Rituximab superior to Mycophenolate mofetil for complete remission of Pemphigus Vulgaris: Study

Pemphigus vulgaris is a rare and often life-threatening autoimmune disease. It is characterized by blistering and erosion of the skin and mucous membranes. It specifically occurs in either middle-aged or older people. The primary lesion of pemphigus vulgaris is a soft blister filled with clear fluid that appears on healthy or irritated skin. Rituximab and mycophenolate mofetil have been actively used to cure pemphigus vulgaris, however, their individual efficacies have never been thoroughly compared.

A study was conducted by a group of researchers from the U.K., to adequately compare Rituximab and Mycophenolate mofetil used in the treatment of pemphigus vulgaris in clinical trials.

The researchers conducted a randomized, controlled trial, wherein they categorized a total of 135 moderate-severe patients suffering from pemphigus vulgaris into two groups and were administered either intravenous rituximab (67 patients with 1000 mg on days 1, 15, 168, and 182) or oral mycophenolate mofetil (68 patients with 2 g per day) in a 1:1 ratio. Additionally, both the groups were also administered an oral glucocorticoid was also administered on the same tapering schedule.

Ø The primary endpoint was sustained complete remission at week 52, defined as the healing of lesions with no new active lesions, as reflected by a Pemphigus Disease Area Index (PDAI) activity a score of 0 (on a scale of 0 to 250, with higher scores indicating greater disease severity), for at least 16 weeks without the use of glucocorticoids.

Ø While the secondary end points were the total dose of glucocorticoids, the number of disease flares, and the change from baseline in the score on the Dermatology Life Quality Index (DLQI; scores range from 0 to 30, with higher scores indicating greater impairment).

The findings were as follows:

Ø The primary outcome was assessed in the modified intention-to-treat population: 62 patients in the rituximab group and 63 in the mycophenolate mofetil group.

Ø The median PDAI activity score was better in the group that received Mycophenolate mofetil (18.3) as compared to the Rituximab group (22.7).

Ø At week 52, in a total of 25 patients, continued complete remission was seen more in the rituximab group (40%) as compared to the mycophenolate mofetil group (10%) (difference, 31 percentage points; 95% confidence interval [CI], 15 to 45; P<0.001).

Ø The average total glucocorticoid dosage during the 52-week treatment period was more in the mycophenolate group (5140 mg) than the rituximab group (3545 mg) (difference, −1595 mg; 95% CI, −2838 to −353; P<0.001).

Ø Also, the disease flares were more in the mycophenolate group (44) as compared to the rituximab group (6) (adjusted rate ratio, 0.12; 95% CI, 0.05 to 0.29; P<0.001).

Ø The mean change in DLQI the score was −8.87 points and −6.00 points, respectively (difference, −2.87 points; 95% CI, −4.58 to −1.17; P=0.001).

Ø Serious adverse events occurred more frequently in the rituximab group (22%) than the mycophenolate mofetil group (15%).

The authors concluded that though Rituximab was more favorable than mycophenolate mofetil in producing sustained complete remission at 52 weeks in patients with pemphigus vulgaris, it caused more serious adverse events. Hence further evaluation to investigate the comparative efficacy and safety of rituximab and mycophenolate mofetil beyond 52 weeks of treatment is required. 

Reference

A study titled, "Rituximab versus Mycophenolate Mofetil in Patients with Pemphigus Vulgaris" by Werth V et. al published in The New England Journal of Medicine.

DOI: 10.1056/NEJMoa2028564