Management of refractory myeloma: a review

Safety and efficacy results from an international expanded access programme to bortezomib for patients with relapsed and/or refractory multiple myeloma: a subset analysis of the Australian and New Zealand data of 111 patients

BACKGROUND

Bortezomib has been shown to be a safe and efficacious for the treatment of relapsed and refractory multiple myeloma (MM). Here we report a subset analysis of Australian and New Zealand data from the International Extended Access Programme for bortezomib.

METHODS

Patients with more than or equal to two prior lines of therapy were given bortezomib 1.3 mg/m(2) (i.v. bolus days 1, 4, 8, 11) for up to eight 21-day cycles (C). Dexamethasone, 20 mg/day p. o. on the day of, and day after, bortezomib was added after C2 for progressive disease or after C4 for stable disease. Efficacy was assessed using modified Southwest Oncology Group criteria in the intent-to-treat group. Results were compared between the Australian and New Zealand and international cohort.

RESULTS

One hundred and eleven patients from 16 centres (55% men, median age 61.9 years) had a median of 5.2 +/- 2.8 treatment cycles of bortezomib. Among them, 82% had > or =3 prior therapies. Grade 3-4 treatment-related adverse events were reported in 57 patients (52%); the most common were thrombocytopenia (25.7%), anaemia (8.3%), peripheral neuropathy (7.3%) and diarrhoea (7.3%). Responses were evaluable in 106 patients: 22% achieved a best response of complete response/response and 20% partial response (overall response rate of 42%). Median times to first and best responses were 42 days and 69 days, respectively. Compared with the international cohort, the cohorts from Australian and New Zealand showed inferior overall response rates (54 vs 42%, P = 0.001), possibly due to heavier pretreatment (82% greater than or equal to three prior therapies vs 68%, P < 0.001).

CONCLUSION

Our analysis confirms that bortezomib is safe and effective in relapsed and refractory MM in a real-life clinical setting.

Novel targets for myeloma bone disease

BACKGROUND

Multiple myeloma (MM) is a plasma cell malignancy in which osteolytic bone lesions develop in over 80% of patients. The increased bone destruction results from increased osteoclast formation and activity, which occurs adjacent to marrow sites involved with MM cells. This is accompanied by suppressed or absent osteoblast differentiation and activity, resulting in severely impaired bone formation and development of purely osteolytic lesions.

OBJECTIVE

The pathophysiology underlying this bone remodeling is reviewed, and potential new strategies to treat MM bone disease are discussed.

RESULTS

Recent advances in our understanding of factors involved in pathogenesis of MM bone disease have identified novel therapeutic targets. Several of these are or will be in clinical trials soon.

CONCLUSION

Agents which target the tumor and bone-destructive process, such as the immunomodulatory drugs (IMiDs) or bortezomib, in combination with novel anti-resorptives should be effective. These combinations should be in clinical trials in the next few years. It is unclear if these treatments will be able to 'heal' bone lesions in MM patients.

Phase I and II pharmacokinetic and pharmacodynamic study of the proteasome inhibitor bortezomib in Japanese patients with relapsed or refractory multiple myeloma

The purpose of this phase I and II study was to evaluate the safety, pharmacokinetics, pharmacodynamics, and efficacy of bortezomib in Japanese patients with relapsed or refractory multiple myeloma. This was a dose-escalation study designed to determine the recommended dose for Japanese patients (phase I) and to investigate the antitumor activity and safety (phase II) of bortezomib administered on days 1, 4, 8, and 11 every 21 days. Thirty-four patients were enrolled. A dose-limiting toxicity was febrile neutropenia, which occurred in one of six patients in the highest-dose cohort in phase I and led to the selection of 1.3 mg/m(2) as the recommended dose. Adverse events >or= grade 3 were rare except for hematological toxicities, although there was one fatal case of interstitial lung disease. The overall response rate was 30% (95% confidence interval, 16-49%). Pharmacokinetic evaluation showed a biexponential decline, characterized by a rapid distribution followed by a longer elimination, after dose administration, whereas the area under the concentration-time curve increased proportionately with the dose. Bortezomib was effective in Japanese patients with relapsed or refractory multiple myeloma. A favorable tolerability profile was also seen, although the potential for pulmonary toxicity should be monitored closely. The pharmacokinetic and pharmacodynamic profiles of bortezomib in the present study warrant further investigations, including more relevant administration schedules.

Proteasome inhibitor, bortezomib, for myeloma and lymphoma

Bortezomib, a boronic acid, is a potent and selective proteasome inhibitor. The 20S proteasome is an enzyme complex present in cells, and it degrades many cell-cycle control factors, signal transduction factors, transcription factors, and oncogene and anti-oncogene products, thus controlling cell proliferation, differentiation, and apoptosis. Bortezomib is a novel molecular targeting agent which was designed to exhibit an antitumor effect by selectively inhibiting the 20S proteasome. Multiple myeloma is one of the incurable B-cell malignancies that continues to relapse with current treatment modalities, and the duration to progression becomes shorter in patients who repeatedly receive chemotherapy. There are no available treatment options in which durable efficacy can be expected after relapse; therefore, an effective therapy with a novel mechanism of action has been desired. In this review article, the results of clinical trials of bortezomib for multiple myeloma, including a Japanese phase I/II and pharmacokinetic/pharmacodynamic study, and those for non-Hodgkin lymphoma, especially for mantle cell lymphoma, are summarized. In the Japanese phase I/II study of bortezomib for relapsed multiple myeloma, this agent showed remarkable efficacy, with acceptable toxicities and unique pharmacokinetic/pharmacodynamic profiles, warranting further investigations, including more relevant administration schedules.

A phase I/II study of arsenic trioxide/bortezomib/ascorbic acid combination therapy for the treatment of relapsed or refractory multiple myeloma

PURPOSE

This multicenter, open-label, phase I/II dose escalation study assessed the safety/tolerability and initial efficacy of arsenic trioxide/bortezomib/ascorbic acid (ABC) combination therapy in patients with relapsed/refractory multiple myeloma.

EXPERIMENTAL DESIGN

Enrolled in six cohorts, patients were given arsenic trioxide (0.125 or 0.250 mg/kg), bortezomib (0.7, 1.0, or 1.3 mg/m(2)), and a fixed dose of ascorbic acid (1 g) i.v. on days 1, 4, 8, and 11 of a 21-day cycle for a maximum of eight cycles. The primary end point was safety/tolerability of the ABC regimen.

RESULTS

Twenty-two patients (median age, 63 years) were enrolled, having failed a median of 4 (range, 3-9) prior therapies. One occurrence of grade 4 thrombocytopenia was observed. One patient had asymptomatic arrhythmia and withdrew from the study. Objective responses were observed in 6 (27%) patients, including two partial responses and four minor responses. Median progression-free survival was 5 months (95% confidence interval, 2-9 months), and median overall survival had not been reached. The 12-month progression-free survival and overall survival rates were 34% and 74%, respectively. One (minor response) of six patients receiving the lowest dose of bortezomib (0.7 mg/m(2)) and 5 (2 partial responses and 3 minor responses) of 16 patients receiving the higher doses (1.0 or 1.3 mg/m(2)) responded.

CONCLUSIONS

The ABC regimen was well tolerated by most patients, and it produced preliminary signs of efficacy with an objective response rate of 27% in this heavily pretreated study population. These findings warrant further clinical evaluation of the ABC combination for treatment of relapsed/refractory multiple myeloma.

Treatment Strategies in Elderly Patients with Multiple Myeloma

Multiple myeloma (MM), a plasma cell malignancy, is a disorder of the elderly with an increasing prevalence as the average life expectancy increases. Survival remains unacceptably low in elderly patients with MM, in whom the gold standard of treatment has been, until recently, oral melphalan and prednisolone, which induces a response rate of approximately 50% and overall survival of <3 years. In the last 15 years, traditional treatment paradigms for elderly patients with MM have been challenged not only as a result of the change in what we define as 'elderly' but also as a result of the reduced morbidity and treatment-related mortality associated with high-dose chemoradiotherapy (HDT) and autologous stem cell transplantation (ASCT), and the emergence of novel therapies including thalidomide, its immunomodulator drug derivative lenalidomide and the first-in-class proteasome inhibitor, bortezomib. In this review, we examine currently available data regarding the treatment of MM in the elderly population. Recent years have seen a paradigm shift in the standard of care of elderly patients with MM from oral melphalan and prednisolone to approaches including HDT with ASCT using intermediate-dose melphalan in selected elderly patients, and the evaluation of and incorporation of drugs such as thalidomide, bortezomib and lenalidomide. Importantly, we now have been able to change the traditional goal of palliation in the elderly group of patients to a more ambitious objective of achieving a complete response or a near complete response, in the hope that this will translate into improved progression-free survival, overall survival and quality of life.

Efficacy and safety of melphalan, arsenic trioxide and ascorbic acid combination therapy in patients with relapsed or refractory multiple myeloma: a prospective, multicentre, phase II, single-arm study

We assessed the safety and efficacy of melphalan, arsenic trioxide (ATO) and ascorbic acid (AA) (MAC) combination therapy for patients with multiple myeloma (MM) who failed more than two different prior regimens. Patients received melphalan (0.1 mg/kg p.o.), ATO (0.25 mg/kg i.v.) and AA (1 g i.v) on days 1-4 of week 1, ATO and AA twice weekly during weeks 2-5 and no treatment during week 6 of cycle 1; during cycles 2-6, the schedule remained the same except ATO and AA were given twice weekly in week 1. Objective responses occurred in 31 of 65 (48%) patients, including two complete, 15 partial and 14 minor responses. Median progression-free survival and overall survival were 7 and 19 months respectively. Twenty-two patients had elevated serum creatinine levels (SCr) at baseline, and 18 of 22 (82%) showed decreased SCr levels during treatment. Specific grade 3/4 haematological (3%) or cardiac adverse events occurred infrequently. Frequent grade 3/4 non-haematological adverse events included fever/chills (15%), pain (8%) and fatigue (6%). This steroid-free regimen was effective and well tolerated in this heavily pretreated group. These results indicate that the MAC regimen is a new therapeutic option for patients with relapsed or refractory MM.

United States Food and Drug Administration Approval Summary: Bortezomib for the Treatment of Progressive Multiple Myeloma after One Prior Therapy

PURPOSE

On March 25, 2005, bortezomib (Velcade for Injection; Millennium Pharmaceuticals, Inc., Cambridge, MA, and Johnson & Johnson Pharmaceutical Research & Development, L.L.C.) received regular approval from the U.S. Food and Drug Administration (U.S. FDA) for the treatment of multiple myeloma (MM) progressing after at least one prior therapy. This approval was based on bortezomib's efficacy and safety which was shown in a single, large, comparative international open-label phase 3 trial that randomized 669 patients with MM previously treated with at least one systemic regimen to receive single-agent bortezomib or high-dose dexamethasone. The FDA analysis of the trial data and bortezomib's regulatory development are summarized here.

EXPERIMENTAL DESIGN AND RESULTS

Following a preplanned interim analysis of time to disease progression (the primary end point), an independent data-monitoring committee advised the sponsor to halt the study and offer bortezomib to all dexamethasone-treated study patients. Time to progression was significantly prolonged in the bortezomib treatment arm (median, 6.2 months) compared with the dexamethasone arm (median, 3.5 months; log-rank test, P < 0.0001; hazard ratio, 0.55; 95% confidence interval, 0.44-0.69). Analysis of overall survival done on the interim database (with 20% of events) showed the superiority of bortezomib for patients (log-rank test, P < 0.05; hazard ratio, 0.57; 95% confidence interval, 0.40-0.81). Using criteria from the European Group for Blood and Marrow Transplantation, the response rate (complete plus partial response) with bortezomib was also superior to dexamethasone (38% versus 18%; P < 0.0001). Adverse events on the bortezomib arm were similar to those previously observed in phase 2 studies; some notable adverse events included asthenia, peripheral neuropathy, thrombocytopenia, and neutropenia.

CONCLUSIONS

The U.S. FDA had earlier (May 2003) granted bortezomib accelerated approval for the treatment of patients with MM progressing after two prior therapies. The results of the phase 3 trial and the FDA analysis of the data, along with the sponsor's completion of other postmarketing commitments, confirm bortezomib's benefit and support regular approval.

Bortezomib treatment for multiple myeloma

OBJECTIVE

To review the pharmacology, pharmacokinetics, and place of bortezomib in the therapy of multiple myeloma (MM).

DATA SOURCES

A MEDLINE search was conducted (1985-May 2003). Meeting abstracts, bibliographies from identified articles, and the package insert were also used. Search terms were bortezomib, multiple myeloma, Velcade, PS-341, LDP-341, MLNM341, and proteasome inhibitor.

STUDY SELECTION AND DATA EXTRACTION

All published information relevant to the clinical activity of bortezomib in MM was considered. All human clinical studies, with an emphasis on Phase II trials, were selected.

DATA SYNTHESIS

Current therapy for MM yields significant, although temporary, responses. Bortezomib is a novel anticancer agent with significant activity in relapsed and refractory MM.

CONCLUSIONS

Although the clinical trial data are incomplete, bortezomib offers a novel therapeutic modality for patients with MM who would otherwise have few options.

Treatment of multiple myeloma

Conventional chemotherapies are no longer the only treatment in multiple myelomatosis. High-dose chemotherapy and autologous transplantation are not curative but do increase relapse-free survival time in young patients. Thalidomide is efficacious in refractory and relapsing myeloma and its evaluation is going on. Curative and preventive treatments of skeletal events, infections and anemia improve quality of life. All together, these strategies imply therapeutic knowledge and choices but allow an about 5-year-long median survival time in modern studies. Treatment options for myeloma now include, not only conventional chemotherapy regimens, but also novel symptomatic drugs and strategies that increase survival and/or quality of life, although they fail to provide a cure. In parallel with this expansion of the treatment armamentarium, physicians must acquire the knowledge needed to select the best treatment for the individual patient. After reviewing the rationale, effectiveness, and safety of each of these treatments, we will discuss the indications that we believe are legitimate.

Gemcitabine alone or combined with cisplatin in relapsed or refractory multiple myeloma

Gemcitabine is a pyrimidine nucleoside analog with antitumor activity against solid tumor malignancies and leukemia. We evaluated its activity as a single agent and combining it with cisplatin in relapsed-refractory multiple myeloma (MM). Sixteen patients with advanced MM received intravenous gemcitabine 1250 mg/mq (days 1, 8 and 15) as a single agent for a total of 3 monthly courses. The responders received another three courses, and the non-responders received three courses of gemcitabine 1000 mg/mq (days 1, 8 and 15) plus cisplatin 80 mg/mq (day 1). No grade 4 hematological toxicity was seen after gemcitabine treatment, whereas > or = 3 grade neutropenia and thrombocytopenia were seen in 21 and 13% of the gemcitabine-cisplatin infusions, respectively. Non-hematological toxicity was negligible for both the regimens. After three courses of gemcitabine as a single agent, th e response rate was 31% (1 complete response, 1 partial response and 3 minimal response). Eight patients (50%) achieved stable disease and 3 (19%) had disease progression. Ten patients received gemcitabine-cisplatin and were evaluable for the response. Two patients progressed, four maintained stable disease whereas four patients, unresponsive to gemcitabine, obtained a response (3 partial response and 1 minimal response). With a median follow-up of 13 months (range 8-17.5), 7 patients (44%) died, 5 (31%) had disease progression, 1 (6%) relapsed, 1 was still in partial response (+11 months) and 2 (13%) had a stable disease. Median time to treatment failure (TTF) was 8 months (CI95%: 7.6-8.4) and median overall survival (OS) was 16 months (CI95%: 10-22). These results showed that gemcitabine and gemcitabine-cisplatin were feasible regimens and well tolerated in advanced relapsed-refractory MM. The response rates, the TTF and OS were similar to other salvage chemotherapy regimens; nevertheless, the quality of response was modest particularly after gemcitabine alone. Better results might be obtained combining gemcitabine with other chemotherapy compounds or with biologically based therapies.

The evaluation of gemcitabine in resistant or relapsing multiple myeloma, phase II: a Southwest Oncology Group study

Gemcitabine is a cytosine arabinoside (Ara-C) analog with activity in many human tumor systems. We evaluated the drug's activity in resistant or relapsing multiple myeloma. Gemcitabine 1000 mg/m2 was administered as a 30 minute infusion on days 1, 8, and 15 of a 28-day cycle. No dose escalations were permitted and dose reductions were scheduled for hematologic toxicity. Twenty-nine eligible patients were entered into Southwest Oncology Group (SWOG)-9803. One patient received no treatment and 5 patients had inadequate response assessments. The major toxicity was hematologic with grade 3/4 neutropenia in 9 and grade 3/4 thrombocytopenia in 15 patients. No responses were seen. Stable disease was confirmed in sixteen patients (57%). Median survival was eight months. Gemcitabine as utilized in this trial has shown little activity and is not to be strongly considered for future multiple myeloma trials.

High-dose melphalan with G-CSF-stimulated whole blood rescue followed by stem cell harvesting and busulphan/cyclophosphamide with autologous stem cell transplantation in multiple myeloma

In 90 consecutive patients with multiple myeloma, we investigated the feasibility of administering a tandem high-dose therapy regimen, using whole blood for rescue after the first and leucapheresis harvested between the two high doses, for rescue after the second high dose. After 5 days of G-CSF 1 litre of whole blood (WB) was obtained, left undisturbed at 4 degrees C and reinfused 24 h after HDM (140 mg/m(2)). Patients not in progression after 3-6 months were again mobilised, leucapheresed and treated with busulphan 16 mg/kg and cyclophosphamide 120 mg/kg (Bu/Cy) and reinfusion. In 90 patients, WB contained a mean (range) of 0.57 (0.02-3.22) x 10(6)/kg CD34(+) cells. Recovery after HDM was in 13 days for granulocytes and in 18 days for platelets, with 11 patients not recovering within 3 months. There were three toxic deaths. Sixty-six patients qualified for harvesting after HDM. In the first 11, marrow was harvested. The subsequent 55 patients were mobilised and in 45 the preset minimum of 1.5 x 10(6) CD34(+) cells was obtained. Forty-nine patients actually received Bu/Cy. Recovery after Bu/Cy and marrow reinfusion was in 35 days for granulocytes and 20 days for platelets, with two of five patients not recovering after 3 months. After Bu/Cy and leucapheresis reinfusion, recovery was in 17 days for granulocytes and in 34 days for platelets. Nine patients did not recover within 3 months. There were four toxic deaths. The median overall survival from diagnosis for patients receiving HDM was 49 months and for patients also receiving Bu/Cy, 84 months. We conclude that WB rescue after HDM followed by leucapheresis and a second transplant is feasible in the majority of patients. Better mobilisation techniques are required to increase the number of patients who can receive the second transplant.

Treatment approaches for relapsing and refractory multiple myeloma

Relapsing patients with multiple myeloma show a response rate higher than 50% with the resumption of the initial chemotherapy. However, since the duration of second responses are short, HDT/autotransplantation is recommended in patients with sensitive relapse. In patients with primary refractory myeloma the best treatment approach seems to be early HDT/autotransplantation. It is crucial to recognize a subset of patients who do not respond to the initial chemotherapy but who have non-progressive disease in order to avoid the administration of salvage regimens until clinical disease progression occurs. The treatment of patients with refractory relapse is disappointing. The most promising agent in this situation is thalidomide. Patients with late relapse after autologous transplantation can benefit from a second autologous transplant. The results of the allogeneic transplantation after autotransplantation are disappointing. In heavily pretreated resistant patients a conservative approach with alternate day prednisone (30 to 50 mg) along with pulse cyclophosphamide (800 to 1,200 mg every 2 to 3 weeks) is recommended.

Satisfactory remission in a case of IgD myeloma: effectiveness of glucocorticoid treatment

IgD myeloma is an infrequent type of multiple myeloma and is characterized by an aggressive clinical behavior and a short survival time. No satisfactory treatments have thus far been established. Recently we treated a patient with IgD(lambda)-type myeloma with glucocorticoids, and succeeded in achieving a complete remission. This case seems to indicate a usefulness of glucocorticoid monotherapy for treating IgD myeloma.

CCNU (lomustine), idarubicin and dexamethasone (CIDEX): an effective oral regimen for the treatment of refractory or relapsed myeloma

We report the results of a non-randomized pilot study of an oral regimen comprising CCNU (lomustine; 25 or 50 mg/m2 on day 1), idarubicin (4-demethoxydaunorubicin) (10 mg/m2 on days 1-3) and dexamethasone (10 mg b.d. on days 1-4) in patients with relapsed or refractory myeloma. Treatment was given every 28 d for a maximum of six courses. Sixty patients were entered of whom 57 were evaluable. Overall response rate (partial or minor response) was 49% with 30% of patients achieving a partial response (50% tumour reduction). Response rates were higher in patients with untested relapse than in those with refractory disease (overall response rates 56% vs. 31%). The major toxicity was neutropenia and the regimen was otherwise well tolerated. The median survival from entry of all patients was 15 months, with 30% of patients alive at 2 years. This regimen represents a useful addition to available treatment options.

[Standard treatment of multiple myeloma]

INTRODUCTION

About 50% of patients with multiple myeloma are older than 65 years and are not eligible for high-dose therapy, which has proved to be more efficacious than standard-dose chemotherapy in young patients.

CURRENT KNOWLEDGE AND KEY POINTS

Apart from high-dose therapy, no clear therapeutic advance has been achieved in the past 20 years, and melphalan-prednisone combinations remain reference treatments for many patients with multiple myeloma. Despite a great number of clinical trials, the use of interferon alpha is still controversial. The role of high-dose dexamethasone has been recently established and we are currently comparing dexamethasone alone, melphalan-dexamethasone and dexamethasone-interferon alpha treatments in a multicenter randomized trial (IFM 95-01). Bisphosphonates have also emerged as an efficacious and well tolerated adjuvant treatment. Optimal use of recently released bisphosphonates at various stages of the disease will possibly lead to a clear therapeutic advantage.

FUTURE PROSPECTS AND PROJECTS

Other drugs, such as erythropoietin or interferon gamma require further evaluation. The recent implication of metalloproteinases in multiple myeloma and the efficacy of metalloproteinase inhibitors in animal models and phase I/II clinical studies in solid tumors provide a strong rationale for the clinical evaluation of these agents in multiple myeloma.

High-dose melphalan with autotransplantation for refractory multiple myeloma: results of a Southwest Oncology Group phase II trial

PURPOSE

To evaluate high-dose melphalan followed by autologous stem-cell transplantation in patients with refractory multiple myeloma.

PATIENTS AND METHODS

Multiple myeloma patients with alkylating agent or vincristine/doxorubicin/dexamethasone-refractory disease were eligible for the phase II multi-institutional Southwest Oncology Group trial S8993. Patients up to age 70 years were enrolled between April 15, 1991, and May 1, 1996. Patients without prior stem-cell collection were primed with high-dose cyclophosphamide (HD-CTX; 6 g/m(2)) and granulocyte-macrophage colony-stimulating factor. After stem-cell procurement, patients received melphalan 200 mg/m(2) with autologous transplantation. Upon recovery from melphalan, patients were to receive interferon alfa-2b until relapse.

RESULTS

Seventy-two patients were enrolled onto S8993; five were ineligible and one received no therapy. Of the 66 assessable patients, 56 patients underwent the transplant procedure; 54 were assessable for response and 56 for toxicity. The response to HD-CTX (n = 37) included three complete remissions (CRs; 8%) and five partial remissions (PR; 14%); response to melphalan (n = 54) included 16 CRs (30%) and 19 PRs (35%), for an overall CR and >/= PR (n = 66; intent-to-treat) of 27% and 58%, respectively. Toxicities included six treatment-related deaths: two during HD-CTX and four during transplantation. The median progression-free survival (PFS) and overall survival (OS) durations on an intent-to-treat basis from transplant registration was 11 months and 19 months (95% confidence interval, 14 to 29 months), respectively. The 3-year actuarial PFS and OS rates were 25% and 31%, respectively.

CONCLUSION

High-dose therapy with melphalan 200 mg/m(2) is feasible with high response rates (58% overall) and an OS of 19 months in patients with refractory multiple myeloma.

Dexamethasone, all trans retinoic acid and interferon alpha 2a in patients with refractory multiple myeloma

Few effective regimen are available for patients with refractory multiple myeloma (RMM). Generally, responses are scarce and disease free survival is very short. We developed a new therapeutic option in these patients using dexamethasone (40 mg/m2, i.v., daily, days 1 to 4), all-trans retinoic acid (45 mg/m2, po, daily, days 5 to 14) and interferon alpha 2a (9.0 MU, daily, subcutaneously, days 5 to 14). The treatment was administered every 21 days for 6 cycles. In a pilot study, 12 patients, heavily treated with chemotherapy and radiotherapy and in some cases with interferon, were allocated to receive the afore mentioned treatment. Response was observed in 10 patients (83%). With a median follow-up of 36.1 months (range 27 to 41), seven patients remain alive and disease-free without any treatment. Two patients were failures and have died due to tumor progression. Toxicity was mild and all patients received treatment according to the planned doses of drugs. The use of biological modifiers in combination with dexamethasone offer a safe and effective therapeutic option in patients with refractory multiple myeloma. More studies are warranted to define the role of this type of treatment.

VAD or VMBCP in multiple myeloma refractory to or relapsing after cyclophosphamide-prednisone therapy (protocol MY 85)

263 patients (median age 65+/-10 years) with multiple myeloma were treated with cyclophosphamide-prednisone. Out of this cohort, 103 patients had progressive disease and were randomly assigned to either VAD (vincristine, doxorubicin, dexamethasone; 50 cases) or VMBCP (vincristine, BCNU, cyclophosphamide, melphalan and prednisone; 53 cases). There were no statistical differences between the two groups with the respect to clinical, biological and radiological parameters. There was no difference in survival between the VAD and VMBCP groups. The 4 months response rate was similar in the two groups (50% VAD, 56% VMBCP). With multivariate analysis for survival (Cox model), two factors had a statistically significant impact: Karnofsky index (> 60) and albuminaemia (< 34 g/l). With both Karnofsky index > 60 and albuminaemia > or = 34 g/l, the median survival was 29 months v 2 months with a Karnofsky index < or = 60 and albuminaemia < 34 g/l (P<0.05). In conclusion, VAD or VMBCP had similar activity for salvage treatment in MM refractory or relapsing to first-line treatment with cyclophosphamide-prednisone.

S-phase induction by interleukin-6 followed by chemotherapy in patients with refractory multiple myeloma

The plasma cell labeling index (PCLI) in patients with multiple myeloma (MM) is relatively low and this has been associated with the low rate of remission following chemotherapy. Interleukin-6 (IL-6) has been demonstrated to be a major growth factor of myeloma cells. In order to increase the S-phase proportion of myeloma cells, which might increase the sensitivity to chemotherapy, we gave rhIL-6 followed by chemotherapy to 15 myeloma patients with refractory disease. A total of 25 treatment cycles were administered since ten patients had two cycles. The rhIL-6 dose was 2.5 (n = 3), 5.0 (n = 6) and 10.0 microg/kg (n = 6) by subcutaneous injection once daily for 5 days and chemotherapy was administered on the last day of rhIL-6 injection. The effect of rhIL-6 treatment on labeling index (LI) was heterogeneous, but no statistically significant change was noted for this particular group as a whole. In two patients an increase (mean 7.7%) in LI of mononuclear bone marrow cells during the rhIL-6 treatment was demonstrated and in one patient a decrease of 2.8% was seen. Assessment of PCLI demonstrated an increase of 2.9% in one out of six patients and a decrease of 1.9% in one out of six patients. None of the 15 patients achieved remission according to standard criteria. During the rhIL-6 treatment, 14 of the 15 patients developed mild constitutional adverse events (AE) well known in patients treated with IL-6, and none of the AE in the subsequent chemotherapy phase were related to IL-6. In conclusion, our study demonstrated that rhIL-6 can be administered safely to patients with refractory MM, but the cell cycle recruitment approach was not sufficiently effective to be of clinical value.

Is multidrug resistance (P-glycoprotein) an intrinsic characteristic of plasma cells in patients with monoclonal gammopathy of undetermined significance, plasmacytoma, multiple myeloma and amyloidosis?

Multiple myeloma is not a curable disease, and most patients relapse after plateau phase. Drug resistance is a major problem in effective chemotherapy in this kind of disease. Current approaches are aimed at reversing or preventing drug resistance late in the disease. We studied a drug resistance marker, P-glycoprotein (P-gp), in a total of 43 patients with monoclonal gammopathy. This group included eight with monoclonal gammopathy of undetermined significance (MGUS), five with plasmacytoma (PCM), nineteen with multiple myeloma (MM; six newly diagnosed, seven plateau, five refractory, one relapse) and eleven amyloidosis (seven newly diagnosed, four after treatment). Using 3-color flow cytometry, a plasma cell gate was selected on the basis of CD38+/45-(dim) staining and the population was examined for the expression of P-gp using two monoclonal antibodies (MRK16 and UIC2). P-gp expression was positive on marrow plasma cells in 42/43 patients. The resistance index (RI) in these cases (range 2.0-7.07) is comparable to that in the positive cell line KG-1A (3.05-3.08). In 2 of 5 patients with refractory MM, the RI for P-gp (5.4, 6.36) was higher than in plateau phase. These data suggest that relative resistance due to the P-gp mechanism is likely to be an intrinsic property of plasma cells in monoclonal gammopathies and may provide a partial explanation as to why these diseases always relapse. The results of our study support strategies for MDR reversal earlier in the course.

[Prognosis of multiple myeloma treated with conventional chemotherapy has not improved in 20 years]

The treatment of multiple myeloma has changed over the last 20 years. We investigated the effects of theses changes on patient survival in the current practice of a rheumatology ward. Two hundred and seventy-nine patients were hospitalised between 1972 and 1993: 30 from 1972 to 1976, 70 from 1977 to 1981, 86 from 1982 to 1986, 75 from 1987 to 1991 and 18 from 1992 to 1993. Staging according to Durie and Salmon was I in 8%, II in 29% and III in 65%. In principle, the initial therapy was monochemotherapy in 65% of the cases and polychemotherapy in 35%. At the time of the present study, 197 patients have died. The actuarial curves of survival were similar in all historical classes defined by the date of first admission. Curves of median of follow-up and of floating means were level between 1972 and 1990. No correlation was found between the date of first admission and survival in the 174 patients who died between 1972 and 1987. The following parameters were associated with longer survival: achievement of an objective response on chemotherapy, lower patient's age, high haemoglobin, low creatinine, low stage according to Durie and Salmon, low number of plasma cells in bone marrow, low calcemia and low levels of IgA, monoclonal component. The comparison of prognosis factors in historical classes showed a difference only for haemoglobin which was lower in the earlier class. The type of the first chemotherapy regimen varied widely between historical classes. The number of responders was significantly greater after polychemotherapy than after monochemotherapy but no correlation was observed between the type of chemotherapy and survival. The frequencies of early death, and the causes of death in general, were not different in the historical classes. The lack of improvement of survival over the last 20 years shows that the efficacy of current chemotherapies is limited, a conclusion which warrants the exploration of other therapeutic avenues.

Mechanisms of inhibition of IL-6-mediated immunoglobulin secretion by dexamethasone and suramin in human lymphoid and myeloma cell lines

The cytokine IL-6 has been proposed as an autocrine growth factor in multiple myeloma, and is also required for stimulation of immunoglobulin production and secretion in normal plasma cells and myeloma cells. In this study, we showed that secreted IL-6 is detectable by Western blot analysis in a panel of lymphoid and myeloma cell lines. Previous studies in our laboratory have shown that dexamethasone and suramin inhibit cell proliferation and IL-6-mediated immunoglobulin secretion in various lymphoblastoid and myeloma cell lines. In the present study, we present study, we present data to examine mechanisms by which dexamethasone and suramin inhibit IL-6-mediated immunoglobulin secretion in the lymphoid cell line SKW 6.4. Cells treated with rIL-6 or the IC10 concentration of dexamethasone respectively undergo a doubling of intracellular IgM. Moreover, rIL-6 and dexamethasone additively stimulate cells to accumulate intracellular IgM. In contrast, cells treated with the IC10 concentration of suramin undergo no significant alteration of total cellular IgM, and do not respond to IL-6 with an increase in intracellular IgM. Northern blot analysis demonstrates that cells treated with exogenous rIL-6 and/or dexamethasone respectively undergo a coordinate one to three fold increase of kappa and mu chain mRNA expression, while there is a 30-40% decrease of kappa and mu chain mRNA when cells are treated with suramin and suramin plus rIL-6. Western blot analysis shows that levels of intracellular IL-6 modestly increase when cells are treated with exogenous rIL-6, whereas treatment with dexamethasone plus rIL-6 causes a 70% decrease of immunoreactive IL-6 protein in comparison with untreated cells. An rtPCR analysis of IL-6 mRNA expression shows an abolished signal in response to dexamethasone or rIL-6 and/or dexamethasone. Using a flow cytometric assay, it is demonstrated that suramin inhibits IL-6 binding to its receptor. Taken together, these results indicate that SKW 6.4 cells treated with rIL-6 and/or dexamethasone undergo increased expression of IgM mRNA leading to increased intracellular IgM levels. Treatment with suramin or suramin plus rIL-6 does not alter the IL-6 protein level or the mRNA levels for IL-6 and IL-6 receptor. Suramin treatment causes a moderate decrease in IgM mRNA, and this is associated with a decreased intracellular level of IgM in SKW 6.4 cells. Overall these findings support the concept that IL-6 is an autocrine factor for immunoglobulin production and secretion in myeloma cells. Suramin interferes with IL-6 binding to its receptor and/or decreases IL-6 receptor expression. Dexamethasone has neither of these effects on IL-6 receptor expression or IL-6 binding to its receptor, and we postulate that it acts through a block in secretion or in degradation of intracellular immunoglobulin by decreasing IL-6 mRNA expression and IL-6 protein content. These studies suggest that the combination of suramin and dexamethasone not only synergistically growth inhibit myeloma cells but also act in concert to inhibit immunoglobulin secretion and represent a therapeutic approach worthy of further investigation.

Experience with poorly myelosuppressive chemotherapy schedules for advanced myeloma. The Cooperative Group of Study and Treatment of Multiple Myeloma

In a multicentre study, 83 patients with advanced and previously uniformly treated multiple myeloma (MM) were randomised between cyclophosphamide (600 mg m-2) and epirubicin (70 mg m-2), administered every 3 weeks for three courses and both associated with prednisone and interferon-alpha2b. Both regimens were administered on an outpatient basis and had low haematological toxicity. Clinical results were similar. Overall response rate (43%) and median response and survival (5.9 and 14.1 months respectively) compare well with those obtained with more aggressive chemotherapy schedules.

The role of chemotherapy in the treatment of multiple myeloma

Plasma cell neoplasms often present in an asymptomatic, stable phase. Treatment should not be started until manifestations, such as bone pain, increased susceptibility to infections, renal failure, anaemia and weight loss, announce that the disease has progressed to the MM phase. Conventional therapy with melphalan and prednisone results in objective improvement in about 50% of patients and improves median survival to about 32 months from the start of treatment. Induction therapy should be continued until the M-protein reaches a stable plateau that lasts for at least 4 months. Maintenance therapy with melphalan prolongs the duration of the initial response, but does not improve overall survival, in comparison with patients receiving no maintenance therapy, because survival following relapse is shortened in those receiving maintenance melphalan. In two randomized clinical trials, maintenance treatment with interferon alpha prolonged remissions durations and overall survival of MM patients who responded to induction chemotherapy. Second-line treatment for MM patients who are primary refractory to melphalan, and for those who respond initially and then relapse with refractory disease, is outlined. Although long-term control is possible for a minority of patients, it is unlikely that MM can be cured with currently available chemotherapeutic agents. We need to learn more about the basic biology of the disease.

Development of a criterion for response to therapy at 6 months in multiple myeloma

To investigate the prognostic value of therapy at 6 months on survival in multiple myeloma, to develop a new criterion assessing response to initial therapy at 6 months, and to compare it to a current criterion. The types of initial and 6-month therapy were considered in a prognostic factor analysis in 70 patients treated in routine practice. Using the response to initial therapy defined by the clinician's decision as grouping variable in this group, a discriminant analysis identified the characteristics of responder patients. The validity of the resulting criterion was tested in another test group. Its prognostic ability was compared to the CLMTF criterion (50% M-component reduction from baseline). The therapy at 6 months, reflecting the clinician's appraisal of response to initial therapy, predicted survival significantly. A criterion combining two variables (M-component change and haemoglobin level at 6 months) classified 70% and 72.4% of patients correctly regarding response status in the training and test groups respectively. This criterion was shown to perform better than the CLMTF criterion in predicting survival.

CONCLUSION

A new criterion for response to therapy at 6 months, also presented in a nomogram, combines M-component change and haemoglobin level at 6 months.

Myeloma during a decade: clinical experience in a single centre

One hundred and fifty-six patients with multiple myeloma were treated over a period of 12 years at St. Bartholomew's Hospital. The progress of the disease was affected in 96/156 patients (61%). Response was defined as achieving a plateau of M component. A partial or complete response was seen in 68/120 patients treated conventionally (56.5%), and in 28/36 patients treated with high-dose therapy (77.7%). The median survival of the group as a whole was 20 months, with a 2-year survival of just over 40%. In the 36 patients treated with high-dose therapy, median survival was 6 years, and in a small group who have had maintenance Interferon therapy, the median has not yet been reached. In a univariate analysis, age, intensity of therapy, haemoglobin and creatinine levels were significant, but multivariate analysis showed that only age and intensity of therapy were independent predictors for survival. The outlook for relapsed patients who showed progression of disease remains poor, but palliation was best achieved by steroid and Interferon in combination. Patients who achieve complete responses and are maintained on Interferon appear to be doing better both in terms of freedom from symptoms and in survival, and methods to enable an elderly population to tolerate this form of therapy need to be explored.

Treatment of multiple myeloma according to the extension of the disease: a prospective, randomised study comparing a less with a more aggressive cystostatic policy. Cooperative Group of Study and Treatment of Multiple Myeloma

The purpose of the study was to ascertain whether the prognostic significance of staging in multiple myeloma (MM) is influenced by the aggressiveness of effective induction treatment and/or by continuing or discontinuing maintenance chemotherapy. Patients with untreated stage I MM (defined according to Durie and Salmon) were randomised between being followed without cytostatics until the disease progressed and receiving six courses of melphalan and prednisone (MP-P) just after diagnosis; stage II patients were uniformly treated with MPH-P and stage III patients were randomised between MPH-P and four courses of combination chemotherapy with Peptichemio, vincristine and prednisone (PTC-VCR-P). Within each stage, responsive patients were randomised between receiving additional therapy only until maximal tumour reduction was reached (plateau phase) and continuing induction therapy indefinitely until relapse. With resistant, progressive or relapsing disease, patients originally treated with MPH-P for induction received combination chemotherapy and vice versa. The overall first response rate was 43.8% (42.2% in 206 stage I, II and III patients treated with MPH-P and 48.0% in 75 stage III patients treated with combination chemotherapy, P = NS). Combination chemotherapy was more myelotoxic than MPH-P and, in particular, caused more non-haematological side-effects. Both the less and the more aggressive induction policies gave the same disease control. Progression of disease was statistically similar in stage I patients who were initially left untreated and in t hose who received MPH-P just after diagnosis; median duration of first response was similar in stage III patients receiving MPH-P and in those on combination chemotherapy. In all stages, discontinuing or continuing maintenance did not alter the median duration of first response. The overall second response rate was 28.5% (34.0% to MPH-P and 25.3% to combination chemotherapy, P = NS). Median survival was greater than 78 months in stage I, was 46.3 months in stage II and was 24.3 months in stage III patients, still independent of both induction and post-induction policies. In MM, the significance of staging for survival is independent of both the aggressiveness of induction and of continuing or discontinuing maintenance chemotherapy after the maximal tumor reduction has been achieved. Both MPH-P and and the association of PTC, VCR and P are effective in inducing first response and also second response in patients failing on the alternative regimen, but PTC-VCR-P causes more side effects. Thus, the overwhelming majority of patients with MM can safely be given MPH-P as first therapy, and this treatment may be delayed in early diseases.

Glucocorticoid receptors and resistance to glucocorticoids in hematologic malignancies

Glucocorticoids are highly effective in inducing the cytolysis of cells of lymphocytic origin. This property has resulted in their incorporation into chemotherapy regimens used in the treatment of hematologic malignancies. Studies at the molecular and cellular levels have demonstrated that the hormone-induced cytolytic response is mediated through a highly specific cytoplasmic glucocorticoid receptor (GR). The GR has been cloned and sequenced and found to be organized into a discrete series of domains which mediate the receptor functions of hormone binding, nuclear translocation, DNA binding and transcriptional modulation. Thus, the binding of glucocorticoids by the GR induces a series of cellular events which result in the activation or repression of a network of glucocorticoid responsive genes and produces a specific cellular response. Prolonged exposure to glucocorticoids ultimately causes resistance to develop; thereby limiting the usefulness of this class of drugs. Studies addressing the mechanism of resistance have shown that the GR is the primary target of genetic alterations that lead to resistance to cytolysis. Using mouse and human cell lines as model systems, it has been shown that the vast majority of glucocorticoid resistant mutants express low levels or altered forms of the GR. Similarly, in vivo studies on patients have suggested that low GR levels are associated with a poor response to glucocorticoid based therapies. Recently, aberrant GR isolated from a patient with multiple myeloma resistant to glucocorticoids were found to harbor deletions in their hormone binding domains. Sequencing of the receptors suggested that each arose as a result of alternate splicing events. In both cases, the latter event produces a receptor unable to bind hormone leading to the speculation that alternate splicing may serve as a mechanism by which a cell evades the effects of glucocorticoids. The therapeutic implications for patients expressing aberrant receptors is discussed.

Salvage therapy for multiple myeloma: the University of Arkansas experience

OBJECTIVE

To summarize a spectrum of salvage regimens for multiple myeloma (MM) developed during the past decade.

DESIGN

We reviewed the experience at the University of Arkansas in the management of patients with MM who failed to achieve remission ("primary unresponsive") or had a relapse despite myelosuppressive doses of chemotherapy ("resistant relapse").

MATERIAL AND METHODS

Results with use of the various chemotherapeutic protocols are presented, and multivariate regression analysis was applied to determine the independent contributions of certain factors toward event-free and overall survival.

RESULTS

The VAD regimen (vincristine sulfate, Adriamycin [doxorubicin hydrochloride], and dexamethasone) yielded responses in 29% of previously unresponsive and 46% of relapsed cases of MM, in comparison with 25% and 21%, respectively, with use of dexamethasone only. Responses occurred more frequently when tumor cell RNA content was high, tumor burden was low, and duration of drug resistance was less than 1 year. The duration of survival in patients who received high doses of melphalan was decreased in those with increased serum levels of lactate dehydrogenase. EDAP (etoposide, dexamethasone, ara-C, and cisplatin) produced 75% or more tumor cytoreduction in 8 of 20 patients. Overall in patients with an increasing number of adverse factors, response rates and survival decreased progressively with less intensive therapy but were unaffected when more intensive therapy was used. In the multivariate analysis, the most important features for extended survival were a low beta 2-microglobulin level before transplantation and application of two bone marrow transplants within 6 months.

CONCLUSION

Variables relative to the patient's overall medical condition, prior treatment, characteristics of MM at diagnosis, and response history should be carefully assessed to determine a plan for salvage therapy that will maximize the opportunity for sustained remission and survival.

Response of resistant idiopathic thrombocytopenic purpura to pulsed high-dose dexamethasone therapy

BACKGROUND

Most patients with chronic idiopathic thrombocytopenic purpura have a response to corticosteroids or intravenous immune globulin, but improvement is often transitory. Splenectomy may provide only a short-term benefit. Because pulsed high-dose therapy with potent synthetic corticosteroids is inexpensive, well tolerated, and effective in patients with secretory B-cell neoplasms, a similar regimen was examined for its efficacy in patients with chronic idiopathic thrombocytopenic purpura that was resistant to other treatments.

METHODS

Ten consecutively referred patients who had persistent symptomatic idiopathic thrombocytopenic purpura after undergoing at least two standard therapies were treated with six cycles of dexamethasone (40 mg per day for 4 sequential days every 28 days).

RESULTS

All patients had increased platelet counts (mean [+/- SD] count before treatment, 12,000 +/- 8200 per cubic millimeter; after treatment, 248,000 +/- 130,000 per cubic millimeter). The platelet counts remained above 100,000 per cubic millimeter for at least six months after the last cycle of treatment. There were no serious side effects. Features of hyperadrenocorticism due to prior corticosteroid therapy resolved during treatment. The cost of the drug was approximately $100 per patient.

CONCLUSIONS

Although the possibility of spontaneous remission and a delayed benefit from prior therapy cannot be excluded in this small group of patients, pulsed high-dose treatment with dexamethasone may provide a low-cost therapeutic option with minimal side effects in patients with refractory idiopathic thrombocytopenic purpura.

Multiple myeloma in the elderly

While multiple myeloma is an incurable disease for nearly all patients, current chemotherapy and supportive care can result in significant disease control and improved duration of survival and quality of life. With the average age of patients about 70, most of the high-dose curative strategies exclude the bulk of patients affected by the disease. Recent advances in understanding the biology and pathophysiology of myeloma have led to novel therapies aimed at altering drug resistance, improving duration of the plateau phase, interrupting the cytokine growth stimulation, and improving management of common complications including infections, anemia, and bone lesions. These latter approaches are not restricted to younger patients, and early evidence indicates that elderly patients are also likely to benefit.

Bi-weekly vincristine, epirubicin and methylprednisolone in alkylator-refractory multiple myeloma

Nine patients with poor-prognosis, alkylator-refractory stage III multiple myeloma (MM) were treated with a 23-h continuous infusion (CI) of a compatible mixture of vincristine (VCR) and epirubicin (EPI) daily for 4 days along with a daily 1-h infusion of high-dose methyl prednisolone (MP) to total of 5 days (VEMP); cycles were repeated every 2 weeks when possible, usually on an outpatient basis. WHO grade 3 or 4 neutropenia and infection were the predominant toxicities encountered, necessitating some treatment delays and dose reductions. Two patients died during treatment. Peripheral neuropathy necessitated discontinuation of the VCR in six patients without obvious loss of efficacy of the regimen. Skeletal muscle dysfunction and cardiomyopathy did not occur; trivial ECG abnormalities occurred during a minority of infusions but were of indeterminate relationship to the chemotherapy. Confusion occurred in two patients; alopecia was frequent but reversible, and mild/moderate dyspepsia and stomatitis were common but easily managed. Eight patients achieved a partial response (PR); another patient experienced early death during his second cycle before response assessment. The median survival from the first VEMP administration was 9 months (range, 1-64 + months), the median response duration was 7 months (range, 1-64 + months). Two patients experienced responses too short to be clinically relevant (< or = 2 months). An analysis of weekly paraprotein estimations suggests that the intended bi-weekly cycle length may be optimal. Six of these nine patients derived major benefit from this bi-weekly regimen, which deserves further exploration.

A phase II trial of didemnin B in myeloma. A Cancer and Leukemia Group B (CALGB) study

Didemnin B is a member of a class of compounds, derived from a marine source, undergoing phase II study. Twenty-two patients with relapsed myeloma were treated with didemnin B at an initial dose of 4.9 mg/m2, given once every 28 days. All were evaluable for toxicity, and 15 were evaluable for myeloma response. No tumor regressions occurred in the 15 patients evaluable for response. Vomiting was the major toxicity, occurring in 73% of patients despite vigorous pre- and post-treatment medication with at least three intravenous antiemetics. Two instances of grade 4 hypersensitivity reaction occurred. We conclude that didemnin B has no activity at this dose and schedule in myeloma that has relapsed after one or two prior therapeutic regimens.

Efficacy of prednisone in refractory multiple myeloma and measurement of glucocorticoid receptors. A Southwest Oncology Group study

BACKGROUND

Prednisone is an active drug in the treatment of multiple myeloma. The optimal dose, frequency, and role of glucocorticoid receptors (GR) in response to prednisone is unknown.

PURPOSE

The purposes of this study were (1) to estimate the response rate of alternate-day high dose prednisone in patients with relapsing and refractory multiple myeloma; (2) to measure the rate of GR levels; and (3) to correlate the response of prednisone with GR status.

PATIENTS AND METHODS

Between 8/86 and 1/90, 127 patients were entered onto the study with 121 evaluable for response. The number of GR sites/cell was determined on mononuclear cells isolated from pretreatment bone marrow aspirates using a one point GR binding assay. Patients received prednisone 100 mg po qod x 2 weeks, followed by 50 mg po qod x 10 weeks.

RESULTS

The overall response rate was 10% (95% CI: 5-15%) with a median survival of 11.8 months. The GR sites/cell ranged from 0-53,212 with a mean of 8,371 sites/cells. Stratification of GR sites into 0-2,500, 2,501-6,000 and > 6,000 sites/cells was associated with a response rate of 6%, 27% and 4% respectively (p = 0.009). The median survival of patients in these categories was 8.1, 14.9 and 10.6 months respectively. This was not significant by the logrank test (p = 0.11). Although myeloma patients with intermediate levels of GR sites/cell initially responded more favorably to prednisone, their long-term survival was not significantly improved.

CONCLUSIONS

Alternate-day high-dose prednisone was well tolerated and may provide palliative benefit for a subset of patients with relapsing and refractory multiple myeloma. The survival of patients on this study was comparable to that reported with other but more toxic doses of glucocorticoids.

Etoposide, doxorubicin, cyclophosphamide and high-dose betamethasone (EACB) as outpatient salvage therapy for refractory multiple myeloma

Fifty-six patients with refractory multiple myeloma were treated with intermittent courses of etoposide, doxorubicin, cyclophosphamide and high-dose betamethasone (EACB) every 4th week. The overall response rate was 30%. Durable remissions exceeding 1 year were obtained in 12 of the 17 responding patients. A significant prolongation of the survival time was found for responding patients (median 13 months) compared to those patients who did not respond (median 9 months) to EACB therapy (p = 0.01). A low frequency of neutropenic fever episodes was noted compared to other salvage treatment regimens. The EACB regimen was usually well tolerated and could be administered safely on an out-patient basis. This regimen might be an alternative especially for elderly patients unresponsive to initial therapy.

VAD regimen in the treatment of resistant multiple myeloma: slow or fast infusion?

The VAD regimen is effective in the treatment of resistant and relapsing multiple myeloma. In the original VAD regimen, vincristine (V) and doxorubicin (A) are given as continuous infusions together with peroral dexamethasone (D). For practical reasons, we have shortened the infusion times: 8 hours for vincristine and 1 hour for doxorubicin. In this retrospective analysis, we have compared the efficacy and toxicity of the original and modified VAD protocols in the treatment of myeloma patients at our institution. Of the 31 consecutive patients with myeloma, primarily or secondarily resistant to alkylating agents, 16 were treated by the original and 15 by the modified VAD protocol. We found no significant difference in the response rates (good responses 31% and 20% respectively), survival times (17 and 9 months respectively) or toxicity between the two protocols. VAD may well be modified so as to consist of short infusions of V and A. The overall efficacy of the traditional and modified regimens is, however, rather unsatisfactory in patients with advanced myeloma.

Modified vincristine, doxorubicin, and dexamethasone regimen in the treatment of resistant or relapsed chronic lymphocytic leukemia. An Eastern Cooperative Oncology Group study

BACKGROUND

Thirty-six patients with relapsing or refractory chronic lymphocytic leukemia were entered into a Phase II study of the Eastern Cooperative Oncology Group.

METHODS

A modified VAD regimen was given: a 96-hour infusion of 1.6 mg vincristine and 36 mg/m2 doxorubicin with dexamethasone 40 mg by mouth daily for 4 days every 3 weeks. The treatment was continued until two cycles beyond maximal response, which was evaluated after two and six cycles.

RESULTS

Of the 33 evaluable patients, 7 (21%) achieved a partial response (PR), with no complete remissions. One-third of the patients (11 of 33) had progressive disease and 15 of 33 (45%) had stable disease, as defined by the National Cancer Institute Working Group criteria. The median duration of PR was 6.5 months, with a median survival time of 14.8 months. A PR was achieved by 3 of 19 patients (16%) who had received prior vincristine +/- doxorubicin and 4 of 14 patients (28%) who had not received vincristine or doxorubicin. Of the nine patients whose disease was refractory to prior therapy, five (55%) achieved a PR. The neurotoxicity of VAD was reduced by decreasing the frequency of the dexamethasone, but 22 of 36 (61%) patients still became infected. Only on infection (2.8%) was life threatening, and there were no infectious deaths.

CONCLUSIONS

Because fludarabine has shown superior responses, VAD should be reserved for patients who do not respond to alkylating agents and fludarabine and in whom alternative treatments are not appropriate.

Interleukin-6, a new target for therapy in multiple myeloma?

During the past few years much insight has been gained into the immunobiology of multiple myeloma. It has become evident that the growth of myeloma cells is regulated by cytokines, notably interleukin-6. In this paper a brief review is given of the evidence derived from in vitro as well as in vivo observations that interleukin-6 is involved in the pathogenesis of multiple myeloma, and the implications of these findings for the development of new therapeutic strategies are discussed.

Biology and treatment of multiple myeloma

The uniformly fatal plasma cell malignancy, multiple myeloma (MM), currently represents 10-15% of hematologic neoplasms in the USA and has been steadily increasing in incidence for several decades. Therapeutic alternatives have lagged significantly behind insights into the biology and pathogenesis of this entity. Traditionally felt to be a neoplasm of fully differentiated plasma cells, evidence has been mounting that the self renewing population consist of cells derived from a much earlier compartment; perhaps prior to B-cell lineage commitment or even at the level of an earlier 'stem cell'. Bcl-2 protein overexpression has been almost uniformly seen in both clinical myeloma specimens as well as in myeloma cell lines. The failure to consistently identify the t(14;18) translocation, normally found in follicular lymphomas and characteristically associated with overexpression of bcl-2, implies a unique mechanism in MM. A number of cytokines, including TNF alpha, IL-1 and IL-6 have been found to play a central role not only in the biology of the malignant clone but also in the bony and other systemic manifestations of this disease. Since both IL-6 and bcl-2 protein have been shown to prevent programmed cell death, this may be the unifying event in MM. Standard therapy for MM has been an alkylating agent and corticosteroid. Combination chemotherapy provides more prompt palliation but no clear survival advantage. In advanced stages, adriamycin may offer some survival advantage. High dose chemotherapy with or without stem cell support offers a potentially curative therapeutic approach. New interventions directed at the complex cytokine networks pertinent to the pathogenesis of MM are an exciting new area of investigation. Identification of new prognostic parameters as well as new active agents remains the central theme in clinical myeloma research.

Treatment of melphalan-resistant multiple myeloma with vincristine, BCNU, doxorubicin, and high-dose dexamethasone (VBAD)

A total of 65 patients (35 male/30 female) with multiple myeloma primarily (33) or secondarily (32) resistant to melphalan and prednisone were treated with vincristine, carmustine (BCNU), doxorubicin, and high-dose dexamethasone (VBAD) at 4-week intervals. Among 60 evaluable patients the overall response was 36.6% (21.6% objective response plus 15% improvements). The response rate was significantly higher in primarily resistant patients than in those becoming resistant after a prior response (48.4 vs. 24.1%, P < 0.05). The median duration of response was 17.5 months. When survival of responders and non-responders were compared by the conventional method, a highly significant difference was observed (P < 0.001). However, using the Mantel and Byar procedure and the landmark method, only a trend for longer survival in the responders was registered. These results indicate that although VBAD is effective in at least one third of patients with advanced multiple myeloma resistant to melphalan, its impact on survival is limited.

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

In view of increasing controversy regarding the role of double hemibody irradiation (DHBI) in the treatment of multiple myeloma, we have analysed the use of this technique at our institution over a 6-year period. Fifty-five patients with multiple myeloma were treated with both upper and lower hemibody irradiation between January 1985 and January 1991; 42 had relapsed post-plateau and 13 were chemoresistant to initial therapy. Fifteen patients received alpha IFN-2b maintenance therapy post-DHBI, at a dose of 3 Mu three times per week, as part of a randomized trial. Ninety-five per cent of patients experienced symptomatic improvement in bone pain post-DHBI, 21% of whom discontinued opiate analgesics altogether; 63% had a minor biochemical response and 38% had a partial biochemical response. The overall survival (OS) and progression free survivals (PFS) in all patients were 11 months and 8 months respectively. No significant difference was noted in either OS or PFS, according to whether patients were chemoresistant or had relapsed post-plateau. alpha IFN did not appear to prolong survival (OS or PFS) post-DHBI. Cytopenia was a significant problem, such that only 60% of patients had counts adequate enough to be eligible for alpha IFN. We conclude that DHBI is an effective treatment in patients with relapsed multiple myeloma and in those who are chemoresistant to initial therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Dexamethasone reverses glucocorticoid receptor RNA depression in multi-drug resistant (MDR) myeloma cell lines

Glucocorticoid receptors and glucocorticoid receptor RNA (GR RNA) were measured in doxorubicin resistant myeloma cell lines to investigate the relationship between multi-drug resistance and glucocorticoid sensitivity. Glucocorticoid binding sites and GR RNA were found to be lowered in all the tested doxorubicin resistant cell lines: R10, R40 and R60 compared to the untreated wild type RPMI 8226 cells (Dalton, et al., 1984). The least resistant cell line, R10, maintained a down regulation of GR RNA after 48 hours of dexamethasone (10(-6) M) treatment of the cells. Interestingly, the R10 cell line has been reported to be very sensitive to dexamethasone treatment. However, the GR RNA levels increased in presence of dexamethasone in the most resistant cell line, R40, R60 by comparison to the wild type. Thus, the reduction of GR RNA by doxorubicin treatment appears to be overcome by dexamethasone in the most resistant cell lines. Steroids may be helpful in reversing resistance and maintaining drug sensitive human tumor populations that will continue to respond to cancer chemotherapeutic agents.

Modulation of multidrug-resistant multiple myeloma by cyclosporin. The Leukaemia Group of the EORTC and the HOVON

Resistance to chemotherapy in refractory multiple myeloma is frequently associated with expression of multidrug resistance (MDR). In resistant cells, intracellular accumulation of doxorubicin and vincristine does not occur because the MDR-1 gene product, a membrane glycoprotein (PgP), is an energy-dependent efflux pump. Cyclosporin is one of several non-cytotoxic drugs that can block the function of PgP. In a prospective study, we assessed the possibility that cyclosporin could be used clinically to modulate MDR. We studied 21 patients with multiple myeloma; disease had progressed during primary chemotherapy in 6 and was resistant to VAD (vincristine, doxorubicin, dexamethasone) in 15. The patients received cyclosporin by continuous infusion during VAD treatment; there were three cyclosporin dosage groups (5, 7.5, 10 mg/kg daily). Serum cyclosporin concentrations adequate for MDR modulation were reached in all patients receiving 7.5 or 10 mg/kg daily. 47% (7) of the VAD-refractory patients and 48% (10) of the whole group responded to VAD. Before treatment, MDR-1 expression was present in 12 patients. After VAD plus cyclosporin, no MDR-1-positive plasma cells were present in 6 of 8 patients tested. The response rate in MDR-1-positive patients was 58% compared with 33% in all our patients. Toxic effects were mild and reversible and did not include nephrotoxic or serious cardiovascular side-effects. 12 months after the start of treatment, survival was 85%, and disease-free survival at a median of 9 months after the response was 65%. Thus, in multiple myeloma clinical resistance to VAD can be circumvented by cyclosporin, which enables the cytotoxic drugs to eliminate resistant myeloma cells.

Continuous-infusion cyclophosphamide in combination with teniposide and dexamethasone in refractory myeloma

Forty-three consecutive patients with refractory myeloma, median age 60, received monthly courses of teniposide 30 mg/m2 i.v. on days 1-2, dexamethasone 40 mg i.v. on days 1-7 and cyclophosphamide 200 mg/m2 by continuous i.v. infusion for seven days. Major response (decrease > 50% of M-protein) was achieved in 18 of 37 evaluable patients and minor response in 9, with an overall response rate of 73%. Response was irrespective of disease status, time from diagnosis and previous treatments, while beta 2 microglobulin > 6 mg/l was a powerful prognostic factor. All patients experienced transient granulocytopenia but extramedullary toxicity was negligible. Median survival of the whole group is 20 months, with 74% of responding patients projected to be alive at 30 months. In refractory myeloma cyclophosphamide appears to be more active when given by continuous infusion.

Multiple myeloma: intensified maintenance therapy with recombinant interferon-alpha-2b plus glucocorticoids

Interferon-alpha-2b has been demonstrated to prolong remission duration and survival in responding multiple myeloma patients. The aim of this study was to evaluate intensification of this maintenance therapy through the addition of glucocorticoids. Eighteen myeloma patients at diagnosis received six-12 courses of conventional chemotherapy and then interferon + glucocorticoids. This treatment included 3 megaunits of interferon three times a week, plus 4 days of pulsed high-dose dexamethasone (40 mg/d for 4 d every 28 d for 6 months/year) in patients < 70 yr old, or oral prednisone (50 mg three times a wk) in patients > 70 yr old. Conventional chemotherapy induced an objective response in 13/18 patients and a further reduction of the M component (> 50%) was achieved during interferon + glucocorticoids treatment in 7/13. 4/18 patients relapsed with a median follow-up of 22 months (range 13-40). These findings indicate that interferon + glucocorticoids, after inductional chemotherapy, further reduces tumor burden and may prolong remission.