Abstract OT1-04-01: Cambridge brain mets trial 1 (CamBMT1): A proof-of-principle phase 1b / randomised phase 2 study of afatinib penetration into brain metastases for patients undergoing neurosurgical resection, both with and without prior low-dose, targeted radiotherapy

Background

Failure of drugs to cross the blood brain barrier (BBB) can be a major reason for treatment failure for patients with brain tumors. For most patients who don't respond to treatment, it is not known whether this is due to inadequate drug concentrations in the tumor, or due to drug resistance. Preliminary data suggest that low-dose radiotherapy may disrupt the BBB, and could facilitate increased drug delivery into brain tumors. Afatinib is a potent, irreversible inhibitor of EGFR / HER2 / HER4 and takes approximately 8 days to achieve steady-state concentrations in cancer patients.

Aims

CamBMT1 has been designed to investigate the delivery of afatinib into brain metastases and whether this might be enhanced by low dose-radiotherapy.

Patient Population

Key eligibility criteria

Patients with operable brain metastases from breast or lung primaries for whom neurosurgical resection would be standard of care, as determined by the local multi-disciplinary team. ECOG PS 0, 1 or 2.

Trial design

After a phase 1b safety run- in, the phase 2 part of the trial randomises patients (n=60) into 3 pre-operative arms:

Arm 1afatinib alone for 11 days, then neurosurgery on day 12Arm 2afatinib for 11 days plus a single 2 Gy fraction on day 10, then neurosurgery on day 12Arm 3afatinib for 11 days plus a single 4 Gy fraction on day 10, then neurosurgery on day 12

Primary endpoint: to compare steady-state afatinib concentration in resected brain metastases, following afatinib administered alone, or in combination with radiotherapy (2 Gy or 4 Gy). Afatinib concentrations are measured in the resected brain metastases and in plasma.

Secondary endpoints: safety of afatinib administration in combination with radiotherapy; and multi-sequence MRI (optional) to detect changes in perfusion, vascular density, blood-brain-barrier permeability and interstitial pressure.

Exploratory endpoints: molecular profiling of resected brain metastases, for comparison with paired primary lung and breast cancers; the establishment and study of patient-derived xenografts.

Statistical methods

With 20 patients randomised in each of 3 arms in the phase 2 part of CamBMT1, the trial has a power of 84% at a significance level of 20% (one-sided) to detect an increase in afatinib concentrations with targeted radiotherapy, measured as a Cohen's D (standardised mean difference) ≥0.5.

Accrual

By the end of q2 2016, phase 1b had nearly completed enrolment. The randomised phase 2 part of CamBMT1 is due to open by q4 2016 at additional Experimental Cancer Medicine Centres.

Acknowledgments

CamBMT1 is funded by Cancer Research UK, the Brain Tumour Charity and Boehringer-Ingelheim.

Citation Format: Baird RD, Ramenatte N, Watts C, Jonson A, Jones L, Biggs H, Harrison E, Oberg I, Bullen G, Williams M, Qian W, Gilbert F, Jodrell D, Caldas C, Karabatsou K, Dunn L, Jena R, Whitfield G, Chalmers A, Jefferies S, Price S. Cambridge brain mets trial 1 (CamBMT1): A proof-of-principle phase 1b / randomised phase 2 study of afatinib penetration into brain metastases for patients undergoing neurosurgical resection, both with and without prior low-dose, targeted radiotherapy [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr OT1-04-01.

DOSE AND GAMMA-RAY SPECTRA FROM NEUTRON-INDUCED RADIOACTIVITY IN MEDICAL LINEAR ACCELERATORS FOLLOWING HIGH-ENERGY TOTAL BODY IRRADIATION

Production of radioisotopes in medical linear accelerators (linacs) is of concern when the beam energy exceeds the threshold for the photonuclear interaction. Staff and patients may receive a radiation dose as a result of the induced radioactivity in the linac. Gamma-ray spectroscopy was used to identify the isotopes produced following the delivery of 18 MV photon beams from a Varian 21EX and an Elekta Synergy. The prominent radioisotopes produced include ¹⁸⁷W, ⁶³Zn, ⁵⁶Mn, ²⁴Na and ²⁸Al in both linac models. The dose rate was measured at the beam exit window (12.6 µSv in the first 10 min) following 18 MV total body irradiation (TBI) beams. For a throughput of 24 TBI patients per year, staff members are estimated to receive an annual dose of up to 750 μSv at the patient location. This can be further reduced to 65 μSv by closing the jaws before re-entering the treatment bunker.

A phase II study of axitinib (AG-013736) in patients with incurable adenoid cystic carcinoma

BACKGROUND

Recurrent/metastatic adenoid cystic carcinoma (ACC) is an incurable disease with no standard treatments. The majority of ACCs express the oncogenic transcription factor MYB (also c-myb), often in the context of a MYB gene rearrangement. This phase II trial of the tyrosine kinase inhibitor (TKI) axitinib (Pfizer) tested the hypothesis that targeting pathways activated by MYB can be therapeutically effective for ACC.

PATIENTS AND METHODS

This is a minimax two-stage, phase II trial that enrolled patients with incurable ACC of any primary site. Progressive or symptomatic disease was required. Patients were treated with axitinib 5 mg oral twice daily; dose escalation was allowed. The primary end point was best overall response (BOR). An exploratory analysis correlating biomarkers to drug benefit was conducted, including next-generation sequencing (NGS) in 11 patients.

RESULTS

Thirty-three patients were registered and evaluable for response. Fifteen patients had the axitinib dose increased. Tumor shrinkage was achieved in 22 (66.7%); 3 (9.1%) had confirmed partial responses. Twenty-five (75.8%) patients had stable disease, 10 of whom had disease stability for >6 months. The median progression-free survival (PFS) was 5.7 months (range 0.92-21.8 months). Grade 3 axitinib-related toxicities included hypertension, oral pain and fatigue. A trend toward superior PFS was noted with the MYB/NFIB rearrangement, although this was not statistically significant. NGS revealed three tumors with 4q12 amplification, producing increased copies of axitinib-targeted genes PDGFR/KDR/KIT. Two 4q12 amplified patients achieved stable disease for >6 months, including one with significant tumor reduction and the longest PFS on study (21.8 months).

CONCLUSIONS

Although the primary end point was not met, axitinib exhibited clinical activity with tumor shrinkage achieved in the majority of patients with progressive disease before trial enrollment. Analysis of MYB biomarkers and genomic profiling suggests the hypothesis that 4q12 amplified ACCs are a disease subset that benefit from TKI therapy.

The symptom phenotype of oncology outpatients remains relatively stable from prior to through 1 week following chemotherapy

Some oncology outpatients experience a higher number of and more severe symptoms during chemotherapy (CTX). However, little is known about whether this high risk phenotype persists over time. Latent transition analysis (LTA) was used to examine the probability that patients remained in the same symptom class when assessed prior to the administration of and following their next dose of CTX. For the patients whose class membership remained consistent, differences in demographic and clinical characteristics, and quality of life (QOL) were evaluated. The Memorial Symptom Assessment Scale (MSAS) was used to evaluate symptom burden. LTA was used to identify subgroups of patients with distinct symptom experiences based on the occurrence of the MSAS symptoms. Of the 906 patients evaluated, 83.9% were classified in the same symptom occurrence class at both assessments. Of these 760 patients, 25.0% were classified as Low-Low, 44.1% as Moderate-Moderate and 30.9% as High-High. Compared to the Low-Low class, the other two classes were younger, more likely to be women and to report child care responsibilities, and had a lower functional status and a higher comorbidity scores. The two higher classes reported lower QOL scores. The use of LTA could assist clinicians to identify higher risk patients and initiate more aggressive interventions.

Reducing the risk of fetal distress with sildenafil study (RIDSTRESS): a double-blind randomised control trial

BACKGROUND

Labour is perhaps the most hazardous time in pregnancy. As many as 20 % of cerebral palsy cases in term infants result from intrapartum events and up to 63 % of babies who develop intrapartum compromise have no prior risk factors. Sildenafil citrate (SC), a phosphodiesterase 5 inhibitor, improves uterine blood supply through vasodilatation and potentially could improve placental perfusion and hence reduce the risk of intrapartum fetal hypoxia. The aim of this study is to evaluate the efficacy of SC to reduce the risk of intrapartum fetal compromise and the need for emergency operative delivery.

METHODS/DESIGN

This is a single centre, double-blind, randomised, phase II clinical trial of SC or placebo given during labour to women (18-50 years of age) with a single, appropriately grown, non-anomalous baby at term (37-42 weeks gestation). Those with cardiovascular, renal, hepatic, ocular or hypertensive disease or contraindication to SC will be excluded. Participants will be randomised to either SC 50 mg or placebo capsules eight hourly (SC maximum 150 mg) to commence when admitted to birth suite for management of labour. Within 3 h of the first dose, a repeat ultrasound scan will be performed to measure any changes in uteroplacental and fetal Doppler indices. Labour will continue otherwise in accordance with hospital clinical guidelines. The primary outcome is emergency caesarean section for intrapartum fetal compromise. Secondary outcomes include the effect of SC on fetal and uteroplacental blood flow, meconium liquor, fetal heart rate abnormalities and neonatal outcomes (admission to neonatal intensive care, Apgar <7 at 5 min, cord pH <7.1 or lactate >4.0 mmol/L, neonatal encephalopathy, death).

CONCLUSION

This is the first reported study evaluating the efficacy of SC on reducing the risk intrapartum fetal compromise.

TRIAL REGISTRATION

Australian New Zealand Clinical Trial Registry ACTRN12615000319572.

A large-scale, rapid public health response to rabies in an organ recipient and the previously undiagnosed organ donor

This article describes and contrasts the public health response to two human rabies cases: one organ recipient diagnosed within days of symptom onset and the transplant donor who was diagnosed 18 months post-symptom onset. In response to an organ-transplant-related rabies case diagnosed in 2013, organ donor and recipient investigations were conducted by multiple public health agencies. Persons with potential exposure to infectious patient materials were assessed for rabies virus exposure. An exposure investigation was conducted to determine the source of the organ donor's infection. Over 100 persons from more than 20 agencies spent over 2700 h conducting contact investigations in healthcare, military and community settings. The 564 persons assessed include 417 healthcare workers [5.8% recommended for post-exposure prophylaxis (PEP)], 96 community contacts (15.6% recommended for PEP), 30 autopsy personnel (50% recommended for PEP), and 21 other persons (4.8% recommended for PEP). Donor contacts represented 188 assessed with 20.2% recommended for PEP, compared with 5.6% of 306 recipient contacts recommended for PEP. Human rabies cases result in substantial use of public health and medical resources, especially when diagnosis is delayed. Although rare, clinicians should consider rabies in cases of encephalitis of unexplained aetiology, particularly for cases that may result in organ donation.

The demographics of the United States haemophilia treatment centre social workers: the results of a national survey

Social Workers (SWs) are vital members of the multidisciplinary health care teams at Hemophilia Treatment Centers (HTCs) across the US. However, little research has been done to identify the demographics and qualifications of HTC SWs. In response to this lack of data, a subcommittee from the Social Work Working Group sponsored by the National Hemophilia Foundation conducted a national online survey in 2010. The authors attempted to ascertain the demographics and characteristics of SWs who work at HTCs across the country. The purpose of this article is to report the results of this online survey and evaluate the parameters of SW demographics in HTCs. Electronic surveys were sent to 143 HTC SWs. Ten were excluded and 100 were completed and returned, yielding a 75% response rate. The great majority of HTC SWs are women and almost half are middle-aged (aged 40-59). They represent a highly educated, very experienced group of professionals. When asked why respondents stayed in their positions at the HTCs, answers appeared to highly correlate to factors related to the HTC multidisciplinary team model. The high survey response rate of 75% reflects the interest of HTC SWs in obtaining data that describe and quantify their qualifications. This information may serve as validation of the haemophilia SW role in times of funding cuts. It may also give a basis for the recruitment and retention of SWs in the haemophilia field.

The effect of irregular breathing patterns on internal target volumes in four-dimensional CT and cone-beam CT images in the context of stereotactic lung radiotherapy

PURPOSE

Stereotactic lung radiotherapy is complicated by tumor motion from patient respiration. Four-dimensional CT (4DCT) imaging is a motion compensation method used in treatment planning to generate a maximum intensity projection (MIP) internal target volume (ITV). Image guided radiotherapy during treatment may involve acquiring a volumetric cone-beam CT (CBCT) image and visually aligning the tumor to the planning 4DCT MIP ITV contour. Moving targets imaged with CBCT can appear blurred and currently there are no studies reporting on the effect that irregular breathing patterns have on CBCT volumes and their alignment to 4DCT MIP ITV contours. The objective of this work was therefore to image a phantom moving with irregular breathing patterns to determine whether any configurations resulted in errors in volume contouring or alignment.

METHODS

A Perspex thorax phantom was used to simulate a patient. Three wooden "lung" inserts with embedded Perspex "lesions" were moved up to 4 cm with computer-generated motion patterns, and up to 1 cm with patient-specific breathing patterns. The phantom was imaged on 4DCT and CBCT with the same acquisition settings used for stereotactic lung patients in the clinic and the volumes on all phantom images were contoured. This project assessed the volumes for qualitative and quantitative changes including volume, length of the volume, and errors in alignment between CBCT volumes and 4DCT MIP ITV contours.

RESULTS

When motion was introduced 4DCT and CBCT volumes were reduced by up to 20% and 30% and shortened by up to 7 and 11 mm, respectively, indicating that volume was being under-represented at the extremes of motion. Banding artifacts were present in 4DCT MIP images, while CBCT volumes were largely reduced in contrast. When variable amplitudes from patient traces were used and CBCT ITVs were compared to 4DCT MIP ITVs there was a distinct trend in reduced ITV with increasing amplitude that was not seen when compared to true ITVs. Breathing patterns with a rest period following expiration resulted in well-defined superior edges and were better aligned using an edge-to-edge alignment technique. In most cases, sinusoidal motion patterns resulted in the closest agreements to true values and the smallest misalignments.

CONCLUSIONS

Strategies are needed to compensate for volume losses at the extremes of motion for both 4DCT MIP and CBCT images for larger and varied amplitudes, and for patterns with rest periods following expiration. Lesions moving greater than 2 cm would warrant larger treatment margins added to the 4DCT MIP ITV to account for the volume being under-represented at the extremes of motion. Lesions moving with a rest period following expiration would be better aligned using an edge-to-edge alignment technique. Sinusoidal patterns represented the ideal clinical scenario, reinforcing the importance of investigating clinically relevant motions and their effects on 4DCT MIP and CBCT volumes. Since most patients do not breathe sinusoidally this may lead to misinterpretation of previous studies using only sinusoidal motion.

Adverse cardiac remodeling due to maternal low protein diet is associated with alterations in expression of genes regulating glucose metabolism

BACKGROUND AND AIMS

We have previously shown that a maternal low protein (LP) diet during pregnancy in the rat results in adverse ventricular remodeling and contractile deficiencies of the neonatal rat heart. Since pathological cardiac hypertrophy is associated with increased expression of genes involved in glucose handling, this study was undertaken to examine if maternal LP diet alters the expression of genes encoding for some key components of glucose metabolism and uptake, and of the insulin receptor (IR) signal transduction in the heart of male offspring.

METHODS AND RESULTS

We determined the effect of maternal LP and normal diet (90 and 180 g/casein/kg respectively) on IR β-subunit, insulin receptor substrate (IRS)-1, phosphotyrosyl protein phosphatase (PTP) 1B, GLUT4 and phosphatidylinositol (PI) 3-kinase in male rat offspring at 24 h and at 1, 4 and 8 wks post-partum. Quantitative real-time RT-PCR revealed significant age-dependent increases in the expression of IR β-subunit, IRS-1, PTP1B, GLUT4 and PI3-kinase in the LP group with concomitant increases in corresponding protein abundance at 4 wks of age. These changes were associated with increases in left ventricular (LV) internal diameters as well as increases in LV wall thickness.

CONCLUSION

A maternal LP diet can induce increases in the gene expression and protein levels of key components of glucose metabolism and the IR signal transduction pathway in the neonatal rat heart, which may be related to accelerated energy supply, demand and utilization for ventricular remodeling due to compromised contractile performance during early life.

A phantom for testing of 4D-CT for radiotherapy of small lesions

PURPOSE

The use of time-resolved four-dimensional computed tomography (4D-CT) in radiotherapy requires strict quality assurance to ensure the accuracy of motion management protocols. The aim of this work was to design and test a phantom capable of large amplitude motion for use in 4D-CT, with particular interest in small lesions typical for stereotactic body radiotherapy.

METHODS

The phantom of "see-saw" design is light weight, capable of including various sample materials and compatible with several surrogate marker signal acquisition systems. It is constructed of polymethylmethacrylate (Perspex) and its movement is controlled via a dc motor and drive wheel. It was tested using two CT scanners with different 4D acquisition methods: the Philips Brilliance Big Bore CT (helical scan, pressure belt) and a General Electric Discovery STE PET∕CT (axial scan, infrared marker). Amplitudes ranging from 1.5 to 6.0 cm and frequencies of up to 40 cycles per minute were used to study the effect of motion on image quality. Maximum intensity projections (MIPs), as well as average intensity projections (AIPs) of moving objects were investigated and their quality dependence on the number of phase reconstruction bins assessed.

RESULTS

CT number discrepancies between moving and stationary objects were found to have no systematic dependence on amplitude, frequency, or specific interphase variability. MIP-delineated amplitudes of motion were found to match physical phantom amplitudes to within 2 mm for all motion scenarios tested. Objects undergoing large amplitude motions (>3.0 cm) were shown to cause artefacts in MIP and AIP projections when ten phase bins were assigned. This problem can be mitigated by increasing the number of phase bins in a 4D-CT scan.

CONCLUSIONS

The phantom was found to be a suitable tool for evaluating the image quality of 4D-CT motion management technology, as well as providing a quality assurance tool for intercenter∕intervendor testing of commercial 4D-CT systems. When imaging objects with large amplitudes, the completeness criterion described here indicates the number of phase bins required to prevent missing data in MIPs and AIPs. This is most relevant for small lesions undergoing large motions.