/337: having four-membered rings, e.g. taxol
- A61K 31/704: attached to a condensed carbocyclic ring system, e.g. sennosides, thiocolchicosides, escin, daunorubicin {(digitoxin A61K31/7048)}
- A61K: PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES (devices or methods specially adapted for bringing pharmaceutical products into particular physical or administering forms A61J3/00; chemical aspects of, or use of materials for deodorisation of air, for disinfection or sterilisation, or for bandages, dressings, absorbent pads or surgical articles A61L; soap compositions C11D)

## Abstract

A composition comprising intact minicells that contain a drug molecule is useful for targeted drug delivery. One targeted drug delivery method employs bispecific ligands, comprising a first arm that carries specificity for a bacterially derived minicell surface structure and a second arm that carries specificity for a mammalian cell surface receptor, to target drug-loaded minicells to specific mammalian cells and to cause endocytosis of the minicells by the mammalian cells. Another drug delivery method exploits the natural ability of phagocytic mammalian cells to engulf minicells without the use of bispecific ligands.

## Claims

### Claim 1

A targeted drug delivery method that comprises
(a) providing a composition comprising (i) at least 107 intact bacterial minicells, wherein said bacterial minicells are derived from Salmonella typhimurium, are approximately 400 nm in diameter, and are loaded with a therapeutically effective amount of a chemotherapeutic drug, and (ii) a bispecific antibody having specificity for a cancer cell surface receptor and specificity for said minicells, wherein said bispecific antibody is attached to said minicells, wherein said composition is free of membrane blebs of 200 nm or less in size, wherein said composition contains fewer than about 1 contaminating parent bacterial cell per 107 minicells; and
(b) contacting said composition with non-phagocytic cancer cells, such that
(i) said bispecific antibody causes said minicells to bind to said cancer cells,
(ii) said minicells are engulfed by said cancer cells, and
(iii) said chemotherapeutic drug is released into the cytoplasm of said cancer cells.

### Claim 2 (depends on 1)

The method of claim 1, wherein said bispecific antibody comprises a first arm that carries specificity for a bacterially derived minicell surface structure and a second arm that carries specificity for a non-phagocytic cancer cell surface receptor.

### Claim 3 (depends on 2)

The method of claim 2, wherein said first arm and said second arm are monospecific.

### Claim 4 (depends on 2)

The method of claim 2, wherein said first arm and said second arm are multivalent.

### Claim 5 (depends on 2)

The method of claim 2, wherein said minicell surface structure is an O-polysaccharide component of a lipopolysaccharide on said minicell surface.

### Claim 6 (depends on 2)

The method of claim 2, wherein said minicell surface structure is selected from the group consisting of outer membrane proteins, pilli, fimbrae, flagella, and cell-surface exposed carbohydrates.

### Claim 7 (depends on 1)

The method of claim 1, wherein said bispecific antibody comprises a humanized antibody.

### Claim 8 (depends on 1)

The method of claim 1, wherein said contacting is in vitro.

### Claim 9 (depends on 1)

The method of claim 1, wherein said contacting is in vivo.

### Claim 10 (depends on 1)

The method of claim 1, wherein said chemotherapeutic drug is doxorubicin and said minicells are loaded with at least 8.5 ng of doxorubicin.

### Claim 11 (depends on 10)

The method of claim 10, wherein said minicells are loaded with at least 66 ng of said chemotherapeutic agent.