Phase III randomized trial of weekly cisplatin and irradiation versus cisplatin and tirapazamine and irradiation in stages IB2, IIA, IIB, IIIB, and IVA cervical carcinoma limited to the pelvis: a Gynecologic Oncology Group study

The cellular-centered view of hypoxia tumor microenvironment: Molecular mechanisms and therapeutic interventions

Cancer is a profoundly dynamic, heterogeneous and aggressive systemic ailment, with a coordinated evolution of various types of tumor niches. Hypoxia plays an indispensable role in the tumor micro-ecosystem, drastically enhancing the plasticity of cancer cells, fibroblasts and immune cells and orchestrating intercellular communication. Hypoxia-induced signals, particularly hypoxia-inducible factor-1α (HIF-1α), drive the reprogramming of genetic, transcriptional, and proteomic profiles. This leads to a spectrum of interconnected processes, including augmented survival of cancer cells, evasion of immune surveillance, metabolic reprogramming, remodeling of the extracellular matrix, and the development of resistance to conventional therapeutic modalities like radiotherapy and chemotherapy. Here, we summarize the latest research on the multifaceted effects of hypoxia, where a multitude of cellular and non-cellular elements crosstalk with each other and co-evolve in a synergistic manner. Additionally, we investigate therapeutic approaches targeting hypoxic niche, encompassing hypoxia-activated prodrugs, HIF inhibitors, nanomedicines, and combination therapies. Finally, we discuss some of the issues to be addressed and highlight the potential of emerging technologies in the treatment of cancer.

A systematic review of stage IVA cervical cancer treatment: Challenges in the management of an understudied group

OBJECTIVE

Stage IVA patients comprise a small proportion of participants in cervical cancer trials, yet survival outcomes are disproportionately poor. We aim to perform a systematic review evaluating stage IVA cervical cancer.

METHODS

This systematic review was completed via PRISMA 2020 guidelines using two databases. Inclusion criteria comprised Phase III trials (2004-2024) assessing stage IVA cervical cancer including patients by stage. Searches had MeSH terms: ((cervical cancer) AND (stage IVA) AND (locally advanced)). 761 were articles identified, including books, trials, reviews, and meta-analyses. Of the articles identified, 12 met inclusion criteria.

RESULTS

A total of 133 (3.8% of study populations) stage IVA and 818 (40% of study populations) stage III-IVA cervical cancer patients were analyzed. Two studies (stage IVA n = 15; 3.1%) established cisplatin as chemoradiotherapy agent of choice, while one study (stage IVA n = 2; 1%) showed no benefit with cisplatin versus radiotherapy alone. Four studies (stage IVA n = 32; 3.6%; stages IIIB-IVA n = 220; 24%) found no benefit with adjuvant chemotherapy, with one analyzing stage IIIB-IVA patients (progression-free survival (PFS) hazard ratio (HR) = 0.84; 95% confidence interval (CI): 0.57-1.23). Three studies (stage IVA n = 71; 5%) found no benefit adding immunomodulator (stage IVA overall survival HR = 3.48; 95% CI: 0.52-23.29), hypoxic cell sensitizer, or immunotherapy (stage III-IVA PFS HR = 0.71; 95% CI: 0.49-1.03) to chemoradiotherapy. One study (stages III-IVA n = 598; 56%) found benefit adding immunotherapy to chemoradiotherapy (stage III-IVA PFS HR = 0.58; 95% CI: 0.42-0.8). One study (stage IVA n = 13; 3.5%) showed benefit with induction chemotherapy.

CONCLUSION

Trials have not included substantial IVA patients to draw reasonable conclusions. Despite mixed results for immunotherapy, adjuvant chemotherapy, and induction chemotherapy, the exact benefit for stage IVA patients remains unknown. Future clinical trials should include a greater number of stage IVA cervical cancer patients and analyze them individually.

Reactive Oxygen Species Modulation in the Current Landscape of Anticancer Therapies

Significance: Reactive oxygen species (ROS) are generated during mitochondrial oxidative metabolism, and are tightly controlled through homeostatic mechanisms to maintain intracellular redox, regulating growth and proliferation in healthy cells. However, ROS production is perturbed in cancers where abnormal accumulation of ROS leads to oxidative stress and genomic instability, triggering oncogenic signaling pathways on one hand, while increasing oxidative damage and triggering ROS-dependent death signaling on the other. Recent Advances: Our review illuminates how critical interactions between ROS and oncogenic signaling, the tumor microenvironment, and DNA damage response (DDR) pathways have led to interest in ROS modulation as a means of enhancing existing anticancer strategies and developing new therapeutic opportunities. Critical Issues: ROS equilibrium exists via a delicate balance of pro-oxidant and antioxidant species within cells. "Antioxidant" approaches have been explored mainly in the form of chemoprevention, but there is insufficient evidence to advocate its routine application. More progress has been made via the "pro-oxidant" approach of targeting cancer vulnerabilities and inducing oxidative stress. Various therapeutic modalities have employed this approach, including direct ROS-inducing agents, chemotherapy, targeted therapies, DDR therapies, radiotherapy, and immunotherapy. Finally, emerging delivery systems such as "nanosensitizers" as radiotherapy enhancers are currently in development. Future Directions: While approaches designed to induce ROS have shown considerable promise in selectively targeting cancer cells and dealing with resistance to conventional therapies, most are still in early phases of development and challenges remain. Further research should endeavor to refine treatment strategies, optimize drug combinations, and identify predictive biomarkers of ROS-based cancer therapies.

Sustained release hypoxia-activated prodrug-loaded BSA nanoparticles enhance transarterial chemoembolization against hepatocellular carcinoma

Transarterial chemoembolization (TACE) is the standard of care for patients with advanced hepatocellular carcinoma (HCC), but facing the problem of low therapeutic effect. Conventional TACE formulations contain Lipiodol (LP) and chemotherapeutic agents characterized by burst release due to the unstable emulsion. Herein, we developed a novel TACE system by inducing bovine serum albumin (BSA) loaded hypoxia-activated prodrug (tirapazamine, TPZ) nanoparticle (BSATPZ) for sustained drug release. In the rabbit VX2 liver cancer model, TACE treatment induced a long-term hypoxic tumor microenvironment as demonstrated by increased expression of HIF-1α in the tumor. BSATPZ nanoparticles combined with LP greatly enhanced the anti-tumor effects of the TACE treatment. Compared to conventional TACE treatment, BSATPZ nanoparticle-based TACE therapy more significantly delayed tumor progression and inhibited the metastases in the lungs. The effects could be partially mediated by the rebuilt immune responses, as BSATPZ nanoparticle can served as an immunogenic cell death (ICD) inducer. Collectively, our results suggest that BSATPZ nanoparticle-based TACE therapy could be a promising strategy to improve clinical outcomes for patients with HCC and provide a preclinical rationale for evaluating TPZ therapy in clinical studies.

New Paradigms in the Treatment of Cervical Cancer

Despite effective screening strategies and the development and implementation of prophylactic high-risk human papillomavirus vaccination, cervical cancer remains a significant public health burden. This burden is most pronounced in under-resourced countries without fully developed screening and vaccination programs, although the disease remains present worldwide, including in industrialized countries. To that end, the World Health Organization (WHO) has an active focus on the elimination of cervical cancer, with objective metrics to be achieved by countries by the year 2030. Although increased vaccination and screening will be needed to approach potential eradication of cervical cancer, as recognized by the WHO initiative, treatment will need to continue to not only be effective in the near term, but to improve outcomes as well. Accordingly, assessments to improve primary treatment options, including surgery for women with early-stage disease, modification of chemoradiation for those with locally advanced cervical cancer, and systemic therapy for those with recurrent or metastatic presentations, are ongoing. Accordingly, we highlight important areas of both recent and ongoing focus as they relate to improving cervical cancer outcomes.

Role of the tumor microenvironment in the lymphatic metastasis of cervical cancer (Review)

Lymphatic metastasis is the primary type of cervical cancer metastasis and is associated with an extremely poor prognosis in patients. The tumor microenvironment primarily includes cancer-associated fibroblasts, tumor-associated macrophages, myeloid-derived suppressor cells, immune and inflammatory cells, and blood and lymphatic vascular networks, which can promote the establishment of lymphatic metastatic sites within immunosuppressive microenvironments or promote lymphatic metastasis by stimulating lymphangiogenesis and epithelial-mesenchymal transformation. As the most important feature of the tumor microenvironment, hypoxia plays an essential role in lymph node metastasis. In this review, the known mechanisms of hypoxia, and the involvement of stromal components and immune inflammatory cells in the tumor microenvironment of lymphatic metastasis of cervical cancer are discussed. Additionally, a summary of the clinical trials targeting the tumor microenvironment for the treatment of cervical cancer is provided, emphasizing the potential and challenges of immunotherapy.

Hypoxia-Targeted Dose Painting in Radiotherapy

Hypoxia (oxygen deprivation) occurs in most solid malignancies, albeit with considerable heterogeneity. Hypoxia is associated with an aggressive cancer phenotype by promotion of genomic instability, evasion of anti-cancer therapies including radiotherapy and enhancement of metastatic risk. Therefore, hypoxia results in poor cancer outcomes. Targeting hypoxia to improve cancer outcomes is an attractive therapeutic strategy. Hypoxia-targeted dose painting escalates radiotherapy dose to hypoxic sub-volumes, as quantified and spatially mapped using hypoxia imaging. This therapeutic approach could overcome hypoxia-induced radioresistance and improve patient outcomes without the need for hypoxia-targeted drugs. This article will review the premise and underpinning evidence for personalized hypoxia-targeted dose painting. It will present data on relevant hypoxia imaging biomarkers, highlight the challenges and potential benefit of this approach and provide recommendations for future research priorities in this field. Personalized hypoxia-based radiotherapy de-escalation strategies will also be addressed.

Technical development and validation of a clinically applicable microenvironment classifier as a biomarker of tumour hypoxia for soft tissue sarcoma

BACKGROUND

Soft tissue sarcomas (STS) are rare, heterogeneous tumours and biomarkers are needed to inform management. We previously derived a prognostic tumour microenvironment classifier (24-gene hypoxia signature). Here, we developed/validated an assay for clinical application.

METHODS

Technical performance of targeted assays (Taqman low-density array, nanoString) was compared in 28 prospectively collected formalin-fixed, paraffin-embedded (FFPE) biopsies. The nanoString assay was biologically validated by comparing to HIF-1α/CAIX immunohistochemistry (IHC) in clinical samples. The Manchester (n = 165) and VORTEX Phase III trial (n = 203) cohorts were used for clinical validation. The primary outcome was overall survival (OS).

RESULTS

Both assays demonstrated excellent reproducibility. The nanoString assay detected upregulation of the 24-gene signature under hypoxia in vitro, and 16/24 hypoxia genes were upregulated in tumours with high CAIX expression in vivo. Patients with hypoxia-high tumours had worse OS in the Manchester (HR 3.05, 95% CI 1.54-5.19, P = 0.0005) and VORTEX (HR 2.13, 95% CI 1.19-3.77, P = 0.009) cohorts. In the combined cohort, it was independently prognostic for OS (HR 2.24, 95% CI 1.42-3.53, P = 0.00096) and associated with worse local recurrence-free survival (HR 2.17, 95% CI 1.01-4.68, P = 0.04).

CONCLUSIONS

This study comprehensively validates a microenvironment classifier befitting FFPE STS biopsies. Future uses include: (1) selecting high-risk patients for perioperative chemotherapy; and (2) biomarker-driven trials of hypoxia-targeted therapies.

Targeting Hypoxia-Inducible Factor-1α for the Management of Hepatocellular Carcinoma

Hypoxia-inducible factor 1 alpha (HIF-1α) is a transcription factor that regulates the cellular response to hypoxia and is upregulated in all types of solid tumor, leading to tumor angiogenesis, growth, and resistance to therapy. Hepatocellular carcinoma (HCC) is a highly vascular tumor, as well as a hypoxic tumor, due to the liver being a relatively hypoxic environment compared to other organs. Trans-arterial chemoembolization (TACE) and trans-arterial embolization (TAE) are locoregional therapies that are part of the treatment guidelines for HCC but can also exacerbate hypoxia in tumors, as seen with HIF-1α upregulation post-hepatic embolization. Hypoxia-activated prodrugs (HAPs) are a novel class of anticancer agent that are selectively activated under hypoxic conditions, potentially allowing for the targeted treatment of hypoxic HCC. Early studies targeting hypoxia show promising results; however, further research is needed to understand the effects of HAPs in combination with embolization in the treatment of HCC. This review aims to summarize current knowledge on the role of hypoxia and HIF-1α in HCC, as well as the potential of HAPs and liver-directed embolization.

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.

Cell proliferation, drug distribution and therapeutic effects in relation to the vascular system of solid tumours

In this perspective, the authors summarise some properties of the solid tumour micro-environment that have been explored during the last 55 years. It is well established that the concentrations of nutrients, including oxygen, decrease with increasing distance from tumour blood vessels, and that low extracellular pH is found in nutrient-poor regions. Cell proliferation is dependent on nutrient metabolites and decreases in regions distal from patent blood vessels. Proliferating cells cause migration of neighbouring cells further from blood vessels where they may die, and their breakdown products pass into regions of necrosis. Anticancer drugs reach solid tumours via the vascular system and establish concentration gradients such that drug concentration within tumours may be quite variable. Treatment with chemotherapy such as doxorubicin or docetaxel can kill well-nourished proliferating cells close to blood vessels, thereby interrupting migration toward necrotic regions and lead to re-oxygenation and renewed proliferation of distal cells, as can occur with radiotherapy. This effect leads to the paradox that cancer treatment can rescue cells that were destined to die in the untreated tumour. Renewed and sometimes accelerated repopulation of surviving tumour cells can counter the effects of cell killing from repeated treatments, leading to tumour shrinkage and regrowth without changes in the intrinsic sensitivity of cells to the administered treatment. Strategies to prevent these effects include the combined use of chemotherapy with agents that selectively kill hypoxic tumour cells, including inhibitors of autophagy, since this is a process that may allow recycling of cellular macromolecules from dying cells and improve their survival.

Concurrent definitive chemoradiation incorporating intensity-modulated radiotherapy followed by adjuvant chemotherapy in high risk locally advanced cervical squamous cancer: a phase II study

BACKGROUND

Although the prognosis of locally advanced cervical cancer has improved dramatically, survival for those with stage IIIB-IVA disease or lymph nodes metastasis remains poor. It is believed that the incorporation of intensity-modulated radiotherapy into the treatment of cervical cancer might yield an improved loco-regional control, whereas more cycles of more potent chemotherapy after the completion of concurrent chemotherapy was associated with a diminished distant metastasis. We therefore initiated a non-randomized prospective phaseII study to evaluate the feasibility of incorporating both these two treatment modality into the treatment of high risk locally advanced cervical cancer.

OBJECTIVES

To determine whether the incorporation of intensity-modulated radiotherapy and the addition of adjuvant paclitaxel plus cisplatin regimen into the treatment policy for patients with high risk locally advanced cervical cancer might improve their oncologic outcomes.

STUDY DESIGN

Patients were enrolled if they had biopsy proven stage IIIA-IVA squamous cervical cancer or stage IIB disease with metastatic regional nodes. Intensity-modulated radiotherapy was delivered with dynamic multi-leaf collimators using 6MV photon beams. Prescription for PTV ranged from 45.0 ~ 50.0 Gy at 1.8 Gy ~ 2.0 Gy/fraction in 25 fractions. Enlarged nodes were contoured separately and PTV-nodes were boosted simultaneously to a total dose of 50.0-65 Gy at 2.0- 2.6 Gy/fraction in 25 fractions. A total dose of 28 ~ 35 Gy high-dose- rate brachytherapy was prescribed to point A in 4 ~ 5 weekly fractions using an iridium- 192 source. Concurrent weekly intravenous cisplatin at 30 mg/m² was initiated on the first day of radiotherapy for over 1-h during external-beam radiotherapy. Adjuvant chemotherapy was scheduled within 4 weeks after the completion of concurrent chemo-radiotherapy and repeated 3 weeks later. Paclitaxel 150 mg/m² was given as a 3-h infusion on day1, followed by cisplatin 35 mg/m² with 1-h infusion on day1-2 (70 mg/m² in total).

RESULTS

Fifty patients achieved complete response 4 weeks after the completion of the treatment protocol, whereas 2 patients had persistent disease. After a median follow-up period of 66 months, loco-regional (including 2 persistent disease), distant, and synchronous treatment failure occurred in 4,5, and 1, respectively. The 5-year disease-free survival, loco-regional recurrence-free survival, distant-metastasis recurrence-free survival was 80.5%, 90.3%, and 88.0%, respectively. Four of the patients died of the disease, and the 5-year overall survival was 92.1%. Most of the toxicities reported during concurrent chemo-radiotherapy were mild and transient. The occurrence of hematological toxicities elevated mildly during adjuvant chemotherapy, as 32% (16/50) and 4% (2/50) patients experienced grade 3-4 leukopenia and thrombocytopenia, respectively. Grade 3-4 late toxicities were reported in 3 patients.

CONCLUSIONS

The incorporation of intensity-modulated radiotherapy and adjuvant paclitaxel plus cisplatin chemotherapy were highly effective and well-tolerated in the treatment of high-risk locally advanced cervical cancer. The former yields an improved loco-regional control, whereas distant metastases could be effectively eradicated with mild toxicities when adjuvant regimen was prescribed.

Bacterial Peptides and Bacteriocins as a Promising Therapy for Solid Tumor

The conventional treatment is faced with limitations in treating solid tumors due to their specific pathophysiology. Several novel therapeutics have been introduced in recent decades to treat solid tumors. Among these new methods, tumor therapy using bacterial products like bacteriocins and peptides has been of great interest due to their unique characteristics and advantages of them in comparison to the conventional treatment, including that they can precisely target tumor cells, selective toxicity for tumor cells, low side effect on normal cells, toxicity activity for MDR cancer cells, used as the target delivery vehicles and enhancing drug delivery. Moreover, their small size and low molecular weight have made them easy to synthesize and modify. Furthermore, in recent years, genetic engineering has expanded the therapeutic ability of peptides to treat solid tumors, which results in overcoming the peptide drawbacks. The present review mainly focuses on the new advances in applying bacterial peptides and bacteriocins in treating human solid tumors.

Interactions of radiation therapy with common and innovative systemic treatments: Antidiabetic treatments, antihypertensives, lipid-lowering medications, immunosuppressive medications and other radiosensitizing methods

The invention and approval of innovative anticancer therapies in the last decade have revolutionized oncology treatment. Radiotherapy is one of the three traditional pillars in oncology treatment with surgery and systemic therapies. Some standard-of-care combinations of chemoradiotherapy widened the therapeutic window of radiation, while some other chemotherapies such as gemcitabine caused unacceptable toxicities when combined with radiation in lung cancers. Fast-paced progress are specially focused on immunotherapies, targeted-therapies, anti-angiogenic treatment, DNA repair inhibitors, hormonotherapy and cell cycle inhibitors. New anticancer therapeutic arsenals provided new possibilities of combined oncological treatments. The interactions of the radiotherapy with other systemic treatments, such as non-anticancer immunomodulatory/immunosuppressive medications are sometimes overlooked even though they could offer a real therapeutic benefit. In this review, we summarize the new opportunities and the risks of historical and novel combined therapies with radiation: non-anticancer immunomodulatory/immunosuppressive drugs, systemic reoxygenation, new therapies such as nanoparticles and SMAC mimetics. Key biological mechanisms, pre-clinical and available clinical data will be provided to demonstrate the promising opportunities in the years to come.

Phase I Dose-Escalation Study of Tirapazamine Chemoembolization for Unresectable Early- and Intermediate-Stage Hepatocellular Carcinoma

PURPOSE

To investigate the safety of replacing doxorubicin with tirapazamine in conventional transarterial chemoembolization (TACE) in an Asian population with hepatocellular carcinoma (HCC), and to determine the optimal tirapazamine dose for phase II studies.

MATERIALS AND METHODS

This was a phase I, 3 + 3 dose-escalation study for patients with unresectable early- and intermediate-stage HCC who received 5, 10, or 20 mg/m2 of intra-arterial (IA) tirapazamine followed by ethiodized oil/gelatin sponge-based embolization. Key eligibilities included HCCs no more than 10 cm in diameter, prior embolization allowed, Eastern Cooperative Oncology Group performance status of 0 or 1, Child-Pugh score of 5-7, and platelet count of ≥60,000 μL. Dose-limiting toxicity (DLT) was defined as any grade 3 nonhematological or grade 4 hematological toxicity, with the exception of transient elevation of aminotransferase levels after the procedure.

RESULTS

Seventeen patients were enrolled, 59% of whom had progression from a prior HCC therapy and 35% of whom had progression or recurrence after TACE. All patients tolerated the tirapazamine TACE well without any DLT or serious adverse event. Using the modified Response Evaluation Criteria in Solid Tumors, the complete response (CR) rate was 47%, and the CR + partial response rate was 65%. The median duration of response was not reached. The median time to progression was 12.6 months (95% confidence interval, 5.1-not reached). The median overall survival was 29.3 months. The selected phase II dose was set at a fixed dose of 35 mg of IA tirapazamine.

CONCLUSIONS

IA tirapazamine with transarterial embolization was well tolerated and showed promising efficacy signals in intermediate-stage HCC, justifying pursuit of a phase II study.

Restoring Tumour Selectivity of the Bioreductive Prodrug PR-104 by Developing an Analogue Resistant to Aerobic Metabolism by Human Aldo-Keto Reductase 1C3

PR-104 is a phosphate ester pre-prodrug that is converted in vivo to its cognate alcohol, PR-104A, a latent alkylator which forms potent cytotoxins upon bioreduction. Hypoxia selectivity results from one-electron nitro reduction of PR-104A, in which cytochrome P450 oxidoreductase (POR) plays an important role. However, PR-104A also undergoes ‘off-target’ two-electron reduction by human aldo-keto reductase 1C3 (AKR1C3), resulting in activation in oxygenated tissues. AKR1C3 expression in human myeloid progenitor cells probably accounts for the dose-limiting myelotoxicity of PR-104 documented in clinical trials, resulting in human PR-104A plasma exposure levels 3.4- to 9.6-fold lower than can be achieved in murine models. Structure-based design to eliminate AKR1C3 activation thus represents a strategy for restoring the therapeutic window of this class of agent in humans. Here, we identified SN29176, a PR-104A analogue resistant to human AKR1C3 activation. SN29176 retains hypoxia selectivity in vitro with aerobic/hypoxic IC50 ratios of 9 to 145, remains a substrate for POR and triggers γH2AX induction and cell cycle arrest in a comparable manner to PR-104A. SN35141, the soluble phosphate pre-prodrug of SN29176, exhibited superior hypoxic tumour log cell kill (>4.0) to PR-104 (2.5–3.7) in vivo at doses predicted to be achievable in humans. Orthologues of human AKR1C3 from mouse, rat and dog were incapable of reducing PR-104A, thus identifying an underlying cause for the discrepancy in PR-104 tolerance in pre-clinical models versus humans. In contrast, the macaque AKR1C3 gene orthologue was able to metabolise PR-104A, indicating that this species may be suitable for evaluating the toxicokinetics of PR-104 analogues for clinical development. We confirmed that SN29176 was not a substrate for AKR1C3 orthologues across all four pre-clinical species, demonstrating that this prodrug analogue class is suitable for further development. Based on these findings, a prodrug candidate was subsequently identified for clinical trials.

Clinical and Preclinical Outcomes of Combining Targeted Therapy With Radiotherapy

In the era of precision medicine, radiation medicine is currently focused on the precise delivery of highly conformal radiation treatments. However, the tremendous developments in targeted therapy are yet to fulfill their full promise and arguably have the potential to dramatically enhance the radiation therapeutic ratio. The increased ability to molecularly profile tumors both at diagnosis and at relapse and the co-incident progress in the field of radiogenomics could potentially pave the way for a more personalized approach to radiation treatment in contrast to the current ‘‘one size fits all’’ paradigm. Few clinical trials to date have shown an improved clinical outcome when combining targeted agents with radiation therapy, however, most have failed to show benefit, which is arguably due to limited preclinical data. Several key molecular pathways could theoretically enhance therapeutic effect of radiation when rationally targeted either by directly enhancing tumor cell kill or indirectly through the abscopal effect of radiation when combined with novel immunotherapies. The timing of combining molecular targeted therapy with radiation is also important to determine and could greatly affect the outcome depending on which pathway is being inhibited.

Impact of hypoxia on cervical cancer outcomes

The annual global incidence of cervical cancer is approximately 604 000 cases/342 000 deaths, making it the fourth most common cancer in women. Cervical cancer is a major healthcare problem in low and middle income countries where 85% of new cases and deaths occur. Secondary prevention measures have reduced incidence and mortality in developed countries over the past 30 years, but cervical cancer remains a major cause of cancer deaths in women. For women who present with Fédération Internationale de Gynécologie et d'Obstétrique (FIGO 2018) stages IB3 or upwards, chemoradiation is the established treatment. Despite high rates of local control, overall survival is less than 50%, largely due to distant relapse. Reducing the health burden of cervical cancer requires greater individualization of treatment, identifying those at risk of relapse and progression for modified or intensified treatment. Hypoxia is a well known feature of solid tumors and an established therapeutic target. Low tumorous oxygenation increases the risk of local invasion, metastasis and treatment failure. While meta-analyses show benefit, many individual trials targeting hypoxia failed in part due to not selecting patients most likely to benefit. This review summarizes the available hypoxia-targeted strategies and identifies further research and new treatment paradigms needed to improve patient outcomes. The applications and limitations of hypoxia biomarkers for treatment selection and response monitoring are discussed. Finally, areas of greatest unmet clinical need are identified to measure and target hypoxia and therefore improve cervical cancer outcomes.

Targeting Hypoxia: Revival of Old Remedies

Tumour hypoxia is significantly correlated with patient survival and treatment outcomes. At the molecular level, hypoxia is a major driving factor for tumour progression and aggressiveness. Despite the accumulative scientific and clinical efforts to target hypoxia, there is still a need to find specific treatments for tumour hypoxia. In this review, we discuss a variety of approaches to alter the low oxygen tumour microenvironment or hypoxia pathways including carbogen breathing, hyperthermia, hypoxia-activated prodrugs, tumour metabolism and hypoxia-inducible factor (HIF) inhibitors. The recent advances in technology and biological understanding reveal the importance of revisiting old therapeutic regimens and repurposing their uses clinically.

Hypoxia-targeted cupric-tirapazamine liposomes potentiate radiotherapy in prostate cancer spheroids

In this study, novel cupric-tirapazamine [Cu(TPZ)₂]-liposomes were developed as an effective hypoxia-targeted therapeutic, which potentiated radiotherapy in a three dimensional (3D) prostate cancer (PCa) model. To overcome the low water solubility of the Cu(TPZ)₂, a remote loading method was developed to efficiently load the lipophilic complex into different liposomal formulations. The effect of pH, temperature, PEGylation, lipid composition, liposome size, lipid: complex ratio on the liposome properties, and drug loading was evaluated. The highest loading efficiency was obtained at neutral pH, which was independent of lipid composition and incubation time. In addition, enhanced drug loading was achieved upon decreasing the lipid:complex molar ratio with minimal effects on liposomes' morphology. Interestingly, the in vitro potency of the developed liposomes was easily manipulated by changing the lipid composition. The hydrophilic nature of our liposomal formulations improved the complex's solubility, leading to enhanced cellular uptake and toxicity, both in PCa monolayers and tumour spheroids. Moreover, Cu(TPZ)₂-loaded liposomes combined with radiation, showed a significant reduction in PCa spheroids growth rate, compared to the free complex or radiation alone, which could potentiate radiotherapy in patients with localised advanced PCa.

Tirapazamine suppress osteosarcoma cells in part through SLC7A11 mediated ferroptosis

Osteosarcoma is the most common primary orthopedic malignant bone tumor in adolescents. However, the traditional neoadjuvant chemotherapy regimen has reached the bottleneck. TPZ is a hypoxic prodrug that has a powerful anti-tumor effect in the hypoxic microenvironment of tumors. And ferroptosis is a newly discovered cell death in 2012, and ferroptosis inducers have been used in anti-tumor therapy research in recent decades. Though, the role of TPZ and ferroptosis in osteosarcoma remains unclear. The aim of this study was to investigate the role of TPZ in osteosarcoma and the specific mechanism. MTT assay showed the extraordinary inhibition of TPZ on three osteosarcoma cells under hypoxia. And fluorescence of Fe2+ staining was enhanced by TPZ. Western blotting showed decreased expression of SLC7A11 and GPX4. Lipid peroxidation was confirmed by MDA assay and C11 BODIPY 581/591 staining. SLC7A11 overexpression could restored the proliferation and migration abilities inhibited by TPZ. Thus, we for the first time demonstrated that TPZ could inhibit the proliferation and migration of osteosarcoma cells, and induce ferroptosis in part through inhibiting SLC7A11.

From oxygen sensing to angiogenesis: Targeting the hypoxia signaling pathway in metastatic kidney cancer

PURPOSE

This article summarizes examples of current and emerging therapies that target the hypoxia and angiogenesis signaling pathways in the clear cell type of renal cell cancer (RCC), with an emphasis on the hypoxia signaling pathway.

SUMMARY

Mammalian cells transduce signals of decreased oxygen to hypoxia inducible factor (HIF), an intracellular heterodimer that mediates the adaptation of normal and tumor cells to oxygen deprivation. HIF is frequently overexpressed in cancer cells and is involved in the transcriptional activation of many genes essential for cell invasion, migration, survival, and angiogenesis (including vascular endothelial growth factor [VEGF]). Moreover, HIF confers resistance to cytotoxic chemotherapy and radiation therapy and is associated with poor prognosis in patients with cancer. Blocking the activity of HIF inhibits the expression of VEGF and oncogenic pathways, resulting in the inhibition of tumor growth. Interestingly, activation of oncogenes and/or inactivation of tumor suppressor genes (eg, the gene encoding von Hippel-Lindau [VHL] tumor suppressor protein) can activate tumorigenesis even with normal levels of oxygen, providing support for the notion that the HIF-VHL-VEGF axis is amenable to targeted therapies for the treatment of RCC. This article highlights the current understanding of the hypoxia signaling pathway and its relevance to RCC development. Pharmacologic agents targeting the hypoxia and angiogenesis signaling pathways are discussed.

CONCLUSION

Development of novel therapeutic agents that target the hypoxia and angiogenesis signaling pathways holds promise in the management of metastatic clear cell RCC.

Phase I Trial on Arterial Embolization with Hypoxia Activated Tirapazamine for Unresectable Hepatocellular Carcinoma

Background

Tirapazamine (TPZ) is a hypoxia activated drug that may be synergistic with transarterial embolization (TAE). The primary objective was to evaluate the safety of combining TPZ and TAE in patients with unresectable HCC and determine the optimal dose for Phase II.

Methods

This was a Phase 1 multicenter, open-label, non-randomized trial with a classic 3+3 dose escalation and an expansion cohort in patients with unresectable HCC, Child Pugh A, ECOG 0 or 1. Two initial cohorts consisted of I.V. administration of Tirapazamine followed by superselective TAE while the remaining three cohorts underwent intraarterial administration of Tirapazamine with superselective TAE. Safety and tolerability were assessed using NCI CTCAE 4.0 with clinical, imaging and laboratory examinations including pharmacokinetic (PK) analysis and an electrocardiogram 1 day pre-dose, at 1, 2, 4, 6, 10, and 24 hours post-TPZ infusion and an additional PK at 15- and 30-minutes post-TPZ. Tumor responses were evaluated using mRECIST criteria.

Results

Twenty-seven patients (mean [range] age of 66.4 [37–79] years) with unresectable HCC were enrolled between July 2015 and January 2018. Two patients were lost to follow-up. Mean tumor size was 6.53 cm ± 2.60 cm with a median of two lesions per patient. Dose limiting toxicity and maximum tolerated dose were not reached. The maximal TPZ dose was 10 mg/m² I.V. and 20 mg/m² I.A. One adverse event (AE) was reported in all patients with fatigue, decreased appetite or pain being most common. Grade 3–5 AE were hypertension and transient elevation of AST/ALT in 70.4% of patients. No serious AE were drug related. Sixty percent (95% CI=38.7–78.9) achieved complete response (CR), and 84% (95% CI=63.9–95.5) had complete and partial response per mRECIST for target lesions.

Discussion

TAE with TPZ was safe and tolerable with encouraging results justifying pursuit of a Phase II trial.

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Moving Forward in Cervical Cancer: Enhancing Susceptibility to DNA Repair Inhibition and Damage, an NCI Clinical Trials Planning Meeting Report

Cervical cancer is the fourth most common cancer in women worldwide, and prognosis is poor for those who experience recurrence or develop metastatic disease, in part due to the lack of active therapeutic directions. The National Cancer Institute convened a Cervical Cancer Clinical Trials Planning Meeting in October 2018 to facilitate the design of hypothesis-driven clinical trials focusing on locally advanced, metastatic, and recurrent cervical cancer around the theme of enhancing susceptibility to DNA repair inhibition and DNA damage. Before the meeting, a group of experts in the field summarized available preclinical and clinical data to identify potentially active inducers and inhibitors of DNA. The goals of the Clinical Trials Planning Meeting focused on identification of novel experimental strategies capitalizing on DNA damage and repair (DDR) regulators and cell cycle aberrations, optimization of radiotherapy as a DDR agent, and design of clinical trials incorporating DDR regulation into the primary and recurrent or metastatic therapies for cervical carcinoma. Meeting deliverables were novel clinical trial concepts to move into the National Clinical Trials Network. This report provides an overview for the rationale of this meeting and the state of the science related to DDR regulation in cervical cancer.

Tumor hypoxia: The major culprit behind cisplatin resistance in cancer patients

Cisplatin is the most commonly used first-line drug for cancer treatment. However, many patients develop resistance to cisplatin therapy which ultimately results in therapy failure and increased mortality. A growing body of evidence shows that the hypoxic microenvironment is the prime factor underlying tumor insensitivity to cisplatin treatment. Since tumors in the majority of cancer patients are under hypoxic stress (low oxygen supply), it becomes necessary to understand the pathobiology behind hypoxia-induced cisplatin resistance in cancer cells. Here, we discuss the molecular events that render hypoxic tumors insensitive to cisplatin therapy. Furthermore, various drugs and tumor oxygenation techniques have been developed to circumvent cisplatin resistance in hypoxic tumors. However, their pharmaceutical applications are limited due to failures in clinical investigations and a lack of preclinical studies in the hypoxic tumor microenvironment. This review addresses these challenges and provides new directions for the strategic deployment of cisplatin sensitizers in the hypoxic tumor microenvironment.

Lost in application: Measuring hypoxia for radiotherapy optimisation

The history of radiotherapy is intertwined with research on hypoxia. There is level 1a evidence that giving hypoxia-targeting treatments with radiotherapy improves locoregional control and survival without compromising late side-effects. Despite coming in and out of vogue over decades, there is now an established role for hypoxia in driving molecular alterations promoting tumour progression and metastases. While tumour genomic complexity and immune profiling offer promise, there is a stronger evidence base for personalising radiotherapy based on hypoxia status. Despite this, there is only one phase III trial targeting hypoxia modification with full transcriptomic data available. There are no biomarkers in routine use for patients undergoing radiotherapy to aid management decisions, and a roadmap is needed to ensure consistency and provide a benchmark for progression to application. Gene expression signatures address past limitations of hypoxia biomarkers and could progress biologically optimised radiotherapy. Here, we review recent developments in generating hypoxia gene expression signatures and highlight progress addressing the challenges that must be overcome to pave the way for their clinical application.

Phase IB study of sorafenib and evofosfamide in patients with advanced hepatocellular and renal cell carcinomas (NCCTG N1135, Alliance)

Background Sorafenib (Sor) remains a first-line option for hepatocellular carcinoma (HCC) or refractory renal cell carcinomas (RCC). PLC/PRF/5 HCC model showed upregulation of hypoxia with enhanced efficacy when Sor is combined with hypoxia-activated prodrug evofosfamide (Evo). Methods This phase IB 3 + 3 design investigated 3 Evo dose levels (240, 340, 480 mg/m² on days 8, 15, 22), combined with Sor 200 mg orally twice daily (po bid) on days 1-28 of a 28-day cycle. Primary objectives included determining maximum tolerated dose (MTD) and recommended phase II dose (RP2D) of Sor + Evo. Results Eighteen patients were enrolled (median age 62.5 years; 17 male /1 female; 12 HCC/6 RCC) across three dose levels (DL0: Sor 200 mg bid/Evo 240 mg/m² [n = 6], DL1:Sor 200 mg bid/Evo 480 mg/m² [n = 5], DL1a: Sor 200 mg bid/Evo 340 mg/m² [n = 7]). Two dose-limiting toxicities (DLTs) were reported with Evo 480 mg/m² (grade 3 mucositis, grade 4 hepatic failure). Grade 3 rash DLT was observed in one patient at Evo 240 mg/m². No DLTs were observed at Evo 340 mg/m². MTD and RP2D were established as Sor 200 mg/Evo 340 mg/m² and Sor 200/Evo 240 mg/m², respectively. The most common treatment-related adverse events included fatigue, hand-foot syndrome, hypertension, and nausea/vomiting. Two partial responses were observed, one each at DL0 and DL1a.; disease control rate was 55%. Conclusions RP2D was established as sorafenib 200 mg bid + Evo 240 mg/m². While preliminary anti-tumor activity was observed, future development must account for advances in immunotherapy in HCC/RCC.

Hypoxia and its therapeutic possibilities in paediatric cancers

In tumours, hypoxia-a condition in which the demand for oxygen is higher than its availability-is well known to be associated with reduced sensitivity to radiotherapy and chemotherapy, and with immunosuppression. The consequences of hypoxia on tumour biology and patient outcomes have therefore led to the investigation of strategies that can alleviate hypoxia in cancer cells, with the aim of sensitising cells to treatments. An alternative therapeutic approach involves the design of prodrugs that are activated by hypoxic cells. Increasing evidence indicates that hypoxia is not just clinically significant in adult cancers but also in paediatric cancers. We evaluate relevant methods to assess the levels and extent of hypoxia in childhood cancers, including novel imaging strategies such as oxygen-enhanced magnetic resonance imaging (MRI). Preclinical and clinical evidence largely supports the use of hypoxia-targeting drugs in children, and we describe the critical need to identify robust predictive biomarkers for the use of such drugs in future paediatric clinical trials. Ultimately, a more personalised approach to treatment that includes targeting hypoxic tumour cells might improve outcomes in subgroups of paediatric cancer patients.

A rat toxicological study of intra-arterial injection of Tirapazamine, a hypoxia-activating Cancer therapeutic agent, followed by hepatic artery ligation

Background Tirapazamine's (TPZ) tolerability after an intra-arterial (IA) injection remains unclear. We investigated TPZ's safety and tolerability in rats by first injecting into the left hepatic artery and then performing a hepatic artery ligation, which recapitulates the transarterial embolization used clinically. Research design and methods: Forty-six rats in five groups were respectively injected with 0, 0.25, 0.50, 1.0, or more than 1.5 mL IA of TPZ (0.7 mg/mL) into the left hepatic artery and then subjected to hepatic artery ligation under laparotomy. Blood samples were collected four times daily up to day 15 after which the rats were euthanized and necropsied. The toxicity profile of IA injection of TPZ followed by hepatic artery ligation was then assessed. Results No significant changes to the rats' body weight and serum total bilirubin were observed. Serum alanine aminotransferase (ALT) levels increased slightly but remained below 100 U/L one day after treatment for most rats. Three rats in Groups 3 and 4 exhibited an over two-fold transient elevation of ALT. All ALT recovered to the baseline at day 14. Liver tissues were collected on day 15 using H&E staining. One rat in Group 3 showed ischemic coagulative necrosis in its liver tissue. Other sporadic pathological changes not related to TPZ doses were observed in Groups 2, 3, 4, and 5. Conclusion TPZ by IA injection followed by embolization is tolerated up to 7 mg/kg. This finding supports the strategy of administering an IA injection of TPZ followed by trans-arterial embolization to the liver.

Bad neighbours: hypoxia and genomic instability in prostate cancer

Prostate cancer (PCa) is a clinically heterogeneous disease and has poor patient outcome when tumours progress to castration-resistant and metastatic states. Understanding the mechanistic basis for transition to late stage aggressive disease is vital for both assigning patient risk status in the localised setting and also identifying novel treatment strategies to prevent progression. Subregions of intratumoral hypoxia are found in all solid tumours and are associated with many biologic drivers of tumour progression. Crucially, more recent findings show the co-presence of hypoxia and genomic instability can confer a uniquely adverse prognosis in localised PCa patients. In-depth informatic and functional studies suggests a role for hypoxia in co-operating with oncogenic drivers (e.g. loss of PTEN) and suppressing DNA repair capacity to alter clonal evolution due to an aggressive mutator phenotype. More specifically, hypoxic suppression of homologous recombination represents a “contextual lethal“ vulnerability in hypoxic prostate tumours which could extend the application of existing DNA repair targeting agents such as poly-ADP ribose polymerase inhibitors. Further investigation is now required to assess this relationship on the background of existing genomic alterations relevant to PCa, and also characterise the role of hypoxia in driving early metastatic spread. On this basis, PCa patients with hypoxic tumours can be better stratified into risk categories and treated with appropriate therapies to prevent progression.

Three dimensional engineered models to study hypoxia biology in breast cancer

Breast cancer is the second leading cause of mortality among women worldwide. Despite the available therapeutic regimes, variable treatment response is reported among different breast cancer subtypes. Recently, the effects of the tumor microenvironment on tumor progression as well as treatment responses have been widely recognized. Hypoxia and hypoxia inducible factors in the tumor microenvironment have long been known as major players in tumor progression and survival. However, the majority of our understanding of hypoxia biology has been derived from two dimensional (2D) models. Although many hypoxia-targeted therapies have elicited promising results in vitro and in vivo, these results have not been successfully translated into clinical trials. These limitations of 2D models underscore the need to develop and integrate three dimensional (3D) models that recapitulate the complex tumor-stroma interactions in vivo. This review summarizes role of hypoxia in various hallmarks of cancer progression. We then compare traditional 2D experimental systems with novel 3D tissue-engineered models giving accounts of different bioengineering platforms available to develop 3D models and how these 3D models are being exploited to understand the role of hypoxia in breast cancer progression.

Individual patient data meta-analysis of FMISO and FAZA hypoxia PET scans from head and neck cancer patients undergoing definitive radio-chemotherapy

BACKGROUND AND PURPOSE

Tumor hypoxia plays an important role in head and neck squamous cell carcinomas (HNSCC). Various positron emission tomography (PET) tracers promise non-invasive assessment of tumor hypoxia. So far, the applicability of hypoxia PET is hampered by monocentric imaging trials with few patients.

MATERIALS AND METHODS

Multicenter individual patient data based meta-analysis of the original PET data from four prospective imaging trials was performed. All patients had localized disease and were treated with curatively intended radio(-chemo)therapy. Hypoxia PET imaging was performed with ¹⁸F-Fluoromisonidazole (FMISO, 102 patients) or ¹⁸F-Fluoroazomycin-arabinoside (FAZA, 51 patients). Impact of hypoxia PET parameters on loco-regional control (LRC) and overall survival (OS) was analyzed by uni- and multivariable Cox regression.

RESULTS

Baseline characteristics between participating centers differed significantly, especially regarding T stage (p < 0.001), tumor volume (p < 0.001) and p16 status (p = 0.009). The commonly used hypoxia parameters, maximal tumor-to-muscle ratio (TMR_max) and hypoxic volume with 1.6 threshold (HV_1.6), showed a strong association with LRC (p = 0.001) and OS (p < 0.001). These findings were irrespective of the radiotracer and the same cut-off values could be applied for FMISO and FAZA (TMR_max > 2.0 or HV_1.6 > 1.5 ml). The effect size of TMR_max was similar for subgroups of patients defined by radiotracer, p16 status and FDG-PET parameters for LRC and OS, respectively.

CONCLUSION

PET measured hypoxia is robust and has a strong impact on LRC and OS in HNSCC. The most commonly investigated tracers FMISO and FAZA can probably be used equivalently in multicenter trials. Optimal strategies to improve the dismal outcome of hypoxic tumors remain elusive.

[18F]-HX4 PET/CT hypoxia in patients with squamous cell carcinoma of the head and neck treated with chemoradiotherapy: Prognostic results from two prospective trials

Introduction

The presence of hypoxia in head-and-neck squamous cell carcinoma is a negative prognostic factor. PET imaging with [18F] HX4 can be used to visualize hypoxia, but it is currently unknown how this correlates with prognosis. We investigated the prognostic value of [18F] HX4 PET imaging in patients treated with definitive radio(chemo)therapy (RTx).

Materials and methods

We analyzed 34 patients included in two prospective clinical trials (NCT01347281, NCT01504815). Static [18F] HX4 PET-CT images were collected, both pre-treatment (median 4 days before start RTx, range 1-16), as well as during RTx (median 13 days after start RTx, range 3-17 days). Static uptake at both time points (n = 33 pretreatment, n = 28 during RTx) and measured changes in hypoxic fraction (HF) and hypoxic volume (HV) (n = 27 with 2 time points) were analyzed. Univariate cox analyses were done for local progression free survival (PFS) and overall survival (OS) at both timepoints. Change in uptake was analyzed by comparing outcome with Kaplan-Meier curves and log-rank test between patients with increased and decreased/stable hypoxia, similarly between patients with and without residual hypoxia (rHV = ratio week 2/baseline HV with cutoff 0.2). Voxelwise Spearman correlation coefficients were calculated between normalized [18F] HX4 PET uptake at baseline and week 2.

Results

Analyses of static images showed no prognostic value for [18F] HX4 uptake. Analysis of dynamic changes showed that both OS and local PFS were significantly shorter (log-rank P < 0.05) in patients with an increase in HV during RTx and OS was significantly shorter in patients with rHV, with no correlation to HPV-status. The voxel-based correlation to evaluate spatial distribution yielded a median Spearman correlation coefficient of 0.45 (range 0.11-0.65).

Conclusion

The change of [18F] HX4 uptake measured on [18F] HX4 PET early during treatment can be considered for implementation in predictive models. With these models patients with a worse prognosis can be selected for treatment intensification.

Intratumoral heterogeneity and hypoxia gene expression signatures: Is a single biopsy adequate?

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A single biopsy may not accurately reflect the global hypoxia status of a tumor due to intratumoral heterogeneity.

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Compared with individual genes, hypoxia gene expression signatures are generally more consistent across multiple biopsies from different regions of a tumor and may give a more reliable estimate of global hypoxia status.

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Wherever possible, the use of multiple biopsies provides greater assurance in correctly classifying a tumor as more or less hypoxic.

Background and Purpose

Gene expression signatures are often used to identify hypoxic tumors. However, intratumoral heterogeneity raises concern that multiple biopsies may be necessary to assess global hypoxia status. The objective of this study was to compare the impact of heterogeneity on the discriminative capacity of several previously described hypoxia gene signatures and determine if a single biopsy is sufficient to obtain a reliable estimate of hypoxia in cervical cancer.

Materials and Methods

Multiple biopsies (33) were obtained from 11 locally advanced (FIGO IB to IVB) cervical cancers prior to treatment. Ten hypoxia gene signatures were analyzed. Variance component analysis was used to determine the ratio of within-tumor variability to total-tumor variability when one to five biopsies are available for analysis (W/T_1–5). The mean standardized error in the signature scores was estimated by comparing the score using one biopsy randomly selected from each tumor to the ‘global’ score using all available biopsies.

Results

The ten hypoxia signatures were comprised of 6–99 genes each. The W/T₁ ratios for individual genes commonly found in the signatures ranged from 0.17 to 0.73. W/T₁ ratios for the signatures were generally lower (0.21–0.45), implying greater capacity to discriminate among tumors. With additional biopsies, the signature W/T ratios (ie W/T_2-5) decreased further. The mean error in the signature scores varied from 0.27 to 0.40 of one standard deviation, suggesting high capacity to discriminate among tumors with different global hypoxia scores.

Conclusions

Compared with individual probes, hypoxia gene expression signatures are generally more consistent across multiple biopsies from different regions of a tumor and more tolerant of intratumoral heterogeneity.

Combination of chemotherapy and radiotherapy: A thirty years evolution

Chemoradiotherapy is now considered the standard of care for many locally advanced diseases. Cytotoxic drugs have been largely evaluated in this setting, with cisplatin and 5FU the most often used drugs. A large amount of pre-clinical studies has demonstrated the synergy between both modalities. Concomitant administration seems the more beneficial in many diseases. Emergence of new approaches, combining targeted therapies and radiotherapy (RT) is now a reality. The main example is the association of cetuximab and RT in head and neck carcinomas, even if, 14 years after the initial publication, the best way to use it is still unknown. New compounds as inhibitors of DNA-repair or immune checkpoints are under investigation and showed early promising results.

Risk-based treatment for patients with first relapse or progression of rhabdomyosarcoma: A report from the Children's Oncology Group

BACKGROUND

The purpose of this study was to evaluate risk and response-based multi-agent therapy for patients with rhabdomyosarcoma (RMS) at first relapse.

METHODS

Patients with RMS and measurable disease at first relapse with unfavorable-risk (UR) features were randomized to a 6-week phase 2 window with 1 of 2 treatment schedules of irinotecan with vincristine (VI) (previously reported). Those with at least a partial response to VI continued to receive 44 weeks of multi-agent chemotherapy including the assigned VI regimen. UR patients who did not have measurable disease at study entry, did not have a radiographic response after the VI window, or declined VI window therapy received 31 weeks of multi-agent chemotherapy including tirapazamine (TPZ) at weeks 1, 4, 10, 19, and 28. Favorable-risk (FR) patients received 31 weeks of the same multi-agent chemotherapy without VI and TPZ.

RESULTS

One hundred thirty-six eligible patients were enrolled. For 61 patients not responding to VI, the 3-year failure-free survival (FFS) and overall survival (OS) rates were 17% (95% confidence interval [CI], 8%-29%) and 24% (13%-37%), respectively. For 30 UR patients not treated with VI, the 3-year FFS and OS rates were 21% (8%-37%) and 39% (20%-57%), respectively. FR patients had 3-year FFS and OS rates of 79% (47%-93%) and 84% (50%-96%), respectively. There were no unexpected toxicities.

CONCLUSIONS

Patients with UR RMS at first relapse or disease progression have a poor prognosis when they are treated with this multi-agent therapy, whereas FR patients have a higher chance of being cured with second-line therapy.

Functional CRISPR and shRNA Screens Identify Involvement of Mitochondrial Electron Transport in the Activation of Evofosfamide

Evofosfamide (TH-302) is a hypoxia-activated DNA-crosslinking prodrug currently in clinical development for cancer therapy. Oxygen-sensitive activation of evofosfamide depends on one-electron reduction, yet the reductases that catalyze this process in tumors are unknown. We used RNA sequencing, whole-genome CRISPR knockout, and reductase-focused short hairpin RNA screens to interrogate modifiers of evofosfamide activation in cancer cell lines. Involvement of mitochondrial electron transport in the activation of evofosfamide and the related nitroaromatic compounds EF5 and FSL-61 was investigated using 143B ρ ⁰ (ρ zero) cells devoid of mitochondrial DNA and biochemical assays in UT-SCC-74B cells. The potency of evofosfamide in 30 genetically diverse cancer cell lines correlated with the expression of genes involved in mitochondrial electron transfer. A whole-genome CRISPR screen in KBM-7 cells identified the DNA damage-response factors SLX4IP, C10orf90 (FATS), and SLFN11, in addition to the key regulator of mitochondrial function, YME1L1, and several complex I constituents as modifiers of evofosfamide sensitivity. A reductase-focused shRNA screen in UT-SCC-74B cells similarly identified mitochondrial respiratory chain factors. Surprisingly, 143B ρ ⁰ cells showed enhanced evofosfamide activation and sensitivity but had global transcriptional changes, including increased expression of nonmitochondrial flavoreductases. In UT-SCC-74B cells, evofosfamide oxidized cytochromes a, b, and c and inhibited respiration at complexes I, II, and IV without quenching reactive oxygen species production. Our results suggest that the mitochondrial electron transport chain contributes to evofosfamide activation and that predicting evofosfamide sensitivity in patients by measuring the expression of canonical bioreductive enzymes such as cytochrome P450 oxidoreductase is likely to be futile.

Effect of tirapazamine on selected kidney parameters in rats treated with cisplatin

Hypoxic cancer cells are more aggressive and responsible for more efficient metastasis and recurrence. It seems worth-while, hence, to supplement current cytostatic drugs therapy (i.e. cisplatin) with hypoxia cytotoxic agents (i.e. tirapazamine), the toxicity of which is activated by hypoxia. Cisplatin and tirapazamine can change a redox equilibrium and consequently lead to changes in cell metabolism, fibrosis and apoptosis. The aim of this study was to evaluate the cisplatin/tirapazamine toxicological synergism. In doing so we tested selected kidney oxidative stress parameters, as well as nephrotoxicity markers, in plasma and urine. Once a week for 6 weeks, rats received intraperitoneally two doses of tirapazamine (5 or 10 mg/kg bw), 2 hours before cisplatin (2 mg/kg bw) was applied. Our results show that Tirapazamine (TP) had no significant adverse effect on the redox balance, oxidative stress and kidney function in rats receiving cisplatin (CP). However, TP significantly increased protein concentration in the kidneys of rats. In all tested groups, a significant decrease in NADH concentration in kidneys was recorded, which could indicate disorder in the cell metabolism. TP also was found to have prevented bacterial infection caused by CP. In summary, there was no nephrotoxic synergy of TP with CP at an unacceptable level.

Clinical and genetic landscape of treatment naive cervical cancer: Alterations in PIK3CA and in epigenetic modulators associated with sub-optimal outcome

BACKGROUND

There is a lack of information as to which molecular processes, present at diagnosis, favor tumour escape from standard-of-care treatments in cervical cancer (CC). RAIDs consortium (www.raids-fp7.eu), conducted a prospectively monitored trial, [BioRAIDs (NCT02428842)] with the objectives to generate high quality samples and molecular assessments to stratify patient populations and to identify molecular patterns associated with poor outcome.

METHODS

Between 2013 and 2017, RAIDs collected a prospective CC sample and clinical dataset involving 419 participant patients from 18 centers in seven EU countries. Next Generation Sequencing has so far been carried out on a total of 182 samples from 377 evaluable (48%) patients, allowing to define dominant genetic alterations. Reverse phase protein expression arrays (RPPA) was applied to group patients into clusters. Activation of key genetic pathways and protein expression signatures were tested for associations with outcome.

FINDINGS

At a median follow up (FU) of 22 months, progression-free survival rates of this FIGO stage IB1-IV population, treated predominantly (87%) by chemoradiation, were65•4% [CI95%: 60•2-71.1]. Dominant oncogenic alterations were seen in PIK3CA (40%), while dominant suppressor gene alterations were seen in KMT2D (15%) and KMT2C (16%). Cumulative frequency of loss-of-function (LOF) mutations in any epigenetic modulator gene alteration was 47% and it was associated with PIK3CA gene alterations in 32%. Patients with tumours harboring alterations in both pathways had a significantly poorer PFS. A new finding was the detection of a high frequency of gains of TLR4 gene amplifications (10%), as well as amplifications, mutations, and non-frame-shift deletions of Androgen receptor (AR) gene in 7% of patients. Finally, RPPA protein expression analysis defined three expression clusters.

INTERPRETATION

Our data suggests that patient population may be stratified into four different treatment strategies based on molecular markers at the outset. FUND: European Union's Seventh Program grant agreement No 304810.

Overcoming Radioresistance: Small Molecule Radiosensitisers and Hypoxia-activated Prodrugs

The role of hypoxia in radiation resistance is well established and many approaches to overcome hypoxia in tumours have been explored, with variable success. Two small molecule strategies for targeting hypoxia have dominated preclinical and clinical efforts. One approach has been the use of electron-affinic nitroheterocycles as oxygen-mimetic sensitisers. These agents are best exemplified by the 5-nitroimidazole nimorazole, which has limited use in conjunction with radiotherapy in head and neck squamous cell carcinoma. The second approach seeks to leverage tumour hypoxia as a tumour-specific address for hypoxia-activated prodrugs. These prodrugs are selectively activated by reductases under hypoxia to release cytotoxins, which in some instances may diffuse to kill surrounding oxic tumour tissue. A number of these hypoxia-activated prodrugs have been examined in clinical trial and the merits and shortcomings of recent examples are discussed. There has been an evolution from delivering DNA-interactive cytotoxins to molecularly targeted agents. Efforts to implement these strategies clinically continue today, but success has been elusive. Several issues have been identified that compromised these clinical campaigns. A failure to consider the extravascular transport and the micropharmacokinetic properties of the prodrugs has reduced efficacy. One key element for these 'targeted' approaches is the need to co-develop biomarkers to identify appropriate patients. Hypoxia-activated prodrugs require biomarkers for hypoxia, but also for appropriate activating reductases in tumours, as well as markers of intrinsic sensitivity to the released drug. The field is still evolving and changes in radiation delivery and the impact of immune-oncology will provide fertile ground for future innovation.

Examining Urban and Rural Differences in How Distance to Care Influences the Initiation and Completion of Treatment among Insured Cervical Cancer Patients

BACKGROUND

Although rural cancer patients encounter substantial barriers to care, they more often report receiving timely care than urban patients. We examined whether geographic distance, a contributor to urban-rural health disparities, differentially influences treatment initiation and completion among insured urban and rural cervical cancer patients.

METHODS

We identified women diagnosed with cervical cancer from 2004 to 2013 from a statewide cancer registry linked to multipayer, insurance claims. Primary outcomes were initiation of guideline-concordant care within 6 weeks of diagnosis and, among stage IB2-IVA cancer patients, completion of concurrent chemoradiotherapy (CCRT) in 56 days. We estimated risk ratios using modified Poisson regressions, stratified by urban/rural status, to examine the association between distance and treatment timing (initiation or completion).

RESULTS

Among 999 stage IA-IVA patients, 48% initiated guideline-concordant care within 6 weeks of diagnosis, and 37% of 492 stage IB2-IVA cancer patients completed CCRT in 56 days. In urban areas, stage IA-IVA patients who lived ≥15 miles from the nearest treatment facility were less likely to initiate timely treatment compared with those <5 miles [risk ratio (RR): 0.72; 95% confidence intervals (CI), 0.54-0.95]. Among IB2-IVA stage cancer patients, rural women residing ≥15 miles from the nearest radiation facility were more likely to complete CCRT in 56 days (RR: 2.49; 95% CI, 1.12-5.51).

CONCLUSIONS

Geographic distance differentially influences the initiation and completion of treatment among urban and rural cervical cancer patients.

IMPACT

Distance was an access barrier for insured cervical cancer patients in urban areas whereas rural patients may require more intensive outreach, support, and resources, even among those living closer to treatment.

Risk factors for pelvic and distant recurrence in locally advanced cervical cancer

OBJECTIVE

Despite the benefits of concomitant radiotherapy and cisplatin for locally advanced cervical cancer, recurrence rates remain high. New treatment strategies such as consolidation chemotherapy and different concomitant chemotherapy combinations have been tested in recent years. Identification of the best candidates for each treatment strategy could optimize results.

STUDY DESIGN

A retrospective review of data from 127 patients with locally advanced cervical cancer (International Federation of Gynecology and Obstetrics Stages IIB-IVA), treated at a single institution from 2005 to 2014. Risk factors for loco-regional and systemic recurrence, and prognostic factors for overall survival (OS) were analysed using Cox regression. Survival of patients treated with consolidation chemotherapy was compared with survival of patients not treated with consolidation chemotherapy in the role cohort and in a propensity-score-matched cohort.

RESULTS

With a median follow-up time of 48.7 months, loco-regional-recurrence-free survival (LRFS), distant-metastasis-free survival (DMFS) and OS at 5 years were 76.6%, 54.0% and 63.0%, respectively. On multivariate analysis, tumour size ≥6 cm was associated with shorter LRFS [hazard ratio (HR) 5.18; 95% confidence interval (CI) 1.45-18.45; p = 0.011], and adenocarcinoma (HR 2.48; 95% CI 1.10-5.57; p = 0.028) and positive lymph nodes (HR 2.21; 95% CI 1.303-4.72; p = 0.041) were associated with shorter DMFS. Tumour size ≥6 cm was associated with shorter OS (HR 2.64; 95% CI 1.09-6.35; p = 0.031). Twenty-two patients were treated with consolidation chemotherapy; on univariate analysis, these patients had longer OS compared with patients who were not treated with consolidation chemotherapy (p = 0.043). In a propensity-score-matched cohort, patients treated with consolidation chemotherapy had longer DMFS and OS compared with patients who were not treated with consolidation chemotherapy, although the difference was not significant.

CONCLUSIONS

Different risk factors are associated with loco-regional and distant metastases in patients with locally advanced cervical cancer, and could potentially lead to particular therapeutic strategies. Although the number of patients treated with consolidation chemotherapy in the study cohort was small, they seemed to live longer and to have better control of distant relapse then patients who were not treated with consolidation chemotherapy.

Hypoxia-targeted drug delivery

Hypoxia is a state of low oxygen tension found in numerous solid tumours. It is typically associated with abnormal vasculature, which results in a reduced supply of oxygen and nutrients, as well as impaired delivery of drugs. The hypoxic nature of tumours often leads to the development of localized heterogeneous environments characterized by variable oxygen concentrations, relatively low pH, and increased levels of reactive oxygen species (ROS). The hypoxic heterogeneity promotes tumour invasiveness, metastasis, angiogenesis, and an increase in multidrug-resistant proteins. These factors decrease the therapeutic efficacy of anticancer drugs and can provide a barrier to advancing drug leads beyond the early stages of preclinical development. This review highlights various hypoxia-targeted and activated design strategies for the formulation of drugs or prodrugs and their mechanism of action for tumour diagnosis and treatment.