IMMU-02. GENOMIC AND TRANSCRIPTOMIC CORRELATES OF IMMUNOTHERAPY RESPONSE WITHIN THE TUMOR MICROENVIRONMENT OF LEPTOMENINGEAL METASTASES

Leptomeningeal disease (LMD) is a devastating complication of solid tumor malignancies, with dire prognosis and no effective systemic treatment options. Over the past decade, the incidence of LMD has steadily increased due to therapeutics that have extended the survival of cancer patients, highlighting the need for new interventions. To examine the efficacy of immune checkpoint inhibitors (ICI) in patients with LMD, we completed two phase II clinical trials utilizing either Pembrolizumab alone or the combination of Ipilimumab and Nivolumab. We investigated the cellular and molecular features underpinning observed patient trajectories in these trials by applying single-cell RNA and cell-free DNA profiling to longitudinal cerebrospinal fluid (CSF) draws from enrolled patients. We isolated and sequenced 34,742 cells from both the malignant and immune compartment within CSF. Amongst the 19 patients included in the cohort, there were 13 pre-treatment and 24 post-treatment samples, and 9 patients were sampled across multiple timepoints. We detected dynamic changes in immune cell recruitment into the CSF and activation within 30 days of ICI, including increased effector T cell activation and IFN-gamma response pathways within T cells. Moreover, the overall level of IFN-gamma response and antigen processing within 30 days of ICI in malignant cells correlated with survival past clinical trial primary endpoint. Lastly, we observed evidence of longitudinal outgrowth of distinct immunogenic clones over the course of ICI. Overall, our study describes the liquid LMD tumor microenvironment prior to and following ICI treatment and provides unique insights into the compartmental and temporal variation during the course of ICI. Moreover, our findings demonstrate the clinical utility of cell- free and single-cell genomic measurements for LMD research.

BIOM-04. SENSITIVE DETECTION OF LEPTOMENINGEAL DISEASE USING CELL-FREE DNA FROM CEREBROSPINAL FLUID

Leptomeningeal disease is a devastating complication of cancer that is frequently underdiagnosed due to the low sensitivity of cerebrospinal fluid cytology, the current gold-standard diagnostic method. We performed genomic sequencing on cerebrospinal fluid specimens obtained from patients with suspected or confirmed leptomeningeal disease to identify tumor-derived cell-free DNA. From the same fluid draw, cerebrospinal fluid cytology was assayed for comparison. 30 patients underwent cytology and cell-free DNA analysis. This study consisted of two patient populations: 22 patients with cytology-confirmed leptomeningeal disease without parenchymal tumors abutting their cerebrospinal fluid and 8 patients with parenchymal brain metastases with no evidence of leptomeningeal disease. The primary outcome was the diagnostic accuracy of cell-free DNA, defined as the number of correct diagnoses out of the total number of tests assayed. A total of 30 patients, 23 female and 7 male, with a median age of 51 participated in this study. Participants mostly presented with metastatic solid malignancies. In patients previously diagnosed with leptomeningeal disease via cytology with no parenchymal tumor abutting cerebrospinal fluid, cell-free DNA was accurate in diagnosis of leptomeningeal disease in 45 of 48 follow-up samples (94%; 95% CI, 83%-99%). Cytology was accurate in 36 of 48 follow-up samples (75%; 95% CI, 60%-86%). Cell-free DNA was significantly more accurate (P=.02) and sensitive (P=.02) than cytology in patients without parenchymal tumors abutting the cerebrospinal fluid. In three patients with parenchymal brain metastases abutting the cerebrospinal fluid and no suspicion for leptomeningeal disease, cytology was negative in all three patients; whereas, cell-free DNA was positive in all three. This study demonstrates the improved sensitivity and accuracy of cell-free DNA in diagnosing leptomeningeal disease with the exception of parenchymal tumors abutting cerebrospinal fluid. Overall, these results will lead to improved diagnosis of leptomeningeal disease and potentially earlier intervention and clinical trial enrollment.

Evaluation of oral health status and oral disorders of children with autism spectrum disorders by gender

AIM

The aim of this study was to evaluate whether there is a relationship between gender and oral health status of children with autism spectrum disorders (CASD).

MATERIAL-METHODS

The study was carried out with 348 children. The children were separated into two groups to evaluate the prevalence of caries and to assess oral disorders in terms of gender. The following factors were evaluated: mean dmft (decayed missed filled permanent tooth in primary dentition), mean DMFT (decayed missed filled permanent tooth in permanent dentition), plaque index, caries prevalence scores, dental crowding, open bite, deep palate, drooling of saliva, tongue thrusting habit, bruxism, dental and soft tissue trauma, tooth wear, delayed eruption, and hypodontia.

RESULTS

The results showed that the mean dmft in boys with CASD (BCASD) was lower than the mean dmft in healthy boys. The mean dmft of the girls with CASD (GCASD) was also lower than that of the healthy girls. The prevalence of dental caries and mean DMFT in GCASD were higher than those of BCASD in permanent dentition. While the plaque index value of BCASD was higher than that of healthy boys, the plaque index value of GCASD was lower than that of healthy girls. The plaque index value of BCASD was higher than that of GCASD. GCASD were reported to have significantly more bruxism than their healthy counterparts. However, no statistically significant difference was found between BCASD and healthy boys regarding bruxism. Moreover, there was no significant difference between BCASD and GCASD in terms of bruxism. Drooling of saliva in BCASD was less than GCASD.

CONCLUSION

There were significant gender differences between CASD and healthy children in terms of dental caries and oral disorders in this study. There were also significant differences regarding dental caries and oral disorders between GCASD and BCASD.

Caries experience, oral disorders, oral hygiene practices and socio-demographic characteristics of autistic children

AIM

The aim of the present study was to comparatively evaluate the oral health status and influential factors, brushing, developmental and orthodontic disorders, bruxism, drug intake, sweet eating habits, sociodemographic factors and lifestyles of autistic and healthy children. Participants in this study were greater in number compared to the previous studies investigating the same phenomenon. Furthermore, it was a more comprehensive study than other studies in the literature in terms of number of variables included.

METHODS

The study was carried out with a total of 407 participants, 285 autistic (test group) and 122 healthy children (control group). The ages ranged from 5 to 16. A total of 407 children were examined. DMFT, dmft, plaque index, dental trauma, oral symptoms, developmental and orthodontic disorders of these children were recorded. Participants were also asked to fill a two-part questionnaire. The first part included questions related to the child's and parents' demographics such as the child's age, gender, number of siblings, the mother's and father's age, education, occupation and income. The second part included questions related to systemic diseases, drug intake, the dental history of children and their parents, brushing and nutrition habits.

RESULTS

The results from the inferential statistics showed that both DMFT and dmft indices values of the autistic children were lower than those of the healthy children. Caries prevalence of the autistic children was lower compared to the control group. There was also no difference in the plaque index values between the two groups. Drooling of saliva of the autistic children was higher than that of the healthy children. The results showed statistically significant differences between the two groups regarding bruxism, deep-palate and tongue thrusting, though no statistically significant differences were found between the two groups regarding open bite. However, significant differences were observed in terms of dental crowding between the two groups in that the healthy children had more dental crowding than the autistic children.

CONCLUSION

One of the main findings of the study was observed in relation to caries prevalence in that autistics had lower caries prevalence values than controls. Another main finding was that no statistically significant differences were found in terms of plaque index values when the groups were compared. When the findings related to deep palate, open bite and dental crowding were examined, it was seen that deep palate was higher but dental crowding was lower in the autistic children. However, in this study there were no statistically significant differences between the two groups in terms of open bite.

The effect of heat on the mechanical properties of glass ionomer cements

AIM

The objective of this study was to assess the effect of heat application on the mechanical properties of glass ionomer cements.

STUDY DESIGN

experimental design. The effect of heat on glass ionomer cements during their setting was evaluated by measuring compressive strength, flexural strength and microhardness. Moroever, temperature changes from one surface of the glass ionomer cement specimens 2, 4, and 6 mm thick to the other surface were measured. A condensable glass ionomer cement (Fuji IX) and a ceramic-reinforced glass ionomer cement (Amalgomer CR) were used as test materials. Heat was applied with soldering iron for 2 minutes at 80±2oC. All mechanical tests were carried out 24 hours after the setting of glass ionomer cements.

RESULTS

No significant differences in compressive strength were found between the control groups and the heated groups. There were no statistically significant differences in the flexural strength value for both groups of Fuji IX. On the contrary, when heat was applied to Amalgomer, its mean flexural strength reached a value that was higher than that of Amalgomer control. Significant differences in microhardness were found between the control groups and the heated groups and between Fuji IX and Amalgomer CR. Temperature rising in both glass ionomer cements was also noted.

STATISTICS

two-way ANOVA was used where appropriate and independent samples t-test was used in case of interaction.

CONCLUSION

It is established that heat application improved the surface mechanical properties of conventional glass ionomer cements.

Immunizing children to protect against the increasing risk of hepatitis A in adolescents and young adults in South Korea

We evaluated the CR326F strain (VAQTA) derived hepatitis A vaccine in Korean children and adolescents >2 years of age to consider a future immunization program. In our study, the pediatric two-dose regimen of VAQTA was found to be generally well tolerated and resulted in 100% (95% CI 94.8, 100.0) seroconversion after 2 doses. Immunizing children with the HAV vaccine routinely should be considered in South Korea, particularly in areas where recent outbreaks have occurred.

Control of hepatitis A through routine vaccination of children

CONTEXT

The impact of routine hepatitis A vaccination of children living in large communities with elevated disease rates has not been evaluated.

OBJECTIVE

To determine the effect of routine vaccination of children on disease incidence in a community with recurrent hepatitis A epidemics.

DESIGN, SETTING, AND PARTICIPANTS

Community-based demonstration project conducted from January 12, 1995, through December 31, 2000, in Butte County, California, among children aged 2 to 17 years.

INTERVENTION

In 1995, vaccination was offered to children aged 2 to 12 years during vaccination clinics conducted on 2 occasions 6 to 12 months apart at most schools in the county. In 1996-2000, vaccine was distributed to community health care clinicians, who vaccinated eligible children without charge. Vaccine was also available at health department clinics, selected child care centers, and other sites.

MAIN OUTCOME MEASURES

Hepatitis A vaccination coverage, hepatitis A incidence, and vaccine effectiveness.

RESULTS

During the study period, 29 789 (66.2%) of an estimated 44 982 eligible children received at least 1 vaccine dose; 17 681 (39.3%) received a second dose. The number of hepatitis A cases among the entire county population declined 93.5% during the study period, from 57 cases in 1995 to 4 in 2000, the lowest number of cases reported in the county since hepatitis A surveillance began in 1966. The 2000 incidence rate of 1.9 per 100 000 population was the lowest of any county in the state. Of the 245 cases reported during the 6-year period, 40 (16.3%) occurred among children 17 years of age or younger, of which 16 (40%) occurred in 1995 and only 1 in 2000. One of the 27 case patients eligible for vaccination had been vaccinated, having received the first dose 3 days before symptom onset. The estimated protective vaccine efficacy was 98% (95% confidence interval, 86%-100%).

CONCLUSIONS

In this population, hepatitis A vaccine was highly effective in preventing disease among recipients. Childhood vaccination appears to have decreased hepatitis A incidence among children and adults and controlled the disease in a community with recurrent epidemics.

A randomized study of a flexible booster dosing regimen of VAQTA in adults: safety, tolerability, and immunogenicity

BACKGROUND

VAQTA (hepatitis A vaccine inactivated, Merck & Co., Inc., West Point, PA) is licensed for use in healthy adults in a two-dose schedule at 0 and 6 months.

OBJECTIVE

to determine whether the responses to a booster dose of VAQTA administered to adults 12 or 18 months after the first dose were similar to the response when the booster dose was administered 6 months after the first dose.

METHODS

healthy adults were randomized to receive 50-U of VAQTA at 6 (Group I), 12 (Group II), or 18 months (Group III) following receipt of Dose 1 on Day 0. Blood samples were collected immediately prior to Doses 1 and 2 and then, 4 weeks following Dose 2. Seropositivity rates (SPRs), geometric mean titers (GMTs) in milli-international units per milliliter (mIU/ml) and booster response rates (BRRs) were compared among treatment groups. Safety data were collected on Vaccination Report Cards.

RESULTS

no serious adverse experiences were reported, and the vaccine was well-tolerated by subjects in the three treatment groups. One month following the booster dose, SPRs and GMTs for Groups I, II, and III, respectively, were, 100% (102/102) and 6726.4 mIU/ml; 97.9% (93/95) and 4863.8 mIU/ml; 100% (86/86) and 6068.3 mIU/ml. The BRRs were 88.2% (Group I), 90.2% (Group II) and 94.2% (Group III).

CONCLUSION

responses to the booster dose were comparable regardless of the timing (i.e. 6, 12, or 18 months following Dose 1). Flexibility in the timing of the booster dose of VAQTA in adults would allow the vaccination schedule to be the same for adults, adolescents, and children and may increase the likelihood that adults receive the booster dose.

An open study of subcutaneous administration of inactivated hepatitis A vaccine (VAQTA) in adults: safety, tolerability, and immunogenicity

A number of patients in clinical practice would be candidates for hepatitis A vaccine administered subcutaneously (SC), including patients with inherited and acquired coagulopathies. To assess the safety, tolerability, and immunogenicity of VAQTA (Hepatitis A Vaccine, Inactivated, Merck and Co. Inc., West Point, PA) was administered SC to healthy adults. A total of 114 healthy adults received two doses of vaccine SC 24 weeks apart. No serious vaccine-related adverse experiences were reported. Four weeks after dose 1, the seropositivity rate (SPR) was 77.9% (CI, 69.1, 85.1%). The geometric mean titer (GMT) was 21.0 mIU/ml. Twenty-four weeks after dose 1 (just prior to dose 2) and 28 weeks after dose 1 (4 weeks following dose 2), the SPRs were 95.3% [corrected] and 100%, respectively; the GMTs were 153.2 and 1563.9 mIU/mL, respectively [corrected]. Although the kinetics of the immune response were slower when VAQTA was administered SC compared to intramuscular injection, SPRs and GMTs increased over time, indicating that the vaccine administered SC demonstrated immunogenicity.

Randomized, double-blind study in healthy adults to assess the boosting effect of Vaqta or Havrix after a single dose of Havrix

A randomized, double-blind, multicenter study was conducted to investigate the boosting effect of Vaqta or Havrix in 537 healthy adults 18-53 years of age who had received a single dose of Havrix either 24 or 52 weeks earlier. Subjects were randomized in a 2 : 1 ratio to receive either Vaqta or Havrix for their second dose of vaccine and followed for clinical reactions for 14 days after dose 2 was administered. Serum samples were collected immediately before dose 2 was administered and again 4 weeks later and evaluated for hepatitis A antibody (modified hepatitis A virus antibody assay). The booster response rate after administration of the second dose of either vaccine was similar (86.1% for Vaqta vs. 80.1% for Havrix). The geometric mean titers were also similar: 3274 mIU/mL (95% confidence interval [CI], 2776-3858) for Vaqta versus 2423 mIU/mL (95% CI, 1911-3074) for Havrix. The proportion of subjects who reported > or =1 injection-site adverse experiences was lower in the patients receiving Vaqta than in those receiving Havrix (36.6% vs. 59.7%; P<.001). The results of this study indicate that a regimen of Havrix followed by Vaqta is generally well tolerated and highly immunogenic.

Measles, mumps, rubella, and varicella combination vaccine: safety and immunogenicity alone and in combination with other vaccines given to children. Measles, Mumps, Rubella, Varicella Vaccine Study Group

Eight hundred and twelve children, 12 months to 3.5 years of age, were enrolled in two clinical studies to evaluate the safety and immunogenicity of a live, attenuated combination vaccine for measles, mumps, rubella, and varicella (MMRV). Children were enrolled in one of two randomized, multicenter studies, involving administration of (1) MMRV and placebo vs. measles, mumps, and rubella vaccine (M-M-R(II)) and varicella-zoster virus vaccine (VARIVAX), given at separate anatomic sites at the same office visit; or (2) MMRV, DTaP (diphtheria, tetanus, and acellular pertussis vaccine) and OPV (oral polio vaccine) vs. M-M-R(II), DTaP, and OPV, with VARIVAX given 6 weeks later. All vaccine regimens were generally well tolerated. More than 95% of vaccinees seroconverted for measles, mumps, rubella, and varicella, regardless of the vaccine or regimen used. In each study, the level of antibody titer to varicella virus was significantly lower in vaccinees receiving MMRV than in those who received VARIVAX in a separate syringe.

The effect of decreasing amounts of live virus, while antigen content remains constant, on immunogenicity of Oka/Merck varicella vaccine

The purpose of the study was to establish the minimum immunizing dose of stored Oka/Merck varicella vaccine and mimic effects of prolonged storage of vaccine at freezer temperatures. Ninety children were randomized to one of three groups: group A (1770 pfu/dose), group B (400-500 pfu/dose), or group C (80-160 pfu/dose). Seroconversion rates for groups A-C were 97%, 96%, and 92%, respectively. Group A and B vaccinees had higher antibody titers at 1 year than did group C subjects (P = .01). The difference between groups B and C approached significance (P = .058). At 1 year after immunization, 73%, 83%, and 80% in groups A-C, respectively, demonstrated cell-mediated responses. Since freshly reconstituted vaccine contains 1770 pfu/dose, vaccine failure from loss of potency is unlikely if vaccine is stored properly and administered promptly after reconstitution.

Sensitive assays for hepatitis A antibodies

Two commercial assay kits for detecting antibody to hepatitis A virus (anti-HAV) have been modified in order to increase their sensitivity. These modifications are made by less dilution of the test serum, in the case of Abbott HAVAB-M assay, or by an increase in the volumetric ratio of the test serum to the labeled anti-HAV in the case of the Abbott HAVAB assay. These modifications result in 5- to 20-fold increases in test sensitivity and enable the detection of anti-HAV at 2-3 weeks following vaccination. The earlier detection of anti-HAV is important to vaccine development in assuring the presence of antibody levels in travelers sooner after vaccination.

Inactivated hepatitis A vaccine in childhood: implications for disease control

The experience to date with the Merck inactivated hepatitis A vaccine in healthy children 2-16 years old is reviewed. Comparison of response to increasing doses indicates that an intramuscular dose of 25 units results in seroconversion of 99% of children by week 4 following a single dose. Antibody persistence rate is nearly 100% six months later, whether or not a second priming dose is given at week 8. This vaccine has proven highly immunogenic in children and has a favourable safety/tolerability profile. It should be useful for pre-exposure prophylaxis and control of hepatitis A, and should eventually replace immune globulin (Ig) for this indication.

Single and booster dose responses to an inactivated hepatitis A virus vaccine: comparison with immune serum globulin prophylaxis

Pre- and postexposure prophylaxis against hepatitis A virus (HAV) infection with immune serum globulin (Ig) is only effective for 4-6 months. We compared the safety, tolerability and immunogenicity of a single i.m. injection of Ig with a single and booster dose of an inactivated hepatitis A virus vaccine (iHAV) in adults. Healthy volunteers (18-50 years) received a single Ig i.m. injection (n = 30), or iHAV i.m. (n = 15) at 0 and 24 weeks, or placebo (n = 4) at the same intervals. Anti-HAV seroconversion was measured by radioimmunoassay (RIA) and neutralizing antibodies by an antigen reduction assay. After Ig injection (0.06 ml/kg), anti-HAV seroconversion occurred in 100% of recipients at week 1, declining to 10% at week 12 and 0% by week 20. In contrast, after a single 25 ng dose, RIA seropositivity in iHAV vaccinees was 80% by week 2, reaching 100% by week 5 and persisted up to week 24, at which time anti-HAV geometric mean titres (GMT) were two fold higher than those seen at week 1 after Ig. Postbooster anti-HAV titres in iHAV recipients rose within 4 weeks to 73-fold greater than the peak GMT seen one week after Ig, and 400-fold higher than GMT at 12 weeks after Ig. Neutralizing antibody titres after iHAV followed a similar pattern, as observed for anti-HAV. iHAV was well tolerated; placebo and vaccine tolerability were indistinguishable, with no serious adverse experiences observed. In conclusion, active vaccination with a single iHAV dose may eventually replace Ig for pre-exposure prophylaxis.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomy of a trial: a historical view of the Monroe inactivated hepatitis A protective efficacy trial

The performance of vaccine protective efficacy trials is often more complex than reports of final results suggest. The current article reviews the background, planning and preparations for the Monroe, NY, protective efficacy trial of a formalin-inactivated, alum-adjuvanted hepatitis A vaccine (VAQTA, manufactured by Merck Research Laboratories). The vaccine trial was carried out at Kiryas Joel, a Hasidic Jewish community which had experienced numerous annual outbreaks in a local environment with similarities to day-care centers. Careful communication, and cooperation of community leadership, a flexible technical resource team, and knowledge of an epidemic already ongoing in a sister community whose members were due to arrive for summer holidays, permitted rapid and efficient completion of the trial with a striking demonstration of protection after a single vaccine dose.

Safety, tolerability, and immunogenicity of an inactivated hepatitis A vaccine: effects of single and booster injections, and comparison to administration of immune globulin

Hepatitis A virus (HAV) infection in adults is often symptomatic and disabling. The present article summarizes our experience with phase 2 studies of an inactivated hepatitis A virus vaccine. Pre- and post-exposure prophylaxis with immune globulin (IG) is only effective for 4-6 months. We compared the safety, tolerability, and immunogenicity of a single i.m. injection of IG with single and booster doses of an inactivated hepatitis A virus vaccine (iHAV) in adults. A total of 75 healthy volunteers (aged 18-50 years) were evaluated in two separate studies. The first included 15 volunteers who received 25 units iHAV i.m. at 0 and 24 weeks. The second, a randomly controlled study, consisted of three groups receiving 25 units iHAV i.m. at 0, 1, and 6 months, or at 0, 2, and 6 months, or 0.06 ml/kg IG i.m. given once. Anti-HAV seroconversion was measured by radioimmunoassay (RIA). After IG injection, anti-HAV seroconversion occurred in 100% of recipients at week 1, declining to 10% at week 12, and 0% by week 20. In contrast, after a single 25-unit dose, RIA seropositivity in iHAV vaccines was 73% by week 2, reaching 100% by week 5, and persisted in all up to week 24, at which time anti-HAV geometric mean titers (GMT) were 2-fold higher than those seen at week 1 after IG. Administration of a booster dose given 1 or 2 months after primary immunization did not significantly improve the quantitative anti-HAV response at 6 months as compared to the effect of the primary dose.(ABSTRACT TRUNCATED AT 250 WORDS)

A controlled trial of a formalin-inactivated hepatitis A vaccine in healthy children

BACKGROUND

Although inactivated hepatitis A vaccine is known to be well tolerated and immunogenic in healthy children and adults, its efficacy has yet to be established.

METHODS

To evaluate the efficacy of the hepatitis A vaccine in protecting against clinically apparent disease, we conducted a double-blind, placebo-controlled trial in an Hasidic Jewish community in upstate New York that has had recurrent outbreaks of hepatitis A. At the beginning of a summer outbreak, 1037 healthy seronegative children 2 to 16 years of age were randomly assigned to receive one intramuscular injection of a highly purified, formalin-inactivated hepatitis A vaccine or placebo. A case was defined by the presence of typical signs and symptoms, a diagnostic increase in IgM antibody to hepatitis A, and a serum concentration of alanine aminotransferase at least twice the upper limit of normal. Cases occurring greater than or equal to 50 days after the injection were included in the evaluation of efficacy. The children were followed for a mean of 103 days.

RESULTS

A total of 519 children received vaccine, and 518 received placebo. The vaccine was well tolerated, with no serious adverse reactions. From day 50 after the injection, 25 cases of clinically apparent hepatitis A occurred in the placebo group and none in the vaccine group (P less than 0.001), confirming that the vaccine had 100 percent protective efficacy. Before day 21, seven cases occurred in the vaccine group and three cases in the placebo group. After that time, there were no cases among vaccine recipients and 34 cases among placebo recipients.

CONCLUSIONS

The inactivated purified hepatitis A vaccine that we tested is well tolerated, and a single dose is highly protective against clinically apparent hepatitis A.