Treatment of myeloma

Abstract

Survival for myeloma has improved from a median of 7 months in the 1950s to about 30 months today. Progress in chemotherapy has contributed a great deal to this improvement, although it may also, in part, reflect the improved treatment of infections, renal failure and hypercalcaemia as well as earlier diagnosis. For over 30 years, the gold standard of treatment has been oral melphalan and prednisolone, producing a clinical response in approximately 60% of patients and a median survival of around 36 months. Relapse is unfortunately inevitable in all but a handful and, for the majority, treatment can only hope to produce significant periods of remission with minimal treatment-related morbidity and mortality. Recently, improved results have been seen with the introduction of aggressive chemotherapy and bone-marrow transplantation. Marrow ablative therapies produce remissions in virtually all patients, with complete remissions in approximately 1/3. The best response is seen in those with a lower tumour burden, which will reduce the development of secondary resistance. Current treatment is moving towards an approach using sequential therapy. This involves induction chemotherapy with VAD or a similar regimen such as VAMP (vincristine, adriamycin and methylprednisolone), proceeding to high-dose therapy, often with some form of stem-cell rescue. This ensures minimal tumour burden prior to high-dose treatment as well as reducing graft infiltration, improving general performance status and allowing recovery of renal function. Relapse remains a problem, although the use of IFN may reduce this by prolonging the plateau phase. High-dose therapy should be given early, before prolonged use of alkylating agents induces stem-cell dysplasia, before significant complications arise from the myeloma, and before drug resistance is significant. Unfortunately, these treatments come at a price, in terms of increased treatment-related toxicity. There also remains uncertainty as to the extra benefits of high-dose treatment with marrow rescue over high-dose chemotherapy alone. We await the current MRC trial with interest. For a very few, there is the tantalising possibility of cure with allografting. For those in complete remission after first-line induction therapy, allogeneic bone-marrow transplantation offers the best hope of survival, but comes at a greatly increased risk of toxicity, and it is uncertain if it is superior to autografting for the majority of patients. It may soon be possible to identify those poor prognosis patients in whom an allogeneic transplant should be offered at an early stage. Candidate biochemical markers include serum beta 2 microglobulin, neopterin, IL-6, plasma cell labelling index, CRP or LDH and prognostic clinical features include IgD myeloma or stage III disease at presentation. Many patients will have primary refractory of relapsing disease in whom survival is short despite all current therapeutic modalities. They should therefore be considered for trials of newer agents, drug combinations and therapeutic interventions such as cytokine manipulation or gene therapy. The lack of effective, curative treatment options for patients with myeloma places great importance on effective palliation. While improving survival duration remains elusive in this condition, all possible efforts must be made to ensure quality of life is maximized.