The UK Divide: Does Having a Pembrolizumab-Chemotherapy Option in Head and Neck Cancer Matter? Real-world Experience of First-line Palliative Pembrolizumab Monotherapy and Pembrolizumab-Chemotherapy Combination in Scotland

AIMS

The Scottish Medical Consortium recently approved first-line pembrolizumab monotherapy or in combination with chemotherapy for head and neck squamous cell carcinoma in the palliative setting, contrasting with the decision made by the National Institute for Health and Care Excellence, who approved monotherapy alone in England and Wales. The aim of this study was to provide real-world performance data for first-line pembrolizumab-containing treatments for head and neck squamous cell carcinoma in the palliative setting in Scotland.

MATERIALS AND METHODS

We analysed the electronic records of patients who started pembrolizumab-containing treatment between 1 March 2020 and 30 September 2021. Outcomes included overall survival, progression-free survival (PFS), the duration of response and the disease control rate. Data were compared with the KEYNOTE-048 study and clinical factors were evaluated for association with survival.

RESULTS

Our cohort included 91 patients (median follow-up 10.8 months). Patient characteristics were similar to those in the KEYNOTE-048 study, although our cohort had a higher proportion of patients with newly diagnosed, non-metastatic disease. For patients receiving monotherapy (n = 76), 12- and 24-month overall survival were 45% and 27%, respectively. For patients receiving pembrolizumab-chemotherapy (n = 15), 12-month overall survival was 60% (24-month overall survival had not yet been reached). Experiencing one or more immune-related adverse event (irAE; versus no irAEs), of any grade, was associated with favourable overall survival and PFS for patients receiving monotherapy in both univariable Log-rank analysis (median overall survival 17.4 months versus 8.6 months, respectively, P = 0.0033; median PFS 10.9 months versus 3.0 months, respectively, P < 0.0001) and multivariable analysis (Cox proportional hazards regression: overall survival hazard ratio 0.31, P = 0.0009; PFS hazard ratio 0.17, P < 0.0001).

CONCLUSION

Our real-world data support the KEYNOTE-048 study findings and the value of combination treatment options. Additionally, our data show that irAEs of any grade, as reported in routine clinical records, are associated with better outcomes in this patient group, adding to the growing body of evidence showing that irAEs are generally a positive marker of programmed death-ligand 1 (PD-L1) inhibitor response.

The Effects of Human Papillomavirus Status and Treatment on the Positive Predictive Value of Post-radiotherapy 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography in Advanced Head and Neck Squamous Cell Carcinoma

AIMS

The high negative predictive value of post-chemoradiation (CRT) positron emission tomography-computed tomography (PET-CT) is well established in head and neck squamous cell cancers (HNSCC). The positive predictive value (PPV) remains under scrutiny, with increasing evidence that it is affected by several factors. The aim of this study was to assess the PPV of post-treatment PET-CT for residual nodal disease when stratified by treatment modality and tumour human papillomavirus (HPV) status.

MATERIALS AND METHODS

This was a retrospective cohort study in a tertiary oncology centre carried out between January 2013 and December 2019. Patients were radically treated with radiotherapy only/CRT for node-positive HNSCC. PET-CT nodal responses were categorised as complete, equivocal (EQR) or incomplete (ICR), and outcomes extracted from electronic records.

RESULTS

In total, 480 patients were evaluated, all had a minimum potential follow-up of 2 years, with a median of 39.2 months. The PPV of 12-week PET-CT was significantly different between HPV-positive (22.5%) and HPV-unrelated (52.7%) disease, P < 0.001. It was also significantly different between the CRT (24.8%) and radiotherapy-only (51.1%) groups, P = 0.001. The PPV of an EQR was significantly less than an ICR, irrespective of HPV status and primary treatment modality. In HPV-positive disease, the PPV of an EQR was 9.0% for the CRT group compared with 21.4% for radiotherapy only, P = 0.278. The PPV in those who achieved an ICR was 34.2% in the CRT group, significantly lower than 70.0% in the radiotherapy-only group, P = 0.03.

CONCLUSION

The PPV of 12-week PET-CT is significantly lower for HPV-positive compared with HPV-unrelated HNSCC. It is poorer in patients with HPV-positive disease treated with CRT compared with radiotherapy alone.

Positron Emission Tomography-Computed Tomography Surveillance after (Chemo)Radiotherapy in Advanced Head and Neck Squamous Cell Cancer: Beyond the PET-NECK Protocol

AIMS

To evaluate the implementation of 18-fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) surveillance after (chemo)radiotherapy, to compare outcomes for those who achieved a complete (CR), equivocal (EQR) and incomplete (ICR) nodal response on 12-week PET-CT according to their human papillomavirus (HPV) status, and to assess the safety of ongoing surveillance beyond 12 weeks in the HPV-positive EQR group.

MATERIALS AND METHODS

All patients with node-positive head and neck squamous cell carcinoma (HNSCC) treated with (chemo)radiotherapy between January 2013 and September 2017 were identified. PET-CT responses were classified as CR, ICR or EQR. Patient outcomes were obtained from electronic records.

RESULTS

In total, 236 patients with a minimum of 2 years of follow-up were identified. The mean age was 59 years; 79.3% had N2 disease; 77.1% of patients had oropharyngeal cancer and 10.1% had squamous cell carcinoma of unknown primary, of whom 82.0% (169) were HPV positive; 78.0% received chemoradiotherapy. The median time from the end of radiotherapy to PET-CT was 91 days. Of the HPV-related HNSCC, 60.4% achieved CR, 29.0% EQR and 10.6% ICR. With a median follow-up of 41.7 months, there was no difference in survival between patients with HPV-related HNSCC achieving CR and EQR (median overall survival not reached for both, P = 0.67) despite the omission of immediate neck dissection in 98.0% of the EQR group.

CONCLUSION

Patients with HPV-positive HNSCC who have achieved EQR have comparable survival outcomes to those who achieved a CR despite the omission of immediate neck dissections; this shows the safety of ongoing surveillance beyond 12 weeks in this group of patients.

Abstract OT1-04-02: Mifepristone treatment for breast cancer patients expressing levels of progesterone receptor isoform A (PRA) higher than those of isoform B (PRB)

Seventy percent of breast cancers express estrogen (ER) and progesterone receptors (PR) and respond to antiestrogen therapies. Emerging evidence from experimental studies and human epidemiology, points to a relevant role for progestins in breast carcinogenesis and cancer growth. Others and we have proposed that there is a role for antiprogestins in the therapeutic armamentarium, but the challenge remains to identify which patients would benefit from targeting the PR in addition to ER. Preclinical data indicates that antiprogestins block cell proliferation and increase apoptosis only in ER+ breast cancers expressing levels of PRA higher than those of PRB. The aim of this study is to evaluate the therapeutic effects of Mifepristone (MFP) on breast cancer patients selected by their PRA/PRB isoform ratio, for 14 days in between core biopsy and surgery (MIPRA trial ClinicalTrials.gov Identifier: NCT02651844). Methods: This is an open label, interventional with single group assignment study. We perform core biopsies on menopausal patients with clinically palpable breast cancers larger than 1.5 cm to confirm diagnosis. We will assess the PRA/PRB ratio by western blotting in frozen samples and total PR in formalin-fixed samples by immunohistochemistry (IHC). Twenty eligible PR+ patients (PR &gt; 50 %) with PRA/PRB ≥1.5 who have signed consent forms, and meet the inclusion criteria will be recruited. Patients will be treated for 14 days with MFP p.o 200 mg. Surgery will be performed on day 15. Samples will be frozen for molecular studies or fixed for IHC. The primary outcome is the evaluation of Ki-67 staining pre- and post treatment. Secondary outcomes include comparatively expression of proliferation/apoptosis/PR signaling markers in core and surgical biopsy samples. Other pre-specified outcomes include molecular profiling, study of liquid biopsies, mammography, and ultrasound studies. Wilcoxon signed rank test will be used to evaluate differences in biomarker expression between core biopsy and surgical samples of each patient.

Citation Format: Liguori M, Lanari C, Gass H, Rojas P, Elia A, Martinez Vazquez P, Burruchaga J, Gonzalez P, Caillet Bois I, Ventura C, San Martin G, Castets A, Lovisi S, Acosta Haab G, Lamb C, Fabris V, Novaro V, Molinolo A. Mifepristone treatment for breast cancer patients expressing levels of progesterone receptor isoform A (PRA) higher than those of isoform B (PRB) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT1-04-02.

Validation of a Magnetic Resonance Imaging-based Auto-contouring Software Tool for Gross Tumour Delineation in Head and Neck Cancer Radiotherapy Planning

AIMS

To carry out statistical validation of a newly developed magnetic resonance imaging (MRI) auto-contouring software tool for gross tumour volume (GTV) delineation in head and neck tumours to assist in radiotherapy planning.

MATERIALS AND METHODS

Axial MRI baseline scans were obtained for 10 oropharyngeal and laryngeal cancer patients. GTV was present on 102 axial slices and auto-contoured using the modified fuzzy c-means clustering integrated with the level set method (FCLSM). Peer-reviewed (C-gold) manual contours were used as the reference standard to validate auto-contoured GTVs (C-auto) and mean manual contours (C-manual) from two expert clinicians (C1 and C2). Multiple geometric metrics, including the Dice similarity coefficient (DSC), were used for quantitative validation. A DSC≥0.7 was deemed acceptable. Inter- and intra-variabilities among the manual contours were also validated. The two-dimensional contours were then reconstructed in three dimensions for GTV volume calculation, comparison and three-dimensional visualisation.

RESULTS

The mean DSC between C-gold and C-auto was 0.79. The mean DSC between C-gold and C-manual was 0.79 and that between C1 and C2 was 0.80. The average time for GTV auto-contouring per patient was 8 min (range 6-13 min; mean 45 s per axial slice) compared with 15 min (range 6-23 min; mean 88 s per axial slice) for C1. The average volume concordance between C-gold and C-auto volumes was 86.51% compared with 74.16% between C-gold and C-manual. The average volume concordance between C1 and C2 volumes was 86.82%.

CONCLUSIONS

This newly designed MRI-based auto-contouring software tool shows initial acceptable results in GTV delineation of oropharyngeal and laryngeal tumours using FCLSM. This auto-contouring software tool may help reduce inter- and intra-variability and can assist clinical oncologists with time-consuming, complex radiotherapy planning.

A protein-truncating R179X variant in RNF186 confers protection against ulcerative colitis

Protein-truncating variants protective against human disease provide in vivo validation of therapeutic targets. Here we used targeted sequencing to conduct a search for protein-truncating variants conferring protection against inflammatory bowel disease exploiting knowledge of common variants associated with the same disease. Through replication genotyping and imputation we found that a predicted protein-truncating variant (rs36095412, p.R179X, genotyped in 11,148 ulcerative colitis patients and 295,446 controls, MAF=up to 0.78%) in RNF186, a single-exon ring finger E3 ligase with strong colonic expression, protects against ulcerative colitis (overall P=6.89 × 10(-7), odds ratio=0.30). We further demonstrate that the truncated protein exhibits reduced expression and altered subcellular localization, suggesting the protective mechanism may reside in the loss of an interaction or function via mislocalization and/or loss of an essential transmembrane domain.

An anatomical study of the superficial palmar communicating branch between the median and ulnar nerves

The palmar communicating branch between the median and ulnar nerves was investigated in 98 hands with the aim of outlining its most common branching patterns and describing its relationship to well-defined anatomical landmarks, including the bistyloid line, wrist crease and flexor retinaculum. Five branching patterns were identified and classified based on their proximal and distal attachments. The palmar communicating branch was found to lie between 26%-79% of the total distance between the metacarpophalangeal joint of the long finger and the wrist crease, and 35%-75% of the total distance between the metacarpophalangeal joint of the long finger and the middle of the bistyloid line. With the aid of the morphometric indices obtained from this study, a risk area where the palmar communicating branch is most likely to be found is outlined. Knowledge of the branching patterns and location of the palmar communicating branch can help clinicians to better assess variations in the patterns of sensation, preserve the nerve during surgical interventions to the palm and better assess post-operative complications involving the branch.

Macrocyclic lactones and isopentenyl esters in the Dufour's gland secretion of halictine bees (Hymenoptera: Halictidae)

The volatile components of the Dufour's gland secretion of female halictid bees have been examined in 18 Nearctic species belonging toAgapostemon, Augochlora, Augochlorella, Augochloropsis, Dialictus, Evylaeus, Halictus, andLasioglossum. Nine saturated and unsaturated macrocyclic lactones ranging from C18 to C26 have been identified. Four of these compounds, the saturated C26 and the unsaturated C20, C22, and C24 lactones, are new natural products reported for halictine bees. A series of eight esters containing branched C5-alkenols and fatty acids has been identified in several species. The cell linings and pollen ball inAugochlora pura pura contain the same major lactones as the Dufour's gland. A discussion of the significance of the Dufour's gland secretion for apoid systematics and its function in the Halictidae is presented.

From formalin to Thiel embalming: What changes? One anatomy department's experiences

In 2009, the Centre for Anatomy and Human Identification started Thiel embalming on a small scale to assess (i) the suitability for our current teaching in which long-lasting dissection courses are key, (ii) the potential for new collaborations and activities, and (iii) the practical implications of changing our embalming method from formalin to Thiel. Twenty six Thiel-embalmed cadavers have been used for dissection by staff and students on a taught MSc course, as a model for clinical and surgical training, and increasingly as a model for evaluation of new medical devices and procedures. Our experiences with dissection were mostly positive especially for teaching the musculoskeletal system. Internal organs handle differently from formalin-fixed organs and dissection manuals need to be adjusted to reflect this. Durability of the cadavers was not an issue, though changes are seen over time due to gradual fluid loss. We have started new collaborations related to postgraduate anatomy teaching and advanced training in surgical and clinical skills. In general, feedback is very positive and demand for cadavers outstrips our current limited supply. Thiel-embalmed cadavers were found to provide a unique opportunity for evaluation of medical products especially in areas where no suitable alternative model is available, and without the complications associated with clinical testing. This has resulted in new collaborations and research projects. As a result Thiel-embalmed cadavers are used for longer and for more activities than formalin cadavers: this requires changes in our procedures and staff roles.

Broad-spectrum acquired resistance in barley induced by the Pseudomonas pathosystem shares transcriptional components with Arabidopsis systemic acquired resistance

Inducible resistance responses play a central role in the defense of plants against pathogen attack. Acquired resistance (AR) is induced alongside defense toward primary attack, providing broad-spectrum protection against subsequent pathogen challenge. The localization and molecular basis of AR in cereals is poorly understood, in contrast with the well-characterized systemic acquired resistance (SAR) response in Arabidopsis. Here, we use Pseudomonas syringae as a biological inducer of AR in barley, providing a clear frame of reference to the Arabidopsis-P. syringae pathosystem. Inoculation of barley leaf tissue with the nonadapted P. syringae pv. tomato avrRpm1 (PstavrRpm1) induced an active local defense response. Furthermore, inoculation of barley with PstavrRpm1 resulted in the induction of broad-spectrum AR at a distance from the local lesion, "adjacent" AR, effective against compatible isolates of P. syringae and Magnaporthe oryzae. Global transcriptional profiling of this adjacent AR revealed similarities with the transcriptional profile of SAR in Arabidopsis, as well as transcripts previously associated with chemically induced AR in cereals, suggesting that AR in barley and SAR in Arabidopsis may be mediated by analogous pathways.

Electron dosimetry of angular fields

Shaping electron fields through the use of lead cut-outs may result in there being acute angles in part of the field. Using both experimental techniques and EGSnrc Monte Carlo simulations an investigation was carried out to determine the dosimetric consequences of this. Measurements were made to investigate how the field dose was related to the angle between adjacent sides in the cut-outs. The study involved two electron energies (9 MeV and 12 MeV) and source-skin distances (SSDs) in the range 1000-1100 mm. For angles less than about 120 degrees the dose received in the angular region decreased significantly, the effect being more pronounced at 12 MeV than at 9 MeV, and at longer SSDs. The planar shapes of the Monte Carlo dose distributions agreed with those experimentally determined to within +/-1.5 mm at 9 MeV and +/-1.0 mm at 12 MeV, demonstrating the validity of using such calculations for this purpose. Graphs are presented which may help in the prospective assessment of the dose reductions likely to be incurred.

Signal interactions between nitric oxide and reactive oxygen intermediates in the plant hypersensitive disease resistance response

Nitric oxide (NO) and reactive oxygen intermediates (ROIs) play key roles in the activation of disease resistance mechanisms both in animals and plants. In animals NO cooperates with ROIs to kill tumor cells and for macrophage killing of bacteria. Such cytotoxic events occur because unregulated NO levels drive a diffusion-limited reaction with O(2)(-) to generate peroxynitrite (ONOO(-)), a mediator of cellular injury in many biological systems. Here we show that in soybean cells unregulated NO production at the onset of a pathogen-induced hypersensitive response (HR) is not sufficient to activate hypersensitive cell death. The HR is triggered only by balanced production of NO and ROIs. Moreover, hypersensitive cell death is activated after interaction of NO not with O(2)- but with H(2)O(2) generated from O(2)(-) by superoxide dismutase. Increasing the level of O(2)(-) reduces NO-mediated toxicity, and ONOO(-) is not a mediator of hypersensitive cell death. During the HR, superoxide dismutase accelerates O(2)(-) dismutation to H(2)O(2) to minimize the loss of NO by reaction with O(2)(-) and to trigger hypersensitive cell death through NO/H(2)O(2) cooperation. However, O(2)(-) rather than H(2)O(2) is the primary ROI signal for pathogen induction of glutathione S-transferase, and the rates of production and dismutation of O(2)(-) generated during the oxidative burst play a crucial role in the modulation and integration of NO/H(2)O(2) signaling in the HR. Thus although plants and animals use a similar repertoire of signals in disease resistance, ROIs and NO are deployed in strikingly different ways to trigger host cell death.

Carbon isotope ratios for chloromethane of biological origin: potential tool in determining biological emissions

Chloromethane (CH3Cl) with a global atmospheric burden of 5.3 million t is the most abundant halocarbon in the atmosphere. However, the origin of ca. 50% of the estimated annual global input of 4 million t of the gas to the atmosphere has yet to be determined. As the oceanic contribution to the global CH3Cl flux is now tightly constrained, an important terrestrial source is either underestimated or unrecognized. It has recently been proposed that higher plants may represent a CH3Cl source of sufficient magnitude to resolve the global budget imbalance. A potentially useful tool in validating CH3Cl emission flux estimates is comparison of the carbon isotope ratio of atmospheric CH3Cl with those of CH3Cl originating from various sources. Here we report the first measurements of delta13C for CH3Cl produced biologically. The CH3Cl released by the higher plant species Batis maritima and Solanum tuberosum was dramatically depleted in 13C with respect to plant tissue (delta13C = -36.8/1000 and -34.5/1000, respectively); CH3Cl released by the fungus Phellinus pomaceus also showed significant 13C depletion with respect to the wood growth substrate (delta13C = -17.9/1000). When reliable delta13C values for the other major sources of atmospheric CH3Cl become available, the distinctive isotopic signature of plant-derived CH3Cl should help constrain the contribution to the atmospheric burden from this source.

Continuous flow stable isotope methods for study of delta(13)C fractionation during halomethane production and degradation

Gas chromatography/mass spectrometry/isotope ratio mass spectrometry (GC/MS/IRMS) methods for delta(13)C measurement of the halomethanes CH(3)Cl, CH(3)Br, CH(3)I and methanethiol (CH(3)SH) during studies of their biological production, biological degradation, and abiotic reactions are presented. Optimisation of gas chromatographic parameters allowed the identification and quantification of CO(2), O(2), CH(3)Cl, CH(3)Br, CH(3)I and CH(3)SH from a single sample, and also the concurrent measurement of delta(13)C for each of the halomethanes and methanethiol. Precision of delta(13)C measurements for halomethane standards decreased (+/-0.3, +/-0.5 and +/-1.3 per thousand) with increasing mass (CH(3)Cl, CH(3)Br, CH(3)I, respectively). Given that carbon isotope effects during biological production, biological degradation and some chemical (abiotic) reactions can be as much as 100 per thousand, stable isotope analysis offers a precise method to study the global sources and sinks of these halogenated compounds that are of considerable importance to our understanding of stratospheric ozone destruction.

Activation tagging identifies a conserved MYB regulator of phenylpropanoid biosynthesis

Plants produce a wide array of natural products, many of which are likely to be useful bioactive structures. Unfortunately, these complex natural products usually occur at very low abundance and with restricted tissue distribution, thereby hindering their evaluation. Here, we report a novel approach for enhancing the accumulation of natural products based on activation tagging by Agrobacterium-mediated transformation with a T-DNA that carries cauliflower mosaic virus 35S enhancer sequences at its right border. Among approximately 5000 Arabidopsis activation-tagged lines, we found a plant that exhibited intense purple pigmentation in many vegetative organs throughout development. This upregulation of pigmentation reflected a dominant mutation that resulted in massive activation of phenylpropanoid biosynthetic genes and enhanced accumulation of lignin, hydroxycinnamic acid esters, and flavonoids, including various anthocyanins that were responsible for the purple color. These phenotypes, caused by insertion of the viral enhancer sequences adjacent to an MYB transcription factor gene, indicate that activation tagging can overcome the stringent genetic controls regulating the accumulation of specific natural products during plant development. Our findings suggest a functional genomics approach to the biotechnological evaluation of phytochemical biodiversity through the generation of massively enriched tissue sources for drug screening and for isolating underlying regulatory and biosynthetic genes.