Prostate antigen standards and uses thereof

Patent metadata

Field	Value
Publication number	US-11921115-B2
Application number	US-201615081331-A
Country	US
Kind code	B2
Filing date	Mar 25, 2016
Priority date	Mar 27, 2015
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

Aspects of the disclosure relate to improved methods for predicting whether a prostate tissue biopsy obtained from a subject will contain detectable prostate cancer. In some embodiments, the disclosure provides improved prostate antigen standards for quantifying levels of prostate antigens.

First claim

What is claimed is:

1. A method comprising:
performing an immunoassay using a tracer antibody to measure a level of a prostate antigen in a sample, wherein the prostate antigen is intact prostate specific antigen (iPSA) and the tracer antibody comprises a 4D4 antibody, wherein the immunoassay comprises:
contacting iPSA present in the sample with a capture antibody specific for iPSA and nicked PSA, under conditions in which the capture antibody binds at least to iPSA, thereby producing a capture-antibody-iPSA complex;
combining the capture-antibody-iPSA complex with the 4D4 antibody in a buffer having a pH of 6.5 to 7.0 such that the 4D4 antibody specifically binds to the capture-antibody-iPSA complex; and
detecting the capture-antibody-iPSA complex bound to the 4D4 antibody;

performing the same immunoassay to measure the level of the prostate antigen in each titer in a set of prostate antigen standards, wherein the set of prostate antigen standards comprises between 3 and 15 titers containing known levels of the prostate antigen, wherein each intermediate titer of the prostate antigen is equidistant from the titer above and below it on a logarithmic scale, wherein the quantity of the smallest non-zero titer of the set is below the limit of quantification of the immunoassay, and wherein the level of the prostate antigen in the largest titer in the set is between i) a blood level of the prostate antigen in the upper quartile of a target population of male subjects and ii) a level of the prostate antigen that is 75-fold higher than the blood level in the upper quartile of the target population of male subjects; and
determining the level of the prostate antigen in the sample based on the measured levels of the prostate antigen in the set of prostate antigen standards.

2. The method of claim 1 , wherein the target population of male subjects consists of men, the median age of which is in a range of 60 to 70 years.

3. The method of claim 1 , wherein the target population of male subjects consists of men, the lower quartile age of which is in a range of 55 to 65 years.

4. The method of claim 1 , wherein the target population of male subjects consists of men, the upper quartile age of which is in a range of 65 to 75 years.

5. The method of claim 1 , wherein the smallest non-zero titer of the set is 0.025 ng/mL iPSA.

6. The method of claim 5 , wherein the largest titer of the set is 15 ng/mL iPSA.

7. The method of claim 1 , wherein the set of prostate antigen standards consists of the following titers of iPSA: 0 ng/mL, 0.025 ng/mL, 0.089 ng/mL, 0.322 ng/mL, 1.157 ng/mL, 4.167 ng/mL, and 15 ng/mL.

8. The method of claim 1 , wherein the set of prostate antigen standards consists of seven titers of the prostate antigen.

9. A prostate antigen detection kit for quantifying levels of the prostate antigen, wherein the prostate antigen is intact prostate specific antigen (iPSA), the kit comprising:
a set of prostate antigen standards for quantifying levels of the prostate antigen in a sample using an immunoassay, wherein each prostate antigen standard is present in a container as a solution, wherein the set of prostate antigen standards comprises at least two titers containing known levels of the prostate antigen, wherein each intermediate titer of the prostate antigen is equidistant from the titer above and below it on a logarithmic scale, wherein the quantity of the smallest non-zero titer of the set is below the limit of quantification of the immunoassay, and wherein the largest titer of the set is between i) a blood level of the prostate antigen in the upper quartile of a target population of male subjects and ii) a level of the prostate antigen that is 75-fold higher than the blood level in the upper quartile of the target population of male subjects;
a tracer antibody comprising a 4D4 antibody;
a buffer having a pH of 6.5 to 7.0; and
instructions for quantifying levels of the prostate antigen.

10. A method comprising:
performing an immunoassay using a tracer antibody to measure a level of a prostate antigen in a sample, wherein the prostate antigen is intact prostate specific antigen (iPSA) and wherein the tracer antibody comprises a 4D4 antibody, wherein the immunoassay comprises:
contacting iPSA present in the sample with a capture antibody specific for iPSA and nicked PSA, under conditions in which the capture antibody binds at least to iPSA, thereby producing a capture-antibody-iPSA complex;
combining the capture-antibody-iPSA complex with the 4D4 antibody in a buffer having a pH of 6.5 to 7.0 such that the 4D4 antibody specifically binds to the capture-antibody-iPSA complex; and
detecting the capture-antibody-iPSA complex bound to the 4D4 antibody;

performing the same immunoassay to measure the level of the prostate antigen in each titer in a set of prostate antigen standards, wherein the set of prostate antigen standards comprises between 5 and 15 titers containing known levels of the prostate antigen, wherein the level of the prostate antigen in the largest titer in the set is less than or equal to 15 ng/mL iPSA, wherein each intermediate titer of the prostate antigen is equidistant from the titer above and below it on a logarithmic scale, and wherein the quantity of the smallest non-zero titer of the set is below the limit of quantification of the immunoassay; and
determining the level of the prostate antigen in the sample based on the measured levels of the prostate antigen in the set of prostate antigen standards.

11. The method of claim 10 , wherein the set of prostate antigen standards consists of seven titers of the prostate antigen.

12. The method of claim 10 , wherein the set of prostate antigen standards consists of the following titers of iPSA: 0 ng/mL, 0.025 ng/mL, 0.089 ng/mL, 0.322 ng/mL, 1.157 ng/mL, 4.167 ng/mL, and 15 ng/mL.

13. The method of claim 1 , wherein the set of prostate antigen standards comprises between 5 and 15 titers containing known levels of the prostate antigen, and wherein the largest titer of the set is between i) the blood prostate antigen concentration of the upper quartile of a target population of subjects and ii) 25-fold higher than that blood prostate antigen concentration.

14. The method of claim 13 , wherein the target population is men having a median age in a range of 60 to 70 years, in a range of 55 to 65 years, or in a range of 65 to 75 years.

15. The method of claim 1 , wherein the largest titer of the set is less than or equal to 15 ng/mL iPSA.

16. The method of claim 10 , wherein the smallest non-zero titer of the set is 0.025 ng/mL iPSA.

17. The method of claim 1 , wherein the limit of quantification is the smallest amount of material detectable and quantifiable with a coefficient of variation of less than 25%.

18. The method of claim 10 , wherein the limit of quantification is the smallest amount of material detectable and quantifiable with a coefficient of variation of less than 25%.

19. A method of determining the quantity of a prostate antigen in a sample from a subject, wherein the prostate antigen is intact prostate specific antigen (iPSA), the method comprising:
1) performing an immunoassay on the sample using a capture antibody and a tracer antibody comprising a 4D4 antibody to generate a signal for detecting the quantity of the prostate antigen in the sample, wherein the immunoassay comprises:
contacting iPSA present in the sample with a capture antibody specific for iPSA and nicked PSA, under conditions in which the capture antibody binds at least to iPSA, thereby producin

Assignees

• Opko Diagnostics Llc

Inventors

• Linder Vincent
• Higgins Christina
• Pettersson Kim

Classifications

• G01N33/57555 Primary

  of the prostate · CPC title

• G01N33/57434 Primary

  Physics · mapped topic

• C12N9/6445

  Kallikreins (3.4.21.34; 3.4.21.35) · CPC title

• G01N2333/96455

  Kallikrein (3.4.21.34; 3.4.21.35) · CPC title

• G01N2496/00

  Reference solutions for assays of biological material · CPC title