Dr. Shaughnessy opened the morning sessions by describing the results of studies looking at genes that were under- and over-expressed in patients with multiple myeloma (MM) and that were correlated with poor survival (i.e., high risk group) or likelihood of survival. Future therapies may target the genes or gene products to improve outcomes for patients.
Dr. Keith Stewart continued the conversation, presenting information about specific mutations present in the cells of patients with myeloma that correlate with the progression of the disease. Specifically, some genes correlate with poor response to chemotherapy and with poor prognosis. He suggested that immunohistochemistry testing is an easy and inexpensive way to identify specific genes that may identify those patients with a poor prognosis. In terms of how MM patients respond to chemotherapy, there are 2 possibilities: that they do not respond to chemotherapy or that they quickly develop resistance to therapy. Analysis of data from patients indicates that patients did respond to therapy but that high risk patients show rapid progression of disease. Information derived from the analysis of overexpressed genes that correlate with disease has provided targets for new therapies that are entering clinical trials.
Dr. Gareth Morgan then reviewed the role of the immune system in protecting the body from infection and from toxins which may cause disease and the role of individuals genes in responding to challenges to the immune system. Dr. Morgan also discussed the role of pharmacogenomics (the genetics used to predict outcomes of disease and side effects of drugs) on myeloma. Two sources of genetic variance exist: variations that are common in populations and variations that are related specifically to families with the latter giving rise to familial diseases. The database created by Bank On A Cure (BOAC) provides samples from patients that allow various studies to be conducted to examine the potential of specific genes being present in families that may predispose patients to MM. Other studies may identify potential mechanisms that trigger the progression of disease from MGUS to MM. Outcome studies evaluate factors that influence survival and development of side effects; these studies also make correlations between genes and the development of MM. Studies on patient samples may also identify the best treatments for individual patients.
Dr. Brian Van Ness discussed the development of MM, the progression of the disease, response to therapies related to the genes expressed, and the abnormalities of those genes. It is recognized that individuals who have poor mechanisms for repairing DNA are at high risk for developing cancer and may have toxicities to therapies. Dr. Van Ness highlighted that BOAC was initiated by the International Myeloma Foundation (IMF) based on the need for a genomic approach to look at associations of genetics and MM risk and outcome. It is likely that the use of data collected from patients by BOAC may provide insight into the correlations between genes and survival by identifying genetic variants that are frequent and correlated with clinical outcomes (survival, progression free survival, etc.). The goal of studies examining the genes of patients with MM is to come to be able to identify right drug and right dose of that drug for the right patient. For example, during clinical trials, the question was raised as to whether there was a correlation between the development of a deep vein thrombosis (DVT) and thalidomide in patients enrolled in clinical trials. Upon genetic analysis, only Factor V showed an association of genetic variations in patients who developed DVTs. Some genes show wide variety of responses in patients so it is likely that some associations are due to chance at this point; a larger sample size will improve likelihood of finding definite signals. Future directions for data collected by BOAC include developing tools to look for cluster of genes that are predictive of clinical outcomes or are predictive of whether a patient will respond to a specific therapy.
Dr. Friedrich Cremer closed the session with a discussion of the biological functions of specific predictor genes that are related to protein and DNA metabolism, cell growth and maintenance, cell communication, response to external stimuli, and cell death. He noted that overexpression of specific genes is related to cell growth, disease progression, and drug resistance. There is a possible pathogenetic role of the upregulation of specific genes (predictor genes, most frequently ribosomal protein genes) since these proteins are found in some cancers and malignant processes. In other tumors (e.g., CLL, ovarian cancer), no correlation between over-expression of these proteins and proliferation is noted.
Plenary Session 8 provided an opportunity to hear the latest results in ongoing global studies. Due to previous findings, it has been established that high-dose therapy (HDT) followed by autologous blood stem cell transplant (SCT) resulted in superior response rates as well as longer event-free survival (EFS) and overall survival (OS). Because patients eventually relapse, global studies are conducting studies to improve clinical outcome. Dr. Pieter Sonneveld presented the updated analysis from the HOVON 24 trial (the Netherlands study), which began in 1995. This trials objective is to demonstrate superior long-term clinical outcome of double versus single high-dose therapy. He reported on the updated analysis, second intensification followed by myeloablative treatment followed by autologous transplant in newly diagnosed patients. Results at 60 months show a significant benefit in complete response (CR), EFS, progression-free survival (PFS), and time to disease progression (TTP), but not OS. Further analysis is to be conducted.
Dr. Harmut Goldschmidt followed with the second analysis of the GMMG-HD2 trial (the German Study). This trial is evaluating single versus double HDT followed by stem cell transplant (SCT) in newly diagnosed MM. Findings on 210 evaluable patients showed the median EFS in the single arm at 23 months versus 29 months in the double arm; no difference is seen in OS; however, a full analysis is not completed yet. He stated that Beta-2 microglobulin is a predictor of EFS in responsive patients.
Dr. Joan Blade presented an update on the PETHEMA/GEM trial (the Spanish study), which compared the efficacy of HDT followed by SCT intensification to the continuation of conventional chemotherapy for those patients responding to chemotherapy. This study was conducted from May 1994 to October 1999 with 216 patients entered. Of the 164 patients randomized, 83 continued to chemotherapy and 81 continued to HDT. After a median follow up of 66 months, the CR rate was significantly higher in the HDT arm; PFS was 9 months longer in the HDT arm, but not statistically significant. OS was not impacted. Dr. Blade also presented the study design from the current PETHEMA/GEM 2000 trial. Several abstracts with preliminary results from this trial are to be presented during the poster sessions at this meeting.
Dr. Michele Cavo offered findings from the Bologna 96 trial (the Italian study), which addressed the issue of single versus double autologous transplantation for patients younger than 60 years of age. At a median follow up of 55 months, double transplantation prolonged the median CR, EFS, and OS. The greatest benefit of double transplant was among patients who failed at least a near CR after first transplant. Dr. Cavo introduced the Bologna 2002 trails which evaluates the efficacy and toxicity of thalidomide-dexamethasone (thal/dex) as primary therapy for patients who are candidates from double autologous transplantation. Preliminary analysis of 100 patients was compared to 100 patients from the Bologna 96 trial. Patients matched in age and other baseline characteristics. Dr. Cavo cautioned the interpretation of data but shared that PR was higher in the thal/dex arm. Thal/dex was also found to significantly reduce tumor cell mass, but carried the higher risk of thrombosis requiring prophylaxis therapy. With this preliminary analysis, thal/dex did not adversely affect SCT collection. Dr. Cavo concluded that thal/dex may provide an easy to administer alternative to standard therapies.
Dr. Jean Paul Fermand represented the MAG group (Myelome-Autogreffe; Paris France). He presented long term follow up form the studies conducted from 1985-2005. Four trials were conducted: Pre-MAG, MAG 90, MAG 91, and MAG 95. Pre-MAG was a Phase 2 trial comparing early versus late HDT followed by SCT, results were similar in both arms. MAG 91 included older patients (55 to 66 years old); no significant differences were seen with OS. MAG 95 evaluated sequential HDT followed by a CD34 selection technique. Dr. Fermand presented the final analysis of this study at a median follow up of 73 months. Results show a significant overall survival advantage with double HDT versus single and CD34 selection showed no survival benefit. Dr. Fermand shared the next study would investigate results in patients younger than 65.
Dr. Anthony Child closed this session with his presentation on the MRC studies (Medical Research Council; United Kingdom). The MRC Myeloma VII trial evaluated standard conventional chemotherapy to HDT. Results from this trial were reported and published 2 years ago. At this meeting, Dr. Childs presented a recent analysis that showed improved PFS and OS with HDT, clearly showing an advantage of intensive transplantation. Dr. Childs also presented the Myeloma IX study that incorporates high-dose melphalan as the standard component of treatment for patients of all age groups. Dr. Childs pointed to future trials that may come out of Myeloma IX will evaluate the enhancement of induction therapy for suboptimal responders, consider new relapse regimens, and determine selective approaches from good and poor prognosis patient subsets.
Dr. Claire Shipman opened the session discussing the interactions between tumor cells and cells in the bone marrow (osteoclasts and osteoblasts) that may influence systems that are involved in the development of bone disease in patients with MM. Myeloma cells may be under the influence of certain molecules (OPG) that support their survival in the bone marrow. Preliminary data from a few patients shows that MGUS cells produce OPG but MM cells may rarely or may not produce OPG. Similarly, cells in the bone marrow microenvironment may protect myeloma cells from factors that would induce apoptosis and thus limit the progression of disease. One of these factors, TRAIL, may mediate antitumor activity.
Dr. Babatunde Oyajobi discussed the role of a specific factor, MIP-1, in osteolysis (bone disease) in MM. MIP-1 is a chemokine that is produced by MM cells and is overexpressed in the bone marrow of MM patients. Experimental results showed that MIP-1a stimulates osteoclast formation and bone resorption in vivo. MIP-1a is dependent on specific signaling pathways (RANK) to affect bone resorption. Use of specific antibodies against MIP-1a inhibited development of osteolytic lesions in a mouse model of MM and decreased the activity of osteoclasts. The antibody also reduced the incidence of splenomegaly in myeloma-bearing mice. Data suggest that blocking MIP-1a reduces tumor burden, bone lesions, and splenomegaly.
Dr. Evangelos Terpos opened his presentation by reviewing that bone disease is one of the most common presentations of MM. Osteoclast activity is induced by cytokines and osteoclast activation is important for MM cell survival. Specific signaling pathways (RANKL) and molecules that interact with those pathways (OPG) may work together to inhibit osteoclast differentiation. Dr. Terpos discussed the relationship between the probability of survival and expression of RANKL/OPG in MM. He closed his discussion suggesting that specific pathways are important for myeloma survival and for the pathogenesis of bone disease, and that molecules in these pathways may serve as targets for antimyeloma agents.
Dr. Erming Tian reviewed that clinical data showing that bisphosphonates stop bone lesions but do not repair bone tissue. Examination of the contributions of the DKK1 gene in patients with myeloma bone disease or in normal bone donors showed that normal donors have lower DKK1 levels than myeloma patients, regardless of whether the myeloma patients have active disease. Use of a monoclonal antibody against DKK1 in a mouse model showed that monoclonal antibody inhibition of DKK1 was associated with increased numbers of osteoblasts, reduced number of osteoclasts, reduced bone loss, and reduced tumor burden. The data suggest that DKK1 produced by myeloma cells in the bone marrow contributes to bone defects. Other results suggest that DKK1 promotes myeloma cell proliferation; blocking DKK1 inhibits myeloma tumor growth. Additionally, data show that DKK1 can be activated by genotoxic and non-genotoxic agents in other tumor cells, activated by tumor and non-tumor cells, activated by thalidomide and other drugs, but not activated by proteasome inhibitors (e.g., bortezomib). Furthermore, these findings suggest that DKK1 may be the mediator of thalidomide embyropathy.
Dr. Toshihiro Hashimoto presented results of studies looking at the ability of macrophage inhibiting protein (MIP)- 1a and ß and MM cells to affect osteoclasts (OC) and dendritic cells (DC). Results suggest that MIP-1 has a role in the formation and function of monocyte-derived OC. Additional data suggest that MIP-1 may be critical to OC cell lineage, maturation, activation, and to inhibition of DC maturation. Consequently, MM cells may be involved in the mechanism that affects bone resorption.
Dr. Gosta Gahrton gave a state-of-the-art update on allogeneic transplantation in MM. Transplantation activity increased dramatically from 1992 to 2002 and a dramatic improvement in survival was noted after 1994, the latter related predominantly to a decrease in transplant related mortality. Relapse rates following transplant are lower if a molecular remission is not achieved. Striking data from long term investigation of allogeneic transplantations show that for male patients, use of a female donor correlates with a significantly lower relapse rate. Dr. Gahrton pointed out that this was a new finding; earlier evaluations transplant mortality showed high mortality in transplants in males with female donor than with male donor. However, since 1994, relapse rates offset mortality rates. Prognostic factors correlating with good outcome of transplants are stage 1 disease, only 1 line of chemotherapy before transplantation, and response to previous therapy. Dr. Gahrton noted that an increase in the number of reduced conditioning (RIC) transplants compared with standard regimen transplants were conducted since 1997. Relapse rates were significantly higher with RIC than with standard transplants but OS was not significantly different. Treatment related mortality is lower in RIC than in standard transplants. Overall, RIC has improved since 2002.
Dr. Francis Ayuk presented results of studies looking at allogeneic stem cell transplant (allo-sct) for MM conducted in the EU. The strategy used was to offer dose reduced melphalan-fludarabin in newly diagnosed MM patients. The treatment strategy was successful, with a low rate of treatment related mortality (18%) and good responses (CR=49%, PR=38%). At 2 years, OS was 59% and progression free survival (PFS) was 39%; relapse at 2 years was 43%. Notably, OS after allografting was better in patients who had not relapsed. Data suggest that auto-allogeneic tandem transplant strategy is a more promising strategy than a salvage strategy. In another trial, patients completed autologous and allogeneic transplantations. Stem cells were the source of cells in more than 90% of the cases and 124 days separated the transplants. Following allogeneic transplant, 6% of patients were in complete response (CR), 37% in partial response (PR), 2% in minor response (MR). After allograft, 55% were in CR, 27% in PR, and 3% had progressive disease. Acute graft versus host disease (GVHD) was seen in 42% of patients; mortality was 7% at 1 year. At 4 years post transplant, OS was 68%. Notably, related and unrelated donors showed no difference in disease free survival. In summary, the data suggest that transplantations should be performed at early stages of disease, that donor lymphocyte infusions (DLI) is effective in relapsed patients, and that thalidomide used in DLI enhances remission rates without occurrence of severe GVHD. Looking forward, dose reduced allografts should be a part of broad treatment strategies which includes autologous transplantation, DLI, and emerging drugs.
Dr. William Bensinger spoke about shifting burden from tumor to T cells to ablate disease. There is a wide range of treatment spectrums available to patients that are related to aggressiveness of the tumor and genetic disparity. Dr. Bensinger and associates adopted a tandem autologus/non-ablative allogeneic stem cell transplant strategy in response to poor outcomes observed with other strategies. Analysis of data at a 3 year follow up showed 60% survival and 40% PFS; only 17% of patients had died of treatment related mortalities (TRM). Lesson learned from CML include the use of high dose busulfan to improve survival and reduce relapse after allograft. Tandem autologous/allogeneic transplants showed a low rate of mortality (20%) and a high response rate (57% CR, 29% PR). Future goals include improving graft versus leukemia (GVL) and GVHD, upregulating target antigens with specific cytokines, and use of post‑transplant
maintenance with agents such a thalidomide.
Dr. Henk Lokhorst talked about strategies to improve graft versus myeloma (GvM) and discussed what can be learned from DLI. Donor T cells are essential for GvM and induction of chronic GVHD is critical for GVM. DLI following non-myeloablative allo-sct showed a 38% response. While the duration of response was short in for patients achieving PR (8 mo), those achieving CR had 30 months duration of response. OS is at least 1 year and has not yet been achieved. Toxicity was of this treatment regimen is low, with 10% TRM, 25% acute GVHD, 43% chronic GVHD. Dr. Lokhorst then discussed the efficacy of thalidomide treatment after allo-sct. Notably, 60% of patients achieved a PR and 24% a very good PR. The duration of response was more than 12 months. GVHD flare up was seen in only 3 patients. New strategies include application of novel agents after transplantation, e.g., thalidomide and Velcade.
Dr. Laura Rosinol discussed the feasibility and efficacy of planned second transplant intensification in patients with MM. Those patients more likely to benefit from a second transplant are those failing initial transplant. More than 50% patients in whom tandem transplants were planned as the second transplant were not performed for multiple reasons, including disease progression or patient refusal. The remaining patients had a second transplant, either autologous transplant or mini-allogeneic transplant. Dose- reduced intensity allogeneic transplant after an autologous procedure resulted in a significantly higher CR rate than a second autologous intensification. Currently available follow up data showed no significant differences in survival between the 2 modalities of second transplant (autologous or mini-allogeneic); EFS and OS were similar for both groups. Dr. Rosinol noted that EFS was better for those patients receiving a second transplant than for those who did not but cautioned that those patients who did not undergo the second transplant overall had a worse prognosis.
presentations of this session focused on the bone marrow homing of MM cells.
Dr. Ivan Van Riet shared Dr. Benjamin Van Camps presentation. MM cells are known to be restricted to the bone marrow (BM). Through studies, he and his colleagues evaluated cell lines from mouse models and reviewed the mechanism of action of homing to MM cells. Further studies revealed that endothelial cells help MM to migrate and concluded that homing of MM cells to BM is a complex process that involves multiple molecular pathways. By targeting these pathways, disease evolution may be affected leading to an emerging therapeutic tool with future extensive studies in human subjects.
Dr. Karin Vanderkerken continued discussions on the role of IGF-1/IGF-1 receptor pathway in the experimental mouse model. IGF-1 induces migration of 5TMM cells that are mediated by the P13K pathway. IGF-1 has also been found to induce DNA synthesis and VEGF secretion. Dr. Vanderkerkens data demonstrated the relevance of receptor pathways in the pathobiology of MM and showed the potential for utilizing receptor pathways in future therapies for the treatment of MM.
Dr. Alan Lichtenstein discussed the therapeutic implications of the AKT kinase in MM. AKT has been known to prevent death in MM cells, however, Dr. Lichtenstein hopes that with certain treatments, this action may be turned against tumor cells. With a preliminary review of the molecular mechanism activating AKT it was shown that AKT inhibits proliferation. With further study, findings showed high AKT activity sensitizes MM cells to certain inhibitors. Dr. Lichtenstein hopes that future trials will be designed to evaluate pre-treatment AKT as a marker of treatment response.
Dr. Martine Amiot put forward a discussion on IL-6, a major MM factor that induces the activation of multiple cell survival pathways. Dr. Amiots studies found 3 major isoforms that are expressed in MM cell lines. These isoforms are also negatively regulated by IL-6. Dr. Amiot proposed that disruption of cell interactions may present a novel therapeutic approach in the treatment of MM.
Dr. Haiming Chen finished this session with a discussion of members of the tumor necrosis factor receptor-associated factor (TRAF) family. TRAFs are adapter proteins that link to the cell surface. TRAFs have been found to regulate signal transduction pathway. Future studies on the effects of TRAFs may provide important clues about MM cell growth, death, and may lead to future clinical applications of novel therapeutic strategy.
Dr. Nikhil Munshi opened the session with a discussion of the development of genetic instability in MM and other cancers. Patients with specific genetic instabilities have a higher risk of cancer and of early onset cancer. In MM, there is significant genetic instability. Using model systems, questions about the types of genetic instabilities, DNA damage, and dysregulations inducible or present in cells (normal and MM cells) were explored to evaluate the possible resulting errors. Experiments were also conducted to explore the effect of inhibiting specific genetic instabilities and the effect of overexpression of specific molecules that challenge DNA integrity. Results from these experiments are being used to study the genetic events that lead to the development of MM.
Dr. Johannes Drach discussed bone marrow (BM) angiogenesis as a hallmark of MM biology and reviewed that high BM microvessel density (MVD) correlates with short survival. Looking at patients with specific genetic abnormalities, tumor specific genetic abnormalities were present in 21% to 73% of MM endothelial cells. Various hematologic malignancies were checked for presence of specific genetic abnormalities. In CML, 63% of endothelial cells were abnormal compared with 42% of MM endothelial cells. Solid tumors were also looked at to find evidence of specific genetic abnormalities but did not show the presence of the abnormalities in endothelial cells. The data support tumor specific chromosomal abnormalities in microvessel cells in hematological malignancies but not in solid tumors. These data support a novel aspect of angiogenesis in hematologic cancer cells and specifically in MM cells.
Dr. Catherine Pellat-Deceunynck presented an overview of CD11 and CD45 as hallmarks of proliferating MM cells. By looking at expression of different forms of CD45 at time of diagnosis or at relapse, a switch between forms (bright, low) and a decrease in the overall expression of CD45 was observed. Data showed that myeloma tumors are always a mix of proliferating bright and non-proliferating low cells; all patients have bright compartment. Plasma cells from bone marrow are a mix of proliferating and non-proliferating plasma cells. In summary, CD45 delineates 2 subsets of bone marrow plasma cells and myeloma cells. CD45 bright is associated with proliferation.
Dr. Brian Van Ness introduced the topic of mouse models of plasma cell malignancies. The approach used was to genetically engineer mice by identifying novel regulators, to assess the involvement of those regulators in stages of disease, and then to develop new mouse models. Notably, mice get hyperproliferative disease but do not develop tumors. Looking to the future, goals include developing mouse plasma cell tumor panels to show genetic heterogeneity, defining protein and gene expression profiles to link these data to human profiles, defining genetic modifications with a specific model system (lenti viral infection) to explore the effects of adding and blocking expression of genes, and identifying therapeutic responses.
Dr. Phillipe Moreau introduced a series of clinical presentations, discussing unfavorable prognostic factors. High-dose melphalan is correlated with a high response rate (87%). Following stem cell transplantation, patients did or did not receive anti-IL6 monoclonal antibody and there was a similar response following each stage of the trial. Results showed that combination of anti-IL6 and high dose melphalan is not superior to high-dose melphalan alone. This result may be related to timing of the addition of the antibody to the treatment regimen. Survival rates with high dose melphalan are encouraging. There is a trend for improved survival in tandem transplant rather than autologous transplant followed by mini-transplant. The incidence of extensive GVHD was more than 50% in mini-transplant. In patients with high risk de novo disease, autologous transplant plus mini-allogeneic transplant is not superior to tandem transplants.
Dr. Henk Lokhorst presented an interim analysis of a Phase 3 study on the effect of thalidomide combined with high dose melphalan in patients with stage 2 and 3 MM. Low molecular weight heparin (LMWH) effectively prevents DVT during thalidomide induction. Thalidomide does not hamper stem cell collection. Auto/allo transplant seems feasible and shows a low TRM. Thalidomide + AD induces a significantly higher response but this response is compensated by intensification of melphalan. These data raise the question as to whether high dose melphalan should be used as intensive therapy.
Dr. Thierry Facon presented interim analysis data from a trial looking at melphalan-prednisone (MP), MP-thalidomide (MP-T), or high dose therapy (melphalan 100, MEL100) in elderly patients (ages 65-70 years). Overall, no toxic deaths were observed among patients treated with MEL100. Hematologic toxicity of MP compared with MP-T was similar. Notably, 36% of patients in these treatment arms had peripheral neuropathy (PN). Incidence of DVT was examined, excluding patients with a history of previous DVT. No toxic deaths were related to DVT. More DVTs were observed in the MP-T treatment arm than other 2 treatment arms. Consequently, neurotoxicity and DVT are concerns in MP-T arm. Complete responses were 3% for MP, 14% for MP-T, and 18% for MEL100. The results of this study suggest that MEL100 is feasible in approximately 2/3 of elderly patients and that MP-T and MEL100 response rates are similar. The Data Safety Monitoring Board (DSMB) agreed that adverse events were what were expected, that there was not an excess of toxic deaths from any treatment, and that OS supported ongoing patient recruitment. The study is ongoing and the second interim analysis will be conducted in approximately 1 year.
For more information regarding these sessions, look for the complete proceedings to be published after the conclusion of this workshop.