Sargramostim (GM-CSF) and lenalidomide in castration-resistant prostate cancer (CRPC): Results from a phase I-II clinical trial

Discovery of an Aldo-Keto reductase 1C3 (AKR1C3) degrader

Aldo-keto reductase 1C3 (AKR1C3) is a protein upregulated in prostate cancer, hematological malignancies, and other cancers where it contributes to proliferation and chemotherapeutic resistance. Androgen receptor splice variant 7 (ARv7) is the most common mutation of the AR receptor that confers resistance to clinical androgen receptor signalling inhibitors in castration-resistant prostate cancer. AKR1C3 interacts with ARv7 promoting stabilization. Herein we report the discovery of the first-in-class AKR1C3 Proteolysis-Targeting Chimera (PROTAC) degrader. This first-generation degrader potently reduced AKR1C3 expression in 22Rv1 prostate cancer cells with a half-maximal degradation concentration (DC50) of 52 nM. Gratifyingly, concomitant degradation of ARv7 was observed with a DC50 = 70 nM, along with degradation of the AKR1C3 isoforms AKR1C1 and AKR1C2 to a lesser extent. This compound represents a highly useful chemical tool and a promising strategy for prostate cancer intervention.

Neurophysiological mechanisms of cancer-induced bone pain

Background

Cancer-induced Bone Pain (CIBP) is an important factor affecting their quality of life of cancer survivors. In addition, current clinical practice and scientific research suggest that neuropathic pain is a representative component of CIBP. However, given the variability of cancer conditions and the complexity of neuropathic pain, related mechanisms have been continuously supplemented but have not been perfected.

Aim of Review

Therefore, the current review highlights the latest progress in basic research on the field and proposes potential therapeutic targets, representative drugs and upcoming therapies.

Key Scientific Concepts of Review

Notably, factors such as central sensitization, neuroinflammation, glial cell activation and an acidic environment are considered to be related to neuropathic pain in CIBP. Nonetheless, further research is needed to ascertain the mechanism of CIBP in order to develop highly effective drugs. Moreover, more attention needs to be paid to the care of patients with advanced cancer.

Transcriptional Regulation of Voltage-Gated Sodium Channels Contributes to GM-CSF-Induced Pain

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induces the production of granulocyte and macrophage populations from the hematopoietic progenitor cells; it is one of the most common growth factors in the blood. GM-CSF is also involved in bone cancer pain development by regulating tumor-nerve interactions, remodeling of peripheral nerves, and sensitization of damage-sensing (nociceptive) nerves. However, the precise mechanism for GM-CSF-dependent pain is unclear. In this study, we found that GM-CSF is highly expressed in human malignant osteosarcoma. Female Sprague Dawley rats implanted with bone cancer cells develop mechanical and thermal hyperalgesia, but antagonizing GM-CSF in these animals significantly reduced such hypersensitivity. The voltage-gated Na⁺ channels Nav1.7, Nav1.8, and Nav1.9 were found to be selectively upregulated in rat DRG neurons treated with GM-CSF, which resulted in enhanced excitability. GM-CSF activated the Janus kinase 2 (Jak2)-signal transducer and activator of transcription protein 3 (Stat3) signaling pathway, which promoted the transcription of Nav1.7-1.9 in DRG neurons. Accordingly, targeted knocking down of either Nav1.7-1.9 or Jak2/Stat3 in DRG neurons in vivo alleviated the hyperalgesia in male Sprague Dawley rats. Our findings describe a novel bone cancer pain mechanism and provide a new insight into the physiological and pathological functions of GM-CSF.SIGNIFICANCE STATEMENT It has been reported that granulocyte-macrophage colony-stimulating factor (GM-CSF) plays a key role in bone cancer pain, yet the underlying mechanisms involved in the GM-CSF-mediated signaling pathway in nociceptors is not fully understood. Here, we showed that GM-CSF promotes bone cancer-associated pain by enhancing the excitability of DRG neurons via the Janus kinase 2 (Jak2)-signal transducer and activator of transcription protein 3 (Stat3)-mediated upregulation of expression of nociceptor-specific voltage-gated sodium channels. Our study provides a detailed understanding of the roles that sodium channels and the Jak2/Stat3 pathway play in the GM-CSF-mediated bone cancer pain; our data also highlight the therapeutic potential of targeting GM-CSF.

Ketoconazole plus Lenalidomide in patients with Castration-Resistant Prostate Cancer (CRPC): results of an open-label phase II study

Introduction Ketoconazole is CYP-17 inhibitor with demonstrated activity in men with castration-resistant prostate cancer (CRPC). Lenalidomide is an antiangiogenic and immunomodulatory agent with broad antitumor activity. We hypothesized that the modulation of the cellular immune response to apoptosis caused by ketoconazole may be increased with the addition of lenalidomide. Methods This is an open-label, non-randomized, single-arm phase II study evaluating the efficacy and safety of the combination of ketoconazole and lenalidomide in patients with CRPC. Treatment schema included standard ketoconazole 400 mg orally three times daily plus hydrocortisone orally (20 mg in the morning and 10 mg at night) in combination with lenalidomide 25 mg orally daily for 21 days in a 28-day cycle and aspirin 75 mg daily. The primary endpoint of this study was response (either by ≥ 50% PSA decline or objective disease assessed by RECIST v1.0). Exploratory endpoints included changes in T cell, dendritic cell (DC) marker counts, and their correlation with PSA response to treatment. Results A total of 34 CRPC patients, median age 69 years, 76% ECOG 0 and 76% with metastases participated in the study. Patients received a median of 2 cycles (range 1-35); nine patients (26%) received >10 cycles of treatment. PSA responses were observed in 17 patients (50%) with 11 patients (32%) achieving a PSA decline of >90%. Among the 9 patients with measurable disease, 2 patients (22%) had PR and 2 other (22%) had SD as best response. Median time to failure (TTF) was 2.7 months (range 0.2-32.8); and 8 patients were treated for ≥ 15 months. Most common adverse events included fatigue (76%), skin reactions (62%), lymphopenia (44%) and anemia (44%). One possible treatment-related death was noted. For 16 patients with available serial correlative data, there was a significant increase in the dendritic cells subsets BDCA-1 (+146.7, -20.1 to +501.1%, p = 0.018) and BDCA-3 (39.8%, -100 to 282.6%, p = 0.001) after 8 weeks of treatment. No association between immune cell counts and PSA response at 8 weeks was observed. Conclusion The combination of ketoconazole and lenalidomide was well tolerated but did not meet the primary endpoint of response, despite durable responses were observed in a selected group of patients. Although ketoconazole has now been replaced with more active novel agents, the combination of novel CYP-17 inhibitors with agents capable of modulating the immune system warrants further prospective investigation. NCT00460031.

Drugs in Clinical Trials for Alzheimer's Disease: The Major Trends

Alzheimer's disease (AD) is characterized by a chronic and progressive neurodegenerative process resulting from the intracellular and extracellular accumulation of fibrillary proteins: beta-amyloid and hyperphosphorylated Tau. Overaccumulation of these aggregates leads to synaptic dysfunction and subsequent neuronal loss. The precise molecular mechanisms of AD are still not fully understood but it is clear that AD is a multifactorial disorder and that advanced age is the main risk factor. Over the last decade, more than 50 drug candidates have successfully passed phase II clinical trials, but none has passed phase III. Here, we summarize data on current "anti-Alzheimer's" agents currently in clinical trials based on findings available in the Thomson Reuters «Integrity» database, on the public website www.clinicaltrials.gov, and on database of the website Alzforum.org. As a result, it was possible to outline some major trends in AD drug discovery: (i) the development of compounds acting on the main stages of the pathogenesis of the disease (the so-called "disease-modifying agents") - these drugs could potentially slow the development of structural and functional abnormalities in the central nervous system providing sustainable improvements of cognitive functions, which persist even after drug withdrawal; (ii) focused design of multitargeted drugs acting on multiple molecular targets involved in the pathogenesis of the disease; (3) finally, the repositioning of old drugs for new (anti-Alzheimer's) application offers a very attractive approach to facilitate the completion of clinical trials.

Gene interference strategies as a new tool for the treatment of prostate cancer

Prostate cancer (PCa) is one of the most common cancer in men. It affects older men and the incidence increases with age; the median age at diagnosis is 67 years. The diagnosis of PCa is essentially based on three tools: digital rectal exam, serum concentration of prostate specific antigen, and transrectal ultrasound-guided biopsy. Currently, the therapeutic treatments of this cancer are different and range from the prostatectomy to hormonal therapy, to radiation therapy, to immunotherapy, and to chemotherapy. However, additional efforts are required in order to find new weapons for the treatment of metastatic setting of disease. The purpose of this review is to highlight new therapeutic strategies based on gene interference; in fact, numerous siRNA and miRNA in the therapeutic treatment of PCa are reported below.

Immunotherapy for castration-resistant prostate cancer: Progress and new paradigms

BACKGROUND

The approval of sipuleucel-T in conjunction with data from other immunotherapeutic trials for prostate cancer and other solid tumors demonstrates the potential of harnessing the patients' immune system for long-term survival. Thus, a range of therapeutic approaches are under evaluation. This review describes the rationale for immunotherapy for prostate cancer, summarizes the approaches under evaluation, and discusses sequencing options for immunotherapy in the current treatment paradigm.

DESIGN

References for this review were identified through searches of PubMed with the search terms "prostate cancer," "immune system," "vaccine," "immunotherapy," and "T cells." Articles were also identified through searches of the authors' own files. The final reference list was generated based on originality and relevance.

RESULTS

The immune system can recognize and respond to prostate tumor antigens, effected through tumor-associated antigens and tumor infiltration of immune effector cells. However, evidence also suggests that prostate tumors are adept at escaping immunological recognition, thus hypothesizing multiple therapeutic strategies. Therapeutic approaches could include vaccination and modulation of T-cell function via the blockade of checkpoint receptors such as cytotoxic T-lymphocyte antigen-4 and programmed death 1. In phase III trials, sipuleucel-T improved overall survival for an M1 patient population with castration-resistant prostate cancer and ipilimumab also did so when given after radiotherapy in a subset of better risk patients. In randomized phase II trials, prostate-specific antigen-TRICOM improved overall survival and tasquinimod improved progression-free survival.

CONCLUSION

Although immunotherapy has the potential to affect advanced prostate cancer, additional research is needed to (1) identify predictive or surrogate markers of activity, (2) understand which agents are clinically effective alone or in combination with other therapies, and (3) define the optimal timing for an immunotherapy to achieve maximal benefit.

Growth factor and signaling pathways and their relevance to prostate cancer therapeutics

Treatments that target the androgen axis represent an effective strategy for patients with advanced prostate cancer, but the disease remains incurable and new therapeutic approaches are necessary. Significant advances have recently occurred in our understanding of the growth factor and signaling pathways that are active in prostate cancer. In conjunction with this, many new targeted therapies with sound preclinical rationale have entered clinical development and are being tested in men with castration-resistant prostate cancer. Some of the most relevant pathways currently being exploited for therapeutic gain are HGF/c-Met signaling, the PI3K/AKT/mTOR pathway, Hedgehog signaling, the endothelin axis, Src kinase signaling, the IGF pathway, and angiogenesis. Here, we summarize the biological basis for the use of selected targeted agents and the results from available clinical trials of these drugs in men with prostate cancer.

Trial Watch: Lenalidomide-based immunochemotherapy

Lenalidomide is a synthetic derivative of thalidomide currently approved by the US Food and Drug Administration for use in patients affected by multiple myeloma (in combination with dexamethasone) and low or intermediate-1 risk myelodysplastic syndromes that harbor 5q cytogenetic abnormalities. For illustrative purposes, the mechanism of action of lenalidomide can be subdivided into a cancer cell-intrinsic, a stromal, and an immunological component. Indeed, lenalidomide not only exerts direct cell cycle-arresting and pro-apoptotic effects on malignant cells, but also interferes with their physical and functional interaction with the tumor microenvironment and mediates a robust, pleiotropic immunostimulatory activity. In particular, lenalidomide has been shown to stimulate the cytotoxic functions of T lymphocytes and natural killer cells, to limit the immunosuppressive impact of regulatory T cells, and to modulate the secretion of a wide range of cytokines, including tumor necrosis factor α, interferon γ as well as interleukin (IL)-6, IL-10, and IL-12. Throughout the last decade, the antineoplastic and immunostimulatory potential of lenalidomide has been investigated in patients affected by a wide variety of hematological and solid malignancies. Here, we discuss the results of these studies and review the status of clinical trials currently assessing the safety and efficacy of this potent immunomodulatory drug in oncological indications.

Trial Watch: Immunostimulatory cytokines

During the past two decades, the notion that cancer would merely constitute a cell-intrinsic disease has gradually been complemented by a model postulating that the immune system plays a relevant role during all stages of oncogenesis and tumor progression. Along with this conceptual shift, several strategies have been devised to stimulate tumor-specific immune responses, including relatively unselective approaches such as the systemic administration of adjuvants or immunomodulatory cytokines. One year ago, in the July issue of OncoImmunology, we described the main biological features of this large group of proteins and discussed the progress of ongoing clinical studies evaluating their safety and therapeutic potential in cancer patients. Here, we summarize the latest developments in this area of clinical research, focusing on high impact studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate which cytokines can be employed as safe and efficient immunostimulatory interventions against cancer.