Phase II Study of Long-Term Androgen Suppression With Bevacizumab and Intensity-Modulated Radiation Therapy (IMRT) in High-Risk Prostate Cancer

Toxicity of locoregional radiotherapy in combination with bevacizumab in patients with non-metastatic breast cancer (TOLERAB): Final long-term evaluation

BACKGROUND AND PURPOSE

Few data are available concerning the safety of bevacizumab (B) in combination with locoregional radiation therapy (RT). The objective of this study was to evaluate the 5-year late toxicity of concurrent B and RT in non-metastatic breast cancer.

MATERIALS AND METHODS

This multicentre prospective study included non-metastatic breast cancer patients enrolled in phase 3 clinical trials evaluating B with concurrent RT versus RT alone. All patients received neoadjuvant or adjuvant chemotherapy and normofractionated breast or chest wall RT, with or without regional lymph node RT. B was administered at an equivalent dose of 5 mg/kg once a week for 1 year. The safety profile was evaluated 1, 3 and 5 years after completion of radiotherapy.

RESULTS

A total of 64 patients were included between November 2007 and April 2010. Median follow-up was 60 months (12-73) and 5-year late toxicity data were available for 46 patients. The majority of tumours were triple-negative (68.8%), tumour size <2cm (41.3%) with negative nodal status (50.8%). Median total dose of B was 15,000mg and median duration was 11.2 months. No grade ≥3 toxicity was observed. Only 8 patients experienced grade 1-2 toxicities: n = 3 (6.5%) grade 1 lymphedema, n = 2 (4.3%) grade 1 pain, n = 1 (2.2%) grade 2 lymphedema, n = 1 (2.2%) grade 1 fibrosis. Five-year overall survival was 93.8%, disease-free survival was 89% and locoregional recurrence-free survival was 93.1%.

CONCLUSION

Concurrent B and locoregional RT are associated with acceptable 5-year toxicity in patients with non-metastatic breast cancer. No grade ≥3 toxicity was observed.

Preclinical study using androgen receptor (AR) degradation enhancer to increase radiotherapy efficacy via targeting radiation-increased AR to better suppress prostate cancer progression

Background

While androgen deprivation therapy (ADT) and radiotherapy (RT) are currently used together to treat locally advanced prostate cancer (PCa), RT might have the adverse effect of increasing the PCa androgen receptor (AR) protein expression, which might then increase the resistance to continued RT.

Methods

We used multiple assays for RT sensitivity, protein and RNA expression of AR and related DDR genes, ROS level, DNA damage/repair level, cell cycle and apoptosis. All statistical comparisons were analyzed with t-test or one-way ANOVA.

Findings

We demonstrated that RT induced AR expression in C4-2 and CWR22Rv-1 cells. We found that combining RT and ASC-J9^®, but not the antiandrogen, Enzalutamide, could increase radiosensitivity via inducing DNA damage, altering the AR mediated and DNA repair pathways, and activating apoptosis. ASC-J9^® had little effects on normal bladder cells.

Interpretation

Targeting ionizing radiation (IR)-increased AR with the AR degradation enhancer, ASC-J9^®, could increase the radiosensitivity while sparing adjacent normal tissue. Mechanism dissection revealed that ASC-J9^®, but not Enzalutamide, treatment could increase radiosensitivity via inducing DNA damage, altering DNA repair pathways, as well as activating the IR-induced apoptosis via suppressing the pATR-CHK1 signals. Importantly, results from preclinical studies using an in vivo mouse model also demonstrated that combining RT with ASC-J9^® to target AR led to better therapeutic efficacy to suppress PCa progression.

•

ASC-J9• enhances efficacy of radiotherapy (RT) in PCa through both AR-dependent and AR-independent mechanistic pathways.

•

In AR-independent pathway, ASC-J9• increases endogenous ROS and DNA damage and makes PCa cells more sensitive to RT

•

ASC-J9• could also reduce the DNA damage repair after RT via suppression of AR dependent DDR genes and apoptotic pathway.

•

From pre-clinical mouse model, we found that combining RT and ASC-J9• can provide better efficacy than RT only.

Issues and promises of bevacizumab in prostate cancer treatment

INTRODUCTION

There is general agreement that increased angiogenesis is an important factor in determining prostate cancer development and prognosis. Vascular Endothelial Growth Factor (VEGF) is thought to play a primary role in the molecular events that lead to prostate cancer progression, from androgen-dependency to castration-resistance until dissemination to the skeleton. Bevacizumab is a recombinant anti-VEGF monoclonal antibody that has exhibited clinical activity in different cancer types. Areas covered: In this review we summarize the data of clinical trials, investigating the effects of bevacizumab in prostate cancer patients. Until now, the drug has demonstrated anti-tumoral activity although with no improvements in overall survival (OS) and a wide range of alarming side effects in metastatic castration-resistant prostate cancer (mCRPC). Recently, promising results were achieved, using bevacizumab in combination with androgen deprivation therapy (ADT) in patients with recurrent prostate cancer after definitive local therapy. Expert opinion: The suboptimal efficacy of bevacizumab may relate to molecular events triggered during disease progression, such as redundancy of angiogenic factors or the interfering influence of androgens on angiogenic pathways. Further studies, using bevacizumab in combination with ADT and/or inhibitors of other key pathways on the subset of patients with low burden, hormone sensitive prostate cancer, need to be conducted.

Electrolyte disorders associated with the use of anticancer drugs

The use of anticancer drugs is beneficial for patients with malignancies but is frequently associated with the occurrence of electrolyte disorders, which can be hazardous and in many cases fatal. The review presents the electrolyte abnormalities that can occur with the use of anticancer drugs and provides the related mechanisms. Platinum-containing anticancer drugs induce hypomagnesemia, hypokalemia and hypocalcemia. Moreover, platinum-containing drugs are associated with hyponatremia, especially when combined with large volumes of hypotonic fluids aiming to prevent nephrotoxicity. Alkylating agents have been linked with the occurrence of hyponatremia [due to syndrome of inappropriate antidiuretic hormone secretion (SIADH)] and Fanconi's syndrome (hypophosphatemia, aminoaciduria, hypouricemia and/or glucosuria). Vinca alkaloids are associated with hyponatremia due to SIADH. Epidermal growth factor receptor monoclonal antibody inhibitors induce hypomagnesemia, hypokalemia and hypocalcemia. Other, monoclonal antibodies, such as cixutumumab, cause hyponatremia due to SIADH. Tyrosine kinase inhibitors are linked to hyponatremia and hypophosphatemia. Mammalian target of rapamycin inhibitors induce hyponatremia (due to aldosterone resistance), hypokalemia and hypophosphatemia. Other drugs such as immunomodulators or methotrexate have been also associated with hyponatremia. The administration of estrogens at high doses, streptozocin, azacitidine and suramin may induce hypophosphatemia. Finally, the drug-related tumor lysis syndrome is associated with hyperphosphatemia, hyperkalemia and hypocalcemia. The prevention of electrolyte derangements may lead to reduction of adverse events during the administration of anticancer drugs.

Activity of Artemisia annua and artemisinin derivatives, in prostate carcinoma

BACKGROUND

Artemisia annua L, artemisinin and artesunate reveal profound activity not only against malaria, but also against cancer in vivo and clinical trials. Longitudinal observations on the efficacy of A. annua in patients are, however missing as of yet.

METHODS

Clinical diagnosis was performed by imaging techniques (MRT, scintigraphy, SPECT/CT) and blood examinations of standard parameters from clinical chemistry. Immunohistochemistry of formalin-fixed, paraffin-embedded tumor material was performed to determine the expression of several biomarkers (cycloxygenase-2 (COX2), epidermal growth factor receptor (EGFR), glutathione S-transferase P1 (GSTP1), Ki-67, MYC, oxidized low density lipoprotein (lectin-like) receptor 1 (LOX1), p53, P-glycoprotein, transferrin receptor (TFR, CD71), vascular endothelial growth factor (VEGF), von Willebrand factor (CD31)). The immunohistochemical expression has been compared with the microarray-based mRNA expression of these markers in two prostate carcinoma cell lines (PC-3, DU-145).

RESULTS

A patient with prostate carcinoma (pT3bN1M1, Gleason score 8 (4+4)) presented with a prostate specific antigen (PSA) level >800 µg/l. After short-term treatment with bacalitumide (50 mg/d for 14 days) and long-term oral treatment with A. annua capsules (continuously 5 × 50 mg/d), the PSA level dropped down to 0.98 µg/l. MRT, scintigraphy and SPECT/CT verified tumor remission. Seven months later, PSA and ostase levels increased, indicating tumor recurrence and skeletal metastases. Substituting A. annua capsules by artesunate injections (2 × 150 mg twice weekly i.v.) did not prohibit tumor recurrence. PSA and ostase levels rose to 1245 µg/l and 434 U/l, respectively, and MRT revealed progressive skeletal metastases, indicating that the tumor acquired resistance. The high expression of MYC, TFR, and VEGFC in the patient biopsy corresponded with high expression of these markers in the artemisinin-sensitive PC-3 cells compared to artemisinin-resistant DU-145 cells.

CONCLUSION

Long-term treatment with A. annua capsules combined with short-term bicalitumide treatment resulted in considerable regression of advanced metastasized prostate carcinoma. Controlled clinical trials are required to evaluate the clinical benefit of A. annua in prostate cancer.

Regulation of vascular endothelial growth factor in prostate cancer

Prostate cancer (PCa) is the most common malignancy affecting men in the western world. Although radical prostatectomy and radiation therapy can successfully treat PCa in the majority of patients, up to ~30% will experience local recurrence or metastatic disease. Prostate carcinogenesis and progression is typically an androgen-dependent process. For this reason, therapies for recurrent PCa target androgen biosynthesis and androgen receptor function. Such androgen deprivation therapies (ADT) are effective initially, but the duration of response is typically ≤24 months. Although ADT and taxane-based chemotherapy have delivered survival benefits, metastatic PCa remains incurable. Therefore, it is essential to establish the cellular and molecular mechanisms that enable localized PCas to invade and disseminate. It has long been accepted that metastases require angiogenesis. In the present review, we examine the essential role for angiogenesis in PCa metastases, and we focus in particular on the current understanding of the regulation of vascular endothelial growth factor (VEGF) in localized and metastatic PCa. We highlight recent advances in understanding the role of VEGF in regulating the interaction of cancer cells with tumor-associated immune cells during the metastatic process of PCa. We summarize the established mechanisms of transcriptional and post-transcriptional regulation of VEGF in PCa cells and outline the molecular insights obtained from preclinical animal models of PCa. Finally, we summarize the current state of anti-angiogenesis therapies for PCa and consider how existing therapies impact VEGF signaling.

Hematologic changes during prostate cancer radiation therapy are dependent on the treatment volume

AIM

To assess hematologic changes of modern prostate radiation therapy (RT) comparing different target volumes.

PATIENTS & METHODS

Blood samples were evaluated before (T1), during (T2-T4) and 6-8 weeks after (T5) RT in a group of 113 patients. Whole-pelvic RT up to 46 Gy was applied in 27 cases. The total dose to the prostatic fossa (n = 46)/prostate (n = 67) was 66/76 Gy.

RESULTS

Erythrocyte, leukocyte and platelet levels decreased significantly relative to baseline levels at T2-T5. Neoadjuvant hormonal therapy had an impact on hemoglobin levels before and during RT. The cumulative incidence of grade 2 leukopenia was 15 versus 2% (p = 0.02) and grade 2 anemia 8 versus 0% (p = 0.03) with versus without whole-pelvic RT, respectively. Lymphocyte decrease was larger at times T2-T5 (36 vs 3% grade 3 toxicity; p < 0.01).

CONCLUSION

Prostate RT has a small but significant and longer effect on the blood count. Lower lymphocyte levels need to be considered when larger volumes are treated.

Low interrater reliability in grading of rectal bleeding using National Cancer Institute Common Toxicity Criteria and Radiation Therapy Oncology Group Toxicity scales: a survey of radiation oncologists

PURPOSE

To measure concordance among genitourinary radiation oncologists in using the National Cancer Institute Common Toxicity Criteria (NCI CTC) and Radiation Therapy Oncology Group (RTOG) grading scales to grade rectal bleeding.

METHODS AND MATERIALS

From June 2013 to January 2014, a Web-based survey was sent to 250 American and Canadian academic radiation oncologists who treat prostate cancer. Participants were provided 4 case vignettes in which patients received radiation therapy and developed rectal bleeding and were asked for management plans and to rate the bleeding according to NCI CTC v.4 and RTOG late toxicity grading (scales provided). In 2 cases, participants were also asked whether they would send the patient for colonoscopy. A multilevel, random intercept modeling approach was used to assess sources of variation (case, respondent) in toxicity grading to calculate the intraclass correlation coefficient (ICC). Agreement on a dichotomous grading scale (low grades 1-2 vs high grades 3-4) was also assessed, using the κ statistic for multiple respondents.

RESULTS

Seventy-two radiation oncologists (28%) completed the survey. Forty-seven (65%) reported having either written or been principal investigator on a study using these scales. Agreement between respondents was moderate (ICC 0.52, 95% confidence interval [CI] 0.47-0.58) when using NCI CTC and fair using the RTOG scale (ICC 0.28, 95% CI 0.20-0.40). Respondents who chose an invasive management were more likely to select a higher toxicity grade (P<.0001). Using the dichotomous scale, we observed moderate agreement (κ = 0.42, 95% CI 0.40-0.44) with the NCI CTC scale, but only slight agreement with the RTOG scale (κ = 0.19, 95% CI 0.17-0.21).

CONCLUSION

Low interrater reliability was observed among radiation oncologists grading rectal bleeding using 2 common scales. Clearer definitions of late rectal bleeding toxicity should be constructed to reduce this variability and avoid ambiguity in both reporting and interpretation.

Role of vascular endothelial growth factor in clinically localized prostate cancer treated with radiation therapy

BACKGROUND

Anti-vascular endothelial growth factor (Anti-VEGF) agents are a promising approach to increase the efficacy of treatment for treatment-resistant prostate cancer.

AIMS

To correlate vascular endothelial growth factor (VEGF) expression and outcome following radiation therapy in the treatment of clinically localized prostate cancer.

STUDY DESIGN

Retrospective observational study.

METHODS

Forty-one patients and clinically localized disease that were treated with radiation therapy were analyzed. For VEGF expression, immunoreactivity scores (IRS) were calculated using percent scores and intensity scores. Twenty-four patients were classified as having low (0 to 4 IRS) and 17 patients were classified as having high (5 to 8 IRS) VEGF expression.

RESULTS

The median age was 71 years, median follow-up was 5.4 years and median radiation therapy dose was 70 Gy. VEGF expression was calculated as low in 24 patients and high in 17 patients. Higher VEGF expression was observed in 6/26 patients with a low Gleason score versus 11/15 patients with a high Gleason score (p=0.02). Biochemical failure (BF) was observed in 2/24 patients with low VEGF expression versus 7/17 patients with high VEGF expression (p=0.01). In univariate analysis, having a higher Gleason score (p<0.01), being in the high risk group (p=0.03) and having higher VEGF expression (p=0.01) predicted BF after definitive radiation therapy. The biochemical failure-free survival rate at 5 years tended to be different (91% vs. 53%) when patients were grouped according to VEGF expression (p=0.06).

CONCLUSION

In attempt to define patients with clinically localized disease that are not sensitive to standard treatment modalities, cellular and/or molecular biological markers may be required.

Interaction of radiation therapy with molecular targeted agents

The development of molecular targeted therapeutics in oncology builds on many years of scientific investigation into the cellular mechanics of malignant transformation and progression. The past two decades have brought an accelerating pace to the clinical investigation of new molecular targeted agents, particularly in the setting of metastatic disease. The integration of molecular targeted agents into phase III clinical trial design has lagged in the curative treatment setting, particularly in combination with established therapeutic modalities such as radiation. In this review, we discuss the interaction of radiation and molecular targeted therapeutics. The dynamics of cellular and tumor response to radiation offer unique opportunities for beneficial interplay with molecular targeted agents that may go unrecognized with conventional screening and monotherapy clinical testing of novel agents. By using epidermal growth factor receptor (EGFR) as a primary example, we discuss recent clinical studies that illustrate the potential synergy of molecular targeted agents with radiation and highlight the clinical value of such interactions. For various molecular targeted agents, their greatest clinical impact may rest in combination with radiation, and efforts to facilitate systematic investigation of this approach appear highly warranted.

Molecularly targeted agents as radiosensitizers in cancer therapy--focus on prostate cancer

As our understanding of the molecular pathways driving tumorigenesis improves and more druggable targets are identified, we have witnessed a concomitant increase in the development and production of novel molecularly targeted agents. Radiotherapy is commonly used in the treatment of various malignancies with a prominent role in the care of prostate cancer patients, and efforts to improve the therapeutic ratio of radiation by technologic and pharmacologic means have led to important advances in cancer care. One promising approach is to combine molecularly targeted systemic agents with radiotherapy to improve tumor response rates and likelihood of durable control. This review first explores the limitations of preclinical studies as well as barriers to successful implementation of clinical trials with radiosensitizers. Special considerations related to and recommendations for the design of preclinical studies and clinical trials involving molecularly targeted agents combined with radiotherapy are provided. We then apply these concepts by reviewing a representative set of targeted therapies that show promise as radiosensitizers in the treatment of prostate cancer.

Design and conduct of early-phase radiotherapy trials with targeted therapeutics: lessons from the PRAVO experience

New strategies to facilitate the improvement of physical and integrated biological optimization of high-precision treatment protocols are an important priority for modern radiation oncology. From a clinical perspective, as knowledge accumulates from molecular radiobiology, there is a complex and exciting opportunity to investigate novel approaches to rational patient treatment stratification based on actionable tumor targets, together with the appropriate design of next-generation early-phase radiotherapy trials utilizing targeted therapeutics, to formally evaluate relevant clinical and biomarker endpoints. A unique aspect in the development pathway of systemic agents with presumed radiosensitizing activity will also be the need for special attention on patient eligibility and the rigorous definition of radiation dose-volume relationships and potential dose-limiting toxicities. Based on recent experience from systematically investigating histone deacetylase inhibitors as radiosensitizing agents, from initial studies in preclinical tumor models through the conduct of a phase I clinical study to evaluate tumor activity of the targeted agent as well as patient safety and tumor response to the combined treatment modality, this communication will summarize principles relating to early clinical evaluation of combining radiotherapy and targeted therapeutics.

Sunitinib plus androgen deprivation and radiation therapy for patients with localized high-risk prostate cancer: results from a multi-institutional phase 1 study

PURPOSE

To evaluate the feasibility of administering sunitinib in combination with androgen deprivation therapy and external-beam intensity modulated radiation therapy (XRT) in patients with localized high-risk prostate cancer.

METHODS AND MATERIALS

Seventeen men with localized adenocarcinoma of the prostate with cT2c-cT4 or Gleason 8-10 or prostate-specific antigen >20 ng/mL received initial androgen deprivation (leuprolide 22.5 mg every 12 weeks plus oral bicalutamide 50 mg daily) for 4-8 weeks before oral sunitinib 12.5, 25, or 37.5 mg daily for 4 weeks as lead-in, then concurrently with and 4 weeks after XRT (75.6 Gy in 42 fractions to prostate and seminal vesicles). A 3+3 sequential dose-escalation design was used to assess the frequency of dose-limiting toxicity (DLT) and establish a maximal tolerated dose of sunitinib.

RESULTS

Sunitinib at 12.5- and 25-mg dose levels was well tolerated. The first 4 patients enrolled at 37.5 mg experienced a DLT during lead-in, and a drug interaction between sunitinib and bicalutamide was suspected. The protocol was revised and concurrent bicalutamide omitted. Of the next 3 patients enrolled at 37.5 mg, 2 of 3 receiving concurrent therapy experienced DLTs during radiation: grade 3 diarrhea and grade 3 proctitis, respectively. Only 1 of 7 patients completed sunitinib at 37.5 mg daily, whereas 3 of 3 patients (25 mg as starting dose) and 3 of 4 patients (25 mg as reduced dose) completed therapy.

CONCLUSIONS

The feasibility of combined vascular endothelial growth factor receptor (VEGFR)/platelet-derived growth factor receptor (PDGFR) inhibitor therapy, androgen deprivation, and radiation therapy for prostate cancer was established. Using a daily dosing regimen with lead-in, concurrent, and post-XRT therapy, the recommended phase 2 dose of sunitinib is 25 mg daily.

Radiosensitization in prostate cancer: mechanisms and targets

Prostate cancer is the second most commonly diagnosed cancer in American men over the age of 45 years and is the third most common cause of cancer related deaths in American men. In 2012 it is estimated that 241,740 men will be diagnosed with prostate cancer and 28,170 men will succumb to prostate cancer. Currently, radiation therapy is one of the most common definitive treatment options for localized prostate cancer. However, significant number of patients undergoing radiation therapy will develop locally persistent/recurrent tumours. The varying response rates to radiation may be due to 1) tumor microenvironment, 2) tumor stage/grade, 3) modality used to deliver radiation, and 4) dose of radiation. Higher doses of radiation has not always proved to be effective and have been associated with increased morbidity. Compounds designed to enhance the killing effects of radiation, radiosensitizers, have been extensively investigated over the past decade. The development of radiosensitizing agents could improve survival, improve quality of life and reduce costs, thus benefiting both patients and healthcare systems. Herin, we shall review the role and mechanisms of various agents that can sensitize tumours, specifically prostate cancer.

Orthotopic administration of (213)Bi-bevacizumab inhibits progression of PC3 xenografts in the prostate

AIM

To investigate orthotopic targeted α-radioimmunotherapy for the control of early-stage PC3 prostate cancer nude mouse xenografts using the radiolabeled bevacizumab (BZ) immunoconjugate ((213)Bi-BZ), which emits short-range α-radiation.

MATERIALS & METHODS

10(6) PC3 human prostate cancer cells were injected into the lower capsule of the mouse prostate gland 1 week prior to α-radioimmunotherapy. Mice were euthanized and assessed for tumour growth at 2 (two mice), 4 (two mice) and 6 weeks (three mice) post-therapy. The no-therapy control mice received a saline injection in equal volume to each BZ administration.

RESULTS

(213)Bi-BZ is significantly more efficacious in inhibiting xenograft progression in the prostate gland compared with BZ alone (p = 0.009) and when compared with the 'no therapy' protocol (p < 0.0001).

CONCLUSION

Orthotopic administration of (213)Bi-BZ greatly improves the early control of organ-confined prostate cancer compared with BZ alone (p < 0.01).