Objective: To explore the efficacies and toxicities in multiple myeloma (MM) patients on the maintenance therapies of thalidomide and interferon-α so as to seek the optimal chemotherapeutic regimen.
Methods: A retrospective analysis was conducted for 57 MM patients on the maintenance therapies of thalidomide and interferon-α after introduction and consolidation. And 56 MM patients without maintenance therapy were enrolled as the control group.
Results: The values of progression-free survival (PFS) and overall survival (OS) were significantly longer in the maintenance group and this translated into an improved estimated 3-year PFS of 75.4% (71.8%, 83.3%) versus 23.2% in the control group (P < 0.01). The estimated 4-year OS was higher in the maintenance group [89.5% (89.7%, 88.9%) vs 33.9%, P < 0.01]. No statistically significant differences existed among different maintenance groups in terms of PFS and OS. The administration of maintenance therapy extended both PFS and OS for MM patients of various M-proteins (P < 0.05). However, in the thalidomide group, PFS and OS were extended only in MM of immunoglobulin G (IgG) and immunoglobulin A (IgA) but not in light-chain patients. Furthermore, the MM patients of Durie-Salmon (DS) stages II and III and international staging system (ISS) stages II and III extended PFS and OS through maintenance (P < 0.05). While in those of ISS stage I, the differences were insignificant in terms of PFS and OS between two groups. The results were similar between the thalidomide and control groups. The patients achieving a partial remission (PR) or higher response level benefited from the maintenance therapy in terms of PFS and OS (P < 0.05). In the thalidomide group, the patients with below PR prolonged OS (P = 0.031) but did not achieve a longer PFS (P = 0.091). Both PFS and OS were extended through maintenance therapy after either stem cell transplantation or consolidation chemotherapies (P < 0.05). There was no significant difference in terms of PFS and OS between MM patients without maintenance therapy after transplantation and those without transplantation. The adverse effects of thalidomide, milder than those of interferon-α, could be tolerated in most patients. The incidence and severity of adverse effects showed no significant difference between the combination maintenance and single agent therapies.
Conclusion: The maintenance therapies of thalidomide and interferon-α could improve the profiles of PFS and OS in MM patients. And there was no significant difference between them in terms of PFS and OS. However, the maintenance therapy of thalidomide is a better option due to its convenient application, milder adverse effects, reasonable cost and better efficacies in MM patients not achieving PR or receiving induction therapy without bortezomib or without transplantation.