Society for Maternal-Fetal Medicine Consult Series #69: Hepatitis B in pregnancy: updated guidelines

More than 290 million people worldwide, and almost 2 million people in the United States, are infected with hepatitis B virus, which can lead to chronic hepatitis B, a vaccine-preventable communicable disease. The prevalence of chronic hepatitis B infection in pregnancy is estimated to be 0.7% to 0.9% in the United States, with >25,000 infants born annually at risk for chronic infection due to perinatal transmission. Given the burden of disease associated with chronic hepatitis B infection, recent national guidance has expanded both the indications for screening for hepatitis B infection and immunity and the indications for vaccination. The purpose of this document is to aid clinicians caring for pregnant patients in screening for hepatitis B infection and immunity status, discuss the perinatal risks of hepatitis B infection in pregnancy, determine whether treatment is indicated for maternal or perinatal indications, and recommend hepatitis B vaccination among susceptible patients. The following are the Society for Maternal-Fetal Medicine recommendations: (1) we recommend triple-panel testing (hepatitis B surface antigen screening, antibody to hepatitis B surface antigen, and total antibody to hepatitis B core antigen) at the initial prenatal visit if not previously documented or known to have been performed (GRADE 1C); (2) we recommend universal hepatitis B surface antigen screening alone at the initial prenatal care visit for all pregnancies where there has been a previously documented negative triple-panel test (GRADE 1B); (3) we recommend that individuals with unknown hepatitis B surface antigen screening status be tested on any presentation for care in pregnancy; we also recommend that those with clinical hepatitis or those with risk factors for acute hepatitis B infection be tested at the time of admission to a birthing facility when delivery is anticipated (GRADE 1B); (4) we do not recommend altering routine intrapartum care in individuals chronically infected with hepatitis B; administration of neonatal immunoprophylaxis is standard of care in these situations (GRADE 1B); (5) we do not recommend cesarean delivery for the sole indication of reducing perinatal hepatitis B virus transmission (GRADE 1B); (6) we recommend that individuals with HBV infection can breastfeed as long as the infant has received immunoprophylaxis at birth (GRADE 1C); (7) we suggest individuals with hepatitis B infection who desire invasive testing may have the procedure performed after an informed discussion on risks and benefits in the context of shared decision-making and in the context of how testing will affect clinical care (GRADE 2C); (8) in individuals with hepatitis viral loads >200,000 IU/mL (>5.3 log 10 IU/mL), we recommend antiretroviral therapy with tenofovir (tenofovir alafenamide at 25 mg daily or tenofovir disoproxil fumarate at 300 mg daily) in the third trimester (initiated at 28-32 weeks of gestation) as an adjunctive strategy to immunoprophylaxis to reduce perinatal transmission (GRADE 1B); (9) we recommend administering hepatitis B vaccine and hepatitis B immunoglobin within 12 hours of birth to all newborns of hepatitis B surface antigen-positive pregnant patients or those with unknown or undocumented hepatitis B surface antigen status, regardless of whether antiviral therapy has been given during the pregnancy to the pregnant patient (GRADE 1B); and (10) we recommend hepatitis B vaccination in pregnancy for all individuals without serologic evidence of immunity or documented history of vaccination (GRADE 1C).

Acceptability, feasibility and potential of an intervention using secret Facebook groups to complement existing HIV prevention strategies among female sex workers in Cameroon, a randomized pilot study

This randomized pilot project evaluated an intervention promoting health care literacy around HIV, pre-exposure prophylaxis (PrEP), and stigma reduction using private social media groups that complemented existing HIV prevention services among female sex workers (FSWs) in Cameroon. The intervention was 12 HIV and sexual health videos tailored to FSWs that were released over 8 weeks through a secret Facebook group platform. In-person surveys were administered before, after the intervention, and three months later. No HIV seroconversions were detected; all participants completed follow-up and agreed to recommend the intervention to a coworker. Although the intervention was assessed to be acceptable and feasible to implement, poor internet connectivity was a key barrier. In time-series analysis, the intervention group participants reported improved PrEP interest, PrEP knowledge, and condom use along with reduced PrEP and HIV-related stigma, but no impact on sex-work related stigma or social cohesion. Similar results occurred in the control group. Cross-contamination and small pilot study size might have hindered the ability to detect the differential impact of this intervention. As communications technology increases in Cameroon, it is essential to learn more about FSWs preferences on the use of social media platforms for HIV prevention strategies.

Declining Prevalence of Trichomonas vaginalis Diagnosed by Wet Mount in a Cohort of U.S. Women With and Without HIV

Background: Women living with HIV (WLWH) are often coinfected with Trichomonas vaginalis (TV), and annual screening is recommended. Our goal was to assess differences in TV prevalence at study entry and over time in enrollment cohorts of the Women's Interagency HIV Study. Methods: In a multisite study, TV was diagnosed by wet mount microscopy. Prevalence was determined across four enrollment waves: 1994-1995, 2001-2002, 2011-2012, and 2013-2015. Generalized estimating equation multivariable logistic regression models assessed changes in visit prevalence across waves after controlling for HIV disease severity and other risks. Results: At 63,824 person-visits (3,508 WLWH and 1,262 women without HIV), TV was diagnosed by wet mount at 1979 visits (3.1%). After multivariable adjustment, HIV status was not associated with TV detection, which was more common among younger women, women with multiple partners, and irregular condom use. All enrollment waves showed a decline in TV detection over time, although p-value for trend did not reach significance for most recent waves. To explore the potential utility of screening among WLWH, we assessed rates of TV detection among women without appreciable vaginal discharge on examination. Initial TV prevalence among asymptomatic women was 3.5%, and prevalence decreased to 0.5%-1% in the most recent wave (2013-2015) (p-trend <0.0001). Conclusions: In this cohort, TV rates are low among WLWH, and HIV does not increase TV risk. Screening may benefit newly diagnosed WLWH, women with risk factors, or those receiving care sporadically but is unlikely to further reduce the low rate of TV among women in care, especially older women without multiple partners. The clinical trials registration number for WIHS is NCT00000797.

1175. Low Treatment Rates and Associated Factors Among Pregnant Women with Syphilis in Zambia

Background

Syphilis in pregnancy is common in Africa with prevalence as high as 10%. In high prevalence areas ( &gt; 5%), WHO recommends universal syphilis screening and benzathine penicillin G treatment at the first antenatal clinic (ANC) visit. Implementation barriers include global stock outs and supply chain issues. Our goal was to document treatment rates and factors associated with lack of treatment among pregnant women with syphilis in Zambia.

Methods

The retrospective cohort study analyzed medical record data from pregnant women who sought care in 10 public ANC clinics in Lusaka, Zambia during 2018-2019 and tested positive for syphilis. Syphilis was diagnosed based on positive RPR testing and treatment was defined as documented penicillin therapy at the same facility. Patient characteristics were compared across treatment status using Wilcoxon Rank Sum Test for continuous variables, and Pearson Chi-Square Test for categorical variables. Simple logistic models with treatment status as the binary outcome were conducted to evaluate potential factors associated with lack of syphilis treatment in pregnancy. A multivariable logistic model was performed and a 2-sided P &lt; 0.05 was accepted as statistically significant.

Results

Among 28,480 pregnant women screened for syphilis, 5.6% (n=1363) tested positive. Among those with syphilis, median age was 27 years, 21% of women were nulliparous and 43% were living with HIV. Most women (72%) had their initial ANC visit during the 2nd trimester and 96% were screened for syphilis at the first visit. The documented treatment rate was 42% and the only factor associated with lack of treatment was ANC entry in 2019 compared to 2018 (aOR 2.2; 95% CI 1.7-2.8; p &lt; 0.001). (refer to Tables 1-2).

Conclusion

Syphilis prevalence among pregnant women tested in ANC clinic in Zambia during 2018-2019 was 5.6%. Recommended penicillin treatment was only documented in 42% of cases. No maternal or clinic characteristic was associated with lack of therapy. Calendar year may have been associated with treatment for unclear reasons. Novel approaches to ensure access to universal diagnosis and early treatment of syphilis among pregnant women in Zambia are needed to improve maternal and neonatal outcomes.

Disclosures

All Authors: No reported disclosures.

219. A Randomized, Double-Masked, Placebo-Controlled Phase IIB Trial of Azithromycin and Trimethoprim-Sulfamethoxazole as Bacterial STI Prophylaxis in Pregnant Women with HIV

Background

This phase IIB randomized clinical trial was designed to test the efficacy of a novel regimen to prevent bacterial sexually transmitted infections and malaria in pregnant women with HIV in Cameroon, where HIV prevalence in pregnancy is 5.7%. Here we present the analysis of STI rates.

Methods

Pregnant women in prenatal care with confirmed HIV, gestational age < 28 weeks and singleton pregnancies were randomized to monthly azithromycin (AZ) 1 gram daily for 3 days and daily trimethoprim-sulfamethoxazole (TMPS) or the standard regimen of daily TMPS with monthly placebo AZ.

The main outcome of interest was the proportion of women with a composite STI measure: chlamydia, gonorrhea and/or incident syphilis at delivery. Nucleic acid amplification testing (NAAT) for CT/NG was performed on provider-collected vaginal swabs. Incident syphilis was defined serologically as a newly positive treponemal test or 4 fold increase in RPR/VDRL titer since baseline. The proportion was compared by relative risk with 95% confidence intervals and a significant p value set at < 0.05.

Results

A total of 308 women were enrolled at three hospital facilities between March 2018 and August 2020. In all, 155 women were randomized to the AZ/TMPS arm and 153 women to the TMPS arm. A total of 260 women (84%) had delivery samples collected. Both groups were similar with median age 32 years, maternal education (71% secondary school or university), HIV diagnosis 3 years prior, and 94% reported excellent adherence to antiretroviral therapy (ART). Median CD4 count was 473 cells/mm3 (IQR 326-663). At baseline, prevalence of chlamydia was 1.4%, gonorrhea 1.0% and syphilis 1.9%. There was no difference in the proportion of women with the composite STI measure (3.2% in the AZ/TMPS arm and 3.3% in the TMPS arm; RR 0.78 (95% CI 0.21 – 2.84); p=0.70). Adverse birth outcomes were lower in the AZ/TMPS arm, but not significantly (preterm delivery 5% vs 10.3% [p=0.1], low birthweight 2.8% vs 5.1% [p=0.34], composite adverse birth outcome 8.4% vs 13.1% [p=0.19]. Table 1:

1938. COVID-19 Vaccine Hesitancy among Adults Who Rely on Social Media for Health Care Information in Cameroon, Africa

Background

In Africa, uptake of effective COVID-19 vaccines has been limited by accessibility and vaccine hesitancy (VH). VH is multifactorial but influences include disinformation through social media with Whats App being the most popular form in Cameroon. The aim of this study was to test our hypothesis that frequent users of social media would have higher vaccine hesitancy due to exposure to disinformation in Cameroon in Central Africa.

Methods

A survey study was conducted at urban and suburban hospital facilities in four of the ten regions of Cameroon. Participants were asked to self-report socio-demographics, perceptions of COVID-19 infection, and interest in vaccination. They were also asked to rank their top two sources of health care information, including social media. Bivariate analysis was used to explore the perceptions of infection and vaccination stratified by social media preference with statistical significance set at p&lt; 0.05.

Results

We found that 18% (151/835) of participants cited social media (SM) as a top source of health care information. Health care professionals were cited by 82% as the most trusted source for health information (n=681). Fewer than one-third of survey participants were interested in receiving the COVID-19 vaccine (31%, 257/835) and rates did not differ by SM preferences. More people in the social media group, 53% vs 38% (p=0.046) stated that more information about vaccine safety may help reduce hesitancy. Perceived risks of COVID-19 vaccination ranged from death (33%) to fetal harm (31%) to supernatural reactions (1.4%). The SM group was not more likely to site perceived risks of the vaccine (p=0.244).

Participant Characteristics.

Conclusion

Although vaccine hesitancy in Cameroon was high at the time of the survey, adults who prefer to get health information from social media were not more likely to express vaccine hesitancy. Public education campaigns led by healthcare professionals may have the greatest impact on vaccine acceptability based on trusted information sources cited by participants.

Disclosures

All Authors: No reported disclosures.

LB1576. High Prevalence of Oral Treponema pallidum by PCR among US Adults with Early Syphilis

Background

Treponema pallidum (T. pallidum) is transmitted from person to person by direct contact with widespread dissemination early after acquisition. Current syphilis diagnostic testing is limited to darkfield microscopy from visible lesions and serologic antibody detection. T. pallidum molecular diagnostics are urgently needed.

Methods

As part of a multicenter US syphilis treatment trial that completed enrollment in March 2022 (NCT 3637660), we randomized 249 adults with early syphilis infection to 1 vs 3 weekly doses of benzathine penicillin G to compare treatment response at 6 months. In a small substudy (n=32) presented here, consenting participants at the University of Alabama at Birmingham (UAB) and Emory University had pre-treatment oral (buccal mucosa and posterior pharynx) and lesion swab samples collected. Following DNA extraction, T. pallidum burden in samples was quantified by targeting the tp0574 gene. Syphilis was staged by experienced providers according to physical examination and serology.

Results

Study participants were men (100%) and most were living with HIV (91%) with mean CD4 count 477 cells/mm³. Syphilis stage was categorized as primary in 6 (19%), secondary in 18 (56%) and early latent in 8 (25%). Oral swab qPCR positivity rates were 17% in primary disease, 44% in secondary disease, and 63% in early latent disease (see Figure). Lesion PCR positivity was similar in primary and secondary syphilis (40% and 38.5%). Mean treponemal burden was highest on oral swabs of participants with early latent syphilis (13,128,969) and lesion swabs of participants with secondary syphilis (2,033,309).

Conclusion

Among adult males, many living with HIV, data suggest a role for oral and lesion swabs for the molecular detection of T. pallidum. Widespread availability of PCR, the relative ease of oral specimen collection, and the opportunity to directly demonstrate T. pallidum in persons with early latent syphilis suggest the opportunity for PCR testing to enhance and refine syphilis diagnostic testing. The elevated proportion of positive oral samples and significant organism burden in secondary and early latent syphilis is consistent with potential for transmission.

Disclosures

All Authors: No reported disclosures.

A227 THE EFFECTIVENESS OF PEG 3350 COMPARED TO LACTULOSE FOR THE TREATMENT OF ACUTE HEPATIC ENCEPHALOPATHY IN ADULT CIRRHOTIC PATIENTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background

Cirrhosis is the leading cause of liver-related death globally. Hepatic encephalopathy (HE) leads to significant morbidity and mortality. Lactulose is the current gold standard treatment for HE; it eliminates nitrogenous waste from the gut. Polyethylene glycol 3350–electrolyte solution (PEG) is a safe, common and effective purgative with recent studies suggesting its efficacy resulting in faster resolution of HE and shorter hospital length of stay.

Aims

To assess the efficacy and safety of PEG 3350 compared to lactulose in adult cirrhotic patients 18 years of age and older with overt hepatic encephalopathy on patient important outcomes including: improvement of hepatic encephalopathy, hospital length of stay and mortality.

Methods

We reviewed databases MEDLINE, EMBASE, OVID, CINAHL, Cochrane Database, PubMed, Trip database, the grey literature, and clinicaltrials.gov from inception to December 2020: PROSPERO CRD42021257641. Search strategy was developed in conjunction with medical librarian. Randomized controlled trials (RCTs), either published or non-published, were included in the review. Continuous data was analyzed using mean difference with random-effects model. Dichotomous data was analyzed using the Mantel-Haenszel method using random-effects model. Statistical effect-size heterogeneity was assessed using Chi2 test and quantifying the relative proportion of variation using I2 statistic. The overall certainty of evidence will be assessed using the Grading of Recommendations, Assessment, Development and Evaluations system (GRADE).

Results

From the 68 studies, 16 were assessed for full text review from which 5 studies were included in the meta-analysis representing a total of 351 patients. The primary outcome of mean change in Hepatic Encephalopathy Scoring Algorithm (HESA) at 24-hours from baseline demonstrated an improvement in the PEG group compared to lactulose group [Mean difference (MD)= 0.60, 95% CI (0.20, 1.01)]. In comparison to lactulose, PEG also demonstrated a shorter hospital length of stay [MD = -1.00, 95% CI (-1.99, -0.01)], shorter time to HE resolution [MD= -1.49, 95% CI (-1.81, -1.16)] and showed a mortality benefit [RR=0.35, 95% CI (0.13 to 0.92)]. There was no significant difference between change in ammonia levels at 24 hours [MD= -25.80, 95% CI (-95.39, 43.78)].

Conclusions

PEG leads to a faster improvement and resolution of HE when compared to the current standard of care, lactulose.

Funding Agencies

None

865. Social Media Secret Facebook Groups for HIV Pre-Exposure Prophylaxis Awareness among Female Sex Workers in Cameroon

Background

About 25% of Cameroonian female sex workers (FSW) lived with HIV in 2018. PrEP was introduced in Cameroon in 2019, with minimal uptake as of 2021. The goal of this pilot project was to evaluate the potential of a novel social media intervention to raise Pre-Exposure Prophylaxis (PrEP) awareness and complement HIV prevention strategies among FSW, a key risk population.

Methods

From October 2020 to April 2021, sixty adult HIV-negative FSW who owned a phone with internet access joined the study; 40 in the intervention arm and 20 in the control arm. The intervention had a Secret Facebook Group (SFG) platform for confidentiality. It included 12 videos on HIV prevention in the local dialect, released over 8 weeks. In-person surveys were administered before and after the intervention, and three months later. Likert scale was used to evaluate the main outcome: PrEP awareness. Data was analyzed using Stata IC/version 14.2.

Results

Demographic characteristics were similar between intervention and control groups for age (29 years, SD7.3), literacy (45% secondary school), parity (1.9, SD1.5), and years as sex worker (7.8, SD5.1). One FSW had heard about PrEP before the intervention. After a brief introduction, 39% (15/38) of FSW in the intervention group and 50% (10/20) in the control group strongly agreed to be interested in taking PrEP (p=0.2). Baseline PrEP knowledge was poor in the intervention group (15/40, 38%) and very poor in the control group (19/20,95%) (p=0.0001). In the second survey, the intervention and control groups’ PrEP knowledge improved (p=0.0001 and p=0.02, respectively). It was more significant in the intervention group, with all FSW reporting good level of knowledge (p=0.0001) (Figure 1). In addition, more FSW in the intervention group (67%,27/40) strongly agreed to be interested in taking PrEP (p=0.01), while numbers remained similar in the control group (55%, 11/20, p=0.8). Three months after the intervention, 31.5% (12/38) of participants reported excellent PrEP knowledge, a significant improvement since the second survey (p=0.02).

Figure 1. Self-reported Pre-Exposure Prophylaxis knowledge before and after intervention in the intervention and control groups.

Conclusion

The use of a social media HIV prevention tool tailored to FSW in Cameroon improved PrEP awareness with good retention of knowledge. Cross contamination between groups might have hindered the differential impact of the brief intervention.

Disclosures

All Authors: No reported disclosures

A146 MANAGEMENT OF ANTITHROMBOTIC THERAPY AFTER GASTROINTESTINAL BLEEDING: A MIXED METHODS STUDY OF HEALTHCARE PROVIDERS

Background

Oral anticoagulants (OAC) are permanently discontinued in up to 50% of patients after gastrointestinal (GI) bleeding despite ongoing thrombotic risk and evidence of benefit to restarting. The reasons for permanent discontinuation of OAC are unclear, but likely include concerns about re-bleeding and a lack of high-quality evidence. There are no studies evaluating healthcare provider values and preferences following OAC-related GI bleeding and their influence on decision-making about whether and when to resume OACs.

Aims

We aimed to (i) identify key factors (attributes) that influence healthcare provider decision-making regarding resumption of OAC after GI bleeding, (ii) determine the relative importance of these attributes, and (iii) to identify preference groups.

Methods

We conducted focus group discussions (FGD) with healthcare providers involved in the care of patients with OAC-related GI bleeding. Participants ranked the relative importance of the attributes identified during the FGD through a dot voting exercise. Transcripts were reviewed and themes (attributes) were identified. Results of the FGD informed a discrete choice experiments survey developed and analyzed using the Sawtooth software platform (Sawtooth Software, USA). The survey was pilot tested and modified by iterative feedback. A sample choice task is shown in Image 1. Hierarchical Bayes analysis was used to estimate preference coefficients (utilities) for each attribute. Latent class analysis was used to identify preference groups.

Results

There were 4 FGD involving 29 participants. The most important attributes identified and included in the survey were thrombosis risk, indication for OAC, index bleed severity, re-bleeding risk, and patient characteristics. There were 130 survey respondents practicing in hematology (n=68), internal medicine (n=30), gastroenterology (n=7), cardiology (n=4), family medicine (n=3), and others (n=18). The mean age was 45 years (±11) and 51% were male. Thrombosis risk and re-bleeding risk equally had the highest utility followed by index bleed severity, patient characteristics, and indication for OAC. Two preference groups were identified. The dominant preference group (78% of respondents) placed the highest utility on thrombosis risk and re-bleeding risk, while a minority (22% of respondents) placed the highest utility on index bleed severity.

Conclusions

Thrombosis risk and re-bleeding risk are equally the most important factors influencing OAC resumption following OAC-related GI bleeding. The severity of the index bleed is the most important factor in decision-making for a minority segment of healthcare providers. Further research on the dose, type and timing of OAC resumption is needed to determine the optimal balance between thrombosis and re-bleeding.

Funding Agencies

Heart and Stroke Foundation

A quantitative analysis of the supercontraction-induced molecular disorientation of major ampullate spider silk

Spider silks exhibit remarkable properties, among which the so-called supercontraction, a physical phenomenon by which fibers undergo a longitudinal shrinkage and a radial swelling when exposed to water. The process is marked by a significant decrease in chain orientation resulting from plasticisation of the amorphous phase. Despite several studies that determined the Hermans orientation function, more quantitative data are required to be able to describe theoretically the macroscopic water-induced shrinkage from molecular reorganization. Here, we have examined the supercontraction of the major ampullate silk single fibers of Nephila clavipes (Nc) and Araneus diadematus (Ad) using polarized Raman spectromicroscopy. We determined the order parameters, the orientation distribution and the secondary structure content. Our data suggest that supercontraction induces a slight increase in β-sheet content, consistently with previous works. The β-sheet orientation is slightly affected by supercontraction compared to that of the amorphous phase, which becomes almost isotropic with shrinkage. Despite an initially lower orientation level, the Ad fiber shows a larger orientation decrease than Nc, consistently with its higher shrinkage amplitude. Although they share similar trends, absolute values of the orientation parameters from this work differ from those found in the literature. We took advantage of having determined the distribution of orientation to estimate the amplitude of shrinkage from changes in macromolecular size resulting from molecular disorientation. Our calculations show that more realistic models are needed to correlate molecular reorientation/refolding to macroscopic shrinkage. This work also underlines that more accurate data relative to molecular orientation are necessary.

Resident reflections on end-of-life education: a mixed-methods study of the 3 Wishes Project

OBJECTIVE

The objectives of this study were to describe residents' experiences with end-of-life (EOL) education during a rotation in the intensive care unit (ICU), and to understand the possible influence of the 3 Wishes Project.

DESIGN

We enrolled dying patients, their families and 1-3 of their clinicians in the 3 Wishes Project, eliciting and honouring a set of 3 wishes to bring peace to the final days of a critically ill patient's life, and ease the grieving process for families. We conducted semistructured interviews with 33 residents who had cared for 50 dying patients to understand their experiences with the project. Interviews were recorded, transcribed verbatim, then analysed using a qualitative descriptive approach.

SETTING

21-bed medical surgical ICU in a tertiary care, university-affiliated hospital.

RESULTS

33 residents participated from internal medicine (24, 72.7%), anaesthesia (8, 24.2%) and laboratory medicine (1, 3.0%) programmes in postgraduate years 1-3. 3 categories and associated themes emerged. (1) EOL care is a challenging component of training in that (a) death in the ICU can invoke helplessness, (b) EOL education is inadequate, (c) personal connections with dying patients is difficult in the ICU and (d) EOL skills are valued by residents. (2) The project reframes the dying process for residents by (a) humanising this aspect of practice, (b) identifying that family engagement is central to the dying process, (c) increasing emotional responsiveness and (d) showing that care shifts, not stops. (3) The project offers experiential education by (a) intentional role modelling, (b) facilitating EOL dialogue, (c) empowering residents to care in a tangible way and (d) encouraging reflection.

CONCLUSIONS

For residents, the 3 Wishes Project integrated many forms of active learning for residents. Practice-based rather than classroom-based programmes may engage trainees to develop EOL skills transferable to other settings.

Phase I study of Aplidine in a dailyx5 one-hour infusion every 3 weeks in patients with solid tumors refractory to standard therapy. A National Cancer Institute of Canada Clinical Trials Group study: NCIC CTG IND 115

BACKGROUND

Aplidine is a cyclic depsipeptide isolated from the marine tunicate Aplidium albicans.

METHODS

This phase I study of Aplidine given as a 1-hour i.v. infusion daily for 5 days every 3 weeks was conducted in patients with refractory solid tumors. Objectives were to define the dose limiting toxicities, the maximal tolerated dose, and the recommended phase II dose.

RESULTS

Thirty-seven patients were accrued on study. Doses ranged from 80 microg/m(2) to 1500 microg/m(2)/day. Eleven patients received more than three cycles of Aplidine. Dose-limiting toxicities occurred at 1500 microg/m(2) and 1350 microg/m(2)/day and consisted of nausea, vomiting, myalgia, fatigue, skin rash and diarrhea. Mild to moderate muscular pain and weakness was noted in patients treated with multiple cycles with no significant drug related neurotoxicity. Bone marrow toxicity was not observed. The recommended dose for phase II studies was 1200 microg/m(2) daily for 5 days, every 3 weeks. Pharmacokinetic studies performed during the first cycle demonstrated that therapeutic plasma levels of Aplidine are reachable well below the recommended dose. Nine patients with progressive disease at study entry had stable disease and two had minor responses, one in non-small cell lung cancer and one in colorectal cancer.

CONCLUSIONS

Aplidine given at a dose of 1200 microg/m(2) daily for 5 days, every 3 weeks is well tolerated with few severe adverse events. This schedule of Aplidine is under evaluation in phase II studies in hematological malignancies and solid tumors.

Oestradiol decreases rat apolipoprotein AI transcription via promoter site B

Oestrogens protect against ischaemic heart disease in the post-menopausal female by increasing serum concentrations of apolipoprotein (apo) AI and the abundance of high-density lipoprotein particles. In men and experimental male animals, the administration of oestrogen has variable effects on apo AI expression. As the major mode of oestrogen action on target genes involves regulating promoter activity and hence transcription, oestrogen is expected to alter transcription of the apo AI gene. To test this hypothesis, the effect of 17beta-oestradiol (E(2)), on rat apo AI promoter activity in male hepatoma HuH-7 cells, was tested by co-transfecting a reporter template, pAI.474.CAT containing-474 to-7 of the rat apo AI promoter and an oestrogen receptor (ER) expression vector, pCMV-ER. Transfected cells exposed to E(2) showed a dose-dependent decrease in chloramphenicol acetyltransferase (CAT)-activity, with a maximum 91+/-1.5% reduction at 1 microM E(2). Deletional analysis of the promoter localized the inhibitory effect of ER and E(2) to site B (-170 to-144) with an adjacent 5' contiguous motif, site S (-186 to-171) acting as an amplifier. HuH-7 cell nuclear extracts showed binding activities with both sites S and B, but recombinant human ER did not. Furthermore, nuclear extracts from E(2)-treated HuH-7 cells showed weaker binding activity to site B, but not to site S. In summary, the inhibitory effect of ER and E(2) on rat apo AI gene activity is mediated by a promoter element, site B. This inhibitory effect arises from a mechanism that does not involve direct ER binding to the B-element. The conclusion that E(2) inhibits apo AI transcription was confirmed in vivo. Treatment of male adult Sprague-Dawley rats with up to 200 microg E(2) for 7 days decreased apo AI protein and hepatic mRNA by 72+/-21% and 68+/-1.4% respectively. Results of 'run-on' transcription of the apo AI gene in isolated hepatic nuclei showed a 55% decrease in hormone-treated male rats. These findings suggest that E(2) exerts primarily an inhibitory effect within male hepatic nuclei.

New adenovirus vectors for protein production and gene transfer

Based on two new adenovirus expression cassettes, we have constructed a series of Ad transfer vectors for the overexpression of one or two genes either in a dicistronic configuration or with separate expression cassettes. Inclusion of the green or blue fluorescent protein in the vectors accelerates the generation of adenovirus recombinants and facilitates the functional characterization of genes both in vitro and in vivo by allowing easy quantification of gene transfer and expression. With our optimized tetracycline-regulated promoter (TR5) we have generated recombinant adenoviruses expressing proteins, that are either cytotoxic or which interfere with adenovirus replication, at levels of 10-15% of total cell protein. Proteins that are not cytotoxic can be produced at levels greater than 20% of total cell protein. As well, these levels of protein production can be achieved with or without adenovirus replication. This yield is similar to what can be obtained with our optimized human cytomegalovirus-immediate early promoter-enhancer (CMV5) for constitutive protein expression in non-complementing cell lines. Using the green fluorescent protein as a reporter, we have shown that a pAdCMV5-derived adenovirus vector expresses about 6-fold more protein in complementing 293 cells and about 12-fold more in non- complementing HeLa cells than an adenovirus vector containing the standard cytomegalovirus promoter. Moreover, a red-shifted variant of green fluorescent protein incorporated in one series of vectors was 12-fold more fluorescent than the S65T mutant, making the detection of the reporter protein possible at much lower levels of expression.

Pilot phase I-II study on 5-aza-2'-deoxycytidine (Decitabine) in patients with metastatic lung cancer

5-Aza-2'-deoxycytidine (5-AZA-CdR, Decitabine) is a nucleoside analog and an active drug for the therapy of acute leukemia. The incorporation of 5-AZA-CdR into DNA blocks DNA methylation and can result in the activation of specific genes, such as tumor suppressor genes. This novel mechanism of action of 5-AZA-CdR stimulated our interest in its potential for cancer therapy in patients with lung cancer. Using a colony assay we observed that 5-AZA-CdR showed a potent antineoplastic effect against two human lung carcinoma cell lines. The objective of this preliminary phase I-II study was to evaluate the toxicity and clinical efficacy of 5-AZA-CdR in patients with stage IV non-small cell lung carcinoma. There were 15 patients that entered the clinical study. For nine assessable patients that received 5-AZA-CdR by a single 8 h i.v. infusion of 200-660 mg/m2 for one or more cycles, the median survival duration was 6.7 months, with three patients surviving more than 15 months. The steady-state plasma concentration of 5-AZA-CdR during the infusion was estimated in some patients and was in the same range that produced activation of a tumor suppressor gene in human lung tumor cell lines as reported by other investigators. The major side effect of 5-AZA-CdR was hematopoietic toxicity which required a 5-6 week recovery period before the next cycle of therapy. This study suggests that 5-AZA-CdR may have some clinical activity against metastatic lung carcinoma using this type of dose schedule.

Improved adenovirus vector provides herpes simplex virus ribonucleotide reductase R1 and R2 subunits very efficiently

We have constructed a new adenovirus (Ad) expression vector, pAdBM5, that allows for the production of unprecedented levels of recombinant protein in the human 293 cell line using the Ad expression system. The main feature of this vector is a combination of enhancer sequences that increases the activity of the ectopic major late promoter (MLP) in recombinant Ad. In 293 cells infected with helper-free Ad recombinants generated with the pAdBM5 transfer vector, both herpes simplex virus (HSV) ribonucleotide reductase R1 and R2 subunits represent the most abundant polypeptides, accounting for as much as 15-20% of total cellular proteins. Our data suggest that this level of expression is probably very close to the upper limit of the system. Furthermore, when compared to the widely utilized baculovirus (Bac)/Sf9 expression system, the improved Ad vector showed a better performance for the production and purification of active HSV-2 ribonucleotide reductase R1 and R2 subunits. The R2 subunit was about 5-fold more abundant in recombinant Ad-infected 293 cells than in Bac-infected Sf9 cells while the R1 subunit was produced at roughly similar levels with either system. However, the amount of active soluble R1 obtained from recombinant Ad-infected 293 cells was at least 5 times higher because most of the R1 produced in Sf9 cells was insoluble.

The importance of dose scheduling with mitoxantrone, 5-fluorouracil and leucovorin in metastatic breast cancer

We have studied a mitoxantrone, 5-fluorouracil (5-FU) and leucovorin chemotherapy regimen in metastatic breast cancer. 8 patients received mitoxantrone 10 mg/m2 on day 1, leucovorin 200 mg/m2 and 5-FU 300 mg/m2 on days 1-5 by intravenous bolus every 28 days in a pilot study. Grades 3-4 granulocytopenia followed 55% of the courses, with 2 patients admitted for febrile neutropenia. Only a 29% objective response rate was seen in a subsequent phase II trial using reduced mitoxantrone doses. Comparison with other trials suggested that 5-day bolus 5-FU administration adversely affects the combination's therapeutic index.

Identification and sequencing of the spheroidin gene of Choristoneura biennis entomopoxvirus

Entomopoxviruses are a class of insect viruses whose virions are embedded in cytoplasmic occlusion bodies. The major component of these protective complexes is a protein called spheroidin. An open reading frame encoding the spheroidin gene of Choristoneura biennis entomopoxvirus has been identified and sequenced in our laboratory. This protein coding region is 1023 nucleotides long and specifies a polypeptide of 38,500 Da. Spheroidin was purified by SDS polyacrylamide gel electrophoresis, electroeluted, and its amino terminus sequence was determined on a gas phase sequencer. We observed that the first 20 N-terminal amino acids were absent in the mature processed form of the spheroidin molecule. Examination of these 20 residues revealed their hydrophobic nature and close resemblance to the consensus signal peptide sequence which is commonly found on membrane proteins. The DNA sequence of the spheroidin gene predicted a processed polypeptide with a molecular weight of 36 kDa. However, spheroidin was observed to aggregate in complexes composed of 50-kDa monomers. Intermolecular disulfide bonds were shown to play major roles in the formation and structure of these viral occlusion bodies. The difference in molecular weight between the predicted protein and its counterpart in infected cells is likely due to post-translational modifications. Indeed, two potential asparagine-linked glycosylation sites are present on the spheroidin molecule. The 5' flanking regions of the spheroidin gene and the vaccinia major core protein precursor gene P4b were shown to share substantial homology.

Oculomotor and vestibular findings in autosomal recessive spastic ataxia of Charlevoix-Saguenay

Electronystagmographic recordings were made of oculomotor and vestibular function in 11 patients with autosomal recessive spastic ataxia of Charlevoix-Saguenay. All had horizontal gaze nystagmus, marked impairment of smooth ocular pursuit and optokinetic nystagmus, and defective fixation suppression of caloric nystagmus. Many had saccadic dysmetria, but saccade velocity was probably unaffected. Abnormalities pointing to brainstem disturbance were sparse. The findings are thought to indicate mainly diffuse cerebellar disease, with particular involvement of vermis and vestibulo-cerebellum.