Lenalidomide: a novel anticancer drug with multiple modalities

The Contribution of Type 2 Diabetes to Parkinson's Disease Aetiology

Type 2 diabetes (T2D) and Parkinson's disease (PD) are chronic disorders that have a significant health impact on a global scale. Epidemiological, preclinical, and clinical research underpins the assumption that insulin resistance and chronic inflammation contribute to the overlapping aetiologies of T2D and PD. This narrative review summarises the recent evidence on the contribution of T2D to the initiation and progression of PD brain pathology. It also briefly discusses the rationale and potential of alternative pharmacological interventions for PD treatment.

The Role of the PTEN Tumor Suppressor Gene and Its Anti-Angiogenic Activity in Melanoma and Other Cancers

Human malignant melanoma and other solid cancers are largely driven by the inactivation of tumor suppressor genes and angiogenesis. Conventional treatments for cancer (surgery, radiation therapy, and chemotherapy) are employed as first-line treatments for solid cancers but are often ineffective as monotherapies due to resistance and toxicity. Thus, targeted therapies, such as bevacizumab, which targets vascular endothelial growth factor, have been approved by the US Food and Drug Administration (FDA) as angiogenesis inhibitors. The downregulation of the tumor suppressor, phosphatase tensin homolog (PTEN), occurs in 30-40% of human malignant melanomas, thereby elucidating the importance of the upregulation of PTEN activity. Phosphatase tensin homolog (PTEN) is modulated at the transcriptional, translational, and post-translational levels and regulates key signaling pathways such as the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) and mitogen-activated protein kinase (MAPK) pathways, which also drive angiogenesis. This review discusses the inhibition of angiogenesis through the upregulation of PTEN and the inhibition of hypoxia-inducible factor 1 alpha (HIF-1-α) in human malignant melanoma, as no targeted therapies have been approved by the FDA for the inhibition of angiogenesis in human malignant melanoma. The emergence of nanocarrier formulations to enhance the pharmacokinetic profile of phytochemicals that upregulate PTEN activity and improve the upregulation of PTEN has also been discussed.

The story of the development of generic lenalidomide: How one company thwarted the Hatch-Waxman Act to generate billions of dollars in revenue

Lenalidomide (Revlimid®) was originally approved by the Food and Drug Administration (FDA) in 2005, however, a generic version was not available until 2022. In that time, the price of lenalidomide has increased more than 20 times, and in 2021 alone, it accounted for >$5.8 billion dollars in Medicare Part D spending. This was a direct consequence of legal tactics employed by the manufacturer to thwart development of generic formulations of lenalidomide. In this report, we review the clinical development of lenalidomide, provide background on generic drug manufacturing in the United States (US), describe the steps that the manufacturer took to prevent entry of generic lenalidomide into the US market, and advocate for legislative reform of the FDA approval process and patent law protections in the US.

Upcoming immunotherapeutic combinations for B-cell lymphoma

After initial introduction for B-cell lymphomas as adjuvant therapies to established cancer treatments, immune checkpoint inhibitors and other immunotherapies are now integrated in mainstream regimens, both in adult and pediatric patients. We here provide an overview of the current status of combination therapies for B-cell lymphoma, by in-depth analysis of combination therapy trials registered between 2015–2020. Our analysis provides new insight into the rapid evolution in lymphoma treatment, as propelled by new additions to the treatment arsenal. We conclude with prospects on upcoming clinical trials which will likely use systematic testing approaches of more combinations of established chemotherapy regimens with new agents, as well as new combinations of immunotherapy and targeted therapy. Future trials will be set up as basket or umbrella-type trials to facilitate the evaluation of new drugs targeting specific genetic changes in the tumor or associated immune microenvironment. As such, lymphoma patients will benefit by receiving more tailored treatment that is based on synergistic effects of chemotherapy combined with new agents targeting specific aspects of tumor biology and the immune system.

Immunomodulatory Drugs in Acute Myeloid Leukemia Treatment

Immunomodulatory drugs (IMiDs) are analogs of thalidomide. They have immunomodulatory, antiangiogenic and proapoptotic properties and exert a role in regulating the tumor microenvironment. Recently IMiDs have been investigated for their pleiotropic properties and their therapeutic applications in both solid tumors (melanoma, prostate carcinoma and differentiated thyroid cancer) and hematological malignancies. Nowadays, they are applied in de novo and relapsed/refractory multiple myeloma, in myelodysplastic syndrome, in del5q syndrome with specific use of lenalidomide and B-cell lymphoma. Several studies have been conducted in the last few years to explore IMiDs possible use in acute myeloid leukemia treatment. Here we report the mechanisms of action of IMiDs in acute myeloid leukemia and their potential future therapeutic application in this disease.

MCLENA-1: A Phase II Clinical Trial for the Assessment of Safety, Tolerability, and Efficacy of Lenalidomide in Patients with Mild Cognitive Impairment Due to Alzheimer's Disease

With the general population reaching higher ages, a surge in Alzheimer's disease (AD) incidence will happen in the coming decades, putting a heavy burden on families and healthcare systems Worldwide. This emphasizes the pressing need for AD therapeutic interventions. Accumulating evidence indicates that inflammation is prominent both in the blood and central nervous system of AD sufferers. These data suggest that systemic inflammation plays a crucial role in the cause and effects of AD neuropathology. Capitalizing on our experience from a previous clinical trial with thalidomide, we hypothesize that modulating inflammation via the pleiotropic immunomodulator lenalidomide may alter AD if administered during a proper time window in the course of the disease. Thus, in this Phase II, proof-of mechanism study, 30 amnestic mild cognitive impairment (aMCI) subjects will be treated with lenalidomide at 10 mg/day for 12 months on a 1:1 ratio, followed by a 6 months washout period. The primary objective of this study is to investigate the effect of lenalidomide on cognition, which is assessed at regular intervals. The secondary objective is to assess the safety and tolerability of lenalidomide in aMCI patients evaluated through adverse events, vital signs, clinical biochemistry, and physical and neurological examinations. Tertiary objectives are to analyze the effects of lenalidomide on brain amyloid loads (Florbetapir PET imaging) and neurodegeneration (volumetric MRI) by comparing pre- and post-dosing data. Finally, exploratory objectives will investigate whether blood inflammatory markers can serve as surrogate markers of therapeutic efficacy. Our study should determine whether lenalidomide is safe in AD subjects and whether it can alter the clinical progression of AD when administered before dementia onset. If effective, lenalidomide would become the first drug capable of delaying the trajectory of AD, which could lead the way to find additional, less toxic treatments in the near future.

Drug Repurposing in the Development of Anticancer Agents

BACKGROUND

Research into repositioning known drugs to treat cancer other than the originally intended disease continues to grow and develop, encouraged in part, by several recent success stories. Many of the studies in this article are geared towards repurposing generic drugs because additional clinical trials are relatively easy to perform and the drug safety profiles have previously been established.

OBJECTIVE

This review provides an overview of anticancer drug development strategies which is one of the important areas of drug restructuring.

METHODS

Repurposed drugs for cancer treatments are classified by their pharmacological effects. The successes and failures of important repurposed drugs as anticancer agents are evaluated in this review.

RESULTS AND CONCLUSION

Drugs could have many off-target effects, and can be intelligently repurposed if the off-target effects can be employed for therapeutic purposes. In cancer, due to the heterogeneity of the disease, often targets are quite diverse, hence a number of already known drugs that interfere with these targets could be deployed or repurposed with appropriate research and development.

Emerging modes-of-action in drug discovery

An increasing focus on complex biology to cure diseases rather than merely treat symptoms has transformed how drug discovery can be approached. Instead of activating or blocking protein function, a growing repertoire of drug modalities can be leveraged or engineered to hijack cellular processes, such as translational regulation or degradation mechanisms. Drug hunters can therefore access a wider arsenal of modes-of-action to modulate biological processes and this review summarises these emerging strategies by highlighting the most representative examples of these approaches.

Overview of small bowel angioectasias: clinical presentation and treatment options

Elderly patients with multiple co-morbidities are at an increased risk of developing small bowel angioectasias. Treating these lesions can be both challenging and costly with patients requiring extensive investigations and recurrent admissions for iron infusions and blood transfusions as well as invasive procedures. This review presents treatment options and describes in detail drugs that should be considered whilst taking into account their effectiveness and their safety profile. Areas covered: A PubMed search was carried out using the following keywords: small bowel angiodysplasias, small bowel angioectasias, small bowel bleeding and obscure gastrointestinal bleeding to assess existing evidence. The pathophysiology and risk factors are covered in this review together with appropriate methods of investigation and management. Treatment options discussed are endoscopic measures, surgical options and pharmacotherapy. The role of serum biomarkers is also discussed. Expert commentary: Future work should be directed at alternative drugs with a good safety profile that target biomarkers. Novel pharmacotherapy directed at biomarkers could potentially provide a non-invasive treatment option for angioectasias particularly in the elderly where management can be challenging.

Selective alkylation/oxidation of N-substituted isoindolinone derivatives: synthesis of N-phthaloylated natural and unnatural α-amino acid analogues

The interchangeability of the isoindolinone group as a nitrogen protecting group for amino acid intermediates is demonstrated by the preparation of several natural and unnatural α-amino acid derivatives using a two-carbon N-isoindolinone (phthalimidine) scaffold. Using a selective benzylic oxidation, the N-isoindolinone group is then converted to the N-phthaloyl group for convenient removal (65-98%). For preparation of the isoindolinone products which were to be the substrates for benzylic oxidation, a range of side chains were installed on the isoindolinone-protected glycine equivalent on deprotonation to demonstrate the utility of the N-protected isoindolinone synthon (51-93%). While the ensuing benzylic oxidation is employed successfully for converting the N-isoindolinone group to the N-phthaloyl group in simple substrates, substrates bearing unsaturated or electron-rich side chains respond poorly to the oxidation.

Thalidomide and lenalidomide for recurrent ovarian cancer: A systematic review of the literature

The present review aimed to assess the safety and efficacy of thalidomide and lenalidomide, two immunomodulatory drugs with anti-angiogenic properties, in women with recurrent ovarian, fallopian tube, and primary peritoneal cancer. A systematic review of the literature was conducted whereby Medline and the Cochrane Central Register of Controlled Trials were searched using terms associated with thalidomide, lenalidomide, and recurrent ovarian, fallopian tube and primary peritoneal cancer. Published English language case reports, trials and studies that described the safety and efficacy of thalidomide or lenalidomide alone, or in combination with other drugs were reviewed. A total of 16 clinical studies involving 394 patients treated with thalidomide (n=188), lenalidomide (n=77) and 129 controls were identified, including five case reports (n=6), three case series (n=45), two phase I trials (n=27), four phase II trials (n=109), and two randomized phase III trials (n=207). In a pooled analysis of thalidomide investigated as a single drug, the overall clinical benefit rate was 43% (43/99) with a mean time to progression of 5.6 months. The response rate (complete response + partial response) was 25%. In a phase III trial, the combination of thalidomide and topotecan significantly increased the overall response rate compared with topotecan alone [14/30 (47%) vs. 8/39 (21%)]. In another phase III trial involving women with asymptomatic biochemical recurrence, compared with tamoxifen, thalidomide was not more effective. Lenalidomide was investigated in three phase I trials and in one phase II trial with an overall clinical benefit rate of 52% (34/65), and a mean time to progression of 4.6 months. The response rate (complete response + partial response) was 6%. Systemic toxicity of both drugs was noted in >77% of patients with pneumonitis/pneumonia, fatigue, neuropathy and venous thromboembolism reported as the most common side effects. Thalidomide and lenalidomide are moderately active in recurrent ovarian cancer. Thalidomide possesses synergistic effects with topotecan. The toxicity of both drugs is considerable and there is a greater amount of data available for thalidomide compared to lenalidomide.

Lenalidomide enhances the function of dendritic cells generated from patients with multiple myeloma

Lenalidomide (LEN) has been used as an immunomodulatory drug with direct and indirect anti-tumor effects. In this study, we evaluated the effect of LEN on the differentiation, maturation, and function of dendritic cells (DCs) in patients with multiple myeloma in vitro. Various doses of LEN were added after the monocytes had differentiated into immature DCs and were activated into mature DCs. LEN (5 μg/mL) was the optimal concentration to promote differentiation and maturation of DCs. Immature DCs treated with LEN exhibited enhanced endocytic capacity. Mature DCs treated with LEN produced higher levels of interleukin-12p70, possessed stronger allogeneic T-cell stimulation capacity, reduced the number of suppressor cells, and generated antigen-specific cytotoxic T lymphocytes more potently compared with control DCs. These results suggest that LEN enhanced the function of DCs generated from patients with multiple myeloma by stimulating the capacity of allogeneic T cells, inhibiting the generation of immunosuppressive cells, inducing naïve T cells toward Th1 polarization, and generating potent myeloma-specific cytotoxic T lymphocytes.

Efficacy and Safety of Lenalidomide in the Treatment of Multiple Myeloma: A Systematic Review and Meta-analysis of Randomized Controlled Trials

BACKGROUND

Lenalidomide has emerged as an important treatment for patients with multiple myeloma (MM). However, its role in the management of MM is still controversial and requires further clarification. The aim of this study was to evaluate efficacy and safety of lenalidomide for MM using a meta-analysis.

METHODS

We searched the electronic databases including: PubMed, EMBASE and the Cochrane Center Register of Controlled Trials. Seven randomized clinical trials were identified, which included a total of 2357 patients with MM who received lenalidomide-containing, noncontaining lenalidomide regimens or placebo as induction therapy or maintenance therapy. The outcomes included overall response (OR) rate, complete response (CR) rate, 3-year progression-free survival (PFS) rate, 3-year overall survival (OS) rate, and different types of treatment-related adverse events. We calculated the risk ratios (RRs) as well as their 95% confidence intervals of these outcomes and pooled the results using RevMan 5.2 software.

RESULTS

For patients with previously untreated MM, OR rate and CR rate was significantly higher in lenalidomide-containing group than the control group. For relapsed or refractory MM patients, lenalidomide-containing regimens significantly improved the OR rate, CR rate, 3-year PFS rate and 3-year OS rate. With regard to MM patients after autologous stem cell transplantation, lenalidomide maintenance therapy significantly improved 3-year PFS rate but did not result in improved 3-year OS rate. In terms of toxicities, lenalidomide therapy has a higher rate of Grade 3-4 grade cytopenias, infection, deep-vein thrombosis, and diarrhea. Furthermore, the incidence of second primary malignancies was significantly higher in the lenalidomide group.

CONCLUSIONS

The lenalidomide-containing regimens as induction therapy clearly increased response rates and improved intervals of survival with acceptable toxicity rates for patients with MM. However, when physicians choose to use the lenalidomide as maintenance therapy, whether the benefits outweigh the risks should be taken into account.

Immune Therapy

Lung cancer has long been considered an unsuitable target for immunotherapy due to its proposed immunoresistant properties. However, recent evidence has shown that anti-tumor immune responses can occur in lung cancer patients, paving the way for lung cancer as a novel target for immunotherapy. In order to take full advantage of the potential of immunotherapy, research is focusing on the presence and function of various immunological cell types in the tumor microenvironment. Immune cells which facilitate or inhibit antitumor responses have been identified and their prognostic value in lung cancer has been established. Knowledge regarding these pro- and anti-tumor immune cells and their mechanisms of action has facilitated the identification of numerous potential immunotherapeutic strategies and opportunities for intervention. A plethora of immunotherapeutic approaches is currently being developed and studied in lung cancer patients and phase 3 clinical trials are ongoing. Many different immunotherapies have shown promising clinical effects in patients with limited and advanced stage lung cancer, however, future years will have to tell whether immunotherapy will earn its place in the standard treatment of lung cancer.

Immunotherapy prospects in the treatment of lung cancer and mesothelioma

A very recent finding is the role of immune activation in cancer. The assumption that stimulating the patient's immune system to attack tumors is a valuable treatment option in malignant diseases has gained more acceptance. However the high immunosuppressive effects caused by the tumor limits this beneficial effect. There is a delicate balance between immunoactivation and immunosuppression in a patient. Especially in non small cell lung cancer (NSCLC), the role of immunosuppressive cells hampering immune activation is high. But also in small cell lung cancer (SCLC) and mesothelioma immunosuppressive activity is high. This is suggested to be related to the type of tumor, advanced stage of the disease, and the tumor load. In this review, we provide an overview of the progress and challenges in the immunotherapeutic approaches in lung cancer. We conclude with the concept that immunotherapy in thoracic malignancies must be tailored made to the balance of the immune system.

From bevacizumab to tasquinimod: angiogenesis as a therapeutic target in prostate cancer

It was first posited in the 1970s that angiogenesis may prove to be a useful target for anticancer therapies. Since then, a number of agents have been developed and tested across a range of tumor types; however, to date, there have unfortunately been more failures than successes. Prostate cancer (PCa) is no exception in this regard, and despite a strong preclinical rationale for targeting angiogenesis in men with PCa, there has yet to be an antiangiogenic therapy proven to prolong survival in this group of patients. Drugs have been developed to target a host of angiogenesis mediators. These include vascular endothelial growth factor (VEGF), the VEGF receptors, antiangiogenic factors (e.g., thrombospondin-1), and downstream mediators of angiogenesis (e.g., hypoxia-inducible factor-1α and MET). At present, there are 2 drugs being tested in the phase III setting for men with PCa: cabozantinib and tasquinimod. Cabozantinib, a dual VEGF receptor-2/MET inhibitor, has shown dramatic beneficial effects on radiographically evident bone metastases and pain in the phase II setting. There are currently 2 large phase III trials underway to further investigate cabozantinib's role in treating men with PCa. Both trials randomize subjects to cabozantinib versus mitoxantrone: one is designed to evaluate overall survival, and the other, pain response durability. The other drug, tasquinimod, has a somewhat poorly understood mechanism of action. It is thought to exert an antiangiogenic effect through the inhibition of myeloid-derived suppressor cells, key to the support of an angiogenic environment, and down-regulation of hypoxia-inducible factor-1α. A phase II trial randomizing men to tasquinimod versus placebo revealed a median progression-free survival advantage in the experimental arm (7.6 vs. 3.3 months with placebo; P = 0.0042). Based on these encouraging phase II results, a randomized, double-blind, placebo-controlled trial in men with metastatic castration-resistant PCa was launched. That trial is powered for a primary endpoint of progression-free survival and is expected to enroll 1200 men.

High expression of cereblon (CRBN) is associated with improved clinical response in patients with multiple myeloma treated with lenalidomide and dexamethasone

Cereblon (CRBN) has recently been identified as a target for immunomodulatory drugs (IMiDs) and its downregulation has been linked to resistance to lenalidomide. Here, we studied CRBN expression by real time polymerase chain reaction in 49 bone marrow samples of newly diagnosed patients with multiple myeloma treated with lenalidomide and dexamethasone. Median CRBN expression was 3·45 in patients who achieved complete response, and 3·75, 2·01, 0·78, and 0·70 in those with very good partial response, partial response, stable disease and progressive disease respectively. CRBN expression levels correlated significantly with response to lenalidomide treatment (r = 0·48; P < 0·001). Among established prognostic parameters, only beta-2-microglobulin correlated with cereblon (r = 0·66; P < 0·001). A close association of CRBN with interferon regulatory factor 4 (IRF4) (P < 0·001) and with CTNNB1 (P < 0·001) was found. Overall, a statistically significant association between baseline CRBN expression and response in MM patients treated with lenalidomide is shown. CRBN expression is closely associated with IRF4, which is an important target of IMiD therapy.

Chemotherapeutic agents increase the risk for pulmonary function test abnormalities in patients with multiple myeloma

Case reports of pulmonary toxicity have been published regarding bortezomib, lenalidomide, and thalidomide but there are no published reports looking at the possible long-term pulmonary effects of these medications. This article describes a possible relationship between the administration of bortezomib and thalidomide and the development of pulmonary function test (PFT) abnormalities. It also suggests that routine pulmonary function testing may be required in patients receiving these medications until larger studies can be performed to confirm this observation.

BACKGROUND

Multiple myeloma is a common malignancy accounting for approximately 1% of all malignancies worldwide. Bortezomib, lenalidomide, and thalidomide are immunomodulatory derivatives that are used in the treatment of multiple myeloma (MM). There have been case reports of pulmonary disease associated with these agents, but the effect of these agents on pulmonary function test (PFT) results is unknown.

PATIENTS AND METHODS

We reviewed the records of 343 patients with MM who underwent PFTs before autologous stem cell transplantation. One hundred nine patients had not received any of the 3 medications, whereas 234 had received 1 or more of these agents.

RESULTS

Patients exposed to bortezomib were more likely to have obstructive PFT results (P = .015) when compared with patients not exposed to this medication. Restrictive PFT results were more likely after exposure to thalidomide (P = .017). A logistic regression model was performed and when adjusted for age, sex, Durie-Salmon (DS) stage, body mass index (BMI), time from diagnosis to transplantation in days, and smoking history, the odds of obstruction were 1.96 times higher for patients who received bortezomib. The odds of restriction were 1.97 times higher after exposure to thalidomide.

CONCLUSION

There appears to be a risk of PFT abnormalities developing in patients treated with bortezomib and thalidomide.

The immunomodulatory drug lenalidomide restores a vitamin D sensitive phenotype to the vitamin D resistant breast cancer cell line MDA-MB-231 through inhibition of BCL-2: potential for breast cancer therapeutics

1α,25-Dihydroxyvitamin D3, (1,25-D3) the biologically active form of vitamin-D, is well established as a cancer cell growth inhibitor in addition to maintaining bone mineralization. In breast cancer cells, inhibitory effects on angiogenesis, and metastasis have been observed together with enhancement of apoptosis and induction of cell cycle arrest. There is a correlation between vitamin-D receptor expression on breast cancer cells and patient survival. However vitamin-D resistance and hypercalcaemia are key limiting factors in clinical use. The IMiD(®) immunomodulatory drug lenalidomide, (Revlimid(®), CC-5013) used in myeloma, can also modulate apoptotic and growth signalling. We studied whether lenalidomide treated breast cancer cells would acquire sensitivity to 1,25-D3 with resulting growth inhibition. The cell lines MCF-12A, MCF-7 and MDA-MB-231, representing non-tumorogenic, tumorogenic, and vitamin-D resistant lines respectively were treated with lenalidomide and/or 1,25-D3(at 100 nM). Whereas lenalidomide alone had no effect on cell growth, a 50% inhibition of cell growth by 1,25-D3 was achieved with additional 1 μM lenalidomide in resistant cells. This effect was through apoptosis measured by PARP cleavage and annexin-V expression. An apoptosis protein array showed that the 1,25-D3 and lenalidomide combination increased pro-apoptotic proteins (phosphorylated p53) and decreased BCL-2 expression. BCL-2 inhibition is proposed as a mechanism of action for the combined drugs in the MDA-MB-231 cell line. In vitamin D resistant cell lines MCF-7VDR and HBL-100 where the combination does not affect BCL-2-no inhibitory effect is observed. These results demonstrate the potential for the combinatorial use of lenalidomide and 1,25-D3 for vitamin D refractory tumours.

Lenalidomide enhances the anti-prostate cancer activity of docetaxel in vitro and in vivo

BACKGROUND

In this study, we investigated the effects of combining lenalidomide and docetaxel on in vitro and in vivo models of prostate cancer as a potential strategy for treatment of castrate resistant prostate cancer (CRPC).

METHODS

The effects of combining lenalidomide and docetaxel on proliferation, apoptosis, invasive potential, anchorage independent growth, and p53 activation in the PC3 and DU145 prostate cell lines were investigated. The effects of the lenalidomide and docetaxel combination on LNCaP prostate cancer cell growth and invasiveness in vitro was also studied. The combination of these two agents was finally tested on a xenograft model of PC3 tumor growth in nude mice.

RESULTS

Lenalidomide decreased the IC(50) of docetaxel by up to 50% (P < 0.05) and also decreased invasion in PC3, LNCaP, and DU145 cells and anchorage independent growth in PC3 cells (P < 0.01). Apoptosis in lenalidomide/docetaxel-treated cells was increased by 2.2-fold over single agent docetaxel and a corresponding increase in p53, p38, and BAD activation was observed in Western blots (P < 0.001). When PC3 challenged mice were treated with lenalidomide and docetaxel, median survival increased from 48 to 59 days and the rate of tumor growth was significantly reduced (P < 0.05).

CONCLUSIONS

Lenalidomide may be a promising candidate for combination with docetaxel in the treatment of CRPC.

Macrophages and mesenchymal stromal cells support survival and proliferation of multiple myeloma cells

Multiple myeloma (MM) is characterized by almost exclusive tropism of malignant cells for the bone marrow (BM) milieu. The survival and proliferation of malignant plasma cells have been shown to rely on interactions with nonmalignant stromal cells, in particular mesenchymal stromal cells (MSCs), in the BM microenvironment. However, the BM microenvironment is composed of a diverse array of cell types. This study examined the role of macrophages, an abundant component of BM stroma, as a potential niche component that supports malignant plasma cells. We investigated the proliferation of MM tumour cell lines when cultured alone or together with MSCs, macrophages, or a combination of MSCs and macrophages, using the carboxyfluorescein succinimidyl ester assay. Consistently, we observed increased proliferation of MM cell lines in the presence of either MSCs or macrophages compared to cell line-only control. Furthermore, the combined co-culture of MSCs plus macrophages induced the greatest degree of proliferation of myeloma cells. In addition to increased proliferation, MSCs and macrophages decreased the rate of apoptosis of myeloma cells. Our in vitro studies provide evidence that highlights the role of macrophages as a key component of the BM microenvironment facilitating the growth of malignant plasma cells in MM.

Targeting angiogenesis for the treatment of prostate cancer

INTRODUCTION

While multiple therapies exist that prolong the lives of men with advanced prostate cancer, none are curative. This had led to a search to uncover novel targets for prostate cancer therapy, distinct from those of traditional hormonal approaches, chemotherapies, immunotherapies and bone-targeting approaches. The process of tumor angiogenesis is one target that is being exploited for therapeutic gain.

AREAS COVERED

The most promising anti-angiogenic approaches for treatment of prostate cancer, focusing on clinical development of selected agents. These include VEGF-directed therapies, tyrosine kinase inhibitors, tumor-vascular disrupting agents, immunomodulatory drugs and miscellaneous anti-angiogenic agents. While none of these drugs have yet entered the market for the treatment of prostate cancer, several are now being tested in Phase III registrational trials.

EXPERT OPINION

The development of anti-angiogenic agents for prostate cancer has met with several challenges. This includes discordance between traditional prostate-specific antigen responses and clinical responses, which have clouded clinical trial design and interpretation, potential inadequate exposure to anti-angiogenic therapies with premature discontinuation of study drugs and the development of resistance to anti-angiogenic monotherapies. These barriers will hopefully be overcome with the advent of more potent agents, the use of dual angiogenesis inhibition and the design of more informative clinical trials.

Therapeutic cancer vaccines: why so few randomised phase III studies reflect the initial optimism of phase II studies

Immunotherapy is showing promise for the treatment of a range of tumours including prostate cancer, melanoma and non small-cell lung cancer. Phase II trial data has been extremely encouraging with regards both clinical outcome and the investigation of the underlying immunological mode-of-action. However, despite the positive phase II data there remains a high failure rate in late stage clinical trials which, in many cases can be ascribed to inappropriate trial design, poor patient selection and inconsistency in patient management. The potential impact of standard cancer treatments and other factors which may vary within patient populations is discussed. A perspective is provided on the failure of late-stage clinical trials across a range of platforms focusing particularly on melanoma and prostate cancer.

[IMiDs in hematology]

IMiDs belong to a new pharmalogical class, whose principal therapeutic agents are the thalidomide and the lenalidomide. They have immunomodulatory and antiangiogenic properties, as well as a direct effect on tumor cells. Thalidomide and lenalidomide were first approved for multiple myeloma, and in 5q-myelodysplastic syndrome for lenalidomide. Several studies have shown the efficacy of these drugs in others hematologic malignancies. A third component has been developed, the pomalidomide, which may be more effective in certain indications. Here we present an overview of IMiDs in hematology, including mechanisms of action and known significant side effects.

Phase I trial of lenalidomide and CCI-779 in patients with relapsed multiple myeloma: evidence for lenalidomide-CCI-779 interaction via P-glycoprotein

PURPOSE

Multiple myeloma (MM) is an incurable plasma-cell neoplasm for which most treatments involve a therapeutic agent combined with dexamethasone. The preclinical combination of lenalidomide with the mTOR inhibitor CCI-779 has displayed synergy in vitro and represents a novel combination in MM.

PATIENTS AND METHODS

A phase I clinical trial was initiated for patients with relapsed myeloma with administration of oral lenalidomide on days 1 to 21 and CCI-779 intravenously once per week during a 28-day cycle. Pharmacokinetic data for both agents were obtained, and in vitro transport and uptake studies were conducted to evaluate potential drug-drug interactions.

RESULTS

Twenty-one patients were treated with 15 to 25 mg lenalidomide and 15 to 20 mg CCI-779. The maximum-tolerated dose (MTD) was determined to be 25 mg lenalidomide with 15 mg CCI-779. Pharmacokinetic analysis indicated increased doses of CCI-779 resulted in statistically significant changes in clearance, maximum concentrations, and areas under the concentration-time curves, with constant doses of lenalidomide. Similar and significant changes for CCI-779 pharmacokinetics were also observed with increased lenalidomide doses. Detailed mechanistic interrogation of this pharmacokinetic interaction demonstrated that lenalidomide was an ABCB1 (P-glycoprotein [P-gp]) substrate.

CONCLUSION

The MTD of this combination regimen was 25 mg lenalidomide with 15 mg CCI-779, with toxicities of fatigue, neutropenia, and electrolyte wasting. Pharmacokinetic and clinical interactions between lenalidomide and CCI-779 seemed to occur, with in vitro data indicating lenalidomide was an ABCB1 (P-gp) substrate. To our knowledge, this is the first report of a clinically significant P-gp-based drug-drug interaction with lenalidomide.

Lenalidomide downregulates the cell survival factor, interferon regulatory factor-4, providing a potential mechanistic link for predicting response

Overexpression of the transcription factor interferon regulatory factor-4 (IRF4), which is common in multiple myeloma (MM), is associated with poor prognosis. Patients with higher IRF4 expression have significantly poorer overall survival than those with low IRF4 expression. Lenalidomide is an IMiD immunomodulatory compound that has both tumouricidal and immunomodulatory activity in MM. This study showed that lenalidomide downregulated IRF4 levels in MM cell lines and bone marrow samples within 8 h of drug exposure. This was associated with a decrease in MYC levels, as well as an initial G1 cell cycle arrest, decreased cell proliferation, and cell death by day 5 of treatment. In eight MM cell lines, high IRF4 levels correlated with increased lenalidomide sensitivity. The clinical significance of this observation was investigated in 154 patients with MM. Among MM patients with high levels of IRF4 expression, treatment with lenalidomide led to a significantly longer overall survival than other therapies in a retrospective analysis. These data confirm the central role of IRF4 in MM pathogenesis; indicate that this is an important mechanism by which lenalidomide exerts its antitumour effects; and may provide a mechanistic biomarker to predict response to lenalidomide.

Higher response to lenalidomide in relapsed/refractory diffuse large B-cell lymphoma in nongerminal center B-cell-like than in germinal center B-cell-like phenotype

BACKGROUND

There is a need to develop novel therapies for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) and to identify biomarkers predictive for therapeutic response. Lenalidomide was previously shown to induce an overall response rate (ORR) of 28% in patients with relapsed/refractory DLBCL. It is currently unknown if response rates differ between patients with different DLBCL subtypes.

METHODS

The authors retrospectively evaluated clinical outcomes of patients with germinal center B-cell-like versus nongerminal center B-cell-like DLBCL treated with salvage lenalidomide at 4 academic institutions.

RESULTS

Forty patients with relapsed/refractory DLBCL were included (24 men; 16 women; median age, 66 years; median of 4 prior treatments, including rituximab chemotherapy). Patients were classified as germinal center B-cell-like (n = 23) or nongerminal center B-cell-like (n = 17) DLBCL according to the Hans algorithm. The subgroups were similar in terms of stage, international prognostic index score, prior number of treatments, and rituximab resistance. A significant difference in clinical response to lenalidomide was observed in nongerminal center B-cell-like versus germinal center B-cell-like patients. ORR was 52.9% versus 8.7% (P = .006); complete response rate was 23.5% versus 4.3%. Median progression-free survival was 6.2 versus 1.7 months (P = .004), although no difference in OS was observed between nongerminal center B-cell-like and germinal center B-cell-like DLBCL patients.

CONCLUSIONS

The data suggest that the 2 major subgroups of patients with DLBCL (germinal center B cell and nongerminal center B cell) have different antitumor responsiveness to lenalidomide in the relapsed/refractory setting. A large international trial (NCT01197560) has been opened to enrollment in an attempt to prospectively validate these retrospective observations.

The immunostimulatory effect of lenalidomide on NK-cell function is profoundly inhibited by concurrent dexamethasone therapy

Lenalidomide combined with dexamethasone is an effective treatment for refractory/relapsed multiple myeloma (MM). Lenalidomide stimulates natural killer (NK) cells and enhances antitumor responses. We assessed NK cell number and function in 25 patients with MM participating in a clinical trial of lenalidomide and dexamethasone. NK cell numbers increased from a mean of 2.20 ± 0.05 × 105/mL (baseline) to a mean of 3.90 ± 0.03 × 105/mL (cycle 6; P = .05); however, in vitro NK-cell–mediated cytotoxicity decreased from 48.9% ± 6.8% to 27.6% ± 5.1% (P = .0028) and could not be rescued by lenalidomide retreatment. Lenalidomide increased normal donor NK-cell cytotoxicity in vitro from 38.5% to 53.3%, but this was completely abrogated by dexamethasone. Dexamethasone suppression of NK cell–mediated cytotoxicity was partially reversed by a 3-day washout, but these cells remained refractory to lenalidomide-induced enhanced function. Lymphocyte subset depletion experiments revealed that lenalidomide's enhancement of NK cell–mediated cytotoxicity was mediated by CD4+ T-cell production of interleukin 2 and that dexamethasone acted by suppressing interleukin-2 production. Similarly, the reduced ability of NK cells from patients with MM to respond to lenalidomide was also due to impaired CD4 T-cell function. Our findings indicate that lenalidomide immunostimulatory effects on patient NK cells are severely blunted by concurrent dexamethasone administration.

The potential of immunomodulatory drugs in the treatment of solid tumors

Lenalidomide (REVLIMID®) CC-5013 (Celgene, NJ, USA) is approved, in both the USA and Europe, in combination with dexamethasone for the treatment of multiple myeloma patients who have received at least one prior therapy, and is rapidly being accepted worldwide for this condition. Lenalidomide is also approved in the USA and Canada for use in transfusion-dependent anemia in patients with low- and intermediate-1-risk myelodysplastic syndromes associated with del (5q) abnormality with or without additional abnormalities. Lenalidomide is an IMiD® immunomodulatory compound, incorporating structural modification of the drug thalidomide, which is active against a wide variety of autoimmune Th-2-dependent disorders, including erythema nodosum of leprosy, leishmaniasis, as well as severe ulcerative disorders such as Behcet's syndrome. Unfortunately, long-term use of thalidomide is limited, particularly by neurotoxicity. To date, results suggest that lenalidomide is more active than thalidomide and does not cause the neurotoxicity seen with thalidomide. Lenalidomide has multiple properties, including anti-inflammatory, antiangiogenic and costimulatory effects, as well as being able to inhibit T-regulatory cells, all of which are properties deemed desirable for anticancer activity. This article covers the evidence that lenalidomide may have a major role in the treatment and control of many cancer types other than del (5q) myelodysplastic syndrome and multiple myeloma.

Targeted therapy in lymphoma

Discovery of new treatments for lymphoma that prolong survival and are less toxic than currently available agents represents an urgent unmet need. We now have a better understanding of the molecular pathogenesis of lymphoma, such as aberrant signal transduction pathways, which have led to the discovery and development of targeted therapeutics. The ubiquitin-proteasome and the Akt/mammalian target of rapamycin (mTOR) pathways are examples of pathological mechanisms that are being targeted in drug development efforts. Bortezomib (a small molecule protease inhibitor) and the mTOR inhibitors temsirolimus, everolimus, and ridaforolimus are some of the targeted therapies currently being studied in the treatment of aggressive, relapsed/refractory lymphoma. This review will discuss the rationale for and summarize the reported findings of initial and ongoing investigations of mTOR inhibitors and other small molecule targeted therapies in the treatment of lymphoma.

Recent Pharmacological Advances: Focus on Small-cell Lung Cancer

Small cell lung cancer (SCLC) represents approximately 15% of all lung cancers, and is the most aggressive form of lung cancer. Left untreated, the time from diagnosis to death is 2–3 months. With current treatment, expected survival is 7–20 months, depending on the stage of disease. A new drug, amrubicin, is approved in Japan for lung cancer and has demonstrated efficacy in U.S. and European phase II trials of SCLC patients with either untreated disease or relapsed refractory illness. In a phase II study of amrubicin in previously untreated patients, response rates reached 75% with a median survival time of almost 1 year. Amrubicin is a fully synthetic 9-aminoanthracycline, and an analog of doxorubicin and epirubicin. The major mechanism of action of amrubicin is inhibition of topoisomerase II. Unlike doxorubicin, however, it exhibits little or no cardiotoxicity in clinical studies and preclinical models. In preclinical rodent tumor models, it is selectively distributed to tumour tissue and is not detected in the heart when compared with doxorubicin, which is distributed equivalently to these sites. The primary metabolite of amrubicin, amrubicinol, is up to 100 times more cytotoxic in vitro than the parent compound. This review describes the mechanisms of action of amrubicin as well as clinical studies which demonstrate the potential of this drug in future SCLC treatment. The review also puts forward hypothetical considerations for the use of other drugs such as lenalidomide, an immunomodulatory drug acting on multiple signalling pathways, or histone deacetylase inhibitors, in combination with amrubicin in SCLC.

Thalidomide-induced limb defects: resolving a 50-year-old puzzle

Despite the recent discovery that thalidomide causes limb defects by targeting highly angiogenic, immature blood vessels, several challenges still remain and new ones have arisen. These include understanding the drug's species specificity, determining molecular target(s) in the endothelial cell, shedding light on the molecular basis of phocomelia and producing a form of the drug that is clinically effective without having side effects. Now that the trigger of thalidomide-induced teratogenesis has been uncovered, a framework is proposed, incorporating and uniting previous models of thalidomide action, explaining how thalidomide causes not just limb defects, but also all the other defects it induces.

Effect of immunoglobulin therapy on the rate of infections in multiple myeloma patients undergoing autologous stem cell transplantation or treated with immunomodulatory agents

Multiple myeloma (MM) is associated with a significant risk of infection due to immune dysfunction. Infections are a major cause of morbidity and mortality in MM patients. There are few data available regarding the prevalence of infection in MM patients, especially in conjunction with newer generations of immunomodulatory drugs (thalidomide, bortezomib, lenalidomide) or post autologous stem cell transplantation (ASCT). Intravenous immunoglobulin (IVIG) has been used successfully to reduce infection rates in the stable phase of MM, with limited data in other stages.

We retrospectively analyzed 47 patients with MM from March 2006 to June 2009 at our institution. All patients received thalidomide and steroid therapy for at least 6 months. Nine patients received bortezomib and 11 lenalidomide subsequent to thalidomide, because of disease progression, and 22 patients underwent ASCT. The median age was 64 years (range 37–86), with a female–to-male ratio of 18:29. The median residual-serum IgG-level at time of infection was 3.2 g/L, IgA 0.3 g/L and IgM 0.2 g/L. Most patients suffered from recurrent moderate to severe bacterial infections, including the ASCT group. Fifteen patients suffered from different degrees of viral infections.

All patients except 3 received IVIG therapy with a significant decline of the rate of infection thereafter (p<001). Our analysis shows that patients with MM treated with the new immunomodulatory drugs in conjunction with steroids are at significant increased risk of infection. Employing IVIG therapy appears to be an effective strategy to prevent infection in this cohort of patients. Further studies to confirm these findings are warranted.

Angiogenesis inhibitors in the treatment of prostate cancer

IMPORTANCE OF THE FIELD

Prostate carcinoma is the most common non-cutaneous malignancy in U.S. men. The efficacy of docetaxel and prednisone in metastatic castrate-resistant prostate cancer (mCRPC) has been shown to improve overall survival; however, its effect is not durable, highlighting the need for new therapies.

AREAS COVERED IN THIS REVIEW

We will review the development of some of the leading compounds with direct and indirect antiangiogenic activity in prostate cancer including antibodies to VEGF and its receptors, small-molecule inhibitors of downstream signaling, immunomodulatory drugs with antiangiogenic activity, and compounds thought to directly inhibit or destroy vascular endothelial cells.

WHAT THE READER WILL GAIN

The reader will gain a basic understanding of the role of angiogenesis in prostate cancer growth and metastasis. Current and potential targets of angiogenesis and their corresponding drugs under development for prostate cancer are discussed.

TAKE HOME MESSAGE

There are now multiple early-phase clinical trials of antiangiogenic agents alone or in combination in prostate cancer. Several of these agents are now in Phase III development. Combined therapy with two antiangiogenic compounds may improve the activity of either compound alone. Multiple targets in the angiogenesis pathway continue to be elucidated and should remain an active area of investigation for the treatment of prostate cancer.