Renal cell carcinoma: review of novel single-agent therapeutics and combination regimens.

A search of the Medline database and ASCO 2003 conference proceedings was conducted to identify clinical trials currently underway using single-agent therapy for renal cell carcinoma (RCC). Combination trials were identified using the ASCO 2003 conference proceedings. Fourteen single-agent therapies employing different mechanisms of action were identified in the published literature: imatinib mesylate (Gleevec); bevacizumab (Avastin); thalidomide (Thalomid); gefitinib (ZD1839) (Iressa); cetuximab (IMC-C225) (Erbitux); bortezomib (PS-341) (Velcade); HSPPC-96 (Oncophage); BAY 59-8862; ABT-510; G250; CCI-779; SU5416; PTK/ZK; and ABX-EGF. Six distinct fields of clinical research have emerged: monoclonal antibodies, small molecules, vaccines, second-generation taxanes, nonapeptides and immunomodulators. Five combination regimens, primarily biological response modifiers (interleukin-2 or interferon-alpha), chemotherapy- or thalidomide-based, were identified. All therapies demonstrated acceptable toxicity profiles. Clinical benefit was assessed based on each study's reported criteria: antitumor response (regression or stability) ranged from 5% to 71%. In the past several years, significant advances in the underlying biological mechanisms of RCC, particularly the role of tumor angiogenesis, have permitted the design of molecularly targeted therapeutics. Based on preliminary and limited studies, combination therapies offer the greatest clinical benefit in the management of this malignancy, although additional basic research is still warranted.     

Treating chronic lymphocytic leukemia with thalidomide and lenalidomide

Introduction: Chronic lymphocytic leukemia (CLL) is biologically, as well as clinically, highly heterogeneous. In CLL patients, immunosuppression is a consequence of the disease, which plays a key role in effecting the quality of life and overall survival. Treatment modalities should ideally not only reduce tumor burden, but also augment immune function in CLL patients.

Areas covered: The current review summarizes biological and clinical data on thalidomide and lenalidomide in CLL.

Expert opinion: Immunomodulatory drugs such as thalidomide and lenalidomide show both antitumor activity and immunostimulation. Three main mechanisms of action seem to play a role in cancer, including i) anti-angiogenic, ii) immunomodulatory and iii) tumoricidal effects. The exact contributions of these effects seem to be unique for different diseases. The two representatives of this family of drugs studied in CLL include thalidomide and its analog lenalidomide. These drugs proved to be effective as single agents and in the combination setting in CLL. Toxicities have been identified but largely controlled by a low starting dose, with gradual dose escalation.     

Proteasome inhibition in hematologic malignancies

Hematologic malignancies, including multiple myeloma (MM), will account for more than 100,000 new cases of cancer and over 57,000 deaths in the United States in 2003. Treatment of MM is a serious challenge, because despite a variety of available therapies, median survival is short. A new therapeutic area focuses on inhibiting the activity of the proteasome, a 26S protease complex involved in cell cycle regulation, cell adhesion, inflammation, and protein turnover. The novel proteasome inhibitor, bortezomib (Velcade®), was recently approved for use in patients with refractory and relapsed MM and to date is the only proteasome inhibitor to have entered clinical trials. Bortezomib has demonstrated activity with manageable toxicity in a variety of hematologic malignancies in addition to MM, including leukemia and non‐Hodgkin's lymphoma. This article reviews clinical information on bortezomib in hematologic malignancies both as monotherapy and in combination with dexamethasone. Preliminary reports of bortezomib in combination with Doxil (pegylated liposomal doxorubicin), melphalan, and thalidomide are discussed, and current trials are described. Available data suggest that bortezomib will be useful in the treatment of a variety of hematologic malignancies.     

Immunomodulatory drugs in multiple myeloma: from molecular mechanisms of action to clinical practice

Multiple myeloma (MM) is a clonal disorder of plasma cells that is considered incurable using the currently available treatments. Cytogenetic, molecular and proteonomic techniques have contributed toward a better understanding of the pathophysiology and prognostic factors of this heterogeneous malignancy, whose management has rapidly evolved over the years. The introduction of thalidomide, and the development of safer and more effective thalidomide analogues, represents the major therapeutic advances. Thalidomide, initially used in the treatment of MM because of its angiogenic properties, has considerable therapeutic activity (alone or in combination with other drugs) at all stages of the disease. However, a number of new analogues, such as lenalidomide and pomalidomide, have been developed and are known as “immunomodulatory drugs” (IMIDs). Although they are analogues of thalidomide, they have direct anti-tumor properties, a better tolerability profile and specific activity in both relapsing refractory MM and newly diagnosed disease. The mechanisms of action of IMIDs are still being investigated, but recent studies suggest that, in addition to their anti-angiogenic activity, they have anti-inflammatory and immunomodulatory properties, and directly and indirectly target tumor activity by interfering with various components of the bone marrow (BM) micro-environment. In this paper, we review the pharmacology, mechanisms of action, pre-clinical and clinical efficacy, and the current status of IMIDs in the treatment of MM.     

Enhanced immune‐modulatory effects of thalidomide and dexamethasone co‐treatment on T cell subsets

Thalidomide (TM) has been reported to have anti‐cancer and anti‐inflammatory properties, and dexamethasone (DX) is known to reduce inflammation and inhibit production of inflammatory cytokines. Many studies have reported that combinatorial therapy with TM and DX is clinically used to treat multiple myeloma and lupus nephritis, but the mechanism responsible for its effects has not been elucidated. In this study, we determined that TM and DX co‐treatment had an enhanced immune‐modulatory effect on T cells through regulating the expression of co‐stimulatory molecules. Splenic naive T cells from C57BL/6 mice were sort‐purified and cultured for CD4⁺ T cell proliferation and regulatory T (Treg) cell conversion in the presence of TM and/or DX. Following incubation with the drugs, cells were collected and OX40, 4‐1BB, and glucocorticoid‐induced tumour necrosis factor receptor‐related protein (GITR) expression was quantified by flow cytometry. TM (1 or 10 μm ) decreased CD4⁺ T cell proliferation in a dose‐dependent manner, whereas TM/DX (0·1 or 1 nm ) co‐treatment further decreased proliferation. Treg cell populations were preserved following drug treatment. Furthermore, expression of co‐stimulatory molecules decreased upon TM/DX co‐treatment in effector T (Teff) cells and was preserved in Treg cells. Splenic CD4⁺ T cells isolated from TM‐ and DX‐treated mice exhibited the same patterns of Teff and Treg cell populations as observed in vitro. Considering the selective effect of TM on different T cell subsets, we suggest that TM may play an immunomodulatory role and that TM/DX combinatorial treatment could further enhance these immunomodulatory effects by regulating GITR, OX40, and 4‐1BB expression in CD4⁺ T cells.     

Early response predicts thalidomide efficiency in patients with advanced multiple myeloma

Sixty-five patients who were primary or secondary refractory to melphalan/prednisone or other type of chemotherapy, or relapsed within 6 months after high dose chemotherapy with stem cell support, were given thalidomide at a dose of 200 mg/d escalating to 800 mg. The patients were followed for a median of 2 years and 22 weeks. Response was evaluated according to M-protein reduction combined with improvement of haemoglobin (Hb) concentration, renal function and pain. Altogether, 14% of patients had a minor response, 14% partial response and 6% complete response. Median survival was 12 months and 29% were alive at last contact. Decline of M protein started early and a minimum 25% reduction of M protein was detected in 14 of 20 responders (70%) after 3 weeks, and in 20 of 22 responders (91%) after 5 weeks of treatment. Reduction of M protein continued for 3 months and further decline was observed in only four patients. The Hb concentration showed a different time course, with a significant increase after 3 months and further increases continued for up to 12 months. Blood concentration levels of thalidomide from 40 patients were used to evaluate the pharmacokinetics of the drug. Rate of absorption, rate of elimination, volume of distribution, clearance and elimination half-life were calculated to be 0.200/h, 0.140/h, 0.886 l/kg, 0.126 l/h/kg and 4.98 h respectively. We found no relationship between thalidomide concentration and effect after 12 weeks.     

Common and rare side-effects of low-dose thalidomide in multiple myeloma: focus on the dose-minimizing peripheral neuropathy

OBJECTIVES: Thalidomide has demonstrated a remarkable efficacy in the treatment of multiple myeloma but its use may cause several toxicities. We have investigated the common and rare side-effects, especially analysing peripheral neuropathy, in order to optimise the thalidomide dose for minimizing this harmful side-effect. METHODS: Fifty-nine patients were treated with thalidomide alone or combined with oral melphalan. The median age was 69 yr. The initial dose of thalidomide was 100 mg/day increasing weekly by 100 mg increments until a maximum dose of 400 mg was attained. Melphalan was administered at a dose of 0.20 mg/kg/d for 4 d every 28 d. RESULTS AND CONCLUSIONS: Nearly one-fourth of patients discontinued thalidomide because of toxicity. Constipation (71%), somnolence (36%) and fatigue (20%) were the most common side-effects and they were not dose dependent. Peripheral neuropathy occurred in 39% of patients and a thalidomide median daily dose of more than 150 mg was significantly associated with higher frequency and actuarial risk of peripheral neuropathy without improving the response rate. Deep venous thrombosis was observed in 7% of patients and other side-effects were rare. In patients with advanced multiple myeloma we found that a thalidomide daily dose of 150 mg minimizes peripheral neuropathy without jeopardizing response and survival.     

New anti-angiogenesis agents: review of the clinical experience with carboxyamido-triazole (CAI), thalidomide, TNP-470 and interleukin-12

Angiogenesis was postulated to be a critical prognostic factor and therapeutic focus for malignancy more than two decades ago. Recent studies indicate quantitative assessments of microvessel count to be an independent prognostic variable for disease-free and overall survival in a wide variety of tumors, and that angiogenesis may be a feasible target against which to intervene pharmacologically. Several new and old agents have been found to have anti-angiogenic activity and have reached clinical trial. This review will focus on four agents under investigation in the US: carboxyamido-triazole (CAI), thalidomide, TNP-470 and interleukin (IL)-12. CAI, originally identified for its anti-invasive capacity, has been shown to inhibit tumor and endothelial cell proliferation by inhibition of calcium uptake. It is administered orally, is generally well tolerated, and has been shown to induce disease stabilization and occasional reductions in tumor mass. Thalidomide was shown to inhibit growth factor-induced neovessel formation, a process that can also explain its earlier devastating clinical toxicity. It is administered orally, and is currently in phase II clinical trials for prostate cancer, glioblastoma multiforme and breast cancer. TNP-470 is a fumagillin analog that has been shown in in vivo models to be a potent inhibitor of angiogenesis at concentrations that are cytostatic to endothelial cells and tumor cells. Lastly, IL-12 may exert its anti-angiogenic effects through activation of interferon- to up-regulate interferon-inducible protein-10, an anti-angiogenic cytokine. Phase I clinical trials of IL-12 have shown disease stabilization in several tumor types in response to s.c. administration or using genetically engineered IL-12-expressing patient fibroblasts. These promising new agents join the matrix metalloproteinase inhibitors as important new drugs in the anti-cancer armamentarium.