POS0094 ALPN-303, AN ENGINEERED DUAL BAFF/APRIL ANTAGONIST, POTENTLY INHIBITS PATHOGENIC LYMPHOCYTE SUBSETS AND FUNCTION IN B-CELL- AND ANTIBODY-RELATED PRECLINICAL MODELS

Background

B-cell activating factor (BAFF) and a proliferation-inducing ligand (APRIL) are tumor necrosis factor (TNF) superfamily members that bind TACI (transmembrane activator and CAML interactor), BCMA (B-cell maturation antigen), and/or BAFF-R on B cells and together support B cell development, differentiation, and survival. ALPN-303 is an Fc fusion protein of a human TACI variant TNFR domain engineered by directed evolution1,2. It mediates significantly improved combined BAFF and APRIL inhibition in vitro and enhanced pharmacokinetic and immunomodulatory properties in preclinical studies, as compared to wild-type (WT) TACI-Fc molecules. B-cell targeting therapies like the WT TACI-Fc fusions atacicept and telitacicept have demonstrated promising clinical potential in B cell-related diseases like systemic lupus erythematosus (SLE). ALPN-303, with enhanced inhibitory activity against BAFF and APRIL, has previously been shown to demonstrate promising efficacy in an (NZB/NZW)F1 mouse model of lupus, and may therefore further improve clinical outcomes in such diseases.

Objectives

To further characterize the comparative activity of ALPN-303 versus an Fc matched control, a WT TACI-Fc comparator (telitacicept), and/or a B cell-depleting therapy (anti-mouse CD20 [anti-mCD20] monoclonal antibody [mAb]), in antibody-related preclinical models.

Methods

The functional activity of ALPN-303, as compared to telitacicept or a depleting anti-mCD20 mAb, was evaluated in a sheep red blood cell (SRBC) immunization mouse model. Mice immunized intraperitoneally with SRBC on Study Day 0 were administered 200 µg ALPN-303 or a molar-matched amount (240 µg) of telitacicept on Days 1 and 6 or were treated with 200 µg anti-mCD20 (rat IgG2b) on Day 1. At study termination on Day 15, serum was collected to measure levels of test article and anti-SRBC immunoglobulin (Ig) titers, and spleens and bone marrow (BM) were collected for immunophenotyping by flow cytometry. A study in the inducible bm12 mouse model of lupus was also conducted, with mice treated twice weekly with 200 µg ALPN-303 or a molar-matched dose of Fc control, starting on Day 5 after splenocyte transfer and continuing through Week 13.

Results

ALPN-303 administration rapidly and potently reduced BM plasma cells, splenic germinal center B cells, follicular T helper cells, and plasmablasts in SRBC-immunized mice, often significantly more so than telitacicept and/or anti-mCD20 mAb. ALPN-303 also significantly reduced serum titers of anti-SRBC IgM, IgG1, IgG2a, and IgG2b as compared to all other treatment groups. In the bm12 model, ALPN-303 treatment significantly impacted the same key lymphocyte subsets affected in the SRBC model, and significantly reduced circulating anti-dsDNA antibodies (Figure 1) and total IgA, IgM, IgG1, IgG2b, and IgG3, and inhibited renal IgG deposits (Figure 1).

Figure 1.

ALPN-303 treatment significantly reduces serum autoantibody titers and renal immune complex deposition in the inducible bm12 mouse model of lupus. *p<0.05, **p<0.01, ****p<0.0001 by the Kruskal-Wallis test.

Conclusion

ALPN-303 is an engineered, potent BAFF/APRIL antagonist that continues to consistently demonstrate encouraging immunomodulatory activity and efficacy in vitro and in vivo, as further demonstrated in the SRBC immunization and bm12 lupus models, with superiority to WT TACI-Fc and anti-CD20 comparators. ALPN-303 may thus be an attractive development candidate for the treatment of multiple autoimmune and inflammatory diseases, particularly B cell- and/or autoantibody-related diseases such as SLE, Sjögren’s syndrome, and other connective tissue diseases. A Phase 1 study of ALPN-303 in adult healthy volunteers (NCT05034484) is ongoing.

References

[1]Dillon SR, Evans LS, Lewis KE, et al. Annals of the Rheumatic Diseases 2021;80:21.

[2]Dillon SR, Evans LS, Lewis KE, et al. Arthritis Rheumatol. 2021; 73 (suppl 10).

Disclosure of Interests

Stacey R. Dillon Employee of: Alpine Immune Sciences, Katherine E. Lewis Employee of: Alpine Immune Sciences Inc, Sherri Mudri Employee of: Alpine Immune Sciences Inc, Kayla Kleist Employee of: Alpine Immune Sciences Inc, Luana Griffin Employee of: Alpine Immune Sciences Inc, Lawrence S. Evans Employee of: Alpine Immune Sciences Inc, Janhavi Bhandari Shareholder of: Amgen, Novo Nordisk, Employee of: Alpine Immune Sciences Inc, Logan Garrett Employee of: Alpine Immune Sciences Inc, Michelle A. Seaberg Employee of: Alpine Immune Sciences Inc, NingXin Wang Employee of: Alpine Immune Sciences Inc, Allison Chunyk Employee of: Alpine Immune Sciences Inc, Daniel Ardourel Employee of: Alpine Immune Sciences Inc, LuAnne Hebb Employee of: Alpine Immune Sciences Inc, Martin F. Wolfson Employee of: Alpine Immune Sciences Inc, Mark W. Rixon Employee of: Alpine Immune Sciences Inc, Pamela Holland Employee of: Alpine Immune Sciences Inc, Stanford L. Peng Employee of: Alpine Immune Sciences Inc

Management of recurrent cervical cancer with peritoneal carcinomatosis with HIPEC

•

Recurrent cervical cancer with peritoneal carcinomatosis is rare.

•

Presenting two cases of recurrent cervical cancer with peritoneal carcinomatosis.

•

HIPEC used in recurrent cervical cancer cases with peritoneal carcinomatosis.

Cervical cancer is the fourth most common malignancy in women in the world; however, a substantial portion of these malignancies are declining with increasingly sophisticated screening. Unfortunately, recurrent cervical cancer has a dismal prognosis and its management continues to be a growing area of research. While the foundation of treatment remains platinum-based chemotherapies, new techniques such as HIPEC have been evaluated. We present two patients with recurrent cervical adenocarcinoma with peritoneal carcinomatosis who were treated with HIPEC during de-bulking surgery with substantial disease-free survival.

One of our patients had 15 months of disease-free survival before developing biliary metastases and the other remains disease free for over 24 months.

Adoption of enhanced recovery after laparotomy in gynecologic oncology

Introduction

Enhanced recovery after surgery (ERAS) pathways combine a comprehensive set of peri-operative practices that have been demonstrated to hasten patient post-operative recovery. We aimed to evaluate the adoption of ERAS components and assess attitudes towards ERAS among gynecologic oncologists.

Methods

We developed and administered a cross-sectional survey of attending, fellow, and resident physicians who were members of the Society of Gynecologic Oncology in January 2018. The χ2 test was used to compare adherence to individual components of ERAS.

Results

There was a 23% survey response rate and we analyzed 289 responses: 79% were attending physicians, 57% were from academic institutions, and 64% were from institutions with an established ERAS pathway. Respondents from ERAS institutions were significantly more likely to adhere to recommendations regarding pre-operative fasting for liquids (ERAS 51%, non-ERAS 28%; p<0.001), carbohydrate loading (63% vs 16%; p<0.001), intra-operative fluid management (78% vs 32%; p<0.001), and extended duration of deep vein thrombosis prophylaxis for malignancy (69% vs 55%; p=0.003). We found no difference in the use of mechanical bowel preparation, use of peritoneal drainage, or use of nasogastric tubes between ERAS and non-ERAS institutions. Nearly all respondents (92%) felt that ERAS pathways were safe.

Discussion

Practicing at an institution with an ERAS pathway increased adoption of many ERAS elements; however, adherence to certain guidelines remains highly variable. Use of bowel preparation, nasogastric tubes, and peritoneal drainage catheters remain common. Future work should identify barriers to the implementation of ERAS and its components.

Financial toxicity in gynecologic oncology

OBJECTIVES

Financial toxicity is increasingly recognized as an adverse outcome of cancer treatment. Our objective was to measure financial toxicity among gynecologic oncology patients and its association with demographic and disease-related characteristics; self-reported overall health; and cost-coping strategies.

METHODS

Follow-up patients at a gynecologic oncology practice completed a survey including the COmprehensive Score for Financial Toxicity (COST) tool and a self-reported overall health assessment, the EQ-VAS. We abstracted disease and treatment characteristics from medical records. We dichotomized COST scores into low and high financial toxicity and assessed the correlation (r) between COST scores and self-reported health. We calculated risk ratios (RR) and 95% confidence intervals (CI) for the associations of demographic and disease-related characteristics with high financial toxicity, as well as the associations between high financial toxicity and cost-coping strategies.

RESULTS

Among 240 respondents, median COST score was 29. Greater financial toxicity was correlated with worse self-reported health (r = 0.47; p < 0.001). In the crude analysis, Black or Hispanic race/ethnicity, government-sponsored health insurance, lower income, unemployment, cervical cancer and treatment with chemotherapy were associated with high financial toxicity. In the multivariable analysis, only government-sponsored health insurance, lower income, and treatment with chemotherapy were significantly associated with high financial toxicity. High financial toxicity was significantly associated with all cost-coping strategies, including delaying or avoiding care (RR: 7.3; 95% CI: 2.8-19.1).

CONCLUSIONS

Among highly-insured gynecologic oncology patients, many respondents reported high levels of financial toxicity. High financial toxicity was significantly associated with worse self-reported overall health and cost-coping strategies, including delaying or avoiding care.

A paternal methyl donor-rich diet altered cognitive and neural functions in offspring mice

Dietary intake of methyl donors, such as folic acid and methionine, shows considerable intra-individual variation in human populations. While it is recognized that maternal departures from the optimum of dietary methyl donor intake can increase the risk for mental health issues and neurological disorders in offspring, it has not been explored whether paternal dietary methyl donor intake influences behavioral and cognitive functions in the next generation. Here, we report that elevated paternal dietary methyl donor intake in a mouse model, transiently applied prior to mating, resulted in offspring animals (methyl donor-rich diet (MD) F1 mice) with deficits in hippocampus-dependent learning and memory, impaired hippocampal synaptic plasticity and reduced hippocampal theta oscillations. Gene expression analyses revealed altered expression of the methionine adenosyltransferase Mat2a and BK channel subunit Kcnmb2, which was associated with changes in Kcnmb2 promoter methylation in MD F1 mice. Hippocampal overexpression of Kcnmb2 in MD F1 mice ameliorated altered spatial learning and memory, supporting a role of this BK channel subunit in the MD F1 behavioral phenotype. Behavioral and gene expression changes did not extend into the F2 offspring generation. Together, our data indicate that paternal dietary factors influence cognitive and neural functions in the offspring generation.

Generation of mice lacking DUF1220 protein domains: effects on fecundity and hyperactivity

Sequences encoding DUF1220 protein domains show the most extreme human lineage-specific copy number increase of any coding region in the genome and have been linked to human brain evolution. In addition, DUF1220 copy number (dosage) has been implicated in influencing brain size within the human species, both in normal populations and in individuals associated with brain size pathologies (1q21-associated microcephaly and macrocephaly). More recently, increasing dosage of a subtype of DUF1220 has been linked with increasing severity of the primary symptoms of autism. Despite these intriguing associations, a function for these domains has not been described. As a first step in addressing this question, we have developed the first transgenic model of DUF1220 function by removing the single DUF1220 domain (the ancestral form) encoded in the mouse genome. In a hypothesis generating exercise, these mice were evaluated by 197 different phenotype measurements. While resulting DUF1220-minus (KO) mice show no obvious anatomical peculiarities, they exhibit a significantly reduced fecundity (χ(2) = 19.1, df = 2, p = 7.0 × 10(-5)). Further extensive phenotypic analyses suggest hyperactivity (p < 0.05) of DUF1220 mice and changes in gene expression levels of brain associated with distinct neurological functions and disease. Other changes that met statistical significance include an increase in plasma glucose concentration (as measured by area under the curve, AUC 0-30 and AUC 30-120) in male mutants, fasting glucose levels, reduce sodium levels in male mutants, increased levels of the liver functional indicator ALAT/GPT in males, levels of alkaline phosphatase (also an indicator of liver function), mean R and SR amplitude by electrocardiography, elevated IgG3 levels, a reduced ratio of CD4:CD8 cells, and a reduced frequency of T cells; though it should be noted that many of these differences are quite small and require further examination. The linking of DUF1220 loss to a hyperactive phenotype is consistent with separate findings in which DUF1220 over expression results in a down-regulation of mitochondrial function, and potentially suggests a role in developmental metabolism. Finally, the substantially reduced fecundity we observe associated with KO mice argues that the ancestral DUF1220 domain provides an important biological functionthat is critical to survivability and reproductive success.

Can telehealth deliver for rural Scotland? Lessons from the Argyll & Bute Telehealth Programme

Policy-makers consider telehealth to be a potential solution to delivery of care in rural Scotland. Telehealth can support patients in the community and may reduce emergency admissions to hospital. The Argyll & Bute telehealth initiative, which commenced in 2007, trialled home telehealth monitoring of patients with chronic obstructive pulmonary disease (COPD), and community- and surgery-based monitoring of general wellbeing and hypertension. An evaluation in 2010 assessed staff and patient satisfaction by questionnaire, impact on hospital and general practice attendance by case record review and detailed opinions on the programme by qualitative interviews with key staff. Home monitoring for COPD was associated with high levels of patient satisfaction and a reduction in hospital admissions and other health service contacts. Delays in implementation and some technical challenges compromised evaluation of the surgery and community initiatives. Patients and staff were generally enthusiastic but also identified potential barriers to development. This paper describes the implementation and outcomes of the initiative and identifies issues that clinicians embarking on telehealth programmes must consider: technical factors; governance and security; staff profiling and training; clinical outcomes; and scalability.

Effects of the probiotic Bifidobacterium infantis in the maternal separation model of depression

The concept that intestinal microbial composition not only affects the health of the gut, but also influences centrally-mediated systems involved in mood, is supported by a growing body of literature. Despite the emergent interest in brain-gut communication and its possible role in the pathogenesis of psychiatric disorders such as depression, particularly subtypes with accompanying gastrointestinal (GI) symptoms, there are few studies dedicated to the search for therapeutic solutions that address both central and peripheral facets of these illnesses. This study aims to assess the potential benefits of the probiotic Bifidobacterium infantis in the rat maternal separation (MS) model, a paradigm that has proven to be of value in the study of stress-related GI and mood disorders. MS adult rat offsprings were chronically treated with bifidobacteria or citalopram and subjected to the forced swim test (FST) to assess motivational state. Cytokine concentrations in stimulated whole blood samples, monoamine levels in the brain, and central and peripheral hypothalamic-pituitary-adrenal (HPA) axis measures were also analysed. MS reduced swim behavior and increased immobility in the FST, decreased noradrenaline (NA) content in the brain, and enhanced peripheral interleukin (IL)-6 release and amygdala corticotrophin-releasing factor mRNA levels. Probiotic treatment resulted in normalization of the immune response, reversal of behavioral deficits, and restoration of basal NA concentrations in the brainstem. These findings point to a more influential role for bifidobacteria in neural function, and suggest that probiotics may have broader therapeutic applications than previously considered.

When 'never-events' occur despite adherence to clinical guidelines: the case of venous thromboembolism in clear cell cancer of the ovary compared with other epithelial histologic subtypes

OBJECTIVE

To determine the incidence of clinically significant venous thromboembolism (VTE) in women diagnosed with clear cell carcinoma of the ovary (CCC-O) interpreted in the context of Centers for Medicare and Medicaid Services (CMS) 'never-events.'

METHODS

Using the institutional pathology Tumor Registry at the Massachusetts General Hospital (MGH), all women diagnosed with a CCC-O from 1994 to 2004 were identified. Controls with epithelial ovarian cancer of other histologies were matched for stage, age and year of diagnosis. Medical records were abstracted and pathology reviewed. All patients had surgical staging and/or cytoreductive surgery by a Gynecologic Oncologist at the MGH. All patients received appropriate peri- and post-operative prophylaxis with subcutaneous heparin and/or sequential compression devices. VTE was diagnosed with standard imaging techniques when clinical suspicion arose.

RESULTS

Fifty-eight (58) women were diagnosed with CCC-O during the study period, 43 of whom had complete data available for analysis. Patients with Stage I or II disease comprised 70% of the patients. The mean age of the cohort was 55 and the mean weight 71 kg. Eighty-six (86) age, stage, and year of diagnosis matched controls were selected. The majority of controls had serous tumors (47%) with the remainder being endometrioid (33%), mucinous (14%), transitional cell (2%), sarcoma (2%) and mixed (2%). CCC-O was often seen in association with endometriosis 70% compared with 22% of controls (p<0.0001). Overall, 18 of 43 CCC-O patients (42%) had VTE while only 19 of 86 control patients (22%) had VTE (p=0.024, OR=2.5 CI 1.1504-5.60). The rate of VTE was not influenced by weight or smoking. In the CCC-O patients, seventeen percent (17%) of VTE was diagnosed at presentation while 50% was diagnosed postoperatively and 33% at the time of disease recurrence or progression. Overall, including cases and controls, late stage disease was more likely associated with VTE (18 of 39, 46%) vs. early stage disease (19 of 90, 21%), p=0.004.

CONCLUSIONS

Women with CCC-O have a 2.5-times greater risk of disease related VTE than women with other histologies of epithelial ovarian cancer despite adherence to prophylactic guidelines. Given the high rate of VTE postoperatively as well as with disease recurrence, one should consider indefinite therapeutic anticoagulation in women with CCC-O. The case of CCC-O is one example of the impracticality of payment denial for 'never-events,' as VTE arises despite best efforts at prevention.

Association of clear cell carcinoma of the endometrium with a high rate of venous thromboembolism

OBJECTIVE

To document the rate of clinically significant venous thromboembolism (VTE) in patients with clear cell carcinoma of the endometrium (CCC-E).

STUDY DESIGN

Institutional review board permission was obtained to identify all cases of CCC-E between 1994 and 2004. Controls with high grade endometrial cancers were matched for stage, age and date of diagnosis.

RESULTS

Complete data were available for 29. Age ranged from 38 to 85 (mean, 64.6) years. Thirty-five percent of the patients had stage I tumors, 10% stage II, 27.5% stage III and 27.5% stage IV tumors. Fifty-eight matched controls were selected. Overall there were 18 VTE events: 10 (34.5%) in patients with CCC-E and 8 (13.8%) in the controls (OR = 3.68, p = 0.032). More VTE occurred in patients with stage III/IV disease (n = 16) than those with early stage (n = 2). VTE in patients with CCC-E occurred at presentation or with disease recurrence rather than in the postoperative period (8 vs. 1). Among patients with CCC-E, VTE had an adverse effect on survival, with a hazard ratio of 3.65 (95% CI, 3.14-4.16; p = 0.011).

CONCLUSION

Patients with CCC-E have greater risk of VTE than patients with other high-risk endometrial cancers. Consideration should be given to extended prophylaxis in patients with CCC-E to prevent VTE.

Risk factors for a serous cancer precursor ("p53 signature") in women with inherited BRCA mutations

OBJECTIVES

Pelvic (ovarian) serous carcinomas frequently contain p53 mutations. Recently, a candidate serous cancer precursor (the p53 signature) with p53 mutations and other features in common with serous cancer has been discovered in distal fallopian tube mucosa. This study examined the relationship of putative ovarian cancer risk factors with the presence of p53 signatures in women with BRCA mutations (BRCA+).

METHODS

Fallopian tubes from 75 BRCA+ women were immunostained for p53 signatures and correlated with age at first childbirth, parity, oral contraceptive use, body mass index (BMI), and BRCA subtype (1 or 2). Statistical analysis was performed with the T-test or Chi-square analysis and logistic regression adjusting for age and parity.

RESULTS

Thirty-eight percent of the tubes contained p53 signatures, which were significantly associated with older age at first childbirth (mean 30.8 vs. 28.4 years; p=0.04) and lower parity (mean 1.4 vs. 2.2; p=0.01) in univariate analyses. The unadjusted odds ratios were 3.8 (p-trend=0.04) for first childbirth>/=30 years versus <30 and 0.2 (p-trend=0.01) for parity >/= 3 versus nulliparous women. After adjusting for age and parity, the trend for age at first childbirth became non-significant (adjusted odds ratio 3.5; p-trend=0.15), while that for parity remained significant (adjusted odds ratio 0.2; p-trend 0.02).

CONCLUSIONS

The p53 signature is significantly associated with lower parity and possibly higher age at first childbirth, further linking this entity to serous cancer via risk factors associated with ovulation. The p53 signature merits consideration as a surrogate marker for serous cancer risk.

The changing role of thoracotomy in gestational trophoblastic neoplasia at the New England Trophoblastic Disease Center

OBJECTIVE

To review our experience with thoracotomy in gestational trophoblastic neoplasia (GTN).

STUDY DESIGN

Nineteen thoracotomy patients from our database were identified. Thoracotomy was performed for therapeutic reasons in 11 patients and to clarify the diagnosis in eight.

RESULTS

Among the 11 patients with chemotherapy-resistant pulmonary tumors, 10 of 11 (90.9%) achieved remission with thoracotomy. Thoracotomy was more likely to be done to clarify diagnosis before 1980 (83%) than after 1980 (23%) (p = 0.04), when it became more likely to be done for therapeutic indications. Ten patients had solitary lung lesions and 9 had multiple lesions. Four patients died (21%), with an average survival after thoracotomy of 149 days; patients had bilateral or multiple lung lesions, median preoperative hCG was 58,000 mIU/mL and all were stage IV. Survivors had lower stage disease, were more likely to have solitary lesions and had lower preoperative hCG levels.

CONCLUSION

There have been several temporal changes in the indications for thoracotomy for GTN. In general, the optimal patient to achieve remission with thoracotomy will have stage III disease, a preoperative hCG of < 1,500 mIU/mL, and a solitary lung nodule resistant to chemotherapy. Likelihood of remission after thoracotomy is high in properly selected patients.

Effects of sevelamer and calcium-based phosphate binders on mortality in hemodialysis patients

Elevated serum phosphorus and calcium are associated with arterial calcification and mortality in dialysis patients. Unlike calcium-based binders, sevelamer attenuates arterial calcification but it is unknown whether sevelamer affects mortality or morbidity. In a multicenter, randomized, open-label, parallel design trial we compared sevelamer and calcium-based binders on all-cause and cause-specific mortality (cardiovascular, infection, and other) in prevalent hemodialysis patients. A total of 2103 patients were initially randomized to treatment and 1068 patients completed the study. All-cause mortality rates and cause-specific mortality rates were not significantly different. There was a significant age interaction on the treatment effect. Only in patients over 65 years of age was there a significant effect of sevelamer in lowering the mortality rate. There was a suggestion that sevelamer was associated with lower overall, but not cardiovascular-linked, mortality in older patients. We suggest that further research is needed to confirm these findings.

Clear cell endometrial cancer patients have an increased risk of venous thrombotic events

5597

Objective: To document the rate of clinically significant venous thromboembolism (VTE) in patients with clear cell carcinoma of the endometrium (CCC-E). Methods: Institutional review board (IRB) permission was obtained for retrospective record review. The pathology database at our institution located cases of CCCs over the time period 1994–2004. Controls with high grade endometrial cancers were matched for stage, age and date of diagnosis. All patients underwent surgical staging with gynecologic oncology staff surgeons and all patients received VTE prophylaxis peri-operatively. Records were reviewed and data were collected regarding patient age, tumor stage, body mass index, surgical procedure, adjuvant therapy, survival, and presence of VTE. All pathology was reviewed at the MGH. Results: Thirty-nine cases of CCC-E were identified. Complete clinical data were available for 29 cases. Age ranged from 38–85 (mean 64.6) years. 35% of patients had stage I tumors, 10% stage II, 27.5% stage III, and 27.5% had stage IV tumors. 58 age and stage matched controls were selected. The majority were grade 3 endometrioid cancers (50%) with the remainder being serous (35%), mixed histology (7%), carcinosarcoma (5%), and undifferentiated carcinoma (3%). The majority of the control patients had a higher BMI than the case patients. Overall there were 18 VTE events, 10 (34.5%) in those with CCC-E and 8 (13.8%) controls p = 0.046. A higher proportion of VTE occurred in those with stage III/IV disease (n=16) as compared to those with early stage (n =2) p =0.01. When considering the timing of VTE, the VTE observed in those with CCC-E occurred at presentation or with disease recurrence (8 vs 1) while nearly all VTE in the control group occurred in the postoperative period. (7 vs 2). This was statistically significant p =0.01 Conclusion: Patients with CCC-E are at increased risk of VTE compared to patients with other high- risk endometrial cancers. This is particularly true for those with advanced stage disease. Presentation with a VTE and postmenopausal bleeding should raise the suspicion for CCC-E. Likewise, in those with known CCC-E development of a VTE may be a harbinger of recurrence. Consideration should be given to extended prophylaxis in patients with CCC-E to prevent VTE.

No significant financial relationships to disclose.

Lineage differentiation of canine lymphoma/leukemias and aberrant expression of CD molecules

Multiparameter flow cytometry analysis and specific cluster differentiation (CD) molecules were used to determine the expression profiles of B- and T-cell antigens on lymph node preparations from 59 dogs with generalized or multisystemic lymphoma. Lymph node samples from 11 healthy dogs were labeled to validate the specificity of antibodies and to formulate guidelines for interpretation of the results obtained from lymphoma samples. In normal lymph nodes, T-lymphocytes expressing CD3, CD4, or CD8 beta represented 59+/-11%, 43+/-8%, or 16+/-5% of the total cells, whereas B-lymphocytes expressing either CD21 or surface IgM (IgM) represented 37+/-9% or 14+/-5%, respectively. Small lymphocytes could be distinguished from large lymphocytes by forward light scatter. Of the patient samples 29 different breeds were represented with Golden and Labrador retriever being the most common. The lymphoma samples segregated into three groups based on CD antigen expression. Thirty cases predominantly expressed one or more combinations of CD79a, IgM, and CD21 representing a B-cell lineage. Three B-cell cases also expressed the stem cell antigen, CD34. Sixteen cases expressed one or more combinations of CD3, CD4, and CD8 consistent with a T-cell lineage and CD3+CD4+CD8--phenotype was the most common. Thirteen cases showed a mixed expression profile for T- and B-cell antigens and in three cases CD14 was highly expressed. Clinical response was poorest for T-cell lymphomas. Leukemic states occurred in all three phenotypes; but mixed cell cases had the greatest proportion. Dual immunofluorescence staining confirmed co-expression of T-cell (CD3) and B-cell antigens (CD79a or CD21) on neoplastic lymphocytes of six mixed cell cases. In one mixed cell case, dual immunostaining identified lymphocyte populations that stained mutually exclusive for CD79a and CD3. Six mixed cell lymphomas tested by PCR showed clonality for rearranged antigen receptor. Four cases that were CD79a+CD3+ had TCRgamma chain gene rearrangements, whereas two cases that were CD3+CD8+CD21+ had Ig heavy chain rearrangement. One case expressing multiple CD molecules (CD3+CD8+CD21+CD14+) was PCR negative for both Ig and TCRgamma gene rearrangement and could not be classified into a B- or T-cell lineage. We show for the first time co-expression of B- and T-cell markers on lymphoma cells that had specific T- or B-cell gene rearrangements. These findings suggest that aberrant CD molecule expression is not an uncommon finding in canine lymphomas and is a useful diagnostic marker for malignancy.

Multiple dose pharmacokinetics and acute safety of piroxicam and cimetidine in the cat

The purpose of this study was to evaluate the multiple dose pharmacokinetics and acute safety of piroxicam and cimetidine alone and in combination in cats. Seven healthy cats were included in this randomized-crossover study. The cats were assigned to groups designated to receive cimetidine alone (15 mg/kg, p.o., q12 h), piroxicam alone (0.3 mg/kg, p.o., q24 h), and piroxicam combined with cimetidine (both at aforementioned doses). The cats were dosed for 10 days followed by at least a 2-week washout period between trials. Serial blood samples were collected following the first and last doses and analyzed utilizing a high-performance liquid chromatography with mass spectrometry detection (LC/MS) assay. Pharmacokinetic parameters were determined using noncompartmental analysis. Endoscopic evaluation of the gastric mucosa was performed and serum urea nitrogen (SUN), creatinine, alkaline phosphatase (ALP), and alanine transaminase (ALT) activities were evaluated. There were not a clinically relevant difference between the pharmacokinetic parameters of piroxicam administered alone or in combination with cimetidine after either the first or last dose. Gastric ulcers were not observed in any cats although gastric erosions were. The SUN, creatinine, ALP, and ALT activities remained within reference ranges for all cats. It appears that once daily, short-term use of piroxicam alone and in combination with cimetidine in cats is relatively safe based on the parameters evaluated in this study. However, further studies are necessary to determine the long-term gastrointestinal safety of piroxicam.

Identification of genes that synergize with Cbfb-MYH11 in the pathogenesis of acute myeloid leukemia

Acute myeloid leukemia subtype M4 with eosinophilia is associated with a chromosome 16 inversion that creates a fusion gene CBFB-MYH11. We have previously shown that CBFB-MYH11 is necessary but not sufficient for leukemogenesis. Here, we report the identification of genes that specifically cooperate with CBFB-MYH11 in leukemogenesis. Neonatal injection of Cbfb-MYH11 knock-in chimeric mice with retrovirus 4070A led to the development of acute myeloid leukemia in 2-5 months. Each leukemia sample contained one or a few viral insertions, suggesting that alteration of one gene could be sufficient to synergize with Cbfb-MYH11. The chromosomal position of 67 independent retroviral insertion sites (RISs) was determined, and 90% of the RISs mapped within 10 kb of a flanking gene. In total, 54 candidate genes were identified; six of them were common insertion sites (CISs). CIS genes included members of a zinc finger transcription factors family, Plag1 and Plagl2, with eight and two independent insertions, respectively. CIS genes also included Runx2, Myb, H2T24, and D6Mm5e. Comparison of the remaining 48 genes with single insertion sites with known leukemia-associated RISs indicated that 18 coincide with known RISs. To our knowledge, this retroviral genetic screen is the first to identify genes that cooperate with a fusion gene important for human myeloid leukemia.

Endothelin-1 and vascular tone in subjects with atherogenic risk factors

Endothelin-1 (ET-1) is a potent vasoconstrictor that increases vascular tone in the resistance vessels of subjects with hypertension. It is unclear whether endogenous ET-1 affects resistance-vessel function equally in patients with other cardiovascular risk factors. Vasoconstriction to ET-1 is mediated principally via the endothelin-A (ETA) receptor on vascular smooth muscle cells. Accordingly, we used an ETA-specific antagonist, BQ-123, to test the hypothesis that endogenous ET-1 increases vascular resistance selectively in subjects with hypertension compared with other risk factors. BQ-123 was infused at 100 nmol/min for 80 minutes into the brachial artery of 10 subjects with hypertension (mean+/-SEM arterial pressure, 106+/-5 mm Hg), 12 subjects with hypercholesterolemia (mean+/-SEM total cholesterol, 7.1+/-0.2 mmol/L), 10 active smokers (mean+/-SEM, 42+/-11 pack-years), and 11 healthy, age-matched individuals. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. BQ-123 dilated resistance arterioles in hypertensive subjects, with FBF's increasing by 46+/-7% from baseline (P<0.001). BQ-123 increased FBF to a lesser extent in hypercholesterolemic (24+/-5%, P<0.001) and healthy (20+/-8%, P=0.007) individuals but did not affect FBF significantly in smokers (10+/-8%, P=0.185). The vasodilator response in hypertensive subjects, but not in hypercholesterolemic patients or smokers, was significantly greater than that in healthy individuals (P=0.012). Endogenous ET-1, acting via the ETA receptor, increases resistance-vessel tone in subjects with hypertension more than in subjects with hypercholesterolemia or in smokers. These results indicate that ET-1 contributes more to the pathophysiology of hypertension than of other risk factors in subjects without overt atherosclerosis.

Contribution of endothelin to pulmonary vascular tone under normoxic and hypoxic conditions

The contribution of endothelin to resting pulmonary vascular tone and hypoxic pulmonary vasoconstriction in humans is unknown. We studied the hemodynamic effects of BQ-123, an endothelin type A receptor antagonist, on healthy volunteers exposed to normoxia and hypoxia. Hemodynamics were measured at room air and after 15 min of exposure to hypoxia (arterial PO(2) 99.8 +/- 1.8 and 49.4 +/- 0.4 mmHg, respectively). Measurements were then repeated in the presence of BQ-123. BQ-123 decreased pulmonary vascular resistance (PVR) 26% and systemic vascular resistance (SVR) 21%, whereas it increased cardiac output (CO) 22% (all P < 0.05). Hypoxia raised CO 28% and PVR 95%, whereas it reduced SVR 23% (all P < 0.01). During BQ-123 infusion, hypoxia increased CO 29% and PVR 97% and decreased SVR 22% (all P < 0.01). The pulmonary vasoconstrictive response to hypoxia was similar in the absence and presence of BQ-123 [P = not significant (NS)]. In vehicle-treated control subjects, hypoxic pulmonary vasoconstriction did not change with repeated exposure to hypoxia (P = NS). Endothelin contributes to basal pulmonary and systemic vascular tone during normoxia, but does not mediate the additional pulmonary vasoconstriction induced by acute hypoxia.

Targeted mutagenesis of Smad1 reveals an essential role in chorioallantoic fusion

The Smad family of intracellular signaling intermediates transduce signals downstream from the transforming growth factor beta (TGF-beta) family of receptor serine threonine kinases. The original member of this family, Smad1, has been shown to mediate signals from receptors for the bone morphogenetic proteins (BMPs), a large group of ligands in the TGF-beta superfamily that mediate important developmental events. We have targeted the Smad1 gene in mice and created mutants null at this locus. Smad1 mutant mice die at approximately 9.5 days postcoitum due to defects in allantois formation. In Smad1 mutant mice, the allantois fails to fuse to the chorion, resulting in a lack of placenta and failure to establish a definitive embryonic circulation. Although vasculogenesis is initiated in the mutant allantois, the vessels formed are disorganized, and VCAM-1 protein, a marker for distal allantois development, is not expressed. Smad1 null fibroblasts are still able to respond to BMP2, however, suggesting that the defect observed in the developing extraembryonic tissue is caused by a very specific loss of transcriptional activity regulated by Smad1. Our data further demonstrate that although highly similar structurally, Smad proteins are not functionally homologous.

Targeted disruption of the methionine synthase gene in mice

Alterations in homocysteine, methionine, folate, and/or B12 homeostasis have been associated with neural tube defects, cardiovascular disease, and cancer. Methionine synthase, one of only two mammalian enzymes known to require vitamin B12 as a cofactor, lies at the intersection of these metabolic pathways. This enzyme catalyzes the transfer of a methyl group from 5-methyl-tetrahydrofolate to homocysteine, generating tetrahydrofolate and methionine. Human patients with methionine synthase deficiency exhibit homocysteinemia, homocysteinuria, and hypomethioninemia. They suffer from megaloblastic anemia with or without some degree of neural dysfunction and mental retardation. To better study the pathophysiology of methionine synthase deficiency, we utilized gene-targeting technology to inactivate the methionine synthase gene in mice. On average, heterozygous knockout mice from an outbred background have slightly elevated plasma homocysteine and methionine compared to wild-type mice but seem to be otherwise indistinguishable. Homozygous knockout embryos survive through implantation but die soon thereafter. Nutritional supplementation during pregnancy was unable to rescue embryos that were completely deficient in methionine synthase. Whether any human patients with methionine synthase deficiency have a complete absence of enzyme activity is unclear. These results demonstrate the importance of this enzyme for early development in mice and suggest either that methionine synthase-deficient patients have residual methionine synthase activity or that humans have a compensatory mechanism that is absent in mice.

Safety profile and tolerability of amprenavir in patients enrolled in an early access program

BACKGROUND

The amprenavir (APV) early or expanded access program was designed to provide open-label APV to patients who would potentially receive benefit beyond that expected from currently available protease inhibitors (PIs) and who were at risk of disease progression before the drug's expected time of regulatory approval.

OBJECTIVE

This study was conducted as part of an early access program to assess the safety profile and tolerability of APV in adults and children (> or =4 years of age) who were either intolerant to or, in the opinion of the patient's physician, virologically failing a previous PI-containing antiretroviral regimen. Specific CD4+ cell count and viral load limits were not imposed by this early access protocol.

METHODS

This open-label, nonrandomized study was conducted at multiple sites throughout the United States. Adults received APV at a dosage of 1200 mg BID. Patients weighing <50 kg received APV at a dosage of 20 mg/kg BID for the solid formulation or 1.5 mL/kg BID for the liquid formulation.

RESULTS

A total of 489 physicians registered for this program; 364 (74.4%) enrolled patients. The safety population of 2217 patients (2048 males [92.4%] and 169 females [7.6%] aged 2 to 74 years) received APV for a median duration of 85 days (range, 2-218 days). Patients in the intent-to-treat population (n = 1427) had extensive experience with antiretroviral therapy. Drug-related treatment-emergent adverse events reported in >3% of patients in the safety population were nausea in 279 patients (12.6%), diarrhea in 197 patients (8.9%), rash in 177 patients (8.0%), vomiting in 148 patients (6.7%), and fatigue in 89 patients (4.0%). Adverse events and laboratory test abnormalities were graded for severity on a scale of 1 to 4 in accordance with AIDS Clinical Trials Group guidelines. Grade 3 treatment-emergent abnormal laboratory values regardless of causality occurring in >3% of patients were neutropenia in 69 of 1887 patients (3.7%; grade 3 toxicity = 500-749/mm3) and elevated triglycerides in 80 of 1593 patients (5.0%; grade 3 toxicity = 751-1200 mg/dL). Most common grade 4 treatment-emergent laboratory abnormalities were elevated serum creatine phosphokinase levels in 36 of 1266 patients (2.8%; grade 4 = >6 times upper normal limit), elevated triglycerides in 39 of 1593 patients (2.4%), and neutropenia in 41 of 1887 patients (2.2%).

CONCLUSIONS

The results of this large cohort of patients support the data from the phase II/III clinical development program and suggest that APV has an acceptable safety profile and is generally well tolerated when used in combination with other antiretroviral drugs in a heavily treatment-experienced, heterogeneous patient population.

Mice with a targeted mutation in the thyroid hormone beta receptor gene exhibit impaired growth and resistance to thyroid hormone

Patients with mutations in the thyroid hormone receptor beta (TRbeta) gene manifest resistance to thyroid hormone (RTH), resulting in a constellation of variable phenotypic abnormalities. To understand the molecular basis underlying the action of mutant TRbeta in vivo, we generated mice with a targeted mutation in the TRbeta gene (TRbetaPV; PV, mutant thyroid hormone receptor kindred PV) by using homologous recombination and the Cre/loxP system. Mice expressing a single PV allele showed the typical abnormalities of thyroid function found in heterozygous humans with RTH. Homozygous PV mice exhibit severe dysfunction of the pituitary-thyroid axis, impaired weight gains, and abnormal bone development. This phenotype is distinct from that seen in mice with a null mutation in the TRbeta gene. Importantly, we identified abnormal expression patterns of several genes in tissues of TRbetaPV mice, demonstrating the interference of the mutant TR with the gene regulatory functions of the wild-type TR in vivo. These results show that the actions of mutant and wild-type TRbeta in vivo are distinct. This model allows further study of the molecular action of mutant TR in vivo, which could lead to better treatment for RTH patients.

Bcl-x and Bax regulate mouse primordial germ cell survival and apoptosis during embryogenesis

Restricted germ cell loss through apoptosis is initiated in the fetal gonad around embryonic day 13.5 (E13.5) as part of normal germ cell development. The mechanism of this germ cell attrition is unknown. We show that Bcl-x plays a crucial role in maintaining the survival of mouse germ cells during gonadogenesis. A bcl-x hypomorphic mouse was generated through the introduction of a neomycin (neo) gene into the promoter of the bcl-x gene by homologous recombination. Mice that contained two copies of the hypomorphic allele had severe reproductive defects attributed to compromised germ cell development. Males with two mutant alleles lacked spermatogonia and were sterile; females showed a severely reduced population of primordial and primary follicles and exhibited greatly impaired fertility. Primordial germ cells (PGCs) in bcl-x hypomorph mice migrated to the genital ridge by E12.5 but were depleted by E15.5, a time when Bcl-x and Bax were present. Two additional bcl-x transcripts were identified in fetal germ cells more than 300 bp upstream of previously reported start sites. Insertion of a neo cassette led to a down-regulation of the bcl-x gene at E12.5 in the hypomorph. Bax was detected by immunohistochemistry in germ cells from bcl-x hypomorph and control testes at E12.5 and E13.5. Bcl-x function was restored, and animals of both genders were fertile after removal of the neo selection cassette using Cre-mediated recombination. Alternatively, the loss of Bcl-x function in the hypomorph was corrected by the deletion of both copies of the bax gene, resulting in a restoration of germ cell survival. These findings demonstrate that the balance of Bcl-x and Bax control PGC survival and apoptosis.

Sedative but not anxiolytic properties of benzodiazepines are mediated by the GABA(A) receptor alpha1 subtype

Inhibitory neurotransmission in the brain is largely mediated by GABA(A) receptors. Potentiation of GABA receptor activation through an allosteric benzodiazepine (BZ) site produces the sedative, anxiolytic, muscle relaxant, anticonvulsant and cognition-impairing effects of clinically used BZs such as diazepam. We created genetically modified mice (alpha1 H101R) with a diazepam-insensitive alpha1 subtype and a selective BZ site ligand, L-838,417, to explore GABA(A) receptor subtypes mediating specific physiological effects. These two complimentary approaches revealed that the alpha1 subtype mediated the sedative, but not the anxiolytic effects of benzodiazepines. This finding suggests ways to improve anxiolytics and to develop drugs for other neurological disorders based on their specificity for GABA(A) receptor subtypes in distinct neuronal circuits.

Effects of providing hospital-based doulas in health maintenance organization hospitals

OBJECTIVE

To evaluate whether providing doulas during hospital-based labor affects mode of delivery, epidural use, breast-feeding, and postpartum perceptions of the birth, self-esteem, and depression.

METHODS

This was a randomized study of nullipara enrollees in a group-model health maintenance organization who delivered in one of three health maintenance organization-managed hospitals; 149 had doulas, and 165 had usual care. Study data were obtained from the mothers' medical charts, study intake forms, and phone interviews conducted 4-6 weeks postpartum.

RESULTS

Women who had doulas had significantly less epidural use (54.4% versus 66.1%, P < .05) than women in the usual-care group. They also were significantly (P < .05) more likely to rate the birth experience as good (82.5% versus 67.4%), to feel they coped very well with labor (46.8% versus 28.3%), and to feel labor had a very positive effect on their feelings as women (58.0% versus 43.7%) and perception of their bodies' strength and performance (58.0% versus 41.0%). The two groups did not differ significantly in rates of cesarean, vaginal, forceps, or vacuum delivery, oxytocin administration; or breast-feeding, nor did they differ on the postpartum depression or self-esteem measures.

CONCLUSION

For this population and setting, labor support from doulas had a desirable effect on epidural use and women's perceptions of birth, but did not alter need for operative deliveries.

Behavioural abnormalities and selective neuronal loss in HD transgenic mice expressing mutated full-length HD cDNA

Huntington disease (HD) is an adult-onset, autosomal dominant inherited human neurodegenerative disorder characterized by hyperkinetic involuntary movements, including motor restlessness and chorea, slowing of voluntary movements and cognitive impairment. Selective regional neuron loss and gliosis in striatum, cerebral cortex, thalamus, subthalamus and hippocampus are well recognized as neuropathological correlates for the clinical manifestations of HD. The underlying genetic mutation is the expansion of CAG trinucleotide repeats (coding for polyglutamines) to 36-121 copies in exon 1 of the HD gene. The HD mRNA and protein product (huntingtin) show widespread distribution, and thus much remains to be understood about the selective and progressive neurodegeneration in HD. To create an experimental animal model for HD, transgenic mice were generated showing widespread expression of full-length human HD cDNA with either 16, 48 or 89 CAG repeats. Only mice with 48 or 89 CAG repeats manifested progressive behavioural and motor dysfunction with neuron loss and gliosis in striatum, cerebral cortex, thalamus and hippocampus. These animals represent clinically relevant models for HD pathogenesis, and may provide insights into the underlying pathophysiological mechanisms of other triplet repeat disorders.