Re-evaluating the need for chronic toxicity studies with therapeutic monoclonal antibodies, using a weight of evidence approach

To support registration of monoclonal antibodies (mAbs) for chronic indications, 6-month toxicity studies have historically been conducted. Experience with mAb development has shown a relatively benign and well-understood safety profile for this class, with most toxicity findings anticipated based on pharmacology. We evaluated whether a 6-month toxicity study is necessary to assess the long-term safety of mAbs. Data on First-in-Human (FIH)-enabling and chronic toxicity studies were shared for 142 mAbs submitted by 11 companies. Opportunities to further optimize study designs to reduce animal usage were identified. For 71% of mAbs, no toxicities or no new toxicities were noted in chronic studies compared to FIH-enabling study findings. New toxicities of potential concern for human safety or that changed trial design were identified in 13.5% of cases, with 7% being considered critical and 2% leading to program termination. An iterative, weight-of-evidence model which considers factors that influence the overall risk for a mAb to cause toxicity was developed. This model enables an evidence-based justification, suggesting when 3-month toxicity studies are likely sufficient to support late-stage clinical development and registration for some mAbs.

The use of recovery animals in nonclinical safety assessment studies with monoclonal antibodies: further 3Rs opportunities remain

Assessment of reversibility from nonclinical toxicity findings in animals with potential adverse clinical impact is required during pharmaceutical development, but there is flexibility around how and when this is performed and if recovery animals are necessary. For monoclonal antibodies (mAbs) and in accordance with ICH S6(R1) if inclusion of recovery animals is warranted, this need only occur in one study. Data on study designs for first-in-human (FIH)-enabling and later-development toxicity studies were shared from a recent collaboration between the NC3Rs, EPAA, Netherlands Medicines Evaluation Board (MEB) and 14 pharmaceutical companies. This enabled a review of practices on recovery animal use during mAb development and identification of opportunities to reduce research animal use. Recovery animals were included in 68% of FIH-enabling and 69% of later-development studies, often in multiple studies in the same program. Recovery groups were commonly in control plus one test article-dosed group or in all dose groups (45% of studies, each design). Based on the shared data review and conclusions, limiting inclusion of recovery to a single nonclinical toxicology study and species, study design optimisation and use of existing knowledge instead of additional recovery groups provide opportunities to further reduce animal use within mAb development programs.

Nonclinical Development of Biologics: Integrating Safety, Pharmacokinetics, and Pharmacodynamics to Create Smarter and More Flexible Nonclinical Safety Programs Optimizing Animal Use

Safety assessment of biological drugs has its challenges due to the multiple new different modalities, for example, antibody-drug conjugates, bispecifics, nanobodies, fusion proteins and advanced therapy medicinal products (ATMPs), their different pharmacokinetic and pharmacodynamic properties, and their ability to trigger immunogenicity and toxicity. In the public and in the pharmaceutical industry, there is a strong and general desire to reduce the number of animals used in research and development of drugs and in particular reducing the use of nonhuman primates. Important discussions and activities are ongoing investigating the smarter designs of early research and dose range finding studies, reuse of animals, and replacing animal experiments with in vitro studies. Other important challenges include absence of a relevant species and design of studies and developing genetically modified animals for special investigative toxicology studies. Then, the learnings and challenges from the development of the first ATMPs are available providing valuable insights in the development path for these new potentially transformative treatments. Finally, development of strategies for assessment of immunogenicity and prediction of translation of immunogenicity and associated findings to the clinic. On this, the eighth meeting for the European BioSafe members, these challenges served as the basis for the presentations and discussions during the meeting. This article serves as the workshop report reviewing the presentations and discussions at the meeting.

Congenital Unilateral Renal Aplasia in a Cynomolgus Monkey (Macaca fascicularis) With Investigation Into Potential Pathogenesis

We describe and characterize unilateral renal aplasia in a cynomolgus monkey (Macaca fascicularis) from a chronic toxicology study adding to the limited histopathology reports of congenital renal anomalies in macaques. In the current case, the affected kidney was macroscopically small and characterized microscopically by a thin cortex with an underdeveloped medulla and an absent papilla. The remnant medulla lacked a corticomedullary junction and contained only a few irregular collecting duct-like structures. The cortex had extensive interstitial mature collagen deposition with fibromuscular collar formation around Bowman's capsules. Due to parenchymal collapse, mature glomeruli were condensed together with occasional atrophic and sclerotic glomeruli. The majority of the cortical tubules were poorly differentiated with only small islands of fully developed cortical tubules present. Histochemical and immunohistochemical stains were utilized to demonstrate key diagnostic features of this congenital defect, to assist with differentiating it from renal dysplasia, and to provide potential mechanistic pathways. Immunostaining (S100, paired box gene 2 [PAX2], aquaporins) of the medulla was compatible with incomplete maturation associated with aplasia, while the immunostaining profile for the cortex (vimentin, calbindin, PAX2-positive cortical tubules, and smooth muscle actin-positive fibromuscular collars) was most compatible with dedifferentiation secondary to degenerative changes.

Opportunities for use of one species for longer-term toxicology testing during drug development: A cross-industry evaluation

An international expert working group representing 37 organisations (pharmaceutical/biotechnology companies, contract research organisations, academic institutions and regulatory bodies) collaborated in a data sharing exercise to evaluate the utility of two species within regulatory general toxicology studies. Anonymised data on 172 drug candidates (92 small molecules, 46 monoclonal antibodies, 15 recombinant proteins, 13 synthetic peptides and 6 antibody-drug conjugates) were submitted by 18 organisations. The use of one or two species across molecule types, the frequency for reduction to a single species within the package of general toxicology studies, and a comparison of target organ toxicities identified in each species in both short and longer-term studies were determined. Reduction to a single species for longer-term toxicity studies, as used for the development of biologicals (ICHS6(R1) guideline) was only applied for 8/133 drug candidates, but might have been possible for more, regardless of drug modality, as similar target organ toxicity profiles were identified in the short-term studies. However, definition and harmonisation around the criteria for similarity of toxicity profiles is needed to enable wider consideration of these principles. Analysis of a more robust dataset would be required to provide clear, evidence-based recommendations for expansion of these principles to small molecules or other modalities where two species toxicity testing is currently recommended.

Characterization of the nonmuscle myosin heavy chain IIB promoter: regulation by E2F

To identify DNA sequences important for the transcriptional regulation of the nonmuscle myosin heavy chain IIB (NMMHC-IIB) gene we isolated and sequenced genomic clones that contain the promoter of the gene for both human and mouse. In addition to considerable homology in the first (untranslated) exon (91%) we found 80% sequence identity in the 700 base pairs immediately upstream of the major start of transcription (+1) as well as significant homologies as far as 1500 base pairs upstream. The promoter region was characterized using luciferase reporter constructs transiently transfected into NIH3T3 cells. Consensus binding sites for several known transcription factors are present that are completely conserved between the mouse and human genes, including CRE/ATF, Sp1, CAAT, and the cell-cycle transcription factor E2F. Gel shift assays indicated that E2F can bind to its putative binding site in vitro. To test whether this site is functional we cotransfected NMMHC-IIB promoter constructs driving luciferase with a vector expressing E2F-1. The E2F-1 vector stimulated luciferase activity from an intact promoter whereas mutation of the site eliminates binding and diminishes transactivation. These data provide strong evidence that E2F or an E2F-related transcription factor is involved in the regulation of nonmuscle myosin expression.

Impact of the Spinal Instability Neoplastic Score on Surgical Referral Patterns and Outcomes

Background

The Spinal Instability Neoplastic Score (sins) was developed to identify patients with spinal metastases who may benefit from surgical consultation. We aimed to assess the distribution of sins in a population-based cohort of patients undergoing palliative spine radiotherapy (rt) and referral rates to spinal surgery pre-rt. Secondary outcomes included referral to a spine surgeon post-rt, overall survival, maintenance of ambulation, need for re-intervention, and presence of spinal adverse events.

Methods

We retrospectively reviewed ct simulation scans and charts of consecutive patients receiving palliative spine rt between 2012 and 2013. Data were analyzed using Student's t-test, Chi-squared, Fisher's exact, and Kaplan-Meier log-rank tests. Patients were stratified into low (<7) and high (≥7) sins groups.

Results

We included 195 patients with a follow-up of 6.1 months. The median sins was 7. The score was 0 to 6 (low, no referral recommended), 7 to 12 (intermediate, consider referral), and 13 to 18 (high, referral suggested) in 34%, 59%, and 7% of patients, respectively. Eleven patients had pre-rt referral to spine surgery, with a surgery performed in 0 of 1 patient with sins 0 to 6, 1 of 7 with sins 7 to 12, and 1 of 3 with sins 13 to 18. Seven patients were referred to a surgeon post-rt with salvage surgery performed in two of those patients. Primary and secondary outcomes did not differ between low and high sins groups.

Conclusion

Higher sins was associated with pre-rt referral to a spine surgeon, but most patients with high sins were not referred. Higher sins was not associated with shorter survival or worse outcome following rt.

Biotherapeutics in non-clinical development: Strengthening the interface between safety, pharmacokinetics-pharmacodynamics and manufacturing

Biological drugs comprise a wide field of different modalities with respect to structure, pharmacokinetics and pharmacological function. Considerable non-clinical experience in the development of proteins (e.g. insulin) and antibodies has been accumulated over the past thirty years. In order to improve the efficacy and the safety of these biotherapeutics, Fc modifications (e.g. Fc silent antibody versions), combinations (antibody-drug conjugates, protein-nanoparticle combinations), and new constructs (darpins, fynomers) have been introduced. In the last decade, advanced therapy medicinal products (ATMPs) in research and development have become a considerable and strongly growing part of the biotherapeutic portfolio. ATMPs consisting of gene and cell therapy modalities or even combinations of them, further expand the level of complexity, which already exists in non-clinical development strategies for biological drugs and has thereby led to a further diversification of expertise in safety and PKPD assessment of biological drugs. It is the fundamental rationale of the BioSafe meetings, held yearly in the EU and in the US, to convene experts on a regular basis and foster knowledge exchange and mutual understanding in this fast growing area. In order to reflect at least partially the variety of the biotherapeutics field, the 2016 EU BioSafe meeting addressed the following topics in six sessions: (i) In vitro Meets in vivo to Leverage Biologics Development (ii) New developments and regulatory considerations in the cell and gene therapy field (iii) CMC Challenges with Biologics development (iv) Minipigs in non-clinical safety assessment (v) Opportunities of PKPD Assessment in Less Common Administration Routes In the breakout sessions the following questions were discussed: (i) Cynomolgus monkey as a reprotoxicology Species: Impact of Immunomodulators on Early Pregnancy Maintenance (ii) Safety Risk of Inflammation and Autoimmunity Induced by Immunomodulators (iii) Experience with non-GMP Material in Pivotal Non-clinical Safety Studies to Support First in Man (FiM) Trials (iv) Safety Assessment of Combination Products for Non-oncology.

Abstract P1-10-06: Hypofractionated nodal radiotherapy (RT) did not increase arm morbidity compared to conventional fractionated nodal RT

Purpose: Regional nodal radiation therapy (RT) can cause adverse arm symptoms and lymphedema. Hypofractionation (HF), defined as &gt;2 Gy/fraction, improves convenience but whether it increases arm morbidity is unclear. This study evaluates patient-reported arm symptoms in women treated with HF compared to conventional fractionation (CF) RT (defined as ≤2Gy/fraction).

Materials / Methods: Provincial cancer registries were used to identify subjects who received 3D, CT-planned nodal RT for pT1-3 pN0-2 M0 breast cancer from 2007-2009 in British Columbia and 2008 – 2010 in Alberta, Canada. Treatment eras were selected to enable sufficient follow-up time to develop late arm symptoms. Following research ethics approval, eligible patients were mailed an explanation letter and an externally validated, Self-reported Arm Symptom Scale (SASS) survey. The SASS included 8 questions about arm symptoms, with responses on a 5-point Likert scale regarding arm/hand problems (numbness, pain, stiffness, immobility and swelling), and 5 questions related to activities of daily living (ADL). Clinicopathologic characteristics and SASS scores were compared between HF vs. CF nodal RT cohorts using non-parametric analysis (on ordinal and scale responses) and binned chi-squared analysis (comparison for responses of 1 vs. &gt; 1).

Results: 800/1759 eligible patients returned a completed survey (45.5%). Upon detailed chart review of responders, 92 cases with recurrence or metastasis were excluded. The remaining 708 cases formed the study cohort. Of these, 406 (57%) patients received HF RT (modal dose/fractionation 40 Gy/15 fractions (fx) and 45 Gy/20 fx), and 302 (43%) received CF RT (45 Gy/25 fx, 48-50 Gy/25 fx, and 50.4 Gy/28 fx). A boost was delivered to the breast in 22% of subjects, equally by fractionation group (p=0.31).

Median time interval since RT completion was 5.67 years. The mean age at diagnosis was 59.0 in HF vs 53.8 years in CF-treated cohorts (p&lt;0.001). The mean # positive (n=3) and excised (n=12) nodes were similar between fractionation cohorts (p=0.44). Primary tumor size was marginally larger in the CF group (2.8 vs. 2.7 cm, p=0.03). 42.9% of patients were treated with partial mastectomy with no significant difference in fractionation (p=0.54). Overall, 602 (75.3%) patients received chemotherapy. A trend toward increased use of CF after chemotherapy was observed (78.8% vs. 72.7%, p=0.07).

The mean sums of responses for the arm symptoms / ADL components of the SASS were 12.5 / 7.6 vs. 13.3 / 7.9 for the HF and CF groups respectively (p=0.17 / 0.85). On analysis of individual questions, the CF group had a higher prevalence of self-reported symptoms, including shoulder stiffness (p=0.04), trouble moving the arm (p=0.02), and ability to reach overhead (p&lt;0.01). There was no difference in self-reported arm swelling between the two groups (p=0.57).

Conclusion: Hypofractionated nodal RT was not associated with an increase in patient-reported arm symptoms or disability compared to conventional fractionated nodal RT. Subjects treated with CF RT reported more disability in certain aspects of arm and shoulder function. These data support the use of shorter fractionation when the regional lymph nodes are part of the therapeutic target.

Citation Format: Leong N, Truong P, Tankel K, Kwan W, Weir L, Olivotto I. Hypofractionated nodal radiotherapy (RT) did not increase arm morbidity compared to conventional fractionated nodal RT [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 P1-10-06.

Nonclinical safety testing of biopharmaceuticals--Addressing current challenges of these novel and emerging therapies

Non-clinical safety testing of biopharmaceuticals can present significant challenges to human risk assessment with these often innovative and complex drugs. Hot Topics in this field were discussed recently at the 4th Annual European Biosafe General Membership meeting. In this feature article, the presentations and subsequent discussions from the main sessions are summarized. The topics covered include: (i) wanted versus unwanted immune activation, (ii) bi-specific protein scaffolds, (iii) use of Pharmacokinetic (PK)/Pharmacodynamic (PD) data to impact/optimize toxicology study design, (iv) cytokine release and challenges to human translation (v) safety testing of cell and gene therapies including chimeric antigen receptor T (CAR-T) cells and retroviral vectors and (vi) biopharmaceutical development strategies encompassing a range of diverse topics including optimizing entry of monoclonal antibodies (mAbs) into the brain, safety testing of therapeutic vaccines, non-clinical testing of biosimilars, infection in toxicology studies with immunomodulators and challenges to human risk assessment, maternal and infant anti-drug antibody (ADA) development and impact in non-human primate (NHP) developmental toxicity studies, and a summary of an NC3Rs workshop on the future vision for non-clinical safety assessment of biopharmaceuticals.

Population-based analysis of the impact and generalizability of the NSABP-B24 study on endocrine therapy for patients with ductal carcinoma in situ of the breast

BACKGROUND

In 1999, the National Surgical Adjuvant Breast and Bowel Project (NSABP)-B24 trial demonstrated that tamoxifen reduced relapse risk in women with ductal carcinoma in situ (DCIS) treated with breast-conserving surgery (BCS) and radiotherapy (RT). In 2002, Allred's subgroup analysis showed that tamoxifen mainly benefitted estrogen receptor (ER)-positive disease. This study evaluates the impact and generalizability of these trial findings at the population level.

PATIENTS AND METHODS

From 1989 to 2009, 2061 women with DCIS underwent BCS + RT in British Columbia. The following cohorts were analyzed: (1) pre-NSABP-B24 era (1989-1998, N = 417); (2) post-NSABP-B24 era (2000-2009, N = 1548). Cohort 2 was further divided into pre- and post-Allred eras.

RESULTS

Endocrine therapy (ET) was used in 404/2061 (20%) patients. Median age of patients treated with compared with without ET, was 53 versus 57 years, (P < 0.0005). One of 417 (0.2%) versus 399/1548 (26%) patients took ET before versus after NSABP-B24. Among the post-Allred era cohort treated with ET (N = 227), tumors were ER-positive in 65%, ER-negative in 1%, and ER-unknown in 33%; whereas of those treated without ET (N = 801), ER was positive in 43%, negative in 15%, and unknown in 42% (P < 0.0005). On multivariable analysis of the post-NSABP-B24 era, ET was associated with improved event-free survival (EFS) (hazard ratio 0.6; P = 0.02); 5-year EFS were 96.9% with ET versus 94.5% without ET.

CONCLUSIONS

ET use in DCIS patients treated with BCS + RT increased significantly after the NSABP-B24 study. ER+ disease and younger age were associated with increased ET use. ET was associated with improved EFS, confirming the generalizability of trial data at a population level.

Abstract P4-16-01: Accelerated hypofractionated whole breast radiotherapy for localized breast cancer: the effect of a boost on patient reported long-term cosmetic outcome

PURPOSE: Equivalent long-term local control and cosmetic outcomes between conventional and accelerated, hypofractionated whole breast radiotherapy (AWBRT) for early-stage breast cancer have been demonstrated. However, there is uncertainty about the long-term cosmetic outcome of a boost to the tumor bed following AWBRT (AWBRT+B). The primary outcome of this study was to evaluate the cosmetic effect of a boost using a patient reported questionnaire. The cosmetic subscale in the questionnaire was used to compare the appearance of the treated versus non treated breast between the boost and non-boost groups.

MATERIALS AND METHODS: Between 2000 and 2005, 4392 women 75 years and under with unilateral early-stage breast cancer received AWBRT alone or AWBRT+B. Random samples of 800 women treated with AWBRT alone and 800 women treated with AWBRT+B were identified from the 3960 women still alive at least 5 years after treatment without contralateral disease. The women were contacted by mail to complete a questionnaire based on the Breast Cancer Treatment Outcomes Scale (22 questions regarding cosmetic, pain and functional outcomes). Cochrane-Armitage (CA) trend test and Wilcoxon Rank-sum (WR) were used to compare baseline patient and treatment variables to long-term cosmetic outcomes between the two treatment groups.

RESULTS: 312 women (154 received AWBRT alone and 158 received AWBRT+B) completed the questionnaire. The median (range) age of respondents was 57 (40–75) years in the AWBRT alone group and 52 (32–75) years in the AWBRT+B group (p &lt; 0.001). The median (range) follow-up time after radiotherapy treatment was 8.7 (5.5–11.5) years in the AWBRT alone group and 7.8 (5.5–11.5) years in the AWBRT+B group (p &lt; 0.001). Boost doses ranged between 7.5 Gy in 3 fractions to 16 Gy in 8 fractions. The most commonly used boost regimen was 10 Gy in 4 fractions (70% of respondents). Women treated with AWBRT+B also had higher T stage, higher grade, were more likely to have had chemotherapy and trended towards having an increased number of positive nodes compared to the AWBRT alone group. Current weight, ER status, and use of hormonal therapy were similar between both groups.

When comparing the overall appearance of the treated to untreated breast, there was no significant difference between the women who received AWBRT alone and those who received AWBRT+B (42% stating no or slight difference vs. 41%) (p = 0.87 CA). Focusing on the cosmetic subscale in the questionnaire, the average summed score for the AWBRT alone group was slightly worse to the score for the AWBRT+B group (2.3 vs. 2.1, p = 0.02 WR). On the functional subscale, the average summed score for the AWBRT alone group was worse than the AWBRT+B group (1.8 versus 1.5, p &lt; 0.001 WR). On the pain subscale, the average summed score for the AWBRT alone group was better than the AWBRT+B group (1.6 versus 2.0, p &lt; 0.0001 WR). However, when the pain subscale was only applied to the area around the scar, the two groups were similar (2.0 for AWBRT alone and 2.0 for AWBRT+B, p = 0.71).

CONCLUSION: Similar to conventionally fractionated WBRT, patients who receive a boost after AWBRT self-report long-term slightly worse cosmetic and pain outcomes compared AWBRT alone.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P4-16-01.

Age over 80 years is not associated with increased hemorrhagic transformation after stroke thrombolysis

Thrombolysis trials have recruited few patients aged ≥80 years, which has led to uncertainty about the likely risk-to-benefit profile in the elderly. Leukoaraiosis (LA) has been associated with hemorrhagic transformation (HT) and increases with advanced age. We tested whether there were any independent associations between age, LA and HT. Consecutive patients treated with intravenous (IV) tissue plasminogen activator (tPA) were identified from a prospective database. LA on baseline CT scans was assessed by two independent raters using the modified Van Swieten Score (mVSS) (maximum score 8, severe >4). HT was assessed on routine 24 hour to 48 hour CT /MRI scans using the European Cooperative Acute Stroke Study criteria for hemorrhagic infarct (HI) or parenchymal hematoma (PH) and judged symptomatic by the treating neurologist as per Safe Implementation of Thrombolysis in Stroke criteria. There were 206 patients treated with IV tPA (mean age: 71.0 years; range: 24-92 years), of whom 65/206 (32%) were aged ≥80 years. Overall, HT occurred in 41/206 patients (20%), HI in 31, PH1 in four (one symptomatic) and PH2 in six (three symptomatic). Age was not associated with HT (any HT: odds ratio [OR]=1.01; 95% confidence interval [CI]=0.5-2.08; p=0.99; PH: OR=0.53; 95% CI=0.12-2.3; p=0.51). There was one patient with PH1 and one patient with PH2 in 65 patients ≥80 years, both asymptomatic. LA was present in 112/208 (54%), and severe in 16.5%. LA increased with age (p<0.001) but was not associated with PH (any LA: OR=0.83; 95% CI=0.25-2.8; p=0.99; severe LA: OR=0.54, 95% CI=0.09-3.5; p=0.99). Age ≥80 years or LA did not increase the risk of HT (including PH) after thrombolysis, although LA increased with age. Neither factor should exclude otherwise eligible patients from tPA treatment.

Impact of internal mammary node inclusion in the radiation treatment volume on the outcomes of patients with breast cancer treated with locoregional radiation after six years of follow-up

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Background: There is ongoing controversy about radiotherapy (RT) to internal mammary nodes (IMNs). Proponents of IMN RT cite the survival benefit seen in postmastectomy RT trials that included IMNs. However, others point out that benefit cannot be definitively attributed to IMN inclusion, as other lymph node regions were included in the RT arms. The issue is important, as IMN RT potentially increases cardiac and respiratory morbidity.

Methods: 2,413 women referred to a provincial RT program with newly diagnosed node positive, or T3/4N0 non-M1 invasive breast cancer, treated with a complete course of locoregional RT from 2001 to 2006, were retrospectively identified in a provincial database. IMN RT inclusion versus exclusion was determined through review of patient charts and RT treatment plans. Breast cancer-specific survival (BCSS), relapse-free survival (RFS), and overall survival (OS) were compared between the two groups using univariate and multivariable analyses.

Results: Analyses were performed at a median follow-up of 6.2 years. 41.4% of the subjects received IMN RT. The 5-year BCSS for the IMN inclusion and exclusion group was 84.8% versus 82.9%, respectively (HR 0.93 [95% CI 0.76, 1.14]; p=.51); the 5-year RFS was 87.4% versus 86.9% (HR 0.993 [0.83, 1.19]; p=0.94); and the 5-year OS was 84.8% versus 82.9% (HR 0.84 [0.70, 1.01]; p=0.06). After controlling for potentially confounding variables, there was no significant difference in BCSS (HR 0.96 [0.78, 1.18], p=0.88), RFS (HR 1.02 [0.84, 1.22], p=0.87), or OS (HR 0.91 [0.76, 1.10]; p=0.35).

Conclusions: After a median follow-up of 6.2 years, this population-based study shows no benefit from including IMNs in the locoregional RT volume after adjusting for other prognostic and treatment variables.

Abstract P4-11-03: The Impact of Fractionation on Local Relapse for Patients with Grade 3 Breast Cancer

Background: Several randomized trials have demonstrated that hypofractionated (HF) and conventionally fractionated (CF) radiotherapy (RT) provide equivalent local control following breast conserving surgery (BCS). However, an update of the Canadian trial suggested that patients with grade 3 disease had an increased risk of local relapse after HF. The risk of local relapse following HF or CF according to grade was investigated among a population-based cohort from British Columbia, Canada. Materials and methods: Female patients diagnosed between 1990 and 2000 with T1-T2N0M0 breast cancer treated with lumpectomy, axillary dissection and RT with at least 6 nodes removed and RT delivered to the breast were identified. Whole breast RT prescriptions were distributed in two groups : HF (typically 42.5 to 44 Gy in 16 fractions), and CF (45Gy to 50 Gy in 25 fractions). The 45 Gy prescription was followed by a boost to the biopsy cavity regardless of the margin status. Patients with close or positive margins received a boost (typically 7.5 to 10Gy in 3 to 4 fractions, or 10 to 20Gy in 5 to 10 fractions). Baseline demographic (age, year of diagnosis), tumour (grade, histology, size, lymphatic vascular space invasion (LVI), presence of extensive DCIS) and treatment factors (margin status, hormonal or chemotherapy use, RT fractionation group, and RT boost use) were abstracted. Cumulative rates of local relapse were estimated using a competing risk approach (distant relapses or death were competing risks) and compared across groups using Gray's test. Factors significant on univariate analysis were included with fractionation group in a multivariate (Fine and Gray) model among grade 3 patients. Results: The cohort consisted of 1,335 patients diagnosed with grade 3 breast cancers: 252 received CF and 1083 patients received HF. The fractionation groups were well balanced for most of the aforementioned factors except median age (56 years for CF vs 52 years for HF (P&lt;0.01), and use of systemic therapy (hormones alone: 26% vs 19%; chemotherapy alone: 27%vs 33%; and chemo+hormone therapy: 8% vs 10% (p=0.04) for HF compared to CF). The 10-year cumulative incidence rate of local relapse in patients with grade 3 breast cancers was 6.9% for the HF group and 6.2 % for the CF group (p=0.99). A Fine and Gray multivariate competing risk model showed that age under 40 years (p=0.02), positive margins (p=0.05) and negative ER status (p=0.01) were associated with an increased risk of local relapse, but fractionation group was not (Hazard ratio=0.95, p=0.88).

Conclusions: There was no evidence that hypofractionation was inferior to conventional fractionation for breast conserving therapy in patients with T1-T2 N0, grade 3 breast cancer in a population-based series.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-11-03.

Adjuvant axillary radiotherapy for breast cancer: Is CT planning with nodal contouring better than traditional planning?

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Background: Historically, adjuvant radiotherapy planning for breast cancer has been based on clinical mark-up then subsequently bony landmarks. The objective of this study is to investigate whether individualized CT-based nodal contour guided planning of axillary fields in breast cancer improves nodal coverage and minimizes dose to normal tissues. There have been no previous studies addressing this issue. Methods: Thirty 4-field radiotherapy plans were selected as ‘traditional’ plans: 15 without nodal contours (traditional field placement) and 15 with radiation oncologists’ nodal contours. The following structures were contoured on each patient CT, regardless of previously contoured structures: level I, level II/III, supraclavicular(SCV)/infraclavicular(ICV) lymph nodes, ipsilateral brachial plexus and lung. Dose volume histograms (DVHs) of the listed contoured structures were obtained for the 30 original plans. All 30 patients were then re-planned with the same anterior dose prescription as the original plan (4000cGy/16 fractions (#) or 4500cGy/25#) but adjusted depth of midplane dose prescription based on nodal depth; MLC blocking was adjusted to the ‘study’ nodal contours. DVHs of the contoured structures for the new nodal-based plans were compared with the DVHs of the original plans, using two-tailed paired t-tests. Results: Volume receiving 90% dose (V90) was significantly improved for SCV nodes: original plan 84.67% vs nodal plan 95.76%(p=0.0005). V90 were similar for level I and level II/III nodes, but hot spots in these nodal groups were significantly hotter in the original vs nodal plan: mean hot spot for level I 120.8% vs 116.3%(p=0.0008), mean hot spot for level II/III 118.1% vs 113.2% (p=0.000003). Dose to 90% of the brachial plexus (D90) was significantly higher in the original vs nodal plan: 79.92% vs 40.92%(p=0.0028). V20 lung were not significantly different. Mean total body dose was significantly higher in the original vs nodal plan 831.8cGy vs 677.7cGy (p=0.0015). Conclusions: CT-based nodal contour guided planning significantly improves coverage of the nodes, particularly supraclavicular nodes, while markedly reducing the dose to critical normal structures, such as brachial plexus.

No significant financial relationships to disclose.

Prognostic significance of the number of axillary lymph nodes removed in patients with node-negative breast cancer

PURPOSE

The objective of the study was to evaluate the association between the number of lymph nodes removed at axillary dissection and recurrence and survival for patients with node-negative invasive breast cancer.

PATIENTS AND METHODS

Subjects were 2,278 women with pathologically node-negative invasive breast cancer, diagnosed from 1989 to 1993 in British Columbia, Canada. Women aged > or = 90 years, with pure in-situ, bilateral invasive breast cancer or T4, N1, N2, or M1 stage, or who had axillary radiation were excluded. Two groups were defined for analysis: node-negative with no systemic therapy (n = 1,468) and node-negative with systemic therapy (n = 810). Median follow-up was 7.5 years. Prognostic variables assessed were age at diagnosis, tumor size, tumor grade, invasion of lymphatics, veins, or nerves, estrogen receptor status, and number of nodes removed.

RESULTS

For patients not receiving systemic therapy, regional relapse was significantly increased with smaller numbers of nodes removed (P =.03). There was a trend toward shorter overall survival with fewer nodes removed (P =.06). Node-negative patients who received systemic therapy did not have a higher regional relapse rate or shorter overall survival when fewer nodes were recovered.

CONCLUSION

Recovery of a small number of negative lymph nodes at axillary dissection likely understages patients and leads to undertreatment, resulting in an increased regional relapse rate and poorer survival. The use of systemic therapy may overcome this effect. The number of nodes removed, in conjunction with other prognostic factors, may be useful in selecting node-negative patients for systemic therapy.

Differences detected in vivo between samples of aflatoxin-contaminated peanut meal, following decontamination by two ammonia-based processes

A sample of peanut meal, highly contaminated with aflatoxins, has been subjected to decontamination by two commercial ammonia-based processes. The original contaminated and the two decontaminated meals were fed to rats for 90 days. No lesions associated with aflatoxin-induced hepatocarcinogenesis were detected histologically following feeding with the two detoxified meals. There were, however, clear differences between the two meals in respect of growth rates of the rats. In addition, feeding one of the detoxified meals resulted in hepatic abnormalities detected using novel immunohistochemical reagents. Differences between the two detoxified meals were also indicated by the results of studies using meals 'spiked' with [14C]-aflatoxin B1 prior to being subjected to the detoxification processes. The meals differed in the bioavailability of the label. It was concluded that peanut meal where an initial, unacceptable level of contamination with aflatoxins had been reduced by two ammonia-based processes to comparable, acceptable levels, may still have different effects in vivo when incorporated into animal diets.

N(2)-Aroylanthranilamide inhibitors of human factor Xa

Reversal of the A-ring amide link in 1,2-dibenzamidobenzene 1 (fXa K(ass) = 0.81 x 10(6) L/mol) led to a series of human factor Xa (hfXa) inhibitors based on N(2)-aroylanthranilamide 4. Expansion of the SAR around 4 showed that only small planar substituents could be accommodated in the A-ring for binding to the S1 site of hfXa. Bulky groups such as 4-isopropyl, 4-tert-butyl, and 4-dimethylamino were favored in the B-ring to interact with the S4 site of hfXa. The central (C) ring containing a 5-methanesulfonamido group yielded greater activity than carbamoyl groups. Combining the beneficial features from the B- and C-ring SAR, compound 55 represents the most potent hfXa inhibitor in the N(2)-aroylanthranilamide 4 series with hfXa K(ass) = 58 x 10(6) L/mol (K(i) = 11.5 nM).

Cancer of the tonsil: the results of ipsilateral radiation treatment

BACKGROUND AND PURPOSE

The use of ipsilateral irradiation techniques to treat patients with carcinoma of the tonsil reduces the acute radiation reaction in the contralateral pharynx and late damage to the contralateral salivary tissue. However, this may also spare microscopic disease in apparently uninvolved contralateral lymph nodes. The purpose of this study was to analyse the survival and recurrence rates and sites of recurrance in a group of patients with carcinoma of the tonsil treated with ipsilateral techniques.

MATERIALS AND METHODS

Between 1975 and 1993, 271 patients with invasive squamous cell cancer of the tonsil were referred to the Vancouver Cancer Centre (VCC). One hundred and seventy-eight received ipsilateral radiation treatment. Three received surgery only, six post-operative radiation, 12 supportive treatment only and 72 bilateral radiation treatment. In the absence of bilateral neck nodes and extensive lymphodenopathy, field sizes were generally kept small to include the primary tumour and the first echelon of nodes. The most common dose was 60 Gy in 25 daily fractions in 5 weeks (2.4 Gy per day).

RESULTS AND DISCUSSION

The disease specific survival for all patients treated by radical radiation treatment was 61% at 5 years. For the 178 patients who received ipsilateral radiation treatment the overall primary tumour control rate by ipsilateral radiation treatment alone was 75% and for T1 and T2 tumours 84%. Eight (7.5%) of 101 of these patients with N0 nodes at presentation and without prior failure at the primary site, developed nodal recurrence (four within the initially radiated high dose volume). Two developed contralateral nodes, and two developed field edge nodal recurrence, one cured by surgery. In 54 patients with N1 disease, five developed nodal recurrence, two within field, two contralateral, one of whom was cured by surgery, and one at field edge. In 23 patients with N2a, N2b or N3 disease node control was achieved from radiation treatment in 11 and two more were cured by surgery. All nodal failures were within the radiated volume. Overall, 10 of the 25 patients with nodal failure were cured by subsequent surgery.

CONCLUSIONS

Ipsilateral treatment of patients with carcinoma of the tonsil gives survival results that are at least as good as those reported with bilateral treatment with fewer side effects and a very low risk of failure in the contralateral neck.

Restenosis in human vein bypass grafts

The restenosis rate in vein bypass grafts is higher than in native coronary arteries, and both the cascade of regulatory factors and the vessel reaction may be altered. In this study, vein bypass atherectomy specimens were classified as primary (n = 10) or restenotic (n = 12). Immunohistochemistry with 11 primary antibodies showed low levels of proliferation in both tissues and similar amounts of extracellular matrix components in both primary and restenotic specimens at the time points at which tissue was removed for clinical reasons. Inflammation appeared increased in restenotic specimens. Using in situ hybridization, transforming growth factor-beta1 messenger RNA was detected in both primary and restenotic tissue, with a trend to higher expression in restenosis (8.4 +/- 5.3 vs. 9.4 +/- 7.4 grains/nucleus) and further increased expression in multiple compared with single restenoses (15.1 +/- 6.1 vs. 5.6 +/- 5.1 grains/nucleus, P < 0.05). Hence, there were no great differences in cell proliferation or extracellular matrix formation between primary and restenosis vein graft tissue, in contrast to previously described findings in arterial tissue. This suggests that primary vein graft tissue is already in a chronic 'restenosis-like' state and subsequent injury creates minimal additional upregulation.

Differential expression of nonmuscle myosin II isoforms in human atherosclerotic plaque

Intimal proliferation and functional changes involving vascular smooth muscle cells are key events in the development of atherosclerosis, including restenosis after percutaneous transluminal angioplasty. Nonmuscle myosin (NMM) is required for cytokinesis and has been shown in cultures of vascular smooth muscle cells to undergo changes of isoform expression depending on the stage of proliferation and differentiation. The purpose of this study was to examine the differential expression of the two most recently identified nonmuscle myosin heavy chain isoform II (NMMHC-II) isoforms A and B in atherosclerotic plaque. Primary atherosclerotic and restenotic atherectomy specimens and non-atherosclerotic controls, were analyzed by Western Blot analysis, immunohistochemistry and in situ hybridization. Nonmuscle myosin heavy chain isoform IIA (NMMHC-IIA) was equally expressed in all types of tissue specimens both at the protein and mRNA levels. In contrast, NMMHC-IIB protein was found in restenotic specimens and normal artery but was at very low levels in primary atherosclerotic plaque. By in situ hybridization NMMHC-IIB mRNA levels were significantly greater in restenotic versus primary atherosclerotic lesions. NMMHC-IIB expression is associated with vascular restenosis but is downregulated in stable atherosclerotic lesions, whereas NMMHC-IIA is expressed in both. These results indicate that these new myosin isoforms have different functions and should be regarded separately with respect to smooth muscle proliferation and restenosis. They should prove to be useful molecular markers for the study of atherosclerosis and restenosis.

Therapeutic angiogenesis following arterial gene transfer of vascular endothelial growth factor in a rabbit model of hindlimb ischemia

The plasmid phVEGF165, expressing the 165-amino-acid isoform of vascular endothelial growth factor (VEGF), an endothelial cell specific mitogen, was applied to the polymer coating of an angioplasty balloon and delivered percutaneously to the iliac artery of rabbits in which the femoral artery had been excised to cause hindlimb ischemia. Site-specific transfection of phVEGF165 resulted in augmented development of collateral vessels documented by serial angiograms, and increased capillary density as well as increased capillary/myocyte ratio documented histochemically at necropsy. Consequent amelioration of the hemodynamic deficit in the ischemic limb was documented by improvement in the calf blood pressure ratio (ischemic/normal limb) to 0.70 +/- 0.08 in the VEGF-transfected group vs 0.50 +/- 0.18 in controls (p < 0.05). These findings suggest that site-specific arterial gene transfer of VEGF165 may achieve physiologically meaningful therapeutic modulation of vascular insufficiency.

Apocrine carcinoma of the lip: a case report including immunohistochemical and ultrastructural study, discussion of differential diagnosis, and review of the literature

The light microscopic, immunohistochemical, and ultrastructural features of a case of apocrine carcinoma of the upper lip of a 54-year-old white man are described. The neoplasm had a cribriform intraductal component resembling apocrine carcinoma of the breast. The tumor had irregular borders and infiltrated skeletal muscle. The neoplastic cells had abundant eosinophilic granular cytoplasm and showed apical decapitation secretion characteristic of apocrine differentiation. The differential diagnosis is discussed with particular reference to distinction of the tumor from oncocytic carcinoma and ductal carcinoma of minor salivary gland.

Arterial gene transfer for therapeutic angiogenesis in patients with peripheral artery disease

The age-adjusted prevalence of peripheral arterial disease (PAD) in the U.S. population has been estimated to approach 12%. The clinical consequences of occlusive peripheral arterial disease (PAD) include pain on walking (claudication), pain at rest, and loss of tissue integrity in the distal limbs; the latter may ultimately lead to amputation of a portion of the lower extremity. Surgical bypass techniques and percutaneous catheter-based interventions may be used to successfully revascularize the limbs of certain patients with PAD. In many patients, however, the anatomic extent and distribution of arterial occlusion is too severe to permit relief of pain and/or healing of ischemic ulcers. No effective medical therapy is available for the treatment of such patients. The purpose of this clinical protocol is to document the safety of therapeutic angiogenesis achieved in this case by percutaneous catheter-based delivery of the gene encoding vascular endothelial growth factor (VEGF) in patients with PAD; and, as secondary objectives, investigate the bioactivity of this strategy to relieve rest pain and heal ischemic ulcers of the lower extremities. The rationale for this human protocol is based upon preclinical studies performed in a rabbit model of hindlimb ischemia. These studies are described in detail below and in the manuscripts enclosed in the Appendix to this proposal. In brief, a single intra-arterial bolus of VEGF recombinant human protein, delivered percutaneously to the ischemic limb via an intravascular catheter, resulted in angiographic, hemodynamic, physiologic, and histologic evidence of augmented collateral artery development. Subsequently, similar results were achieved using an angioplasty catheter with a hydrogel-coated balloon to deliver 400 micrograms of a plasmid containing the cDNA for VEGF to the internal iliac artery in the same animal model. Accordingly, we propose to administer arterial gene (VEGF) therapy to patients with rest pain and/or ischemic leg ulcers considered not to be candidates for conventional revascularization techniques. The dose of plasmid to be administered will be progressively escalated beginning with 500 micrograms for the first four patients, 1000 micrograms for the following six patients, 2000 micrograms for the third group of six patients, and 400 micrograms for the fourth group of six patients.

Processing of chimeric antisense oligonucleotides by human vascular smooth muscle cells and human atherosclerotic plaque. Implications for antisense therapy of restenosis after angioplasty

BACKGROUND

Antisense oligonucleotides have been used in animals to inhibit the accumulation of vascular smooth muscle cells (VSMCs) after arterial injury. This has raised prospects for an oligonucleotide-mediated approach to prevent restenosis in patients undergoing angioplasty. However, little is known about the processing of oligonucleotides by human VSMCs or their bioavailability in human atherosclerotic tissue.

METHODS AND RESULTS

Oligonucleotides were synthesized with a mixture of unmodified and sulfur-modified linkages (S-chimeric oligonucleotides). These were more stable than unmodified oligonucleotides and could be recovered from within human VSMCs after 36 hours. Oligonucleotide antisense to human proliferating cell nuclear antigen mRNA specifically reduced DNA synthesis (P < .01) and proliferating cell nuclear antigen protein content (P < .05) in human VSMCs. Confocal microscopy of both live and fixed cells showed modest oligonucleotide uptake that was primarily nuclear. Surprisingly, cationic liposomes did not enhance nuclear uptake but led to extensive, punctated cytoplasmic loading without an enhanced antisense effect. Oligonucleotides incubated with human coronary atherosclerosis fragments associated with cells within 1 hour, despite the presence of abundant extracellular matrix.

CONCLUSIONS

S-chimeric oligonucleotides are stable and can specifically inhibit gene expression in human VSMCs. Nuclear transport is a feature of oligonucleotide processing by human VSMCs, indicating a potential influence at the nuclear level rather than with cytoplasmic mRNA. Cationic liposomes increased oligonucleotide uptake but not intracellular bioavailability, and S-chimeric oligonucleotides can be incorporated into cells within human atherosclerotic plaque, despite the presence of a dense extracellular matrix.

Radiation treatment of cervical lymph node metastases from an unknown primary: an analysis of outcome by treatment volume and other prognostic factors

One hundred and forty-four patients with diagnosis of carcinoma involving cervical lymph nodes from an unknown primary site were seen at the Princess Margaret Hospital, Toronto between 1970 and 1986. This paper addresses the outcome of two treatment approaches using radiation treatment as potentially curative therapy. The treatment approaches compared in a retrospective analysis are radiation to the involved node regions alone (85 cases), and radiation to both the nodes and to potential primary sites in the head and neck (59 cases). The overall 5-year survival rate of the entire group of 144 cases was 41%. There was a trend to increased survival in favour of the group receiving radiation to the nodes and potential primary sites (p = 0.07), however, when differences in extent of nodal involvement were considered and adjusted for using the Cox Proportional Hazard Model, no difference in survival, or cause-specific survival was found between the two treatment groups (p = 0.18 and 0.22, respectively). A total of seven head and neck primary cancers were subsequently discovered, six in the group receiving radiation only to the nodes and one in the group receiving radiation to the nodes and primary sites. The results of this retrospective analysis need to be interpreted with caution but suggest that, for some patients with this diagnosis, radiation to the involved node region alone is adequate. A discussion of the literature is presented with attention to the effect of extent of treatment on outcome.

Expression of gax, a growth arrest homeobox gene, is rapidly down-regulated in the rat carotid artery during the proliferative response to balloon injury

gax is a recently described homeobox gene whose expression in the adult is largely confined to cardiovascular tissues, gax has been shown to be rapidly down-regulated in cultured vascular smooth muscle cells (VSMC) upon stimulation by serum or platelet-derived growth factor. The temporal profile of gax expression in vitro matches that of two families of growth arrest genes: the gas genes and the gadd genes. All of these genes are expressed at their highest levels in quiescent cells and are down-regulated following mitogen activation. Here we report that gax is also down-regulated in vivo in the vascular wall in response to endothelial denudation by balloon angioplasty. The reduction in steady state levels of gax mRNA is transient and occurs with a similar time course to that seen in vitro. The down-regulation of gax in response to balloon injury mirrors the up-regulation seen in a number of early response genes such as c-myc and c-fos. This report is the first to document the in vivo expression of a growth arrest gene which regulates proliferation of vascular smooth muscle cells. In addition, in contrast with previous reports which have demonstrated up-regulation of several genes following balloon injury and/or angioplasty, the present report demonstrates the down-regulation of a regulatory gene within hours of balloon injury. The characteristics of gax suggest it may be required to maintain the gene expression of proteins in VSMC that are associated with the nonproliferative or contractile phenotype in smooth muscle cells.

Use of the rabbit ear artery to serially assess foreign protein secretion after site-specific arterial gene transfer in vivo. Evidence that anatomic identification of successful gene transfer may underestimate the potential magnitude of transgene expression

BACKGROUND

The development of molecular strategies for the treatment of restenosis has been hindered by low efficiencies of in vivo arterial transfection. Expression of intracellular marker proteins is generally evident in < 1% of vascular smooth muscle cells after in vivo arterial transfection. Efforts to improve the efficiency of in vivo gene transfer have been further impeded by the use of transgenes encoding for intracellular marker proteins, necessitating tissue removal and limiting survey for expression to one point in time.

METHODS AND RESULTS

To study gene expression on a serial basis in vivo and determine the relation between a secreted gene product and transfection efficiency after in vivo arterial gene transfer, a method for performing and serially monitoring gene expression in vivo was developed using the central artery of the rabbit ear. Liposome-mediated transfection of plasmid DNA containing the gene for human growth hormone (hGH) was successfully performed in 18 of 23 arteries. Serum hGH levels measured 5 days after transfection ranged from 0.1 to 3.8 ng/mL (mean, 0.97 ng/mL); in contrast, serum drawn from the control arteries demonstrated no evidence of hGH production. Serial measurement of hGH from transfected arteries demonstrated maximum hGH secretion 5 days after transfection and no detectable hormone after 20 days. Despite these levels of secreted gene product documented in vivo, immunohistochemical staining of sections taken from the rabbit ear artery at necropsy disclosed only rare cells in which there was evidence of successful transfection.

CONCLUSIONS

These experiments demonstrate a useful method of performing serial in vivo analyses of gene expression after vascular transfection and that anatomic analyses of transfection efficiency may underestimate the potential magnitude of expression in the case of a secreted gene product. These findings have implications for the clinical application of somatic gene therapy because low-efficiency transfection with a gene encoding for a secreted protein may achieve therapeutic effects not realized by transfection with genes encoding for proteins that remain intracellular.