KINETICS OF PARAPROTEIN CLEARANCE AFTER AUTOGRAFTING FOR MULTIPLE-MYELOMA

The kinetics of paraprotein clearance after autografting for multiple myeloma have not been described. We studied 33 myeloma patients in pla teau phase with detectable paraprotein (3-34 g/l, median 10 g/l) at th e time of ABMT who received melphalan (200 mg/m(2) and methylprednisol one (1.5 g x 5) for conditioning. Fifteen patients received interferon -alpha post-transplant as part of a randomized study. Twenty-four of 3 3 (72.7%) patients eventually cleared the paraprotein at a median of 4 7 days (range 5-783) post-transplant. The probability of clearance was lower (46.7 vs 94.4%, P = 0.004) and the time taken to clear paraprot ein longer (142 vs 29 days, P = 0.003) in patients with a higher level (>10 g/l) at the time of the transplant. However, clearance occurred within 6 months in 23 of 24 (95.8%) patients who ultimately cleared th e paraprotein. Interferon-alpha did not influence the clearance of par aprotein. We conclude that after autografting for myeloma, the time ta ken to clear paraprotein is longer and the probability of clearance lo wer with higher levels at the time of ABMT, and most patients who even tually clear the paraprotein do so within 6 months. Because the probab ility of clearing paraprotein (and thus attaining remission) in patien ts with detectable paraprotein 6 months post-transplant is low, a deci sion about further treatment may be made at this point.