Title:  Pulmonary delivery of protonated/acidified nucleic acids

United States Patent:  6,211,162

Assignee:  Oligos Etc. Inc. (Wilsonville, OR)

Filed:  March 31, 1999

The present invention provides a method of treating bacterial respiratory infections by pulmonary administration of protonated/acidified nucleic acids. These modified nucleic acids are effective as bactericidal and/or bacteriostatic agents without regard to the class of bacteria, so are especially useful when diagnosis is difficult or when multiple infectious organisms are present. The antibiotic activity of nucleic acids of the invention is not dependent on either the specific sequence of the nucleic acid or the length of the nucleic acid molecule.

SUMMARY OF THE INVENTION

The present invention provides a method of treating bacterial respiratory infections by pulmonary administration of protonated/acidified nucleic acids. These modified nucleic acids are effective as bactericidal and/or bacteriostatic agents without regard to the class of bacteria, so are especially useful when diagnosis is difficult or when multiple infectious organisms are present. The antibiotic activity of nucleic acids of the invention is not dependent on either the specific sequence of the nucleic acid or the length of the nucleic acid molecule. The nucleic acids of the invention are protonated/acidified to give a pH when dissolved in water of less than pH 7 to about 1, more preferably less than pH 4.5 to about 1, and even more preferably less than pH 2 to about 1. Formulations of aerosolized protonated/acidified nucleic acids are preferably aerosolized and administered via hand-held, self-contained, disposable units.

The nucleic acids of the invention may have nuclease resistant backbones, acid resistant backbones, and, in their preferred embodiment, have both acid resistant and nuclease resistant backbones.

The preferred method of treatment comprises aerosolized delivery of protonated/acidified nucleic acids to the bronchial tubes of an animal, and in particular humans, in an amount sufficient to inhibit or prevent bacterial growth, to alleviate the symptom of the bacterial growth, or in an amount effective for treatment of a bacterial infection.

In another embodiment, the invention provides for pulmonary delivery of protonated/acidified nucleic acids to treat or prevent a primary respiratory disease involving viral infection, inflammatory diseases, cancer, fungal infections, etc., wherein the nucleic acids targeted to treat these disorders are additionally protonated in order to simultaneously treat or prevent a bacterial infection. Preferably, nucleic acids of this embodiment control expression of a gene known to be involved in the primary respiratory disease, e.g., a gene encoding a viral structural protein or an endogenous gene involved in cancer, e.g., an oncogene.

The dose of nucleic acid administered varies with a number of factors, including the inspiratory rate of the patient, the location of the infected region (i.e., upper or lower respiratory tract), the extent of the infection, and the particular species of bacteria involved in the infection. It is often preferable to target the dosage to a particular area of the lungs to better treat an infected region. For example, to achieve deposition of particles in the lower respiratory tract, e.g., to treat pneumonia, it is desirable to get the aerosolized formulation deeply into the lung. Delivery of particles can be controlled, in part, by adjusting particle sizes. In addition to adjusting particle size, delivery of the protonated/acidified nucleic acids can be obtained by releasing an aerosolized dose at a desired point in a patient's respiratory cycle.

Another object is to provide a method of administering a protonated/acidified oligonucleotide formulation to a patient wherein the formulation is repeatedly delivered to a patient at the same measured inspiratory flow rate (in the range of 0.1 to 2.0 liters/second) and separately determined inspiratory volume (in the range of 0.15 to 1.5 liters). Preferably, the oligonucleotide is from 2 to 100 nucleic acids in length.

Another object is to provide a method of administering a protonated/acidified nucleic acid monomer formulation to a patient wherein the formulation is repeatedly delivered to a patient at the same measured inspiratory flow rate (in the range of 0.1 to 2.0 liters/second) and separately determined inspiratory volume (in the range of 0.15 to 1.5 liters).

It is an object of the invention to use protonated/acidified nucleic acids to treat respiratory ailments caused by pathogenic bacteria.

It is another object of the invention to use protonated/acidified nucleic acids to treat respiratory ailments caused by non-bacterial pathogens, e.g., viral infections and fungal infections, and to simultaneously treat and/or prevent a secondary bacterial infection.

It is yet another object of the invention to treat pulmonary immune response activity by administering protonated/acidified nucleic acids to suppress an immune response and to simultaneously treat and/or prevent a secondary bacterial infection.

It is yet another object of the invention to treat a pulmonary neoplasm by administering protonated/acidified nucleic acids to suppress oncogenesis, metastasis, and/or dedifferentiation and to simultaneously treat and/or prevent a secondary bacterial infection.

It is an advantage of the invention that the mechanism of action of the protonated/acidified nucleic acids appears to be relatively non-specific, allowing them to be effective against any bacterium including clinically relevant pathogenic bacteria.

It is another advantage of the invention that the protonated/acidified nucleic acids are non-toxic to a subject treated with the modified nucleic acids.

It is yet another advantage of the invention that a subject treated with the modified nucleic acids display virtually no unwanted side effects from the nucleic acids.

It is a further advantage that the antibacterial effectiveness of protonated/acidified nucleic acids is neither length- nor sequence-dependent.

Claim 1 of 15 Claims

That which is claimed is:

1. A method of treating a pulmonary bacterial infection in a mammalian subject, said method comprising the steps of:

aerosolizing a formulation to create particles comprising a nucleic acid comprising a backbone structure modified from that of a naturally occurring nucleotide polymer the nucleic acid being protonated to an extent that the nucleic acid exhibits a pH in a range of about 0 to about 5 at a concentration of 1 mg/ml of water and the nucleic acid is characterized by a pH stability of at least one hour at pH about 1 to about 5; and

inhaling the aerosolized formulation into lungs of a patient and allowing aerosolized particles of the formulation to deposit on lung tissue.

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