Treatment paradigms for the newly diagnosed patient with multiple myeloma

The management of newly diagnosed multiple myeloma is currently being revolutionized by the emergence of novel therapeutic agents. Thalidomide, the thalidomide analogue lenalidomide, and the proteasome inhibitor bortezomib each have potential roles to play in the initial therapy of myeloma that are supported by encouraging clinical trials results. While evaluation for stem cell transplantation (SCT) remains a part of the algorithm for management of the newly diagnosed patient, these drugs offer improved options for induction before, and possibly maintenance after, SCT. For the patient who is not a candidate for SCT the armamentarium for management has been significantly expanded. This review will summarize currently available data regarding these exciting agents and will describe therapeutic strategies currently on the horizon.

Lenalidomide and thalidomide: mechanisms of action--similarities and differences

Multiple myeloma is a B-cell malignancy characterized by an excess of monotypic plasma cells in the bone marrow. The molecular mechanisms that are involved in disease progression depend on the interaction between the multiple myeloma cells and the bone microenvironment. Because these mechanisms have been well characterized, it is possible to develop regimens that are more specific to pathways involved in the pathogenesis of multiple myeloma than is typical for conventional chemotherapy in disease management. Thalidomide and immunomodulatory drugs (IMiDs) have now been shown to block several pathways important for disease progression in multiple myeloma. First established as agents with antiangiogenic properties, thalidomide and IMiDs inhibit the production of interleukin (IL)-6, which is a growth factor for the proliferation of myeloma cells. In addition, they activate apoptotic pathways through caspase 8-mediated cell death. At the mitochondrial level, they are responsible for c-jun terminal kinase (JNK)-dependent release of cytochrome-c and Smac into the cytosol of cells, where they regulate the activity of molecules that affect apoptosis. By activating T cells to produce IL-2, thalidomide and IMiDs alter natural killer (NK) cell numbers and function, thus augmenting the activity of NK-dependent cytotoxicity. Data delineating these events have been derived from experiments done in resistant and sensitive multiple myeloma cell lines. Although thalidomide and IMiDs demonstrate similar biologic activities, IMiDs are more potent than thalidomide and achieve responses at lower doses. Lenalidomide, a thalidomide derivative, has also been shown to have a different toxicity profile. Our understanding of the mechanism of action of these agents has provided a platform for exciting clinical trials evaluating combinations of thalidomide and lenalidomide with both conventional chemotherapy and newer targeted agents.

Enhancement of ligand-dependent activation of human natural killer T cells by lenalidomide: therapeutic implications

Natural killer T (NKT) cells are CD1d-restricted glycolipid reactive innate lymphocytes that play an important role in protection from pathogens and tumors. Pharmacologic approaches to enhance NKT cell function will facilitate specific NKT targeting in the clinic. Here we show that lenalidomide (LEN), a novel thalidomide (Thal) analog, enhances antigen-specific expansion of NKT cells in response to the NKT ligand alpha-galactosylceramide (alpha-GalCer) in both healthy donors and patients with myeloma. NKT cells activated in the presence of LEN have greater ability to secrete interferon-gamma. Antigen-dependent activation of NKT cells was greater in the presence of dexamethasone (DEX) plus LEN than with DEX alone. Therapy with LEN/Thal also led to an increase in NKT cells in vivo in patients with myeloma and del5q myelodysplastic syndrome. Together these data demonstrate that LEN and its analogues enhance CD1d-mediated presentation of glycolipid antigens and support combining these agents with NKT targeted approaches for protection against tumors.

Immunomodulatory analogues of thalidomide in the treatment of multiple myeloma

The design of innovative, more effective, less toxic therapy for multiple myeloma (MM) is emerging in parallel to a better understanding of the underlying pathophysiology of this common hematologic malignancy. Thalidomide has changed the treatment paradigm for patients with myeloma. Its efficacy, however, has been compromised to some degree by its side effects. Immunomodulatory drugs (IMiDs) are structural and functional analogues of thalidomide that were specifically designed to produce new agents with enhanced immunomodulating and anticancer properties but with less toxicity. In this article, we review the clinical trial development of second-generation IMiDs lenalidomide and CC-4047. Both agents demonstrate potent activity with manageable toxicities and provide another treatment opportunity for patients with MM.

Interstitial granulomatous dermatitis associated with the use of tumor necrosis factor alpha inhibitors

BACKGROUND

Tumor necrosis factor alpha (TNF-alpha) has been implicated in the pathogenesis of numerous inflammatory and autoimmune disorders. Accordingly, TNF-alpha inhibitors, such as thalidomide, infliximab (Remicade), adalimumab (Humira), and etanercept (Enbrel), have been used with success in the treatment of autoimmune disorders, including psoriasis, rheumatoid arthritis, inflammatory bowel diseases, and lymphoproliferative disorders. Although anti-TNF-alpha therapy is safe and well tolerated, various adverse cutaneous reactions have been reported.

OBSERVATIONS

We encountered 5 patients who developed erythematous annular plaques on the trunk and extremities while receiving 4 different medications with inhibitory activity against TNF-alpha. One patient was treated with lenalidomide (Revlimid) for multiple myeloma, 2 received infliximab, and 1 received etanercept for severe rheumatoid arthritis; the last patient was in a clinical trial of adalimumab for psoriatic arthritis. Skin biopsy specimens revealed diffuse interstitial granulomatous infiltrates of lymphocytes, histiocytes, and eosinophils, palisading degenerated collagen. Withdrawal of the medications led to complete resolution of the skin lesions.

CONCLUSION

Interstitial granulomatous dermatitis should be considered in the differential diagnosis of skin lesions occurring in the setting of anti-TNF-alpha therapy.

Immunomodulatory drug lenalidomide (CC-5013, IMiD3) augments anti-CD40 SGN-40-induced cytotoxicity in human multiple myeloma: clinical implications

SGN-40, a humanized immoglobulin G1 (IgG1) anti-CD40 monoclonal antibody, mediates cytotoxicity against human multiple myeloma (MM) cells via suppression of interleukin (IL)-6-induced proliferative and antiapoptotic effects as well as antibody-dependent cell-mediated cytotoxicity (ADCC). Here, we studied the clinical significance of an immunomodulatory drug lenalidomide on SGN-40-induced cytotoxicity against CD138(+)CD40(+) MM lines and patient MM cells. Pretreatment with lenalidomide sensitized MM cells to SGN-40-induced cell death. Combined lenalidomide and SGN-40 significantly induced MM apoptosis, evidenced by enhanced cleavage of caspase-3/8/poly(ADP-ribose)polymerase and increased sub-G(0) cells, compared with either single agent at the same doses. Pretreatment of effector cells with lenalidomide augmented SGN-40-induced MM cell lysis, associated with an increased number of CD56(+)CD3(-) natural killer (NK) cells expressing CD16 and LFA-1. Importantly, pretreatment with lenalidomide or lenalidomide and SGN-40 markedly enhanced NK-cell-mediated lysis of autologous patient MM cells triggered by SGN-40. Lenalidomide also up-regulated CD40L on CD56(+)CD3(-) NK cells, facilitating IL-2-mediated activation of NK cells. In addition, lenalidomide induced the CD56(dim) NK subset, which are more potent mediators of ADCC against target MM cells than the CD56(bright) NK subset. Finally, pretreatment of both effector and target MM cells with lenalidomide markedly enhanced SGN-40-mediated ADCC against CD40-expressing MM cells. These studies, therefore, show that the addition of lenalidomide to SGN-40 enhances cytotoxicity against MM cells, providing the framework for combined lenalidomide and SGN-40 in a new treatment paradigm to both target MM cells directly and induce immune effectors against MM.

Biological and prognostic significance of chromosome 5q deletions in myeloid malignancies

The presence of del(5q), either as the sole karyotypic abnormality or as part of a more complex karyotype, has distinct clinical implications for myelodysplastic syndromes (MDS) and acute myeloid leukemia. The 5q- syndrome, a subtype of low-risk MDS, is characterized by an isolated 5q deletion and <5% blasts in the bone marrow and can serve as a useful model for studying the role of 5q deletions in the pathogenesis and prognosis of myeloid malignancies. Recent clinical results with lenalidomide, an oral immunomodulatory drug, have shown durable erythroid responses, including transfusion independence and complete cytogenetic remissions in patients with del(5q) MDS with or without additional chromosomal abnormalities. These results indicate that lenalidomide can overcome the pathogenic effect of 5q deletion in MDS and restore bone marrow balance. The data provide important new insights into the pathobiology of 5q chromosomal deletions in myeloid malignancies.

Current therapeutic uses of lenalidomide in multiple myeloma

Thalidomide has demonstrated a broad spectrum of pharmacological and immunological effects, with potential therapeutic applications that span a wide spectrum of diseases: cancer and related conditions; infectious diseases; autoimmune diseases; dermatological diseases; and other disorders such as sarcoidosis, macular degeneration and diabetic retinopathy. Immunomodulatory derivative lenalidomide has more potent antitumour and anti-inflammatory effects. The molecular mechanisms of antitumour activity of lenalidomide have been extensively studied in multiple myeloma (MM). It directly induces growth arrest and/or apoptosis of even drug-resistant MM cells; inhibits binding of MM cells to bone marrow extracellular matrix proteins and stromal cells; modulates cytokine secretion and inhibits angiogenesis in the bone marrow milieu; and augments host antitumour immunity. Importantly, lenalidomide induces significant clinical responses even in patients with relapsed/refractory MM. Therefore, lenalidomide represents a new class of antitumour agents that is useful in the treatment of MM. Lenalidomide has received fast track designation from the FDA for the treatment of MM and myelodysplastic syndromes.

Promising systemic therapy for renal cell carcinoma

In the United States, advanced kidney cancer accounts for over 12,000 deaths each year. Immunotherapy with either interferon or interleukin-2 (IL-2) has been the standard of care for over two decades. High-dose IL-2 can apparently cure 10% to 15% of patients treated, but due to the required inpatient care and the attendant toxicities, it is only administered to less than 1,000 patients per year in the United States (Chiron, personal communication). Interferon is a less active agent than IL-2 but it has still been shown to be superior to therapy with either megesterol or vinblastine. Interferon typically results in very few long-term responses and is given to most patients with metastatic kidney cancer. Median survival after interferon therapy is dependent on risk group but is typically 12 to 15 months. Thus, new therapies are urgently needed in this refractory disease. Novel compounds currently being tested in clinical trials are showing promise in advanced kidney cancer. The molecular targets of these drugs include interfering with the vascular endothelial growth factor receptors or the raf kinase pathway, angiogenesis inhibition, and antimicrotubule agents. A review of the preclinical and early clinical development of some of these novel compounds will be discussed.

[Prognostic factors and new treatments of multiple myeloma]

Multiple myeloma is a blood disease that is often easy to diagnose, relying on a combination of an excessive medullary plasmacytosis, a serum and/or urinary monoclonal immunoglobulin and one or several signs of organ involvement (anemia, renal failure, bone lesions, hypercalcaemia, infections). The beta2m, serum albumin, and certain chromosomal anomalies of the malignant clone are the essential prognostic factors. Intensive treatment with auto-transplantation of stem cells of peripheral blood is a significant development from which patients less than or equal to 65 years of age have benefited. The diphosphonates are combined with chemotherapy in order to limit the effect on bones, and recombinant erythropoietin is used in certain patients. Above all, therapeutic progress has been made thanks to thalidomide, bortezomib and lenalidomide, even if the optimal utilisation of these molecules is still to be determined.

Immunomodulatory drugs

After nearly decades of extinction as a sedative and antiemetic, thalidomide reemerged as the parent compound of a novel and promising class of therapeutics termed the immunomodulatory drugs (IMiDs). The analogues of thalidomide, CC-5013 (lenalidomide, Revlimid) and CC-4047 (Actimid) are more potent regulators of cellular immune and cytokine response while lacking some of the dose limiting side effects of the parent compound, such as neurologic toxicity. Preclinical data will be reviewed that outlines these drugs' effects on tumor necrosis alpha, interleukin 12, angiogenesis, and T-cell function. The evolution of the use of thalidomide as a therapeutic for diseases such as multiple myeloma and myelodysplastic syndrome and the promising initial results of the new IMiDs will be reviewed.

Novel Treatment Approaches for Patients with Multiple Myeloma

Treatment options for patients with multiple myeloma are a rapidly progressing area of clinical and scientific development. The discovery of key signaling pathways needed for myeloma cell growth and proliferation has resulted in a plethora of new and different treatment options. Chief among these new agents are the proteasome inhibitor bortezomib and the immunomodulatory agents thalidomide and lenalidomide. Efficacy for these agents has been extensively studied in the relapsed and refractory states, and more recently in induction therapy. Impressive responses have been observed in the induction and relapsed disease states, completely changing the disease treatment paradigms. Building on these successes and strong preclinical work, other signal transduction inhibitors are being tested in phase I and phase II clinical trials. These include agents that target histone acetylation, farnesylation, heat shock proteins, and direct AKT-targeting agents. Additionally, monoclonal antibody targets are being developed in an effort to target the tumor cells extracellularly. Clinical trial development based on preclinically designed rational combinations and targets have the potential to rapidly translate these findings into meaningful clinical responses.

Treatment of the 5q– Syndrome

Defined by isolated del 5q and no excess of marrow blasts, the “5q– syndrome” is a specific type of myelodysplastic syndrome (MDS) with particular characteristics, including severe anemia, frequent thrombocytosis, typical dysmegakaryopoiesis and favorable outcome. Its pathogenesis remains uncertain, in particular the role of inactivation of gene(s) situated in 5q. It should be differentiated from other MDS with del 5q having an excess of marrow blasts and/or additional cytogenetic abnormalities, which carry a poor prognosis.

Until the advent of lenalidomide, repeated RBC transfusions were generally the only treatment of the 5q– syndrome, which was resistant to other therapeutic approaches. Lenalidomide can lead to RBC transfusion independence in at least two thirds of cases of the 5q– syndrome, two thirds of those responses persisting after 2 years of treatment. Importantly, not only reversal of anemia but also frequent complete pathological and cytogenetic responses are obtained. Grade 3 or 4 neutropenia and thrombocytopenia, especially during the first 6 to 8 weeks of treatment, are the major side effect of lenalidomide, justifying close monitoring of blood counts and regular patient visits.

Preliminary results suggest that lenalidomide is also very active in MDS with del 5q other than the 5q–syndrome. Although its mechanism of action remains uncertain, lenalidomide appears to target specifically the del 5q clone. By doing this, lenalidomide may have an effect on disease course and survival, which is currently being assessed in clinical trials.

Treatment of multiple myeloma: an emphasis on new developments

Not all patients who fulfill the minimal criteria for diagnosis of multiple myeloma should be treated. If doubt exists about beginning therapy, one should wait and re-evaluate the patient in 2 or 3 months. There is no evidence that early treatment of multiple myeloma is advantageous. All patients should be considered possible candidates for an autologous stem cell transplantation. If they are deemed to be eligible, they should be treated for 3 to 4 months with therapy that does not damage the hematopoietic stem cells. Currently, most physicians use thalidomide plus dexamethasone or dexamethasone alone for induction. Vincristine, doxorubicin (Adriamycin), and dexamethasone (VAD) have been used in the past. Autologous stem cell transplantation prolongs disease-free survival and overall survival. The treatment-related mortality rate is 1% to 2%. Melphalan, 200 mg/m2, is the most widely used preparative regimen. Although allogeneic transplantation is attractive, the mortality rate (about 20%) is too high to recommend conventional allogeneic transplantation. Non-myeloablative transplantation is currently under investigation. If the patient is not a candidate for autologous stem cell transplantation, therapy with melphalan and prednisone is a good choice. Patients with relapsed or refractory disease may be treated with dexamethasone, thalidomide and dexamethasone, bortezomib (Velcade, PS-341), or lenalidomide (Revlimid, not yet approved by the Food and Drug Administration).

Immunomodulatory drug CC-5013 or CC-4047 and rituximab enhance antitumor activity in a severe combined immunodeficient mouse lymphoma model

New thalidomide derivatives CC-5013 and CC-4047 (immunomodulatory drugs, IMiD) are up to 10,000 times more potent than Thalidomide. The biological effects of IMiDs are presumed to be mediated by (a) activation of some components of the innate [natural killer (NK) cells] or adoptive immune system (T cells), (b) modification of cytokine microenvironment in the tumor bed, or by (c) inhibition of angiogenesis. In this article, we tested an innovative combination strategy involving rituximab and IMiDs in aggressive lymphoma cell lines and human lymphoma xenografts. Treatment of non-Hodgkin's lymphoma cells with CC-5013 resulted in a 40% to 70% growth inhibition when compared with controls (P < 0.05). Exposure of lymphoma cells to CC-4047 resulted in a lesser degree of growth inhibition. Induction of apoptosis was shown in 10% to 26% of lymphoma cells 24 hours following exposure to either IMiD. In vivo studies in severe combined immunodeficient mice showed synergistic activity between CC-4047 (and to a lesser degree, CC-5013) plus rituximab. Animals treated with the CC-4047/rituximab combination had a median survival of 74 days (P = 0.0012) compared with 58 days (P = 0.167) in CC-5013/rituximab-treated animals compared with 45 days in rituximab monotherapy-treated animals. The synergistic effect between IMiDs and rituximab in our mouse model was attributed to NK cell expansion. The enhancement of rituximab activity by IMiDs was abrogated by in vivo depletion of NK cells. Augmenting NK cell function by CC-4047 or CC-5013 exposure may increase the antitumor effects of rituximab against B-cell lymphomas and warrants further exploration in the context of a clinical trial.

New treatments for multiple myeloma

In 2004, multiple myeloma was diagnosed in more than 15,000 people in the United States and will account for approximately 20% of deaths due to hematologic malignancies. Although traditional therapies such as melphalan (Alkeran)/prednisone, combination chemotherapy with VAD (vincristine, doxorubicin [Adriamycin], and dexamethasone), and high-dose chemotherapy with stem cell transplantation have shown some success, median survival remains between 3 to 5 years. Treatment options for patients with multiple myeloma have increased in recent years, with the promise of improvement in survival. New agents, such as the proteasome inhibitor bortezomib (Velcade), the antiangiogenic and immunomodulator thalidomide (Thalomid) and its analogs, such as lenalidomide (Revlimid), together with other small molecules, including arsenic trioxide (Trisenox), and other targeted therapies, have been studied alone and in combination with other antineoplastic therapies, either as induction therapy prior to stem cell transplantation or in patients with relapsed disease. Bortezomib recently was approved in the United States for the treatment of multiple myeloma in patients who have received at least one prior therapy. The use of bortezomib-based regimens as front-line therapy as well as the use of other agents in multiple myeloma remain under investigation, and approvals for both thalidomide and lenalidomide are hoped for soon, with the overall prospect of patient outcome continuing to be increasingly positive.

Recent clinical studies of the immunomodulatory drug (IMiD) lenalidomide

Thalidomide is effective in the treatment of multiple myeloma. The immunomodulatory drug and thalidomide analogue lenalidomide is currently in late stage clinical development for MDS and multiple myeloma. This minireview highlights the course of initial and ongoing lenalidomide clinical development in oncology with reference to earlier thalidomide studies.