METHODS OF TREATING PEMPHIGUS BY ADMINISTERING (R)-2-[3-[4-AMINO-3-(2-FLUORO-4-PHENOXY-PHENYL)PYRAZOLO[3,4-D]PYRIMIDIN-1-YL]PIPERIDINE-1-CARBONYL]-4-METHYL-4-[4-(OXETAN-3-YL)PIPERAZIN-1-YL]PENT-2-ENENITRILE

1 . A method of treating pemphigus in a human patient in need thereof comprising administering to the human patient a dose of at least 400 mg of (R)-2-[3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)pyrazolo[3,4-d]pyrimidin-1-yl]piperidine-1-carbonyl]-4-methyl-4-[4-(oxetan-3-yl)piperazin-1-yl]pent-2-enenitrile (PRN1008) once a day (QD) for at least 14 days.

2 . The method of claim 1 , comprising administering to the human patient a dose of at least 400 mg of PRN1008 QD for 14 to 168 days.

3 - 12 . (canceled)

13 . The method of claim 1 , comprising:

administering to the human patient a first dose of 400 mg of PRN1008 QD for 14 days; and

administering to the human patient a second dose of 400 mg of PRN1008 twice a day (BID) for at least 14 days following the administration of the first dose.

14 . The method of claim 13 , comprising administering to the human patient a second dose of 400 mg of PRN1008 BID for 14 to 154 days following the administration of the first dose.

15 . The method of claim 1 , comprising:

administering to the human patient a first dose of 400 mg of PRN1008 QD for 14 days; and

administering to the human patient a second dose of 400 mg of PRN1008 twice a day (BID) for 14 days following the administration of the first dose; and

administering to the human patient a third dose of 600 mg of PRN1008 BID following the administration of the second dose.

16 . The method of claim 15 , comprising administering to the human patient a third dose of 600 mg of PRN1008 BID for at most 140 days following the administration of the second dose.

17 . (canceled)

18 . A method of treating pemphigus in a human patient in need thereof comprising administering to the human patient a dose of at least 400 mg of (R)-2-[3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)pyrazolo[3,4-d]pyrimidin-1-yl]piperidine-1-carbonyl]-4-methyl-4-[4-(oxetan-3-yl)piperazin-1-yl]pent-2-enenitrile (PRN1008) twice a day (BID) for at least 14 days.

19 . The method of claim 18 , comprising administering to the human patient a dose of at least 400 mg of PRN1008 BID for 14 to 84 days.

20 - 27 . (canceled)

28 . The method of claim 18 , comprising:

administering to the human patient a first dose of 400 mg of PRN1008 BID for at least 14 days; and

administering to the human patient a second dose of 500 mg of PRN1008 BID following the administration of the first dose.

29 . The method of claim 28 , comprising administering to the human patient a first dose of 400 mg of PRN1008 BID for 14 to 28 days.

30 - 32 . (canceled)

33 . The method of claim 18 , comprising:

administering to the human patient a first dose of 400 mg of PRN1008 BID for at least 14 days; and

administering to the human patient a second dose of 600 mg of PRN1008 BID following the administration of the first dose.

34 . The method of claim 33 , comprising administering to the human patient a first dose of 400 mg of PRN1008 BID for 14 to 28 days.

35 - 38 . (canceled)

39 . The method of claim 18 , comprising:

administering to the human patient a first dose of 400 mg of PRN1008 BID for at least 14 days;

administering to the human patient a second dose of 500 mg of PRN1008 BID for at least 14 days following the administration of the first dose; and

administering to the human patient a third dose of 600 mg of PRN1008 BID following the administration of the second dose.

40 . The method of claim 39 , comprising administering to the human patient a first dose of 400 mg of PRN1008 BID for 14 to 28 days.

41 . (canceled)

42 . (canceled)

43 . The method of claim 1 , comprising administering PRN1008 in combination with a first corticosteroid at a dose of less than or equal to 0.5 mg/kg/day.

44 . The method of claim 43 , wherein the first corticosteroid is chosen from prednisone, prednisolone, and methylprednisolone.

45 . The method of claim 1 , wherein the human patient is characterized by naïve or relapsing pemphigus prior to the administration of PRN1008.

46 . (canceled)

47 . (canceled)

48 . The method of claim 1 , wherein the human patient is characterized by a pemphigus disease activity index (PDAI) skin score from 8 points to 60 points prior to the administration of PRN1008.

49 . The method of claim 1 , wherein the human patient is characterized by a maintenance dose of less than or equal to 0.5 mg/kg/day of a second corticosteroid prior to the administration of PRN1008.

50 - 52 . (canceled)

53 . The method of claim 1 , wherein PRN1008 comprises the (E) isomer of (R)-2-[3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)pyrazolo[3,4-d]pyrimidin-1-yl]piperidine-1-carbonyl]-4-methyl-4-[4-(oxetan-3-yl)piperazin-1-yl]pent-2-enenitrile.

54 . The method of claim 1 , wherein PRN1008 comprises the (Z) isomer of (R)-2-[3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)pyrazolo[3,4-d]pyrimidin-1-yl]piperidine-1-carbonyl]-4-methyl-4-[4-(oxetan-3-yl)piperazin-1-yl]pent-2-enenitrile.

55 . The method of claim 1 , wherein PRN1008 comprises a mixture of (E) and (Z) isomers of (R)-2-[3-[4-amino-3-(2-fluoro-4-phenoxy-phenyl)pyrazolo[3,4-d]pyrimidin-1-yl]piperidine-1-carbonyl]-4-methyl-4-[4-(oxetan-3-yl)piperazin-1-yl]pent-2-enenitrile.

56 . The method of claim 1 , comprising treating pemphigus vulgaris.

57 . The method of claim 1 , comprising treating pemphigus foliaceus.

58 . The method of claim 1 , comprising reducing average daily corticosteroid usage by the human patient.

59 - 61 . (canceled)

62 . The method of claim 1 , comprising healing at least 50% of established pemphigus lesions.

63 . The method of claim 1 , comprising preventing new pemphigus lesion formation.

64 . The method of claim 1 , comprising reducing a pemphigus disease activity index (PDAI) skin score.

65 . (canceled)

66 . The method of claim 1 , wherein the human patient is characterized by a pemphigus disease activity index (PDAI) skin score of 0 or 1 following the administration of PRN1008.

67 . (canceled)

68 . (canceled)

69 . The method of claim 1 , further comprising achieving a control of disease activity of pemphigus.

70 . The method of claim 1 , further comprising achieving an end of consolidation phase of pemphigus.

71 . (canceled)

72 . (canceled)

73 . The method of claim 1 , wherein PRN1008 is orally administered to the human patient.

74 - 77 . (canceled)