Low-dose interferon-alpha in stage-I multiple myeloma and in IgM monoclonal gammopathy. Eastern Cooperative Study Group on Monoclonal Gammopathies

Viewpoint on the impact of interferon in the treatment of multiple myeloma: benefit for a small proportion of patients?

Interferon-alpha (IFN-alpha) generally inhibits myeloma cell growth. However, a growth stimulatory effect for myeloma cells has also been reported. In patients with untreated multiple myeloma (MM) IFN-alpha, used as a single agent, produced an objective response rate ranging from 10 to 25%. In previously untreated patients: (1) the time to response is short, (2) the median duration of response is similar to the duration of response observed in patients given chemotherapy, and (3) the patients who are more likely to benefit are those with IgA myeloma type. Concerning the results of IFN-alpha given as a single agent in relapsing and resistant MM, they are poor, with a response rate ranging between 10-20%. The combination of high-dose glucocorticoids and IFN-alpha for relapsing/resistant patients produced controversial results. Some studies showed an increased response rate and/or longer survival with chemotherapy plus IFN-alpha versus chemotherapy alone in previously untreated patients. In contrast, most reports did not show a significant increase in response rate or survival benefit by adding IFN-alpha to the initial chemotherapy. Perhaps the most encouraging role for IFN in MM is as maintenance therapy in patients responding to first line treatment (ie conventional chemotherapy followed or not by high-dose intensification/autotransplantation). In spite of that, several reports failed to show longer response duration. The majority of studies have shown a modest but significant prolongation in response duration in favour of the IFN arm. However, most of these studies have failed to show a significant survival advantage with IFN maintenance. A meta-analysis, by the Myeloma Trialists' Collaborative Group in Oxford, based on the individual data from 4012 patients included in 24 randomized trials (induction and/or maintenance) has shown that IFN produced a moderate improvement in relapse-free survival and a minor improvement in overall survival. In summary, the only role of IFN in MM is as maintenance treatment after a response is achieved. However, looking at the published data, it seems that the vast majority of patients do not benefit from IFN maintenance, while a small proportion of them, in the range of 5-10%, obtain a significant prolongation in event-free survival and overall survival. Unfortunately, there are no predictive factors that can identify the patients who are likely to benefit from IFN maintenance.

Prognostic factors in low tumour mass asymptomatic multiple myeloma: a report on 91 patients. The Groupe d'Etudes et de Recherche sur le Myélome (GERM)

Between January 1985 and July 1989 we diagnosed asymptomatic stage I multiple myeloma according to Durie and Salmon [Durie and Salmon: Cancer 36:842, 1975] in 91 patients. All patients were followed without chemotherapy. Disease progression occurred in 41 patients and the median time to progression for all patients was 48 months. In the Cox multivariate regression analysis, hemoglobin levels < 12 g/dl (P < .01), bone marrow plasmacytosis > 25% (P < .01), and M-component size > or = 30 g/l for Ig G or > or = 25 g/l for Ig A (P < .01) were the only significant prognostic factors for progression. The 38 patients without any harmful factor remained free of progression for a median of more than 50 months. The 18 patients with two or three of these characteristics (high-risk group) had the shortest median time to progression of 6 months. Despite different times to progression, the response rate and survival after chemotherapy were similar for all groups of patients. Patients in the high-risk group for progression have to be frequently monitored for disease progression and might benefit from early treatment.

Phase II trial of recombinant interferon alfa-2 in the treatment of primary systemic amyloidosis

Primary systemic amyloidosis (AL) is a rare disorder characterized by production of an aberrant monoclonal light chain. This insoluble light chain, or a fragment thereof, deposits in tissues as amyloid and results in disruption of organ function and, ultimately, death. Although melphalan and prednisone were reported to benefit subsets of patients with the disease, many patients showed no benefit; the median survival with the disease is approximately 2 years. There is a need to develop new agents for patients who fail to respond to a trial of cytotoxic chemotherapy. A study was undertaken of interferon alfa-2 in the treatment of 15 patients with AL because of its reported benefits in the induction and maintenance therapy for patients with multiple myeloma, a disease that has many characteristics in common with AL. None of the patients showed any objective regression of their disease; the median survival of the entire group was 26.3 months. This survival is not superior to that reported with other agents used for this disease. We conclude that interferon alpha-2 is not a valuable agent in the treatment of AL.