Based on open studies, D-penicillamine (DPA) has been used for the treatmen
t of systemic sclerosis (SSc) but we believe the controlled trial of this d
rug in SSc does not support its use to treat this disease. Open trials are
inevitably biased by selection bias and randomized, blinded, controlled stu
dies are required to minimize both known and unknown confounding variables.
The high vs. low dose DPA, trial was a well-controlled, randomized, double
-blind study which met criteria for a high quality study, although it was n
ot placebo-controlled. Toxicity was increased in the high dose group, thus
showing a biologic response, although the study showed no clinical efficacy
differences between a mean dose of 120mg DPA every other day (equivalent t
o 60mg qd) and a mean dose of 822mg DPA daily. One might argue that 60mg DP
A is effective, but we believe this is highly unlikely, as doses significan
tly higher than this have been shown to be ineffective in other connective
tissue diseases such as rheumatoid arthritis. In our opinion, D-penicillami
ne is, unfortunately, ineffective in treating early, diffuse, systemic scle
rosis.