Double hemibody irradiation (DHBI) in the management of relapsed and primary chemoresistant multiple myeloma

WITHDRAWN: Radiotherapy for the palliation of painful bone metastases

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Therapeutic options in the management of myeloma bone disease

Advanced multiple myeloma is typically accompanied by osteolytic bone lesions resulting from heightened osteolytic activity of osteoclasts and decreased rates of osteogenesis by osteoblasts. Therefore, patients with myeloma bone disease are at increased risk for skeletal-related events (SREs) such as pathologic fracture, the need for radiotherapy or surgery to bone, spinal cord compression, and hypercalcemia of malignancy. Each of these can reduce patients' functional independence, quality of life, and survival. Radiotherapy and surgery are often used to palliate bone pain and to stabilize, repair, or prevent bone fractures. Bisphosphonates (BPs) may reduce the risk of SREs. In particular, clodronate, pamidronate, and zoledronic acid (ZOL) have demonstrated efficacy for delaying the onset of potentially life-threatening SREs. Overall, BPs have a well established tolerability profile. The introduction of BPs for multiple myeloma was practice-changing, and patients now experience far fewer serious fractures and hypercalcemia of malignancy. Ongoing studies will help further refine and optimize the timing and duration of BP therapy in patients with myeloma bone disease.

PS-341–mediated selective targeting of multiple myeloma cells by synergistic increase in ionizing radiation-induced apoptosis

OBJECTIVE

Multiple myeloma remains incurable with current therapy. The proteosome inhibitor, PS-341, has shown objective clinical responses in relapsed refractory myeloma patients. We investigated the potential of enhancing the radiosensitivity of myeloma cells by combining with PS-341; the underlying mechanisms were delineated.

MATERIALS AND METHODS

Clonogenic assays were used to evaluate cell survival after exposure to PS-341, ionizing radiation (IR), or PS-341 followed by IR. Apoptosis was studied by annexin V-propidium iodide staining and caspase activation. Cell-cycle phase distribution of cells was determined. Nuclear factor-kappaB (NF-kappaB) activity was monitored by enzyme-linked immunosorbent assay and Western blotting. The expression of death receptor Fas/APO-1/CD95 was analyzed by flow cytometry. The consequential caspase-8 activation was detected by Western blotting.

RESULTS

In clonogenic assays, sequential exposure to nontoxic doses of PS-341 (10 nM) and IR (6 Gy) resulted in synergistic inhibition of proliferation of myeloma cells by modulating the apoptotic sensitivity of these cells. Biochemically, sublethal dose of IR led to potent induction of NF-kappaB activity, and this response was significantly inhibited by pretreatment with PS-341, or by the NF-kappaB inhibitory peptide SN-50. Enhanced Fas expression was seen in myeloma cells exposed sequentially to PS-341 and IR. Finally, PS-341 sensitized primary myeloma (CD138+ve) cells to IR but had little effect on CD138-ve bone marrow cells from myeloma patients.

CONCLUSION

These data indicate that PS-341 can sensitize myeloma cells to IR by both intrinsic and extrinsic apoptotic pathways. The study indicates improved therapeutic benefits in treatment of multiple myeloma by combining PS-341 with conventional radiotherapy.

Myeloma bone disease: pathophysiology and management

Bone disease is a major feature of multiple myeloma. Myeloma-induced bone destruction is the result of an increased activity of osteoclasts, which is not accompanied by a comparable increase of osteoblast function. Recent studies have revealed that new molecules such as the receptor activator of nuclear factor-kappa B (RANK), its ligand (RANKL), osteoprotegerin (OPG), and macrophage inflammatory protein-1alpha are implicated in osteoclast activation and differentiation, while proteins such as dickkopf-1 inhibit osteoblastic bone formation. These new molecules seem to interfere not only with the biology of myeloma bone destruction but also with tumour growth and survival, creating novel targets for the development of new antimyeloma treatment. Currently, bisphosphonates play a major role in the management of myeloma bone disease. Clodronate, pamidronate and zoledronic acid are the most effective bisphosphonates in symptomatic myeloma patients. Biochemical markers of bone remodeling have been used in an attempt to identify patients more likely to benefit from early treatment with bisphosphonates. Furthermore, using microarray techniques, myeloma patients may be subdivided into molecular subgroups with certain clinical characteristics, such as propensity for lytic lesions that may need early prophylactic treatment. Recent phase I studies with recombinant OPG and monoclonal antibodies to RANKL appear promising.

Interferon-alpha treatment in multiple myeloma: meta-analysis of 30 randomised trials among 3948 patients

BACKGROUND

After two decades of interferon (IFN) treatment in myeloma patients and many randomised clinical trials, no definite proof of its benefits exists. This meta-analysis of all available relevant published data tests the differences between IFN and control arms in a large patient population and addresses the issue of cost-effectiveness.

PATIENTS AND METHODS

Meta-analysis was performed on 17 trials among 2333 patients who received IFN-chemotherapy induction treatment or chemotherapy alone and on 13 trials among 1615 patients on IFN maintenance therapy or without treatment. Response rates and parameters of published Kaplan Meier relapse-free and overall survival curves were analysed.

RESULTS

Patients in IFN arms showed significantly better results in all investigated parameters: IFN-chemotherapy induction treatment yielded 6.6% higher response rates (2P < 0.002) as well as 4.8-month and 3.1-month prolongations of relapse-free (P < 0.01) and overall survival (P < 0.01), respectively. Interferon maintenance therapy lead to 4.4-month (P < 0.01) and 7.0-month (P < 0.01) prolongations of relapse-free and overall survival, respectively. Meta-analysis of all IFN trials combined resulted in 4.6-month and 3.7-month IFN-related gains in relapse-free and overall survival, respectively. As early as 6 and 12 months after the start of IFN treatment, percentages of cumulative relapse-free and overall survival were always significantly higher in IFN trial arms. IFN drug expenses for a one-year survival gain, as determined from AUCs of best-fitted Gompertz functions of IFN and control survival curves, were estimated to be US$42,482.28 for induction therapy and US$18,968.16 for maintenance treatment.

CONCLUSIONS

Significantly superior outcomes were consistently found in IFN trial arms by meta-analysis of published data. These results are in accordance with a concomittantly conducted meta-analysis on individual patient data but were much easier to accrue. Taking all our results into account. i.e., the consistently significant, although limited, improvement of clinical outcomes and its acceptable cost-effectiveness, IFN treatment of patients with multiple myeloma seems worthwhile to be considered.

Radiotherapy for the palliation of painful bone metastases

BACKGROUND

Radiotherapy is used commonly to provide pain relief for painful bone metastases, and there is a perception that of the three-quarters of patients who achieve pain relief, half of these stay free from pain. However, the precise contribution from radiotherapy may be unclear because of difficulties in assessing the numbers of people achieving relief, the extent of relief and its duration, and the influence of other contemporaneous interventions, such as analgesics.

OBJECTIVES

To assess pain relief from: 1. localised bone metastases achieved by radiotherapy, comparing the efficacy of different fractionation schedules 2. more generalised metastatic disease achieved by radiotherapy or radioisotopes.

SEARCH STRATEGY

Studies were identified by searching Medline (1966 to August 1998), Embase (1980 to 1998), the Cochrane Library (1998 Issue 3) and the Oxford Pain Relief Database (1950 to 1994).

SELECTION CRITERIA

The inclusion criteria used were: full journal publication, patients with pain due to bone metastases, and random allocation to a radiotherapeutic intervention (either external irradiation or administration of radioisotopes).

DATA COLLECTION AND ANALYSIS

The number of patients achieving complete pain relief and at least 50% at one month were compared with an assumed natural history of 1 in 100 patients achieving pain relief without treatment to obtain the number-needed-to-treat (NNT). Summed pain relief or pain intensity difference over four to six hours was extracted, converted into dichotomous information yielding the number of patients with at least 50% pain relief, and used to calculate the relative benefit and the NNT for one patient to achieve at least 50% pain relief.

MAIN RESULTS

Twenty trials reported on 43 different radiotherapy fractionation schedules and eight studies of radioisotopes. Radiotherapy produced complete pain relief at one month in 395/1580 (25%) patients, and at least 50% relief in 788/1933 (41%) patients at some time during the trials. There were no differences in the proportions of patients achieving these outcomes between single or multiple fraction schedules. The number-needed-to-treat (NNT) to achieve complete relief at one month (compared with an assumed natural history of 1 in 100 patients whose pain resolved without treatment) was 4.2 (95% CI 3.7-4.7). No pooled estimates of speed of onset of relief, or of its duration, could be obtained. In the largest trial (759 patients) 52% of those who had complete relief had achieved it within four weeks, and the median duration of complete relief was 12 weeks. For more generalised disease, radioisotopes produced similar analgesic results to external irradiation. Adverse effect reporting was poor. There were no obvious differences between the various fractionation schedules in the incidence of nausea and vomiting, diarrhoea or pathological fractures.

REVIEWER'S CONCLUSIONS

Radiotherapy is clearly effective at reducing pain from painful bone metastases. There was no evidence of any difference in efficacy between different fractionation schedules, nor indeed of a dose-response with total dose of radiation. For treatment of generalised bone pain both hemibody irradiation and radioisotopes can reduce the number of painful new sites.

Interferon-alpha for induction and maintenance in multiple myeloma: results of two multicenter randomized trials and summary of other studies

BACKGROUND

Interferon (IFN) treatment trials in multiple myeloma have yielded discordant results regarding response rates, maintenance duration, and survival times. Further randomized trials and global evaluations of available data are urgently needed for clarification.

PATIENTS AND METHODS

256 patients participated in a randomized trial, 125 on IFN + VMCP, and 131 on VMCP alone. 100 patients were randomized to IFN maintenance (n = 46) or were untreated controls (n = 54). Global evaluations are based on 1,518 patients in induction and 924 in maintenance trials.

RESULTS

The induction trial demonstrated a significantly (p < 0.05) lower rate of progressive disease under IFN + VMCP (10.6%) than under VMCP (22.9%), but this benefit was limited to stage I or II patients. Median progression-free survival was longer in the IFN + VMCP arm (23.2 months vs. 15.8 months); median overall survival did not differ significantly (38.9 vs. 30.2 months). The IFN maintenance treatment trial showed significantly superior results in the IFN arm versus controls (median maintenance duration: 17.8 months and 8.2 months (p < 0.01), survival: 50.6 and 34.4 months (p < 0.05), respectively). Previous IFN treatment increased the benefits of IFN maintenance therapy. Adverse effects of IFN during induction were hematologic toxicity, fever, and infections, requiring dose reductions. Toxic effects of IFN maintenance treatment were mild. Global evaluations of randomized trials showed small but significant benefits of combined IFN induction therapy and significantly prolonged maintenance duration and survival under IFN maintenance.

CONCLUSIONS

Presently available data support the use of IFN maintenance treatment because it significantly prolongs maintenance duration and survival. IFN added to induction chemotherapy resulted in minor improvements at the expense of increased toxicity, highlighting the need for better induction regimens.