1. ¹Department of Internal Medicine, Barnes-Jewish Hospital, Washington University School of Medicine, Saint Louis, MO, USA
2. ²Department of Internal Medicine, Division of Oncology, Section of Bone Marrow Transplantation and Leukemia, Siteman Cancer Center and Washington University School of Medicine, Saint Louis, MO, USA

Correspondence: Dr R Vij, Washington University School of Medicine, Division of Oncology, Section of Bone Marrow Transplantation and Leukemia, 660 S Euclid Avenue, Campus Box 8007, Saint Louis, MO 63110-1093, USA; E-mail: rvij@im.wustl.edu

Received 26 October 2004; Accepted 19 January 2005; Published online 4 April 2005.

Abstract

Interleukin 6 (IL-6) is a major growth factor for myeloma cells and retinoids have been shown to inhibit expression of the interleukin 6 receptor (IL-6R). We performed a pilot study to assess the efficacy and tolerability of 13cis retinoic acid (13cRA) and dexamethasone (Dex), when added to interferon (IFN) as maintenance therapy post autologous stem cell transplantation. Between 90 and 120 days post stem cell transplantation, 33 patients were started on 13cRA 1 mg/kg p.o. daily for 14 days and Dex 40 mg p.o daily for 5 days every month. 13cRA was dose escalated by 0.5 mg/kg/month to 2 mg/kg. Seventeen patients had a persistent paraprotein post transplant. Overall, a response to therapy was observed in 11/17 (64%), with a complete response in 4/17 (23.5%) and a partial response (50% paraprotein decline) in 7/17 (41%). With a median follow-up of 34.8 months, 22/33 (66%) demonstrated disease progression and 11/33 (33%) died. The median progression-free survival from diagnosis was 34.7 months. Although a decline in paraprotein was frequently observed on triple therapy, many patients discontinued therapy due to the side-effects of the IFN. Future trials should be designed using 13cRA and Dex alone.