A 15-year (1973-1988) prospective study was conducted to determine the effectiveness of D-penicillamine (D-pen) in the treatment of rapidly progressive systemic sclerosis (SSc) of recent onset. Sixty-nine consecutive patients fulfilling strict criteria for rapidly progressive diffuse SSc of less than 18 months of duration were enrolled. Sixty received at least 750 mg/day of D-pen for at least 6 months, whereas 9 did not complete 6 months of treatment because of toxicity, noncompliance or death. In 58 of the 60 patients treated for longer than 6 months, there was an arrest in the progression of skin sclerosis followed by regression with softening, increased pliability and reappearance of sweating and hair. In these cases, the extent of sclerotic skin decreased from a maximum of 64.6 +/- 23.1% total body surface to 15.7 +/- 13.2%. In addition, in the group of patients that received D-pen for longer than 6 months, SSc renal disease was uncommon and pulmonary involvement was not progressive. The overall survival in this group was 88.3%. In conclusion, our prospective study showed that the administration of D-pen resulted in significant improvement of skin sclerosis and in prolonged survival of patients with early, rapidly progressive SSc with diffuse cutaneous involvement.