Improvement in psoriasis after intradermal administration of delipidated, deglycolipidated Mycobacterium vaccae (PVAC™): results of an open-label trial

Abstract

The aim of new treatments for psoriasis is to induce extended remissions with fewer side-effects. Previous studies suggest that Mycobacterium vaccae, a harmless organism prepared as a heat-killed suspension, may induce periods of remission in some psoriasis patients after intradermal administration. To assess a more potent derivative of M. vaccae, we conducted an open-label study in which 20 patients with moderate to severe psoriasis (Psoriasis Area and Severity Index of 12-35) received two intradermal inoculations of heat-killed, delipidated, deglycolipidated M. vaccae (DD-MVAC or 'PVAC') in lesion-free deltoid skin, separated by a period of 3 weeks. Twelve weeks after the injections, 13 out of 20 patients (65%) showed marked improvement in the PASI score (> 50% reduction), three were unchanged (< 25% reduction), three had worsened (> 5% increase), and one was withdrawn from the trial because of an exfoliative flare. At 24 weeks, 13 out of 19 patients continued to show > 50% improvement that, in some, lasted for 6 months or longer. Patients classified as good responders at 12 or 24 weeks were then offered additional PVAC injections after 24 weeks if the PASI reached 8 or higher. Intra-dermal administration of PVAC was safe, well tolerated, and induced clinically significant improvement in many psoriasis patients. A randomized, double-blind, controlled study is warranted.

A randomised placebo controlled trial of delipidated, deglycolipidated Mycobacterium vaccae as immunotherapy for psoriatic arthritis

“…25 Despite previous studies showing beneficial effects of M vaccae in skin disease, this study found no difference between the two groups for the PASI, which reflects the severity of psoriasis. One explanation may be that in previous studies of PVAC in psoriasis, 10 patients had much more severe psoriasis but very low rates of DMARD use, compared with the patients in our study. This study was not designed to investigate the efficacy of PVAC in psoriasis and, indeed, patients with PsA often have mild psoriasis.…”

“…9 To explore this further, an open label study of PVAC for treatment of psoriasis was conducted. 10 In this study two 50 mg doses of PVAC were given intradermally to 20 adult patients with moderate to severe psoriasis (Psoriasis Activity and Severity Index (PASI) 11 score 12-35). By 12 weeks, 13/20 (65%) patients had improved with a .50% fall in their PASI score.…”

The production of a new extracellular putative long-chain saturated polyester by smooth variants of Mycobacterium vaccae interferes with Th1-cytokine production

“…Heat-hilled M. vaccae preparations used in previous studies were mainly obtained from two strains, the NCTC 11659 strain that displays a rough morphology and the ATCC 15483 T which is a smooth strain (Mayo and Stanford 2000;Balagon et al 2001;Shirtcliffe et al 2001;Abbot et al 2002;O'Brien et al 2004). To our knowledge, no study has been performed to analyse the possible influence of colonial morphology on the induced immune response.…”

A Review of Possible Triggering or Therapeutic Effects of Antimicrobial Vaccines on Psoriasis

“…Mycobacterium vaccae, a nonpathogenic organism usually applied as a heat-killed suspension, has been used as an adjunct immunotherapy for tuberculosis and leprosy [54]. The immunotherapy trials began after discovery of the therapeutic effect of M. vaccae injection in psoriasis skin lesions of leprosy patients with concomitant psoriasis [55].…”