Changes in multimodality functional imaging parameters early during chemoradiation predict treatment response in patients with locally advanced head and neck cancer

OBJECTIVE

To assess the optimal timing and predictive value of early intra-treatment changes in multimodality functional and molecular imaging (FMI) parameters as biomarkers for clinical remission in patients receiving chemoradiation for head and neck squamous cell carcinoma (HNSCC).

METHODS

Thirty-five patients with stage III-IVb (AJCC 7th edition) HNSCC prospectively underwent 18F-FDG-PET/CT, and diffusion-weighted (DW), dynamic contrast-enhanced (DCE) and susceptibility-weighted MRI at baseline, week 1 and week 2 of chemoradiation. Patients with evidence of persistent or recurrent disease during follow-up were classed as non-responders. Changes in FMI parameters at week 1 and week 2 were compared between responders and non-responders with the Mann-Whitney U test. The significance threshold was set at a p value of <0.05.

RESULTS

There were 27 responders and 8 non-responders. Responders showed a greater reduction in PET-derived tumor total lesion glycolysis (TLG40%; p = 0.007) and maximum standardized uptake value (SUVmax; p = 0.034) after week 1 than non-responders but these differences were absent by week 2. In contrast, it was not until week 2 that MRI-derived parameters were able to discriminate between the two groups: larger fractional increases in primary tumor apparent diffusion coefficient (ADC; p < 0.001), volume transfer constant (Ktrans; p = 0.012) and interstitial space volume fraction (Ve; p = 0.047) were observed in responders versus non-responders. ADC was the most powerful predictor (∆ >17%, AUC 0.937).

CONCLUSION

Early intra-treatment changes in FDG-PET, DW and DCE MRI-derived parameters are predictive of ultimate response to chemoradiation in HNSCC. However, the optimal timing for assessment with FDG-PET parameters (week 1) differed from MRI parameters (week 2). This highlighted the importance of scanning time points for the design of FMI risk-stratified interventional studies.

Nivolumab vs investigator's choice in recurrent or metastatic squamous cell carcinoma of the head and neck: 2-year long-term survival update of CheckMate 141 with analyses by tumor PD-L1 expression

OBJECTIVES

We report 2-year results from CheckMate 141 to establish the long-term efficacy and safety profile of nivolumab and outcomes by tumor PD-L1 expression in patients with recurrent or metastatic (R/M),platinum-refractory squamous cell carcinoma of the head and neck (SCCHN).

METHODS

Patients with R/M SCCHN with tumor progression/recurrence within 6 months of platinum therapy were randomized 2:1 to nivolumab 3 mg/kg every 2 weeks or investigator's choice (IC). Primary endpoint: overall survival (OS). Data cutoff: September 2017.

RESULTS

With 24.2 months' minimum follow-up, nivolumab (n = 240) continued to improve OS vs IC (n = 121), hazard ratio (HR) = 0.68 (95% CI 0.54-0.86). Nivolumab nearly tripled the estimated 24-month OS rate (16.9%) vs IC (6.0%), and demonstrated OS benefit across patients with tumor PD-L1 expression ≥1% (HR [95% CI] = 0.55 [0.39-0.78]) and  < 1% (HR [95% CI] = 0.73 [0.49-1.09]), and regardless of tumor HPV status. Estimated OS rates at 18, 24, and 30 months with nivolumab were consistent irrespective of PD-L1 expression (<1%/≥1%). In the nivolumab arm, there were no observed differences in baseline characteristics or safety profile between long-term survivors and the overall population. Grade 3-4 treatment-related adverse event rates were 15.3% and 36.9% for nivolumab and IC, respectively.

CONCLUSION

Nivolumab significantly improved OS at the primary analysis and demonstrated prolonged OS benefit vs IC and maintenance of a manageable and consistent safety profile with 2-year follow-up. OS benefit was observed with nivolumab irrespective of PD-L1 expression and HPV status. (Clinicaltrials.gov: NCT02105636).

HER3-Mediated Resistance to Hsp90 Inhibition Detected in Breast Cancer Xenografts by Affibody-Based PET Imaging

Purpose: Recent studies have highlighted a role of HER3 in HER2-driven cancers (e.g., breast cancer), implicating the upregulation of the receptor in resistance to HER-targeted therapies and Hsp90 inhibitors (e.g., AUY922). Therefore, we have developed an affibody-based PET radioconjugate that quantitatively assesses HER3 changes induced by Hsp90 inhibition in vivoExperimental Design: ZHER3:8698 affibody molecules were conjugated via the C-terminus cysteine to DFO-maleimide for 89Zr radiolabeling. The probe was characterized in vitro and in vivo in a panel of human breast cell lines and xenograft models with varying HER3 receptor levels. In addition, the radioconjugate was investigated as a tool to monitor the outcome of AUY922, an Hsp90 inhibitor, in an MCF-7 xenograft model.Results: We demonstrated that 89Zr-DFO-ZHER3:8698 can track changes in receptor expression in HER3-positive xenograft models and monitor the outcome of AUY922 treatment. Our in vitro findings showed that MCF-7 cells, which are phenotypically different from BT474, develop resistance to treatment with AUY922 through HER3/IGF-1Rβ-mediated signaling. Of note, the lack of response in vitro due to HER3 recovery was confirmed in vivo using 89Zr-DFO-ZHER3:8698-based imaging. Upon AUY922 treatment, higher radioconjugate uptake was detected in treated MCF-7 xenografts, correlating with an AUY922-induced HER3 upregulation concomitant with an increase in IGF-1Rβ expression.Conclusions: These data underline the potential of HER3-based PET imaging to noninvasively provide information about HER3 expression and to identify patients not responding to targeted therapies due to HER3 recovery. Clin Cancer Res; 24(8); 1853-65. ©2018 AACR.

Dosimetric Implications of Computerised Tomography-Only versus Magnetic Resonance-Fusion Contouring in Stereotactic Body Radiotherapy for Prostate Cancer

Background: Magnetic resonance (MR)-fusion contouring is the standard of care in prostate stereotactic body radiotherapy (SBRT) for target volume localisation. However, the planning computerised tomography (CT) scan continues to be used for dose calculation and treatment planning and verification. Discrepancies between the planning MR and CT scans may negate the benefits of MR-fusion contouring and it adds a significant resource burden. We aimed to determine whether CT-only contouring resulted in a dosimetric detriment compared with MR-fusion contouring in prostate SBRT planning. Methods: We retrospectively compared target volumes and SBRT plans for 20 patients treated clinically with MR-fusion contouring (standard of care) with those produced by re-contouring using CT data only. Dose was 36.25 Gy in 5 fractions. CT-only contouring was done on two occasions blind to MR data and reviewed by a separate observer. Primary outcome was the difference in rectal volume receiving 36 Gy or above. Results: Absolute target volumes were similar: 63.5 cc (SD ± 27.9) versus 63.2 (SD ± 26.5), Dice coefficient 0.86 (SD ± 0.04). Mean difference in apex superior-inferior position was 1.1 (SD ± 3.5; CI: −0.4–2.6). Small dosimetric differences in favour of CT-only contours were seen, with the mean rectal V36 Gy 0.3 cc (95% CI: 0.1–0.5) lower for CT-only contouring. Conclusions: Prostate SBRT can be successfully planned without MR-fusion contouring. Consideration can be given to omitting MR-fusion from the prostate SBRT workflow, provided reference to diagnostic MR imaging is available. Development of MR-only work flow is a key research priority to gain access to the anatomical fidelity of MR imaging.

Targeting HOX/PBX dimers in cancer

The HOX and PBX gene families encode transcription factors that have key roles in establishing the identity of cells and tissues in early development. Over the last 20 years it has become apparent that they are also dysregulated in a wide range of solid and haematological malignancies and have a predominantly pro-oncogenic function. A key mode of transcriptional regulation by HOX and PBX proteins is through their interaction as a heterodimer or larger complex that enhances their binding affinity and specificity for DNA, and there is growing evidence that this interaction is a potential therapeutic target in malignancies that include prostate, breast, renal, ovarian and lung cancer, melanoma, myeloma, and acute myeloid leukaemia. This review summarizes the roles of HOX and PBX genes in cancer and assesses the therapeutic potential of HOX/PBX dimer inhibition, including the availability of biomarkers for its application in precision medicine.

MRI-based Assessment of 3D Intrafractional Motion of Head and Neck Cancer for Radiation Therapy

PURPOSE

To determine the 3-dimensional (3D) intrafractional motion of head and neck squamous cell carcinoma (HNSCC).

METHODS AND MATERIALS

Dynamic contrast-enhanced magnetic resonance images from 56 patients with HNSCC in the treatment position were analyzed. Dynamic contrast-enhanced magnetic resonance imaging consisted of 3D images acquired every 2.9 seconds for 4 minutes 50 seconds. Intrafractional tumor motion was studied in the 3 minutes 43 seconds of images obtained after initial contrast enhancement. To assess tumor motion, rigid registration (translations only) was performed using a region of interest (ROI) mask around the tumor. The results were compared with bulk body motion from registration to all voxels. Motion was split into systematic motion and random motion. Correlations between the tumor site and random motion were tested. The within-subject coefficient of variation was determined from 8 patients with repeated baseline measures. Random motion was also assessed at the end of the first week (38 patients) and second week (25 patients) of radiation therapy to investigate trends of motion.

RESULTS

Tumors showed irregular occasional rapid motion (eg, swallowing or coughing), periodic intermediate motion (respiration), and slower systematic drifts throughout treatment. For 95% of the patients, displacements due to systematic and random motion were <1.4 mm and <2.1 mm, respectively, 95% of the time. The motion without an ROI mask was significantly (P<.0001, Wilcoxon signed rank test) less than the motion with an ROI mask, indicating that tumors can move independently from the bony anatomy. Tumor motion was significantly (P=.005, Mann-Whitney U test) larger in the hypopharynx and larynx than in the oropharynx. The within-subject coefficient of variation for random motion was 0.33. The average random tumor motion did not increase notably during the first 2 weeks of treatment.

CONCLUSIONS

The 3D intrafractional tumor motion of HNSCC is small, with systematic motion <1.4 mm and random motion <2.1 mm 95% of the time.

Genetically modified lentiviruses that preserve microvascular function protect against late radiation damage in normal tissues

Improvements in cancer survival mean that long-term toxicities, which contribute to the morbidity of cancer survivorship, are being increasingly recognized. Late adverse effects (LAEs) in normal tissues after radiotherapy (RT) are characterized by vascular dysfunction and fibrosis causing volume loss and tissue contracture, for example, in the free flaps used for immediate breast reconstruction after mastectomy. We evaluated the efficacy of lentivirally delivered superoxide dismutase 2 (SOD2) overexpression and connective tissue growth factor (CTGF) knockdown by short hairpin RNA in reducing the severity of LAEs in an animal model of free flap LAEs. Vectors were delivered by intra-arterial injection, ex vivo, to target the vascular compartment. LVSOD2 and LVshCTGF monotherapy before irradiation resulted in preservation of flap volume or reduction in skin contracture, respectively. Flaps transduced with combination therapy experienced improvements in both volume loss and skin contracture. Both therapies reduced the fibrotic burden after irradiation. LAEs were associated with impaired vascular perfusion, loss of endothelial permeability, and stromal hypoxia, which were all reversed in the treatment model. Using a tumor recurrence model, we showed that SOD2 overexpression in normal tissues did not compromise the efficacy of RT against tumor cells but appeared to enhance it. LVSOD2 and LVshCTGF combination therapy by targeted, intravascular delivery reduced LAE severities in normal tissues without compromising the efficacy of RT and warrants translational evaluation as a free flap-targeted gene therapy.

Intravenous delivery of oncolytic reovirus to brain tumor patients immunologically primes for subsequent checkpoint blockade

Immune checkpoint inhibitors, including those targeting programmed cell death protein 1 (PD-1), are reshaping cancer therapeutic strategies. Evidence suggests, however, that tumor response and patient survival are determined by tumor programmed death ligand 1 (PD-L1) expression. We hypothesized that preconditioning of the tumor immune microenvironment using targeted, virus-mediated interferon (IFN) stimulation would up-regulate tumor PD-L1 protein expression and increase cytotoxic T cell infiltration, improving the efficacy of subsequent checkpoint blockade. Oncolytic viruses (OVs) represent a promising form of cancer immunotherapy. For brain tumors, almost all studies to date have used direct intralesional injection of OV, because of the largely untested belief that intravenous administration will not deliver virus to this site. We show, in a window-of-opportunity clinical study, that intravenous infusion of oncolytic human Orthoreovirus (referred to herein as reovirus) leads to infection of tumor cells subsequently resected as part of standard clinical care, both in high-grade glioma and in brain metastases, and increases cytotoxic T cell tumor infiltration relative to patients not treated with virus. We further show that reovirus up-regulates IFN-regulated gene expression, as well as the PD-1/PD-L1 axis in tumors, via an IFN-mediated mechanism. Finally, we show that addition of PD-1 blockade to reovirus enhances systemic therapy in a preclinical glioma model. These results support the development of combined systemic immunovirotherapy strategies for the treatment of both primary and secondary tumors in the brain.

Warthin Tumor–Like Mucoepidermoid Carcinoma

Mucoepidermoid carcinoma (MEC) shows a wide morphologic spectrum, including epithelium with oncocytic or squamous metaplastic changes overlying a prominent cystic architecture, as well as tumor-associated lymphoid tissue. We illustrate a case of MEC of the parotid in a 17-year-old female, in which all these features occurred extensively, such that they accounted for almost the entire neoplasm, and closely mimicked Warthin tumor histologically. This highlights the need for diagnostic awareness of this particular morphologic variant of MEC, as patients could potentially be inappropriately discharged from follow-up if diagnosed with a benign neoplasm.

A practical guide to the handling and administration of talimogene laherparepvec in Europe

Talimogene laherparepvec is a herpes simplex virus-1-based intralesional oncolytic immunotherapy and is the first oncolytic virus to be approved in Europe. It is indicated for the treatment of adults with unresectable melanoma that is regionally or distantly metastatic (stage IIIB, IIIC, and IVM1a) with no bone, brain, lung, or other visceral disease. Talimogene laherparepvec is a genetically modified viral therapy, and its handling needs special attention due to its deep freeze, cold-chain requirements, its potential for viral shedding, and its administration by direct intralesional injection. This review provides a practical overview of handling, storage, and administration procedures for this agent in Europe. Talimogene laherparepvec vials should be transported/stored frozen at a temperature of −90°C to −70°C, and once thawed, vials must not be refrozen. Universal precautions for preparation, administration, and handling should be followed to avoid accidental exposure. Health care providers should wear personal protective equipment, and materials that come into contact with talimogene laherparepvec should be disposed of in accordance with local institutional procedures. Individuals who are immunocompromised or pregnant should not prepare or administer this agent. Talimogene laherparepvec is administered by intralesional injection into cutaneous, subcutaneous, and/or nodal lesions that are visible, palpable, or detectable by ultrasound. Treatment should be continued for ≥6 months. As with other immunotherapies, patients may experience an increase in the size of existing lesion(s) or the appearance of new lesions (ie, progression) prior to achieving a response (“pseudo-progression”). As several health care professionals (eg, physicians [dermatologists, surgeons, oncologists, radiologists], pharmacists, nurses) are involved in different stages of the process, there is a need for good interdisciplinary collaboration when using talimogene laherparepvec. Although there are specific requirements for this agent’s storage, handling, administration, and disposal, these can be effectively managed in a real-world clinical setting through the implementation of training programs and straightforward standard operating procedures.

Noninvasive Imaging of Cycling Hypoxia in Head and Neck Cancer Using Intrinsic Susceptibility MRI

Purpose: To evaluate intrinsic susceptibility (IS) MRI for the identification of cycling hypoxia, and the assessment of its extent and spatial distribution, in head and neck squamous cell carcinoma (HNSCC) xenografts and patients.Experimental Design: Quantitation of the transverse relaxation rate, R2*, which is sensitive to paramagnetic deoxyhemoglobin, using serial IS-MRI acquisitions, was used to monitor temporal oscillations in levels of paramagnetic deoxyhemoglobin in human CALR xenografts and patients with HNSCC at 3T. Autocovariance and power spectrum analysis of variations in R2* was performed for each imaged voxel, to assess statistical significance and frequencies of cycling changes in tumor blood oxygenation. Pathologic correlates with tumor perfusion (Hoechst 33342), hypoxia (pimonidazole), and vascular density (CD31) were sought in the xenografts, and dynamic contrast-enhanced (DCE) MRI was used to assess patient tumor vascularization. The prevalence of fluctuations within patient tumors, DCE parameters, and treatment outcome were reported.Results: Spontaneous R2* fluctuations with a median periodicity of 15 minutes were detected in both xenografts and patient tumors. Spatially, these fluctuations were predominantly associated with regions of heterogeneous perfusion and hypoxia in the CALR xenografts. In patients, R2* fluctuations spatially correlated with regions of lymph nodes with low Ktrans values, typically in the vicinity of necrotic cores.Conclusions: IS-MRI can be used to monitor variations in levels of paramagnetic deoxyhemoglobin, associated with cycling hypoxia. The presence of such fluctuations may be linked with impaired tumor vasculature, the presence of which may impact treatment outcome. Clin Cancer Res; 23(15); 4233-41. ©2017 AACR.

Abstract CT084: A Phase I dose-escalation study of ATR inhibitor monotherapy with AZD6738 in advanced solid tumors (PATRIOT Part A)

Many cancers have high levels of replication stress and a poorly functional G1/S DNA damage checkpoint. This may render them more susceptible than normal tissues to inhibition of ATR, an apical kinase in the DNA damage response and critical part of the response to DNA replication stress.

We report the early results of the monotherapy dose-escalation phase of the PATRIOT study of AZD6738, an orally active ATR inhibitor in patients (pts) with advanced solid tumors (NCT02223923), whose endpoints were MTD, safety, tolerability, pharmacokinetics (PK) and preliminary efficacy.

26 pts were enrolled between July 2014 and July 2016 in a 3+3 design. Pts received continuous BD dosing. PK analyses were performed.

Dose limiting toxicities (table 1) were thrombocytopenia (G3 with epistaxis, 1 participant; G4, 2 participants), pancytopenia (G4, 1 participant), increased amylase (G3, 1 participant).

Other treatment-related AEs (probably or definitely caused by AZD6738) affecting ≥2 participants were fatigue (9; 35% G1-4, 0% G3-4), anemia (7; 23% G1-4, 12% G3-4), nausea (4; 15% G1-4, 0% G3-4), thrombocytopenia (5; 19% G1-4, 15% G3-4), anorexia (3; 12% G1-4, 0% G3-4), dysgeusia (3; 12% G1-4, 0% G3-4), vomiting (2; 8% G1-4, 0% G3-4).

The MTD was 160 mg BD, given continuously.

Two RECIST partial responses were observed in pts with SCCHN and nasopharyngeal carcinoma, one confirmed.

Median duration taking AZD6738 was 97 days, range 30-279 days (evaluable patients only).

Two pts remain on treatment, three pts discontinued due to treatment-related toxicity.

Expansion cohorts have been initiated at 160mg BD, exploring a number of alternative treatment schedules designed to offset cumulative toxicity and test efficacy of AZD6738 monotherapy and the presence of high replication stress, DNA damage response deficiencies or ATM loss. Schedules include: AZD6738 given at 160mg BD for 21 of a 28 day cycle and 5 days on, 2 days off. A parallel study is investigating AZD6738 in combination with palliative radiotherapy.[Funded by CRUK CRUKD/14/007]

Dose Level (mg)Evaluable (total treated)Number DLTsG3-4 AEs203 (3)0elevation GGT (1, G3)403 (3)0nil806 (7)1Thrombocytopenia with epistaxis (1, G3)1606 (6)0Anaemia (1, G3)2406 (7)4Thrombocytopenia (2, G4), pancytopenia (1, G4), elevated amylase (1, G3), photosensitivity (1, G3), mucositis (1, G3), anemia (1, G3)Baseline DemographicsTumor TypesMedian (range) age59 (40-79)SCCHN6 (23%)Median (range) prior systemic therapy2 (1-4)Colorectal6 (23%)% Female31Nasopharyngeal2 (8%)Other12 (46%)

Citation Format: Magnus T. Dillon, Aude Espinasse, Sally Ellis, Kabir Mohammed, Lorna G. Grove, Lyndall McLellan, Simon A. Smith, Graham Ross, Sola Adeleke, Kin Woo, Eleni Josephides, James F. Spicer, Martin D. Forster, Kevin J. Harrington. A Phase I dose-escalation study of ATR inhibitor monotherapy with AZD6738 in advanced solid tumors (PATRIOT Part A) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr CT084. doi:10.1158/1538-7445.AM2017-CT084

Nivolumab versus standard, single-agent therapy of investigator's choice in recurrent or metastatic squamous cell carcinoma of the head and neck (CheckMate 141): health-related quality-of-life results from a randomised, phase 3 trial

BACKGROUND

Patients with platinum-refractory recurrent or metastatic squamous cell carcinoma of the head and neck have few treatment options and poor prognosis. Nivolumab significantly improved survival of this patient population when compared with standard single-agent therapy of investigator's choice in Checkmate 141; here we report the effect of nivolumab on patient-reported outcomes (PROs).

METHODS

CheckMate 141 was a randomised, open-label, phase 3 trial in patients with recurrent or metastatic squamous cell carcinoma of the head and neck who progressed within 6 months after platinum-based chemotherapy. Patients were randomly assigned (2:1) to nivolumab 3 mg/kg every 2 weeks (n=240) or investigator's choice (n=121) of methotrexate (40-60 mg/m² of body surface area), docetaxel (30-40 mg/m²), or cetuximab (250 mg/m² after a loading dose of 400 mg/m²) until disease progression, intolerable toxicity, or withdrawal of consent. On Jan 26, 2016, the independent data monitoring committee reviewed the data at the planned interim analysis and declared overall survival superiority for nivolumab over investigator's choice therapy (primary endpoint; described previously). The protocol was amended to allow patients in the investigator's choice group to cross over to nivolumab. All patients not on active therapy are being followed for survival. As an exploratory endpoint, PROs were assessed at baseline, week 9, and every 6 weeks thereafter using the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire-Core 30 (QLQ-C30), the EORTC head and neck cancer-specific module (EORTC QLQ-H&N35), and the three-level European Quality of Life-5 Dimensions (EQ-5D) questionnaire. Differences within and between treatment groups in PROs were analysed by ANCOVA among patients with baseline and at least one other assessment. All randomised patients were included in the time to clinically meaningful deterioration analyses. Median time to clinically meaningful deterioration was analysed by Kaplan-Meier methods. CheckMate 141 was registered with ClinicalTrials.org, number NCT02105636.

FINDINGS

Patients were enrolled between May 29, 2014, and July 31, 2015, and subsequently 361 patients were randomly assigned to receive nivolumab (n=240) or investigator's choice (n=121). Among them, 129 patients (93 in the nivolumab group and 36 in the investigator's choice group) completed any of the PRO questionnaires at baseline and at least one other assessment. Treatment with nivolumab resulted in adjusted mean changes from baseline to week 15 ranging from -2·1 to 5·4 across functional and symptom domains measured by the EORTC QLQ-C30, with no domains indicating clinically meaningful deterioration. By contrast, eight (53%) of the 15 domains in the investigator's choice group showed clinically meaningful deterioration (10 points or more) at week 15 (change from baseline range, -24·5 to 2·4). Similarly, on the EORTC QLQ-H&N35, clinically meaningful worsening at week 15 was seen in no domains in the nivolumab group and eight (44%) of 18 domains in the investigator's choice group. Patients in the nivolumab group had a clinically meaningful improvement (according to a difference of 7 points or greater) in adjusted mean change from baseline to week 15 on the EQ-5D visual analogue scale, in contrast to a clinically meaningful deterioration in the investigator's choice group (7·3 vs -7·8). Differences between groups were significant and clinically meaningful at weeks 9 and 15 in favour of nivolumab for role functioning, social functioning, fatigue, dyspnoea, and appetite loss on the EORTC QLQ-C30 and pain and sensory problems on the EORTC QLQ-H&N35. Median time to deterioration was significantly longer with nivolumab versus investigator's choice for 13 (37%) of 35 domains assessed across the three questionnaires.

INTERPRETATION

In this exploratory analysis of CheckMate 141, nivolumab stabilised symptoms and functioning from baseline to weeks 9 and 15, whereas investigator's choice led to clinically meaningful deterioration. Nivolumab delayed time to deterioration of patient-reported quality-of-life outcomes compared with single-agent therapy of investigator's choice in patients with platinum-refractory recurrent or metastatic squamous cell carcinoma of the head and neck. In view of the major unmet need in this population and the importance of maintaining or improving quality of life for patients with recurrent or metastatic squamous cell carcinoma of the head and neck, these data support nivolumab as a new standard-of-care option in this setting.

FUNDING

Bristol-Myers Squibb.

The effect of parotid gland-sparing intensity-modulated radiotherapy on salivary composition, flow rate and xerostomia measures

OBJECTIVES

To describe parotid gland (PG) saliva organic and inorganic composition and flow rate changes, after curative intensity-modulated radiotherapy (IMRT) for head and neck cancer (HNC), and analyse the relationship between PG saliva analytes and xerostomia measures.

METHODS AND MATERIALS

Twenty-six patients recruited to five prospective phase 2 or 3 trials which assessed toxicity and efficacy of IMRT by HNC subsite, provided longitudinal PG saliva. Salivary flow rate, and subjective and objective xerostomia measures were prospectively collected and saliva tested for inorganic and organic analytes. Statistical comparisons of longitudinal analyte changes and analysis for a relationship between dichotomized xerostomia score and saliva analytes were performed.

RESULTS

One hundred and forty-two PG saliva samples from 26 patients were analysed. At 3-6 months after IMRT, stimulated and unstimulated saliva showed significantly decreased flow rate, total protein (TP) secretion rate, phosphate concentration and increased lactoferrin (LF) concentration. Stimulated saliva alone had elevated LF secretion rate and beta-2-microglobulin (B₂ M) concentration with decreased calcium (Ca²⁺ ) and magnesium (Mg²⁺ ) concentrations and Ca²⁺ secretion rate. At >12 months, under stimulated and unstimulated conditions, increased LF concentration and decreased Mg²⁺ and phosphate concentration persisted and, in stimulated saliva, there was decreased potassium (K⁺ ) and Mg²⁺ concentration. Unstimulated TP secretion rate was lower in the presence of high-grade xerostomia. Otherwise, no relationship between xerostomia grade and PG salivary flow rate, TP and Ca²⁺ secretion rate was found.

CONCLUSION

Fewer significant differences in PG saliva analytes >12 months after IMRT indicate good functional recovery. Residual xerostomia after IMRT will only be further reduced by addressing the sparing of subsites of the PG or other salivary gland tissues, in addition to the PG.

Evidence-Based Treatment Options in Recurrent and/or Metastatic Squamous Cell Carcinoma of the Head and Neck

The major development of the past decade in the first-line treatment of recurrent and/or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN) was the introduction of cetuximab in combination with platinum plus 5-fluorouracil chemotherapy (CT), followed by maintenance cetuximab (the "EXTREME" regimen). This regimen is supported by a phase 3 randomized trial and subsequent observational studies, and it confers well-documented survival benefits, with median survival ranging between approximately 10 and 14 months, overall response rates between 36 and 44%, and disease control rates of over 80%. Furthermore, as indicated by patient-reported outcome measures, the addition of cetuximab to platinum-based CT leads to a significant reduction in pain and problems with social eating and speech. Conversely, until very recently, there has been a lack of evidence-based second-line treatment options, and the therapies that have been available have shown low response rates and poor survival outcomes. Presently, a promising new treatment option in R/M SCCHN has emerged: immune checkpoint inhibitors (ICIs), which have demonstrated favorable results in second-line clinical trials. Nivolumab and pembrolizumab are the first two ICIs that were approved by the US Food and Drug Administration. We note that the trials that showed benefit with ICIs included not only patients who previously received ≥1 platinum-based regimens for R/M SCCHN but also patients who experienced recurrence within 6 months after combined modality therapy with a platinum agent for locally advanced disease. In this review, we outline the available clinical and observational evidence for the EXTREME regimen and the initial results from clinical trials for ICIs in patients with R/M SCCHN. We propose that these treatment options can be integrated into a new continuum of care paradigm, with first-line EXTREME regimen followed by second-line ICIs. A number of ongoing clinical trials are comparing regimens with ICIs, alone and in combination with other ICIs or CT, with the EXTREME regimen for first-line treatment of R/M SCCHN. As we eagerly await the results of these trials, the EXTREME regimen remains the standard of care for the first-line treatment of R/M SCCHN.

The emerging potential of magnetic resonance imaging in personalizing radiotherapy for head and neck cancer: an oncologist's perspective

Head and neck cancer (HNC) is a challenging tumour site for radiotherapy delivery owing to its complex anatomy and proximity to organs at risk (OARs) such as the spinal cord and optic apparatus. Despite significant advances in radiotherapy planning techniques, radiation-induced morbidities remain substantial. Further improvement would require high-quality imaging and tailored radiotherapy based on intratreatment response. For these reasons, the use of MRI in radiotherapy planning for HNC is rapidly gaining popularity. MRI provides superior soft-tissue contrast in comparison with CT, allowing better definition of the tumour and OARs. The lack of additional radiation exposure is another attractive feature for intratreatment monitoring. In addition, advanced MRI techniques such as diffusion-weighted, dynamic contrast-enhanced and intrinsic susceptibility-weighted MRI techniques are capable of characterizing tumour biology further by providing quantitative functional parameters such as tissue cellularity, vascular permeability/perfusion and hypoxia. These functional parameters are known to have radiobiological relevance, which potentially could guide treatment adaptation based on their changes prior to or during radiotherapy. In this article, we first present an overview of the applications of anatomical MRI sequences in head and neck radiotherapy, followed by the potentials and limitations of functional MRI sequences in personalizing therapy.

Normal Tissue Complication Probability (NTCP) Modelling of Severe Acute Mucositis using a Novel Oral Mucosal Surface Organ at Risk

AIMS

A normal tissue complication probability (NTCP) model of severe acute mucositis would be highly useful to guide clinical decision making and inform radiotherapy planning. We aimed to improve upon our previous model by using a novel oral mucosal surface organ at risk (OAR) in place of an oral cavity OAR.

MATERIALS AND METHODS

Predictive models of severe acute mucositis were generated using radiotherapy dose to the oral cavity OAR or mucosal surface OAR and clinical data. Penalised logistic regression and random forest classification (RFC) models were generated for both OARs and compared. Internal validation was carried out with 100-iteration stratified shuffle split cross-validation, using multiple metrics to assess different aspects of model performance. Associations between treatment covariates and severe mucositis were explored using RFC feature importance.

RESULTS

Penalised logistic regression and RFC models using the oral cavity OAR performed at least as well as the models using mucosal surface OAR. Associations between dose metrics and severe mucositis were similar between the mucosal surface and oral cavity models. The volumes of oral cavity or mucosal surface receiving intermediate and high doses were most strongly associated with severe mucositis.

CONCLUSIONS

The simpler oral cavity OAR should be preferred over the mucosal surface OAR for NTCP modelling of severe mucositis. We recommend minimising the volume of mucosa receiving intermediate and high doses, where possible.

Characterization of potential predictive biomarkers of response to nivolumab in CheckMate-141 in patients with squamous cell carcinoma of the head and neck (SCCHN)

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Background: Nivolumab, an anti-programmed death-1 (PD-1) monoclonal antibody, demonstrated longer median overall survival (7.5 vs. 5.1 months) and improved response (13.3% vs. 5.8%) versus investigator choice chemotherapy (ICC) in patients with recurrent SCCHN after platinum failure in CheckMate 141 (NCT02105636), a randomized, open-label Phase 3 trial. We screened peripheral blood lymphocytes (PBL) to identify biomarkers which may predict response to nivolumab. Methods: Paired baseline (day 1) and on treatment (day 43) PBL samples (n=36; 24 nivolumab; 12 ICC) were analyzed using multicolor flow cytometry and a non-competing anti-PD-1 antibody. Results were correlated with clinical outcome: responders (complete/partial response) and non-responders (stable or progressive disease). Results: Levels of CD8+ T cells at baseline and on treatment were higher in nivolumab responders compared to non-responders (23% vs. 13%; p<0.05). Interestingly, PD-1+ CD8+ and PD-1+ CTLA-4+ CD8+ effector T cells (likely exhausted T cells) decreased about 2-fold following nivolumab in both responders and non-responders (p<0.05), whereas, the decrease in CTLA-4+ CD8+ effector T cells following nivolumab was significant in responders only (8% vs. 5%; p<0.05). Levels of PD-1+ TIM-3+ CD8+ effector cells decreased following nivolumab in non-responders only (11% vs. 7%; p<0.05), a similar non-significant reduction was observed in responders. Levels of PD-1+Tregs were lower in responders than non-responders at baseline (19% vs. 33%; p<0.01), and following nivolumab (12% vs. 20%; p<0.001). As in T effector cell populations, PD-1+ Tregs decreased about 1.6-fold after nivolumab in both responders and non-responders (p<0.01). Interestingly, baseline Ki67+ Treg levels were lower in non-responders (28% vs. 17%; p<0.05). Conclusions: Response to nivolumab may be associated with higher levels of CD8+ T cells and CTLA-4+ CD8+ effector T cells, and lower PD-1+ CD8+ effector T cells and PD-1+ Tregs at baseline. Targeting both PD-1 and CTLA-4 axes is warranted in SCCHN to overcome suppressive signals in CD8+ effector T cells and in Treg cells expressing both checkpoint receptors. Clinical trial information: NCT02105636.