Method of treating a dopamine related disorder in a subject by administering levodopa, in combination with a dopamine decarboxylase inhibitor and a catechol-o-methyltransferase inhibitor

1. A method of treating a dopamine related disorder in a subject who has received prior therapy with an intestinal gel that delivers levodopa in combination with a dopamine decarboxylase inhibitor (DDI) according to a reference regimen optimized for the subject, so that the subject received an optimized dose of the levodopa and DDI over a selected time period, the method comprising a step of:

administering to the subject a combination therapy with levodopa in combination with both a DDI and a catechol-O-methyltransferase (COMT) inhibitor, so that, over the selected time period one or more of:

(i) the administered dose of levodopa is lower than the prior optimized dose;

(ii) the administered dose of DDI is lower than the prior optimized dose;

(iii) the dosing of levodopa is less frequent than in the reference regimen; or

(iv) the dosing of DDI is less frequent than in the reference regimen,

wherein the DDI is selected from the group consisting of carbidopa, benzerazide, and combinations thereof, and

wherein at least the levodopa and the DDI are administered via an intestinal gel.

2. The method of claim 1 , wherein the reference regimen comprises administering the levodopa in combination with the DDI, but not with the COMT inhibitor.

3. The method of claim 1 , wherein the subject experiences a reduced rate of levodopa-related side effects when receiving the combination therapy compared to the reference regimen over the selected time period.

4. The method of claim 3 , wherein the levodopa-related side effects are one or more of nausea, vomiting, dyskinesia, motor fluctuation, or neurographic abnormalities.

5. The method of claim 1 , wherein the step of administering the combination therapy comprises administering the levodopa, DDI, and COMT inhibitor simultaneously.

6. The method of claim 1 , wherein the step of administering the combination therapy comprises administering at least one of the levodopa, DDI, and COMT inhibitor so that timing of administration is staggered.

7. The method of claim 1 , wherein the step of administering the combination therapy comprises administering the levodopa, DDI, and COMT inhibitor in separate compositions.

8. The method of claim 1 , wherein the step of administering the combination therapy comprises administering the levodopa, DDI, and COMT inhibitor in the same composition.

9. The method of claim 1 , wherein the step of administering the combination therapy comprises administering two of the levodopa, DDI, and COMT inhibitor in the same composition, and the third is administered in a second composition.

10. The method of claim 1 , wherein the step of administering the combination therapy further comprises administering-one or more anticholinergics, one or more glutamate antagonists, or one or more amantadine derivatives.

11. The method of claim 1 , wherein the COMT inhibitor is selected from the group consisting of entacapone, tolcapone, opicapone, and any combination thereof.

12. The method of claim 1 , wherein the DDI is carbidopa and the COMT inhibitor is entacapone.

13. The method of claim 1 , wherein the dopamine-related disorder is selected from the group consisting of albinism, Alzheimer's disease, amblyopia, angelman syndrome, anterior ischemic optic neuropathy, aphasia, back pain, depression, dopamine beta- hydroxylase deficiency, drug dependence, drug abuse, dyslexia, dystonic cerebral palsy, Huntington's disease, hypotensive syncope, impulse control disorder, medullary carcinoma, motor neuron disease, movement disorders, multisystemic atrophy, orthostatic hypotension, orthostatic intolerance, Parkinson's disease, prion disease, restless legs syndrome, retinal diseases, schizophrenia, spinal cord injury, spinal muscular atrophy, spinocerebellar ataxia, stroke, thyroid carcinoma, thyroid neoplasm, and tourette syndrome.

14. The method of claim 13 , wherein the dopamine-related disorder is selected from the group consisting of Alzheimer's disease, Huntington's disease, and Parkinson's disease.

15. A method of identifying or characterizing an agent selected from the group consisting of one or more dopamine decarboxylase inhibitors (DDIs), one or more catechol-O-methyltransferase (COMT) inhibitors, or combinations thereof for use in improving levodopa delivery comprising:

providing a test composition that is a gel comprising levodopa and the agent;

assessing a feature of levodopa as present in or provided by the gel composition when administered to a subject;

comparing the assessed feature with that of a comparable reference gel composition lacking the agent; and

detecting improvement of the assessed feature, thereby identifying or characterizing the agent.

16. A method of improving levodopa delivery comprising:

providing a test composition that is a gel comprising a levodopa, a dopamine decarboxylase inhibitor (DDI), and a catechol-O-methyltransferase (COMT) inhibitor;

assessing a feature of levodopa delivery as present in or provided by the gel composition when administered to a subject; and

determining that the assessed feature is improved relative to that observed for a comparable reference gel composition lacking the DDI, the COMT, or both, thereby improving levodopa delivery.

17. The method of claim 15 , wherein the DDI is selected from the group consisting of carbidopa, benzerazide, and any combination thereof; and wherein the COMT inhibitor is selected from the group consisting of entacapone, tolcapone, opicapone, and any combination thereof.

18. The method of claim 16 , wherein the DDI is selected from the group consisting of carbidopa, benzerazide, and any combination thereof; and wherein the COMT inhibitor is selected from the group consisting of entacapone, tolcapone, opicapone, and any combination thereof.

19. A method comprising steps of:

administering to a subject in need thereof a combination therapy with levodopa in combination with both a dopamine decarboxylase inhibitor (DDI) and a catechol-O-methyltransferase (COMT) inhibitor, wherein the DDI is selected from the group consisting of carbidopa, benzerazide, and combinations thereof, at least the levodopa and the DDI are administered by intestinal gel and further wherein the combination therapy comprises a plurality of doses of levodopa over a selected time period and achieves a 0-24 hour AUC that is above 61.6 h*ng/ml per mg of levodopa.

20. The method of claim 19 , wherein the combination therapy achieves a 0-24 hour AUC that is above about 70 h*ng/ml per mg of levodopa.

21. The method of claim 19 , wherein the combination therapy achieves a 0-24 hour AUC that is above about 90 h*ng/ml per mg of levodopa.

22. The method of claim 19 , wherein the combination therapy achieves a 0-24 hour AUC that is at least 10-50% above 61.6 h*ng/ml per mg of levodopa.

23. In a method of treating a dopamine related disorder by administration of levodopa in combination with a dopamine decarboxylase inhibitor (DDI) in an intestinal gel, the improvement that comprises further administering a catechol-O-methyltransferase (COMT) inhibitor demonstrated to achieve an average increase in levodopa AUC of about 55%.

24. The method of claim 23 , wherein the improvement comprises including the COMT in the intestinal gel.

25. The method of claim 23 , wherein the intestinal gel includes 20 mg/ml levodopa.

26. The method of claim 23 , wherein the intestinal gel includes 5 mg/ml carbidopa.

27. The method of claim 23 , wherein the intestinal gel includes 20 mg/ml levodopa and 5 mg/ml carbidopa.

28. The method of claim 23 , wherein the improvement comprises including entacapone at 20 mg/ml in the intestinal gel.

29. A method of treating a dopamine related disorder in a subject who has received prior therapy with an intestinal gel that delivers levodopa in combination with a dopamine decarboxylase inhibitor (DDI) selected from the group consisting of carbidopa, benzerazide, and combinations thereof according to a reference regimen that delivers a desired amount of the levodopa and the DDI per day, the method comprising a step of: administering the intestinal gel to the subject in combination with a catechol-O-methyltransferase (COMT) inhibitor so that one or more pharmacokinetic properties of the levodopa or the DDI or both is increased relative to that observed with the reference regimen.

30. The method of claim 29 , wherein the one or more pharmacokinetic properties comprises bioavailability of levodopa, which is increased more than 40%.

31. The method of claim 30 , wherein the one or more pharmacokinetic properties comprises bioavailability of levodopa, which is increased on average about 55%.

32. The method of claim 29 , wherein the one or more pharmacokinetic properties comprises bioavailability of levodopa, which is increased by an amount within a range of 1.5-3.0 fold.

33. The method of claim 29 , wherein the intestinal gel includes levodopa and carbidopa at a ratio of 4:1.

34. The method of claim 29 , wherein the intestinal gel includes levodopa at 20 mg/ml and carbidopa at 5 mg/ml.

35. The method of claim 29 , wherein the COMT inhibitor is entacapone.

36. The method of claim 29 , wherein the COMT inhibitor is included in the intestinal gel.

37. The method of claim 29 , wherein the COMT inhibitor is entacapone in the intestinal gel, which gel includes levodopa at 20 mg/ml, carbidopa at 5 mg/ml, and entacapone at 20 mg/ml.

38. The method of claim 1 , wherein the intestinal gel also delivers the COMT.

39. The method of claim 38 , wherein the COMT inhibitor is entacapone.

40. The method of claim 39 , wherein the intestinal gel includes levodopa at 20 mg/ml, carbidopa at 5 mg/ml, and entacapone at 20 mg/ml.

41. The method of claim 1 , wherein the intestinal gel includes levodopa and carbidopa at a ratio of 4:1.

42. The method of claim 1 , wherein the intestinal gel includes levodopa at 20 mg/ml and carbidopa at 5 mg/ml.

43. The method of claim 1 , wherein the COMT inhibitor is entacapone.

44. The method of claim 1 , wherein the combination therapy achieves a 0-24 hour AUC in the subject that is, on average, 55% greater than that observed with the reference regimen over the selected time period.

45. The method of claim 1 , wherein the administered dose of levodopa is reduced to 80% of the prior optimized dose delivered by the reference regimen over the selected time period.

46. The method of claim 1 , wherein the administered dose of DDI is reduced to 80% of the prior optimized dose delivered by the reference regimen over the selected time period.

47. The method of claim 1 , wherein each of the administered dose of levodopa and the administered dose of DDI is reduced to 80% of the prior optimized dose delivered by the reference regimen over the selected time period.

48. The method of claim 1 , wherein the step of administering achieves a 0-24 hour AUC that is above the 61.6*ng/ml per mg of levodopa.