Corticosteroids (CS)
Since the time of their approval in the 1950s, corticosteroids have been the mainstay of treatment of PV.
Mechanism of Action
Corticosteroids have strong anti-inflammatory and immunosuppressive effects. They affect almost every aspect of the immune system. They are potent inhibitors of NFkappa B activation and have effects on leukocyte movement, leukocyte function, and humoral factors. In addition they have inhibitory effects on many known cytokines [11].
The first case series on corticosteroid use in PV was published in 1972.
The publications reporting use of corticosteroids in PV are summarized in Table 1. This table includes papers that had systemic corticosteroids as the primary medication used. Topical steroids were also used in many of the reports. In addition, adjuvant drugs were added in most cases. These adjuvants included azathioprine, methotrexate, cyclophosphamide, dapsone, gold, levamisole, cyclosporine, and mycophenolate. Adjuvants were usually administered one at a time; however, they were changed when lack of response was noted, and therefore some patients had multiple adjuvants used sequentially over the period of treatment.
Publication Type, Patient Profiles, and Sample Sizes
Seventeen case series were found, with the number of cases included in the individual papers ranging from 4 to 1111 cases (a total of 1704 patients were included in the 17 case series, of which 1681 had PV and 23 had either pemphigus foliaceous, pemphigus vegetans, or pemphigus erythematous). Six case reports describing single patients, one prospective cohort study (n = 74), two randomized controlled trials (n = 20 and n = 120), and five retrospective cohort studies (n = 15, n = 16, n = 23, n = 32, and n = 154) are summarized in the Table 1. In all, the total number of cases in these 31 publications was 2164 out of which 2141 were PV patients, and the rest had pemphigus foliaceous or pemphigus vegetans or pemphigus erythematous. These 31 reports originated from the USA, Israel, Iran, Sri Lanka, India, Scotland, Italy, Greece, Spain, the Netherlands, Germany, France, Singapore and Turkey.
Age at initial diagnosis of PV in these publications ranged from 4 to 89 years.
Medication Use
Prednisone and prednisolone were the most commonly used corticosteroids. Starting doses ranged from 15 to 180 mg prednisone equivalent daily in all but one of the reports where doses as high as 400 mg daily were used [12, 13].
Duration of PV Before Corticosteroids Were Started
This ranged from 0.15 months to 6 years.
Duration of Total Follow-up
Duration of total clinical follow-up of the individual patients ranged from 9 months to 22 years.
Duration Before Any Clinical Improvement Was Noted
Seven publications reported on the duration before any clinical improvement after the start of corticosteroids was apparent, and this ranged from 3 days to 19 weeks [14–20].
Duration to Start of Taper of Corticosteroids
Information regarding tapering of corticosteroids was reported in seven publications. The duration before the start of taper of corticosteroids ranged from 0.5 to 12 months in these seven publications comprising of 156 patients.
Duration to Complete Remission (On and Off Therapy)
Duration to complete remission on therapy was reported in 15 articles, and ranged from 1.5 to 42 months (3.5 years), in 797 patients.
Duration to complete remission off therapy was reported in 15 articles, and ranged from 4 to 120 months (10 years) in 321 patients.
Remission
Of a total of 2141 patients reported on in Table 1, at the end of follow-up 97 patients had achieved partial remission on therapy, 797 patients had achieved complete remission on therapy, and 321 patients had achieved complete remission off therapy. A total of 485 patients were still being treated at the time of publication, 156 patients were lost to follow-up, death occurred in 177 patients, and 47 patients were classified as non-responders and referred elsewhere for treatment.
Duration of Medication Use
Total duration of medication use for all reported patients including those still on therapy at the time of publication ranged from 1.5 to 240 months (20 years).
Follow-up Duration After Discontinuation of Medications
Follow-up ranged from 2 to 156 months (13 years) after discontinuation of treatment in the 321 patients with complete remission off therapy, during which time there was no recurrence.
Mortality
Death occurred in a total of 177 of 2141 patients (8.26 %) with PV in all reports. These included deaths from all causes. Of these, the reports published between 1970 and 1980 included 127 patients with 61 deaths (48.03 %), between 1981 and 1990 included 183 patients with 26 deaths (14.2 %), between 1991 and 2000 included 190 patients with 7 deaths (3.6 %), and those published between 2001 and 2010 included 1589 patients with 83 deaths (5.2 %).
Adverse Effects
Adverse effects from corticosteroids reported in these papers included Cushingoid symptoms, diabetes mellitus, osteoporosis, hypertension, insomnia, GI upset, increased weight, candidiasis, tuberculosis, mood change, abnormal liver function test, fungal and viral infection, fatigue, acute psychosis, hyperglycemia, electrolyte imbalance, hypocalcemia, acidosis, hyperkalemia, phlebitis, herpes simplex, hyperlipidemia, bone marrow depression, cataract, and myopathy.
Azathioprine (AZA)
Azathioprine was approved by the US Food and Drug Administration (FDA) in 1968 as an immunosuppressant to prevent organ transplant rejection.
Mechanism of Action
This drug restricts synthesis of DNA, RNA, and proteins by inhibiting metabolism of purine. It also interferes with cellular metabolism and mitosis [8].
Publication Type, Patient Profiles, and Sample Sizes
The studies reporting use of AZA in PV are summarized in Tables 1 and 2. Of the 31 papers in Table 1, 17 had included azathioprine as one of the treatment modalities. Table 2 includes only those publications that reported on comparative analyses of outcomes for patients on prednisone alone vs. those on prednisone in combination with azathioprine. The first case series on use of AZA in PV was published in 1986.
One randomized double blind controlled study (n = 56) and two retrospective cohort studies (n = 48 and n = 36) are summarized in Table 2. In all, a total of 140 patients were included in these three reports.
Age at initial diagnosis of PV in these publications ranged from 16 to 83 years.
Medication Use
The dosage of azathioprine used was 40 mg/day up to 3 mg/kg/day in all reports. Prednisone was used concomitantly with azathioprine in all reports. Azathioprine was added at the onset of treatment in the three reports in Table 2 and sometime after onset of corticosteroid use in the reports in Table 1.
Duration of PV Before Azathioprine Was Started in the Reports Summarized in Table 2
This ranged from 4 to 10 months.
Duration of Follow-up in the Reports Summarized in Table 2
Duration of clinical follow-up of the individual patients on azathioprine in these reports ranged from 12 months to 10 years.
Duration to Complete Remission (On and Off therapy) for the Azathioprine Plus Prednisone Group in Table 2
Duration to complete remission on therapy was reported in three articles and, ranged from 6 to 12 months, in 67 patients.
Duration to complete remission off therapy was reported in two articles and, ranged from 6 to 12 months, in eight patients.
Patients on prednisone and azathioprine had better responses as compared to patients on prednisone alone, with more patients achieving remission, and with fewer side effects.
Remission
Of a total of 140 patients, at the end of follow-up 11 patients had achieved partial remission and mean duration to achieve that was 234.4 days, 67 patients had achieved complete remission on therapy, and eight patients had achieved complete remission off therapy. Six patients were still being treated at the time of publication. No response was seen in 17 patients. Treatment failed in five patients. Death occurred in 13 patients and 13 patients were lost to follow-up.
Adverse Effects Reported in Table 2
Adverse effects in patients on azathioprine and corticosteroids reported in these publications included leukopenia, anemia, thrombocytopenia, pancytopenia, hepatotoxicity, hypertension, gastrointestinal problems, lethargy, weight gain, muscle weakness, adrenal suppression, alopecia, and rash-like skin disorders.
Mycophenolate Mofetil (MMF)
Mycophenolate Mofetil was approved by the FDA in 1995 as an immunosuppressant to prevent organ transplant rejection.
Mechanism of Action
After oral administration, mycophenolate is absorbed rapidly and then gets converted to the active metabolite mycophenolic acid (MPA). This active metabolite inhibits inosine monophosphate dehydrogenase selectively and hence inhibits de novo pathway of purine synthesis in T and B cells, which results in inhibition of T and B cell proliferation [20].
Publications reporting use of MMF as an adjuvant to corticosteroids in PV were included in Table 1. Additional papers which have reported on the use of mycophenolate in patients with refractory PV (previous treatment with corticosteroids and azathioprine was unsuccessful in achieving remission) are summarized in Table 3. Of 31 papers in Table 1, three had included MMF as one of the treatment modalities.
Publication Type, Patient Profiles, and Sample Sizes
The first case series on use of MMF in PV patients was published in 1999.
Four case series were included, with the number of cases included in the individual papers ranging from 9 to 31 cases (a total of 64 patients in four case series); two were case reports describing single patients and two were randomized prospective trials (n = 94 and n = 21, respectively). One additional randomized clinical trial enrolled both PV and PF patients [n = 36 (PV) + 11 (PF); results were not reported separately for the PV and PF patients in this study] and one retrospective analysis (n = 18) is summarized in the tables. The total number of patients treated with MMF in these 10 reports was 247.
Age at initial diagnosis of PV in these publications ranged from 6 to 78 years.
Medication Use and Duration of PV Before MMF Was Started
Medication use and duration of PV before MMF was started ranged from 1 month to 14 years. During this period patients were on a combination of corticosteroids and azathioprine. At the time mycophenolate was added, the azathioprine was discontinued; however, the patients continued to be on corticosteroids. One publication (Powell et al.) reported on patients in whom multiple medications like methotrexate, cyclophosphamide, IVIg, dapsone, gold, thalidomide, and minocycline along with azathioprine and corticosteroids were tried prior to addition of mycophenolate [21].
The starting dosage of mycophenolate mofetil used was 2–3 g/day in all reports.
Duration of Follow-up
Duration of clinical follow-up of the individual patients after the start of MMF therapy ranged from 5 to 130 months.
Duration Before Any Clinical Improvement Was Noted
First improvement in lesions was noted after 2–24 weeks after addition of mycophenolate to the existing medication regimen.
Duration to Complete Remission (On and Off Therapy) After Addition of MMF
Duration to complete remission on therapy was reported in six articles and, ranged from 2 to 16 months, in 104 patients.
Duration to complete remission off therapy was reported in one article and, ranged from 24 to 36 months, in 17 patients.
Remission
Of a total of 247 patients, 104 patients achieved complete remission on therapy and 17 patients achieved complete remission off therapy. A total of 76 patients achieved partial remission, and the duration to achieve that ranged from 129 to 150 days after the start of therapy. Failure of MMF was mentioned in four reports (N = 176) in 18 patients who were referred for treatment with rituximab or IVIg. Two patients were still being treated at the time of publication, 29 patients were lost to follow-up or withdrawn from study, and death occurred in one patient.
Adverse Effects
Adverse effects in patients on mycophenolate and corticosteroids reported in these publications included gastrointestinal problems, myalgia, neutropenia, and lymphopenia, which were the most common side effects reported. Headache, increased fasting blood glucose level, and hypertension, nausea, depression, pyrexia, redistribution of body fat, eye disease, weight gain, fatigue, and arthralgia were also reported.
In the one publication where enteric coated mycophenolate sodium was used, the side effects reported were headache and increased fasting blood glucose level.
Intravenous Immunoglobulin (IVIg)
IVIg was approved by the FDA for primary immune deficiency in 1952 [22].
Mechanism of Action
Intravenous immunoglobulins (IVIg) are obtained from a plasma pool of thousands of donors [22].
These immunoglobulins neutralize and slow down the production of circulating pemphigus antibodies [23].
Publication Type, Patient Profiles, and Sample Sizes
The studies reporting use of IVIg in PV are summarized in Table 4. The first case series on IVIg in PV was published in 2002.
One case series (n = 6), two case reports describing single patients, and one randomized placebo-controlled double-blind trial (n = 40) are summarized in Table 4, with a total of 48 patients included in these four papers. These reports included patients previously treated with corticosteroids, cyclophosphamide, azathioprine, and methotrexate without adequate response, prior to start of IVIg.
Age at initial diagnosis of PV in these publications ranged from 41 to 78 years.
Medication Use
The dosage of IVIg used was 400 mg/kg/day for 5 days followed by long- or short-term single doses of 400 mg/kg/day every 6 weeks for 6 months to 1 year. Concomitant drugs mainly used were corticosteroids in the published studies.
Duration of PV Before IVIg Was Started
This ranged from 2 months to 5 years.
Duration of Total Follow-up
Duration of total clinical follow-up of the individual patients ranged from 2 months to 2 years.
Duration Before Any Clinical Improvement Was Noted
First improvement in lesions was reported within 2–3 weeks of first IVIg infusion in all 48 patients.
Duration to Start of Taper of Corticosteroids
Only one case series of six patients described the duration to the start of taper of corticosteroids and only mentioned that the median time was 16 days after the start of IVIg infusions.
Duration to Complete Remission (On and Off Therapy)
This information was not available from the publications. However, all reports discussed improvement in all patients treated with IVIg; in six patients this was achieved within 3 weeks and in 29 patients within 3–12 months. Thirteen patients in the placebo group had no improvement.
Adverse Effects in Patients on IVIg Reported in Table 4
Headache, abdominal discomfort, nausea, constipation, lymphopenia, hepatitis C, and palpitations.
Methotrexate
Methotrexate was approved by the FDA for psoriasis in 1971 and for rheumatoid arthritis in 1988.
Mechanism of Action
Methotrexate inhibits the metabolism of folic acid and is used as a chemotherapeutic and immunosuppressive agent. Methotrexate allosterically inhibits dihydrofolate reductase, which plays a role in tetrahydrofolate synthesis. As folic acid is essential for normal cell growth and replication, methotrexate is effective against malignant cell growth and has anti-inflammatory effects [24].
Publication Type, Patient Profiles, and Sample Sizes
The studies reporting use of methotrexate in PV are summarized in Table 5. The first case series on MTX in PV was published in 1969.
Publications reporting use of methotrexate in PV were included in Table 1 (7 of 31 papers included methotrexate), and additional papers that reported on the use of methotrexate as the initial adjunctive treatment to corticosteroids are summarized in Table 5.
Six case series were included, with the number of cases included in the individual papers ranging from 3 to 53 cases (total of 121 patients in six case series), and one retrospective cohort study (n = 30) are summarized in the tables. In all, a total of 151 patients treated with MTX are reported in seven studies.
Age at initial diagnosis of PV in these publications ranged from 20 to 83 years.
Medication Use
The dosage of MTX used in these publications ranged from 12.5 to 150 mg/week. Concomitant drug used along with methotrexate was prednisone.
Duration of PV Before Methotrexate Was Started
This ranged from 11 months to 7 years.
Duration of Follow-up
Duration of clinical follow-up of the individual patients after the start of MTX ranged from 5 to 15 years.
Duration Before Any Clinical Improvement Was Noted
First improvement in lesions was reported within 1–30 weeks after the start of methotrexate therapy.
Duration to Complete Remission (On and Off Therapy)
Duration to complete remission on therapy was reported in six articles and, ranged from 1 to 30 weeks, in 51 patients.
Duration to complete remission off therapy was reported in one article and, ranged from 3 months to 8 years, in 14 patients.
Remission
Of a total of 151 patients, at the end of follow-up, 56 patients had achieved partial remission and the duration to achieve that was within 6 months after the start of MTX therapy; 51 patients had achieved complete remission on therapy; and 14 patients had achieved complete remission off therapy. Twelve patients were lost to follow-up. Treatment was not effective in nine patients. Death unrelated to MTX occurred in six patients.
Adverse Effects in Patients on MTX Reported in Table 5
Nausea, leukopenia, GI upset, fatigue, bacterial infection, bronchopneumonia, septicemia, necrotizing gingivitis, diarrhea, and pyoderma.
Rituximab
Rituximab was approved in 1997 by the FDA to treat B cell non-Hodgkin lymphoma and in 2006 to treat rheumatoid arthritis.
Mechanism of Action
Rituximab is a human–mouse chimeric monoclonal antibody to CD20 antigen on B cells. CD20 is a membrane protein that is involved in activation and proliferation of B cell [25].
Publication Type, Patient Profiles, and Sample Sizes
The studies reporting use of rituximab in PV are summarized in Table 6. The first case series on PV treated by rituximab was published in 2002.
Publications which have reported on the use of rituximab in patients with refractory PV (previous treatment with corticosteroids, azathioprine, methotrexate, mycophenolate, IVIg, and cyclophosphamide were unsuccessful in achieving remission) are summarized in Table 6.
Nineteen case series were included, with the number of cases included in the individual papers ranging from 3 to 84 cases (total of 339 patients in 19 case series), 24 were case reports describing single patients, three open label pilot studies (n = 5, n = 9, and n = 17), one randomized prospective trial (n = 15), two retrospective analysis (n = 25 and n = 19), and one phase 2 clinical trial (n = 40) are summarized in the tables. In all, a total of 493 patients were treated with rituximab.
Age of patients treated with rituximab for PV in these publications ranged from 15 to 86.
Medication Use
The dosage of rituximab used was 375 mg/m2 body surface area (BSA) once weekly for 4 weeks or two infusions of 1000 mg at 2 weeks apart. Previously failed treatments before rituximab were prednisone, MMF, AZA, IVIg, MTX, dapsone, CyclP, plasmapheresis, protein A immunoadsorption, cyclosporine, dexamethasone, and gold. Concomitant drug used was prednisone, MMF, AZA, and IVIg.
Duration of PV Before Rituximab Was Started
This ranged from 1 months to 23 years.
Duration of Follow-up
Duration of clinical follow-up of the individual patients after the start of rituximab therapy ranged from 6 to 80 months.
Duration Before Any Clinical Improvement Was Noted
First improvement in lesions was reported within 2 weeks to 8 months after the first rituximab infusion.
Duration to Complete Remission (On and Off Therapy)
Duration to complete remission on therapy was reported in 32 articles and, ranged from 1 to 36 months, in 184 patients.
Duration to complete remission off therapy was reported in 22 articles and, ranged from 2 to 59 months, in 229 patients.
Remission
Of a total of 493 patients reported in Table 6, at the end of follow-up, 80 patients had achieved partial remission, and duration to achieve that ranged from 3 to 27 months; 184 patients achieved complete remission on therapy; and 229 patients achieved complete remission off therapy. Death due to sepsis occurred in three patients. Relapses were seen in nine patients. No response to rituximab was seen in 11 patients. However, these patients had response after addition of IVIg or additional cycles of rituximab.
Adverse Effects in Patients on Rituximab Reported in Table 6
Local pain, nausea, cough, chills, sepsis, and angioedema related to infusion.