Long-Term Disease Control with Triapine-Based Radiochemotherapy for Patients with Stage IB2-IIIB Cervical Cancer

Adjuvant chemotherapy following chemoradiotherapy as primary treatment for locally advanced cervical cancer versus chemoradiotherapy alone (OUTBACK): an international, open-label, randomised, phase 3 trial

BACKGROUND

Standard treatment for locally advanced cervical cancer is chemoradiotherapy, but many patients relapse and die of metastatic disease. We aimed to determine the effects on survival of adjuvant chemotherapy after chemoradiotherapy.

METHODS

The OUTBACK trial was a multicentre, open-label, randomised, phase 3 trial done in 157 hospitals in Australia, China, Canada, New Zealand, Saudi Arabia, Singapore, and the USA. Eligible participants were aged 18 year or older with histologically confirmed squamous cell carcinoma, adenosquamous cell carcinoma, or adenocarcinoma of the cervix (FIGO 2008 stage IB1 disease with nodal involvement, or stage IB2, II, IIIB, or IVA disease), Eastern Cooperative Oncology Group performance status 0-2, and adequate bone marrow and organ function. Participants were randomly assigned centrally (1:1) using a minimisation approach and stratified by pelvic or common iliac nodal involvement, requirement for extended-field radiotherapy, FIGO 2008 stage, age, and site to receive standard cisplatin-based chemoradiotherapy (40 mg/m2 cisplatin intravenously once-a-week for 5 weeks, during radiotherapy with 45·0-50·4 Gy external beam radiotherapy delivered in fractions of 1·8 Gy to the whole pelvis plus brachytherapy; chemoradiotherapy only group) or standard cisplatin-based chemoradiotherapy followed by adjuvant chemotherapy with four cycles of carboplatin (area under the receiver operator curve 5) and paclitaxel (155 mg/m2) given intravenously on day 1 of a 21 day cycle (adjuvant chemotherapy group). The primary endpoint was overall survival at 5 years, analysed in the intention-to-treat population (ie, all eligible patients who were randomly assigned). Safety was assessed in all patients in the chemoradiotherapy only group who started chemoradiotherapy and all patients in the adjuvant chemotherapy group who received at least one dose of adjuvant chemotherapy. The OUTBACK trial is registered with ClinicalTrials.gov, NCT01414608, and the Australia New Zealand Clinical Trial Registry, ACTRN12610000732088.

FINDINGS

Between April 15, 2011, and June 26, 2017, 926 patients were enrolled and randomly assigned to the chemoradiotherapy only group (n=461) or the adjuvant chemotherapy group (n=465), of whom 919 were eligible (456 in the chemoradiotherapy only group and 463 in the adjuvant chemotherapy group; median age 46 years [IQR 37 to 55]; 663 [72%] were White, 121 [13%] were Black or African American, 53 [6%] were Asian, 24 [3%] were Aboriginal or Pacific islander, and 57 [6%] were other races) and included in the analysis. As of data cutoff (April 12, 2021), median follow-up was 60 months (IQR 45 to 65). 5-year overall survival was 72% (95% CI 67 to 76) in the adjuvant chemotherapy group (105 deaths) and 71% (66 to 75) in the chemoradiotherapy only group (116 deaths; difference 1% [95% CI -6 to 7]; hazard ratio 0·90 [95% CI 0·70 to 1·17]; p=0·81). In the safety population, the most common clinically significant grade 3-4 adverse events were decreased neutrophils (71 [20%] in the adjuvant chemotherapy group vs 34 [8%] in the chemoradiotherapy only group), and anaemia (66 [18%] vs 34 [8%]). Serious adverse events occurred in 107 (30%) in the adjuvant chemotherapy group versus 98 (22%) in the chemoradiotherapy only group, most commonly due to infectious complications. There were no treatment-related deaths.

INTERPRETATION

Adjuvant carboplatin and paclitaxel chemotherapy given after standard cisplatin-based chemoradiotherapy for unselected locally advanced cervical cancer increased short-term toxicity and did not improve overall survival; therefore, it should not be given in this setting.

FUNDING

National Health and Medical Research Council and National Cancer Institute.

Antiproliferative Activity and DNA Interaction Studies of a Series of N4,N4-Dimethylated Thiosemicarbazone Derivatives

The exploitation of bioactive natural sources to obtain new anticancer agents with novel modes of action may represent an innovative and successful strategy in the field of medicinal chemistry. Many natural products and their chemical analogues have been proposed as starting molecules to synthesise compounds with increased biological potential. In this work, the design, synthesis, and characterisation of a new series of N4,N4-dimethylated thiosemicarbazone Cu(II), Ni(II), and Pt(II) complexes are reported and investigated for their in vitro toxicological profile against a leukaemia cell line (U937). The antiproliferative activity was studied by MTS assay to determine the GI50 value for each compound after 24 h of treatment, while the genotoxic potential was investigated to determine if the complexes could cause DNA damage. In addition, the interaction between the synthesised molecules and DNA was explored by means of spectroscopic techniques, showing that for Pt and Ni derivatives a single mode of action can be postulated, while the Cu analogue behaves differently.

New Iron Metabolic Pathways and Chelation Targeting Strategies Affecting the Treatment of All Types and Stages of Cancer

There is new and increasing evidence from in vitro, in vivo and clinical studies implicating the pivotal role of iron and associated metabolic pathways in the initiation, progression and development of cancer and in cancer metastasis. New metabolic and toxicity mechanisms and pathways, as well as genomic, transcription and other factors, have been linked to cancer and many are related to iron. Accordingly, a number of new targets for iron chelators have been identified and characterized in new anticancer strategies, in addition to the classical restriction of/reduction in iron supply, the inhibition of transferrin iron delivery, the inhibition of ribonucleotide reductase in DNA synthesis and high antioxidant potential. The new targets include the removal of excess iron from iron-laden macrophages, which affects anticancer activity; the modulation of ferroptosis; ferritin iron removal and the control of hyperferritinemia; the inhibition of hypoxia related to the role of hypoxia-inducible factor (HIF); modulation of the function of new molecular species such as STEAP4 metalloreductase and the metastasis suppressor N-MYC downstream-regulated gene-1 (NDRG1); modulation of the metabolic pathways of oxidative stress damage affecting mitochondrial function, etc. Many of these new, but also previously known associated iron metabolic pathways appear to affect all stages of cancer, as well as metastasis and drug resistance. Iron-chelating drugs and especially deferiprone (L1), has been shown in many recent studies to fulfill the role of multi-target anticancer drug linked to the above and also other iron targets, and has been proposed for phase II trials in cancer patients. In contrast, lipophilic chelators and their iron complexes are proposed for the induction of ferroptosis in some refractory or recurring tumors in drug resistance and metastasis where effective treatments are absent. There is a need to readdress cancer therapy and include therapeutic strategies targeting multifactorial processes, including the application of multi-targeting drugs involving iron chelators and iron-chelator complexes. New therapeutic protocols including drug combinations with L1 and other chelating drugs could increase anticancer activity, decrease drug resistance and metastasis, improve treatments, reduce toxicity and increase overall survival in cancer patients.

Mechanistic Insights of Chelator Complexes with Essential Transition Metals: Antioxidant/Pro-Oxidant Activity and Applications in Medicine

The antioxidant/pro-oxidant activity of drugs and dietary molecules and their role in the maintenance of redox homeostasis, as well as the implications in health and different diseases, have not yet been fully evaluated. In particular, the redox activity and other interactions of drugs with essential redox metal ions, such as iron and copper, need further investigation. These metal ions are ubiquitous in human nutrition but also widely found in dietary supplements and appear to exert major effects on redox homeostasis in health, but also on many diseases of free radical pathology. In this context, the redox mechanistic insights of mainly three prototype groups of drugs, namely alpha-ketohydroxypyridines (alpha-hydroxypyridones), e.g., deferiprone, anthraquinones, e.g., doxorubicin and thiosemicarbazones, e.g., triapine and their metal complexes were examined; details of the mechanisms of their redox activity were reviewed, with emphasis on the biological implications and potential clinical applications, including anticancer activity. Furthermore, the redox properties of these three classes of chelators were compared to those of the iron chelating drugs and also to vitamin C, with an emphasis on their potential clinical interactions and future clinical application prospects in cancer, neurodegenerative and other diseases.

Iron overload during the treatment of acute leukemia: pretransplant transfusion experience

BACKGROUND

Recent studies have shown the increased risk of mortality in cases with acute leukemia and iron overload. We aimed to determine the status of iron overload in patients with acute leukemia.

MATERIALS & METHODS

Patients diagnosed with acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) between January 2015 and December 2019 were included in the study.

RESULTS

At 6 months, there were statistically more patients with serum ferritin >1000 in the AML group compared to the ALL group (p = 0,011).

CONCLUSION

Iron overload occurs earlier in patients with AML; the difference disappears after 6 months of treatment. It is the correct point to emphasize that iron overload is an important factor of pretransplant morbidity, especially in AML cases.

Targeting iron metabolism in cancer therapy

Iron is a critical component of many cellular functions including DNA replication and repair, and it is essential for cell vitality. As an essential element, iron is critical for maintaining human health. However, excess iron can be highly toxic, resulting in oxidative DNA damage. Many studies have observed significant associations between iron and cancer, and the association appears to be more than just coincidental. The chief characteristic of cancers, hyper-proliferation, makes them even more dependent on iron than normal cells. Cancer therapeutics are becoming as diverse as the disease itself. Targeting iron metabolism in cancer cells is an emerging, formidable field of therapeutics. It is a strategy that is highly diverse with regard to specific targets and the various ways to reach them. This review will discuss the importance of iron metabolism in cancer and highlight the ways in which it is being explored as the medicine of tomorrow.

In silico screening identifies a novel small molecule inhibitor that counteracts PARP inhibitor resistance in ovarian cancer

Poly ADP-ribose polymerase (PARP) inhibitors are promising targeted therapy for epithelial ovarian cancer (EOC) with BRCA mutations or defective homologous recombination (HR) repair. However, reversion of BRCA mutation and restoration of HR repair in EOC lead to PARP inhibitor resistance and reduced clinical efficacy of PARP inhibitors. We have previously shown that triapine, a small molecule inhibitor of ribonucleotide reductase (RNR), impaired HR repair and sensitized HR repair-proficient EOC to PARP inhibitors. In this study, we performed in silico screening of small molecule libraries to identify novel compounds that bind to the triapine-binding pocket on the R2 subunit of RNR and inhibit RNR in EOC cells. Following experimental validation of selected top-ranking in silico hits for inhibition of dNTP and DNA synthesis, we identified, DB4, a putative RNR pocket-binding inhibitor markedly abrogated HR repair and sensitized BRCA-wild-type EOC cells to the PARP inhibitor olaparib. Furthermore, we demonstrated that the combination of DB4 and olaparib deterred the progression of BRCA-wild type EOC xenografts and significantly prolonged the survival time of tumor-bearing mice. Herein we report the discovery of a putative small molecule inhibitor of RNR and HR repair for combination with PARP inhibitors to treat PARP inhibitor-resistant and HR repair-proficient EOC.

Expanding Our Impact in Cervical Cancer Treatment: Novel Immunotherapies, Radiation Innovations, and Consideration of Rare Histologies

Cervical cancer is a socially and scientifically distinguishable disease. Its pathogenesis, sexual transmission of high-risk HPV to a metaplastic portion of the uterine cervix, makes cervical cancer preventable by safe and effective HPV vaccines commercially available since 2006. Despite this, cervical cancer remains the deadliest gynecologic cancer in the world. Regrettably, global incidence and mortality rates disproportionately affect populations where women are marginalized, where HIV infection is endemic, and where access to preventive vaccination and screening for preinvasive disease are limited. In the United States, cervical cancer incidence has gradually declined over the last 25 years, but mortality rates remain both constant and disparately higher among communities of color because of the adverse roles that racism and poverty play in outcome. Until these conditions improve and widespread prevention is possible, treatment innovations are warranted. The last standard-of-care treatment changes occurred in 1999 for locally advanced disease and in 2014 for metastatic and recurrent disease. The viral and immunologic nature of HPV-induced cervical cancer creates opportunities for both radiation and immunotherapy to improve outcomes. With the advent of T cell-directed therapy, immune checkpoint inhibition, and techniques to increase the therapeutic window of radiation treatment, an overdue wave of innovation is currently emerging in cervical cancer treatment. The purpose of this review is to describe the contemporary developmental therapeutic landscape for cervical cancer that applies to most tumors and to discuss notable rare histologic subtypes that will not be adequately addressed with these treatment innovations.

Reversing oncogenic transformation with iron chelation

Cancer cells accumulate iron to supplement their aberrant growth and metabolism. Depleting cells of iron by iron chelators has been shown to be selectively cytotoxic to cancer cells in vitro and in vivo. Iron chelators are effective at combating a range of cancers including those which are difficult to treat such as androgen insensitive prostate cancer and cancer stem cells. This review will evaluate the impact of iron chelation on cancer cell survival and the underlying mechanisms of action. A plethora of studies have shown iron chelators can reverse some of the major hallmarks and enabling characteristics of cancer. Iron chelators inhibit signalling pathways that drive proliferation, migration and metastasis as well as return tumour suppressive signalling. In addition to this, iron chelators stimulate apoptotic and ER stress signalling pathways inducing cell death even in cells lacking a functional p53 gene. Iron chelators can sensitise cancer cells to PARP inhibitors through mimicking BRCAness; a feature of cancers trademark genomic instability. Iron chelators target cancer cell metabolism, attenuating oxidative phosphorylation and glycolysis. Moreover, iron chelators may reverse the major characteristics of oncogenic transformation. Iron chelation therefore represent a promising selective mode of cancer therapy.

Palladium(ii) complexes with thiosemicarbazones derived from pyrene as topoisomerase IB inhibitors

New palladium complexes with thiosemicarbazonate ligands derived from pyrene exhibit potent antiproliferative activity against A2780 and cisplatin-resistant A2780Cis human ovarian cancer cells, which is dependent on substituent groups of the thiosemicarbazone ligands. Cellular accumulation and distribution studies confirmed that palladium enters the cell nucleus. DNA and topoisomerase IB studies show that one complex is a potent TopIB inhibitor, with selectivity for cancer versus normal cells.

Combining novel agents with radiotherapy for gynecologic malignancies: beyond the era of cisplatin

Therapeutic strategies combining radiation therapy with novel agents have become an area of intense research focus in oncology and are actively being investigated for a wide range of solid tumors. The mechanism of action of these systemic agents can be stratified into three general categories: (1) enhancement or alteration of the immune system; (2) disruption of DNA damage response mechanisms; and (3) impediment of cellular signaling pathways involving growth, angiogenesis, and hypoxia. Pre-clinical data suggest that radiation therapy has immunogenic qualities and may optimize response to immuno-oncology therapies by priming the immune system, whereas other novel systemic agents can enhance radiosensitivity through augmentation of genomic instability and alteration of central signaling pathways related to growth and survival. Gynecologic cancers in particular have the potential for synergistic response to combination approaches incorporating radiation therapy and novel systemic therapies. Several clinical trials have been proposed to elucidate the efficacy and safety of such approaches. Here we discuss the mechanisms of novel therapies and the rationale for these combination strategies, reviewing the relevant pre-clinical and clinical data. We explore their optimal use with respect to indications, interactions, and potential synergy in combination with radiation therapy and review ongoing trials and active areas of investigation.

Novel tetranuclear PdII and PtII anticancer complexes derived from pyrene thiosemicarbazones

Cyclometallated palladium(ii) and platinum(ii) pyrenyl-derived thiosemicarbazone (H₂PrR) complexes of the type [M₄(μ-S-PrR-κ³-C,N,S)₄] (M = Pd^II, Pt^II; R = ethyl, cyclohexyl) have been synthesised in good yields and fully characterised.

Combination of triapine, olaparib, and cediranib suppresses progression of BRCA-wild type and PARP inhibitor-resistant epithelial ovarian cancer

PARP inhibitors target BRCA mutations and defective homologous recombination repair (HRR) for the treatment of epithelial ovarian cancer (EOC). However, the treatment of HRR-proficient EOC with PARP inhibitors remains challenging. The objective of this study was to determine whether the combination of triapine (ribonucleotide reductase inhibitor), cediranib (vascular endothelial growth factor receptor tyrosine kinase inhibitor), and the PARP inhibitor olaparib synergized against BRCA wild-type and HRR-proficient EOC in xenograft mouse models. In addition, the mechanisms by which cediranib augmented the efficacy of triapine and olaparib were investigated. BRCA-wild type and PARP inhibitor-resistant EOC cell lines were implanted subcutaneously (s.c.) into nude mice or injected intraperitoneally (i.p.) into SCID-Beige mice. Mice were then treated i.p. with olaparib, cediranib, triapine, various double and triple combinations. The volume of s.c tumor in nude mice and the abdominal circumference of SCID-Beige mice were measured to evaluate the effectiveness of the treatment to delay tumor growth and prolong the survival time of mice. In both xenograft mouse models, the combination of triapine, olaparib and cediranib resulted in marked suppression of BRCA-wild type EOC growth and significant prolongation of the survival time of mice, with efficacy greater than any double combinations and single drugs. Furthermore, we identified that cediranib abrogated pro-survival and anti-apoptotic AKT signaling, thereby enhancing the efficacy of triapine and olaparib against BRCA-wild type EOC cells. Taken together, our results demonstrate a proof-of-principle approach and the combination regiment holds promise in treating BRCA-wild type and PARP inhibitor-resistant EOC.

p53 tumor suppressor and iron homeostasis

Iron is an essential nutrient for all living organisms and plays a vital role in many fundamental biochemical processes, such as oxygen transport, energy metabolism, and DNA synthesis. Due to its capability to produce free radicals, iron has deleterious effects and thus, its level needs to be tightly controlled in the body. Deregulation of iron metabolism is known to cause diseases, including anemia by iron deficiency and hereditary hemochromatosis by iron overload. Interestingly, dysregulated iron metabolism occurs frequently in tumor cells and contributes to tumorigenesis. In this review, we will discuss the role of p53 tumor suppressor in iron homeostasis.

Targeting Cyclin-Dependent Kinases for Treatment of Gynecologic Cancers

Ovarian, uterine/endometrial, and cervical cancers are major gynecologic malignancies estimated to cause nearly 30,000 deaths in 2018 in US. Defective cell cycle regulation is the hallmark of cancers underpinning the development and progression of the disease. Normal cell cycle is driven by the coordinated and sequential rise and fall of cyclin-dependent kinases (CDK) activity. The transition of cell cycle phases is governed by the respective checkpoints that prevent the entry into the next phase until cellular or genetic defects are repaired. Checkpoint activation is achieved by p53- and ATM/ATR-mediated inactivation of CDKs in response to DNA damage. Therefore, an aberrant increase in CDK activity and/or defects in checkpoint activation lead to unrestricted cell cycle phase transition and uncontrolled proliferation that give rise to cancers and perpetuate malignant progression. Given that CDK activity is also required for homologous recombination (HR) repair, pharmacological inhibition of CDKs can be exploited as a synthetic lethal approach to augment the therapeutic efficacy of PARP inhibitors and other DNA damaging modalities for the treatment of gynecologic cancers. Here, we overview the basic of cell cycle and discuss the mechanistic studies that establish the intimate link between CDKs and HR repair. In addition, we present the perspective of preclinical and clinical development in small molecule inhibitors of CDKs and CDK-associated protein targets, as well as their potential use in combination with hormonal therapy, PARP inhibitors, chemotherapy, and radiation to improve treatment outcomes.

Phase I Trial of Triapine-Cisplatin-Paclitaxel Chemotherapy for Advanced Stage or Metastatic Solid Tumor Cancers

Ribonucleotide reductase (RNR) is an enzyme involved in the de novo synthesis of deoxyribonucleotides, which are critical for DNA replication and DNA repair. Triapine is a small-molecule RNR inhibitor. A phase I trial studied the safety of triapine in combination with cisplatin–paclitaxel in patients with advanced stage or metastatic solid tumor cancers in an effort to capitalize on disrupted DNA damage repair. A total of 13 patients with various previously treated cancers were given a 96-h continuous intravenous (i.v.) infusion of triapine (40–120 mg/m²) on day 1, and then 3-h i.v. paclitaxel (80 mg/m²) followed by 1-h i.v. cisplatin (50–75 mg/m²) on day 3. This combination regimen was repeated every 21 days. The maximum tolerated dose (MTD) for each agent was identified to be triapine (80 mg/m²), cisplatin (50 mg/m²), and paclitaxel (80 mg/m²). Common grade 3 or 4 toxicities included reversible anemia, leukopenia, thrombocytopenia, or electrolyte abnormalities. The combination regimen of triapine–cisplatin–paclitaxel resulted in no objective responses; however, five (83%) of six patients treated at the MTD had stable disease between 1 and 8 months duration. This phase I study showed that the combination regimen of triapine–cisplatin–paclitaxel was safe and provides a rational basis for a follow-up phase II trial to evaluate efficacy and progression-free survival in women with metastatic or recurrent uterine cervix cancer.

Modulating the DNA Damage Response to Improve Treatment Response in Cervical Cancer

Cervical cancer is the fourth most common cause of cancer-related death in women worldwide and new therapeutic approaches are needed to improve clinical outcomes for this group of patients. Current treatment protocols for locally advanced and metastatic disease consist of ionising radiation and chemotherapy. Chemoradiation induces cytotoxic levels of DNA double-strand breaks, which activates programmed cell death via the DNA damage response (DDR). Cervical cancers are unique given an almost exclusive association with human papillomavirus (HPV) infection; a potent manipulator of the DDR, with the potential to alter tumour sensitivity to DNA-damaging agents and influence treatment response. This review highlights the wide range of therapeutic strategies in development that have the potential to modulate DDR and sensitise cervical tumours to DNA-damaging agents in the context of HPV oncogenesis.

Phase I trial of daily triapine in combination with cisplatin chemotherapy for advanced-stage malignancies

PURPOSE

Advanced-stage malignancies have increased deoxyribonucleotide demands in DNA replication and repair, making deoxyribonucleotide supply a potential exploitable target for therapy based on ribonucleotide reductase (RNR) inhibition.

METHODS

A dose-finding phase I trial was conducted of intravenous (i.v.) triapine, a small-molecule RNR inhibitor, and cisplatin chemotherapy in patients with advanced-stage solid tumor malignancies. Patients received dose-finding levels of i.v. triapine (48-96 mg/m²) and i.v. cisplatin (20-75 mg/m²) on 1 of 3 different schedules. The primary endpoint was to identify the maximum tolerated dose of a triapine-cisplatin combination. Secondary endpoints included the rate of triapine-cisplatin objective response and the pharmacokinetics and bioavailability of a single oral triapine dose. (Clinicaltrials.gov number, NCT00024323).

RESULTS

The MTD was 96 mg/m² triapine daily days 1-4 and 75 mg/m² cisplatin split over day 2 and day 3. Frequent grade 3 or 4 adverse events included fatigue, dyspnea, leukopenia, thrombocytopenia, and electrolyte abnormalities. No objective responses were observed; 5 (50%) of 10 patients treated at the MTD had stable disease. Pharmacokinetics indicated an oral triapine bioavailability of 88%.

CONCLUSIONS

The triapine-cisplatin combination may be given safely in patients with advanced-stage solid tumor malignancies. On the basis of these results, a phase I trial adequately powered to evaluate oral triapine bioavailability in women with advanced-stage uterine cervix or vulvar cancers is underway.

The effect of human papillomavirus on DNA repair in head and neck squamous cell carcinoma

Much of the current literature regarding the molecular pathophysiology of human papillomavirus (HPV) in head and neck squamous cell carcinoma (HNSCC) has focused on the virus's effect on cell cycle modulation and cell proliferation. A second mechanism of pathogenicity employed by HPV, dysregulation of cellular DNA repair processes, has been more sparsely studied. The purpose of this review is to describe current understanding about the effect of HPV on DNA repair in HNSCC, taking cues from cervical cancer literature. HPV affects DNA-damage response pathways by interacting with many proteins, including ATM, ATR, MRN, γ-H2AX, Chk1, Chk2, p53, BRCA1, BRCA2, RAD51, Rb-related proteins 107 and 130, Tip60, and p16INK4A. Further elucidation of these pathways could lead to development of targeted therapies and improvement of current treatment protocols.

Radiation-Therapeutic Agent Clinical Trials: Leveraging Advantages of a National Cancer Institute Programmatic Collaboration

A number of oncology phase II radiochemotherapy trials with promising results have been conducted late in the overall experimental therapeutic agent development process. Accelerated development and approval of experimental therapeutic agents have stimulated further interest in much earlier radiation-agent studies to increase the likelihood of success in phase III trials. To sustain this interest, more forward-thinking preclinical radiobiology experimental designs are needed to improve discovery of promising radiochemotherapy plus agent combinations for clinical trial testing. These experimental designs should better inform next-step radiation-agent clinical trial dose, schedule, exposure, and therapeutic effect. Recognizing the need for a better strategy to develop preclinical data supporting radiation-agent phase I or II trials, the National Cancer Institute (NCI)-Cancer Therapy Evaluation Program (CTEP) and the NCI-Molecular Radiation Therapeutics Branch of the Radiation Research Program have partnered to promote earlier radiobiology studies of CTEP portfolio agents. In this Seminars in Radiation Oncology article, four key components of this effort are discussed. First, we outline steps for accessing CTEP agents for preclinical testing. Second, we propose radiobiology studies that facilitate transition from preclinical testing to early phase trial activation. Third, we navigate steps that walk through CTEP agent strategic development paths available for radiation-agent testing. Fourth, we highlight a new NCI-sponsored cooperative agreement grant supporting in vitro and in vivo radiation-CTEP agent testing that informs early phase trial designs. Throughout the article, we include contemporary examples of successful radiation-agent development initiatives.

Triapine potentiates platinum-based combination therapy by disruption of homologous recombination repair

Background:

Platinum resistance may be attributable to inherent or acquired proficiency in homologous recombination repair (HRR) in epithelial ovarian cancer (EOC). The objective of this study was to evaluate the efficacy of the small molecule inhibitor triapine to disrupt HRR and sensitise BRCA wild-type EOC cells to platinum-based combination therapy in vitro and in vivo.

Methods:

The sensitivity of BRCA wild-type cancer cells to olaparib, cisplatin, carboplatin, doxorubicin, or etoposide in combination with triapine was evaluated by clonogenic survival assays. The effects of triapine on HRR activity in cells were measured with a DR-GFP reporter assay. The ability of triapine to enhance the effects of the carboplatin-doxil combination on EOC tumour growth delay was determined using a xenograft tumour mouse model.

Results:

Platinum resistance is associated with wild-type BRCA status. Triapine inhibits HRR activity and enhances the sensitivity of BRCA wild-type cancer cells to cisplatin, olaparib, and doxorubicin. However, sequential combination of triapine and cisplatin is necessary to achieve synergism. Moreover, triapine potentiates platinum-based combination therapy against BRCA wild-type EOC cells and produces significant delay of EOC tumour growth.

Conclusions:

Triapine promises to augment the clinical efficacy of platinum-based combination regimens for treatment of platinum-resistant EOC with wild-type BRCA and proficient HRR activity.

Emerging drugs for the treatment of cervical cancer

INTRODUCTION

Worldwide, most cervical cancer (CC) patients require the use of drug therapy either adjuvant, concurrent with radiation or palliative.

AREAS COVERED

This review briefly discusses the current achievements in treating CC with an emphasis in emerging agents.

EXPERT OPINION

Concurrent cisplatin with radiation and lately, gemcitabine-cisplatin chemoradiation has resulted in small but significant improvements in the treatment of locally advanced and high-risk early-stage patients. So far, only antiangiogenic therapy with bevacizumab added to cisplatin chemoradiation has demonstrated safety and encouraging results in a Phase II study. In advanced disease, cisplatin doublets yield median survival rates not exceeding 14 months. The first Phase III study of bevacizumab, added to standard chemotherapy cisplatin- or non-cisplatin-containing doublet, has shown significant increase in both overall survival and progression-free survival. Further studies are needed before bevacizumab plus chemotherapy can be considered the standard of care for advanced disease. The characterization of the mutational landscape of CC and developments of novel targeted therapies may result in more effective and individualized treatments for CC. The potential efficacy of knocking down the key alterations in CC, E6 and E7 human papilloma virus oncoproteins must not be overlooked.