Methods of treating and imaging tumor micrometastases using photoactive immunoconjugates

Patent metadata

Field	Value
Publication number	US-11547300-B2
Application number	US-201515114881-A
Country	US
Kind code	B2
Filing date	Feb 2, 2015
Priority date	Jan 31, 2014
Publication date	Jan 10, 2023
Grant date	Jan 10, 2023

Abstract

Methods for evaluating micrometastases in a tissue region of a subject are described. The methods include administering to the subject a detectably effective amount of a tumor-targeted photoactivatable immunoconjugate; allowing a sufficient amount of time for the tumor-targeted photoactivatable immunoconjugate to enter micrometastases in the tissue region; illuminating the tumor-targeted photoactivatable immunoconjugate; obtaining an image of the tissue region of the subject using a fluorescent imaging device, and evaluating the micrometastases in the tissue region by conducting algorithmic analysis of the image. Methods of treating micrometastases in a tissue region of a subject are also described.

First claim

What is claimed is:

1. A method for evaluating micrometastases in vivo in a tissue region of a subject comprising:
(a) administering to the subject a detectably effective amount of a tumor-targeted photoactivatable immunoconjugate, wherein the tumor-targeted photoactivatable immunoconjugate is a tumor-targeted antibody linked to a benzoporphyrin derivative that is configured to be dequenched upon intracellular localization into micrometastases in the tissue region;
(b) allowing a sufficient amount of time for the tumor-targeted photoactivatable immunoconjugate to enter the micrometastases in the tissue region, wherein the micrometastases have a size of 1 mm or less;
(c) illuminating the tumor-targeted photoactivatable immunoconjugate in vivo;
(d) obtaining an in vivo image of the tissue region of the subject using a fluorescent imaging device, and
(e) evaluating the micrometastases in the tissue region by conducting algorithmic analysis of the in vivo image;
wherein the algorithmic analysis comprises selecting each pixel within the in vivo image having an intensity value greater than a first threshold value, wherein the first threshold value is calculated from a plurality of intensity values taken from a control environment free of metastases taken at one or more times following single or multiple administrations of the tumor-targeted photoactivatable immunoconjugate and an internal organ tissue-specific pharmacokinetic model, wherein the internal organ tissue-specific pharmacokinetic model is derived using intensity values obtained from background calibration images of corresponding internal organ tissue;
clustering the selected pixels to form at least one object;
rejecting any object having a largest dimension less than a second threshold value; and
calculating an aggregate intensity value for each object as the sum of the intensity values of the selected pixels comprising the object where each pixel intensity value is corrected using a tissue-specific pharmacokinetic model database.

2. The method of claim 1 , wherein the intensity value for each pixel comprises a ratio of a raw intensity value of the pixel to a calibration value representing an intensity of the photoactivatable immunoconjugate.

3. The method of claim 1 , the method further comprising determining an average background intensity value for a given type of internal organ tissue associated with the tissue region, the intensity value for each pixel comprising a ratio of a difference between a raw intensity value of the pixel and a background intensity of the photoactivatable immunoconjugate and a background intensity value.

4. The method of claim 1 , further comprising applying a mask to the in vivo image, such that pixels that are not expected to be illuminated by the fluorescent imaging device are excluded from the analysis;
calculating an autofluorescence intensity value as an average intensity value for all pixels not excluded by the mask; and
subtracting the autofluorescence intensity value from the intensity value for each pixel.

5. The method of claim 1 , further comprising applying a Gaussian noise filter to the in vivo image.

6. The method of claim 1 , wherein the benzoporphyrin derivative is verteporfin.

7. The method of claim 1 , further comprising using a microendoscope to obtain the in vivo image.

8. A method for in vivo treatment of micrometastases in a tissue region of a subject, comprising:
(a) administering to the subject a therapeutically effective amount of a tumor-targeted photoactivatable immunoconjugate, wherein the tumor-targeted photoactivatable immunoconjugate is a tumor-targeted antibody linked to a benzoporphyrin derivative that is configured to be dequenched upon intracellular localization into micrometastases in the tissue region;
(b) allowing a sufficient amount of time for the tumor-targeted photoactivatable immunoconjugate to enter the micrometastases in the tissue region, wherein the micrometastases have a size of 1 mm or less;
(c) photoactivating the tumor-targeted photoactivatable immunoconjugate in vivo to treat the micrometastases;
(d) obtaining an in vivo image of the tissue region of the subject using a fluorescent imaging device;
(e) conducting an algorithmic analysis of the in vivo image of the tissue region, wherein the algorithmic analysis comprises selecting each pixel within the in vivo image having an intensity value greater than a threshold value, wherein the first threshold value is calculated from a plurality of intensity values taken from a control environment free of metastases taken at one or more times following single or multiple administrations of the tumor-targeted photoactivatable immunoconjugate and an internal organ tissue-specific pharmacokinetic model, wherein the internal organ tissue-specific pharmacokinetic model is derived using intensity values obtained from background calibration images of corresponding internal organ tissue;
clustering the selected pixels to form at least one object;
rejecting any object having a largest dimension less than a second threshold value; and
calculating an aggregate intensity value for each object as the sum of the intensity values of the selected pixels comprising the object where each pixel intensity value is corrected using a tissue-specific pharmacokinetic model database, and

(f) providing additional treatment if imaging of the tissue region indicates that a significant number of micrometastases remain in the tissue region, wherein the additional treatment is selected from administering additional tumor-targeted photoactivatable immunoconjugate, cryoablation, thermal ablation, radiotherapy, radiofrequency ablation, electroporation, alcohol ablation, high intensity focused ultrasound, or administration of an anticancer agent.

9. The method of claim 8 , wherein the tumor-targeted photoactivatable immunoconjugate is epidermal growth factor receptor specific.

10. The method of claim 8 , wherein the tumor-targeted photoactivatable immunoconjugate comprises a plurality of quenched photoactivatable compounds.

11. The method of claim 8 , wherein the benzoporphyrin derivative is verteporfin and the micrometastases comprise ovarian cancer cells.

12. The method of claim 8 , further comprising using a microendoscope to obtain the in vivo image.

13. The method of claim 8 , wherein the intensity value for each pixel comprises a ratio of a raw intensity value of the pixel to a calibration value representing an intensity of the photoactivatable immunoconjugate.

14. The method of claim 8 , the method further comprising determining an average background intensity value for a given type of internal organ tissue associated with the tissue region, the intensity value for each pixel comprising a ratio of a difference between a raw intensity value of the pixel and a background intensity value to a difference between a calibration value representing an intensity of the photoactivatable immunoconjugate and the background intensity value.

15. The method of claim 8 , further comprising:
applying a mask to the in vivo image, such that the pixels that are not expected to be illuminated by the fluorescent imaging device are excluded from the analysis;
calculating an autofluorescence intensity value as an average intensity value for all pixels not excluded by the mask; and
subtracting the autofluorescence intensity value from the intensity value for each pixel.

16. The method of claim 8 , further comprising applying a Gaussian noise filter to the in vivo image.

Assignees

• Massachusetts Gen Hospital

Inventors

• Hasan Tayyaba
• Spring Bryan Q
• Palanisami Akilan

Classifications

• A61P35/04

  specific for metastasis · CPC title

• A61B1/043

  for fluorescence imaging · CPC title

• A61B5/725

  using specific filters therefor, e.g. Kalman or adaptive filters (specific diagnostics methods using using bioelectric or biomagnetic signals A61B5/316) · CPC title

• A61B5/7203

  for noise prevention, reduction or removal · CPC title

• A61K41/0057

  Photodynamic therapy with a photosensitizer, i.e. agent able to produce reactive oxygen species upon exposure to light or radiation, e.g. UV or visible light; photocleavage of nucleic acids with an agent · CPC title