Recurrent Cervical Cancer, Recurrent Vaginal Cancer, Stage IB Cervical Cancer, Stage IIA Cervical Cancer, Stage IIB Cervical Cancer, Stage III Cervical Cancer, Stage III Vaginal Cancer, Stage II Vaginal Cancer, Stage IVA Cervical Cancer, Stage IVA Vaginal Cancer, Stage IVB Cervical Cancer, Stage IVB Vaginal Cancer, Therapy-related Toxicity
Conditions
Brief summary
This phase II trial is studying how triapine and cisplatin given together with radiation therapy works in treating patients with cervical cancer or vaginal cancer. Triapine may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Drugs used in chemotherapy, such as cisplatin, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Radiation therapy uses high-energy x-rays to kill tumor cells. Giving triapine together with cisplatin may make tumor cells more sensitive to radiation therapy.
Detailed description
PRIMARY OBJECTIVES: I. To determine three-month fasting F-18 fluorodeoxyglucose (FDG) positron emission tomography (PET/CT) imaging complete metabolic response as defined by the European Organization for Research and Treatment of Cancer (EORTC) PET study group. SECONDARY OBJECTIVES: I. To determine 6-month progression-free survival rate as calculated from the date of first treatment until date of disease progression, relapse, or death. II. To quantitate change in pre-treatment standard uptake value (SUV) on PET/CT and post-treatment PET/CT or disease progression PET/CT. III. To quantitate pre-treatment, during treatment and 3-mo post-treatment grade 2 or higher gastrointestinal, genitourinary, and sexual function toxicity resulting from Triapine®, cisplatin, and radiation therapy as measured by CTCAE v3.0, which will be utilized until December 31, 2010; CTCAE v4.0 will be utilized beginning January 1, 2011. IV. To associate smoking habit (non-smoker, smoker who quit during therapy, smoker) with 3-mo post-treatment PET/CT metabolic response and 3-mo best overall clinical response as measured by RECIST criteria after Triapine®, cisplatin, and radiation therapy. V. To associate HPV or non-HPV sub-type cervical cancer with 3-mo post-treatment PET/CT metabolic response and 3-mo best overall clinical response as measured by RECIST criteria after Triapine®, cisplatin, and radiation therapy. OUTLINE: This is a multicenter study. Patients are stratified according to brachytherapy treatment (planned intracavitary brachytherapy vs none). Patients receive cisplatin IV over 90 minutes on days 2, 9, 16, 23, and 30 and triapine IV on days 1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26, 29, 31, and 33. Patients also undergo pelvic external beam radiotherapy 5 days a week during weeks 1-5. Patients may undergo parametrial boost radiation and intracavitary low-dose or high-dose rate brachytherapy as clinically indicated. Patients undergo whole-body F-18 fluorodeoxyglucose-PET/CT imaging at baseline, at 3 months after completion of study treatment, and at disease progression. Patients complete Sexual Function-Vaginal Changes Questionnaire and a smoking behavior questionnaire at baseline, at 3 months after completion of study treatment, and at disease progression. After completion of study treatment, patients are followed periodically for up to 5 years.
Interventions
DRUGcisplatin
Given IV
DRUGtriapine
Given IV
RADIATIONexternal beam radiation therapy
Undergo pelvic external beam radiation therapy
PROCEDUREquality-of-life assessment
Ancillary studies
OTHERquestionnaire administration
Ancillary studies
RADIATIONfludeoxyglucose F 18
Undergo FDG-PET/CT
PROCEDUREpositron emission tomography
Undergo FDG-PET/CT
PROCEDUREcomputed tomography
Undergo FDG-PET/CT
Sponsors
National Cancer Institute (NCI)
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
FEMALE
Age
18 Years to No maximum
Healthy volunteers
No
Inclusion criteria
* Female patients must have histologically confirmed (tumor tissue biopsy) primary clinical stage IB2-IVB cervical cancer or clinical stage II-IVB vaginal cancer not amenable to curative surgical resection alone to be eligible; patients with stage IVB cervical cancer may receive systemic chemotherapy for treatment of metastatic disease a) after the 3-month post-therapy PET scan and b) if the 3-month post-therapy PET scan documents progressive disease at the discretion of the treating physician * Patients with other active invasive malignancies are excluded; patients with prior malignancies (except non-melanoma skin cancer or prior in situ carcinoma of the cervix, patients with synchronous or past history of primary endometrial cancer meeting all conditions of a) stage not greater than IB, b) no more than superficial myometrial invasion, c) without vascular or lymphatic invasion, and d) no poorly differentiated subtypes including papillary serous, clear cell or other FIGO grade 3 lesions; patients with other invasive malignancies who had (or have) cancer present within the last five years are excluded; patients are excluded if they have received prior low abdominal or pelvic radiotherapy for any reason that would contribute radiation dose that would exceed tolerance of normal tissues * Life expectancy of greater than 3 months * Absolute neutrophil count \>= 1,500/uL * Platelets \>= 100,000/uL * Hemoglobin \>= 10 g/dL * Total bilirubin =\< 2.0 mg/dL * AST(SGOT)/ALT(SGPT) =\< 2.5 X institutional upper limit of normal * PT/aPTT =\< 1.5 X institutional upper limit of normal * Patients should have a serum creatinine =\< 1.5mg/dL to receive weekly intravenous cisplatin chemotherapy * Patients whose serum creatinine is between 1.5 and 1.9 mg/dL are eligible for cisplatin chemotherapy if the estimated creatinine clearance is \>= 30 ml/min; patients eligible for cisplatin chemotherapy using the criteria for creatinine clearance may also receive intravenous Triapine® * Women of child-bearing potential and male partners must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation; should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately * Patients must demonstrate ability to understand and the willingness to sign a written informed consent document
Exclusion criteria
* Patients who have had chemotherapy or radiotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier are excluded * Patients may not be receiving any other investigational agents * Patients with known brain metastases should be excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurological dysfunction that would confound the evaluation of neurological and other adverse events * History of allergic reactions attributed to compounds of similar chemical or biologic composition to Triapine® or other agents used in study * Patients unable to receive intravenous chemotherapies as a consequence of poor vascular access are ineligible * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, known inadequately controlled hypertension, significant pulmonary disease including dyspnea at rest, patients requiring supplemental oxygen, or poor pulmonary reserve; proteinuria or clinically significant renal function impairment (baseline serum creatinine \> 2mg/dL), or psychiatric illness/social situations that would limit compliance with study requirements are excluded * Patients with known glucose-6-phosphate dehydrogenase deficiency (G6PD) are excluded as the antidote methylene blue for Triapine® toxicity may be at best ineffective in such patients and may have the potential to complicate the clinical situation by provoking hemolysis * Pregnant women are excluded from this study because Triapine® is a heterocyclic carboxaldehyde thiosemicarbazone with the potential for teratogenic or abortifacient effects; screening beta-hcg levels and diagnostic tests will be used to determine eligibility; because there is an unknown but potential risk for adverse events in nursing infants secondary to treatment of the mother with Triapine®, breastfeeding should be discontinued if the mother is treated with Triapine®; these potential risks may also apply to other agents used in this study * Patients not willing to agree to use appropriate contraception while on trial will be excluded * HIV-positive patients on combination antiretroviral therapy are ineligible because of the potential for pharmacokinetic interactions with Triapine®; in addition, these patients are at increased risk of lethal infections when treated with marrow-suppressive therapy; appropriate studies will be undertaken in patients receiving combination antiretroviral therapy when indicated; HIV testing is not mandatory; patients that are known to be HIV-positive are ineligible if they are receiving combination antiretroviral therapy
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Fasting F-18 Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET/CT) Imaging Complete Metabolic Response, Reported Following National Cancer Institute (NCI) and European Organization for Research and Treatment of Cancer (EORTC) Guidelines. | post therapy at 3 months | To quantitate change in pre-treatment standard uptake value (SUV) on PET/CT and posttreatment PET/CT or disease progression PET/CT. Change in PET/CT SUV will be associated with 3-month best overall clinical response. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Percent of Patients With Incidence of Grade 2 or Higher Gastrointestinal and Genitourinary Toxicity, Assessed Using CTCAE v3.0 Until December 31, 2010 and CTCAE v4.0 Beginning January 1, 2011 | After 5 weeks of radiation therapy | Information will include the type, severity, time of onset, time of resolution, and the probable association with the study regimen. Frequency tables will be constructed to summarize observed incidence by severity and type of toxicity. |
| Progression-free Survival | at 18 months from study entry | Percentage of patients that did not have disease progression. Estimates of progression-free survival will be computed using the product-limit estimate of Kaplan and Meier. |
| PET/CT Scan Metabolic Activity | Baseline (pre-therapy) | Descriptive tabular data reporting mean, standard deviation, minimum, maximum provided by metabolic response cohort. Status of 3-month post-treatment metabolic response associated with clinical response measured by RECIST criteria and with overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation used. Tests of equivalence of the estimates compared using the Wilcoxon long-rank test using P 0.05. Cox proportional hazards regression models used in multivariate analyses. |
| Clinical and Objective Response Assignment | post therapy at 3 months | Number of patients with a complete clinical responses defined as disappearance of all target lesions. A complete metabolic response on PET/CT will be defined as absence of abnormal FDG uptake at sites of abnormal FDG uptake noted on pre-treatment FDG-PET study. |
| Change in Smoking Behavior, Assessed Using the Smoking Questionnaire and Cessation Counseling | 18 months from study entry | — |
| Progression Free Survival by HPV Subtype | Baseline | Tabular descriptive data will be presented. HPV sub-type will be associated with treatment related toxicity, clinical response, PET metabolic response, and overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation will be used. Tests of equivalence of the estimates will be compared using the Wilcoxon long-rank test using a threshold for statistical significance of P 0.05. Cox proportional hazards regression models will be used in multivariate analyses. |
| Change in Sexual Function, Assessed Using the Sexual Function-Vaginal Changes Questionnaire | Baseline to up to 5 years | — |
Countries
United States
Participant flow
Recruitment details
Patients were recruited from local medical clinic from July 2009 through November 2011
Participants by arm
| Arm | Count |
|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) Patients receive cisplatin IV over 90 minutes on days 2, 9, 16, 23, and 30 and triapine IV on days 1, 3, 5, 8, 10, 12, 15, 17, 19, 22, 24, 26, 29, 31, and 33. Patients also undergo pelvic external beam radiotherapy 5 days a week during weeks 1-5. Patients may undergo parametrial boost radiation and intracavitary low-dose or high-dose rate brachytherapy as clinically indicated.
Patients undergo whole-body F-18 fluorodeoxyglucose-PET/CT imaging at baseline, at 3 months after completion of study treatment, and at disease progression. Patients complete Sexual Function-Vaginal Changes Questionnaire and a smoking behavior questionnaire at baseline, at 3 months after completion of study treatment, and at disease progression. | 26 |
| Total | 26 |
Withdrawals & dropouts
| Period | Reason | FG000 |
|---|---|---|
| Overall Study | Patient non-compliant | 1 |
Baseline characteristics
| Characteristic | Treatment (Cisplatin, Triapine, Radiation Therapy) |
|---|---|
| Age, Customized 30-39 | 1 participants |
| Age, Customized 40-49 | 7 participants |
| Age, Customized 50-59 | 11 participants |
| Age, Customized 60-69 | 6 participants |
| Age, Customized 70-79 | 1 participants |
| Cervical Stromal Invasion 2/3rds or greater invasion | 22 participants |
| Cervical Stromal Invasion Less than 2/3rds invasion | 3 participants |
| Ethnicity (NIH/OMB) Hispanic or Latino | 2 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 24 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| GOG Performance Status 0 | 23 participants |
| GOG Performance Status 1 | 2 participants |
| Histopathology Adenocarcinoma | 1 participants |
| Histopathology Adenosquamous carcinoma | 1 participants |
| Histopathology Squamous cell carcinoma | 23 participants |
| HPV Genotyping HPV 16 | 15 participants |
| HPV Genotyping HPV 18 | 4 participants |
| HPV Genotyping HPV-naive | 6 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IB2 Node Negative | 1 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IB2 Node Positive | 4 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IIA | 4 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IIB | 1 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IIIB | 10 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Cervix IVB | 2 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Vagina II | 2 participants |
| International Federation of Gynecology and Obstetrics (FIGO) Stage Vagina IVA | 1 participants |
| Lymphovascular invasion Absent | 7 participants |
| Lymphovascular invasion Present | 18 participants |
| Race (NIH/OMB) American Indian or Alaska Native | 0 Participants |
| Race (NIH/OMB) Asian | 0 Participants |
| Race (NIH/OMB) Black or African American | 7 Participants |
| Race (NIH/OMB) More than one race | 1 Participants |
| Race (NIH/OMB) Native Hawaiian or Other Pacific Islander | 0 Participants |
| Race (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race (NIH/OMB) White | 18 Participants |
| Region of Enrollment United States | 26 participants |
| Sex: Female, Male Female | 26 Participants |
| Sex: Female, Male Male | 0 Participants |
| Tumor Grade Grade 2 | 13 participants |
| Tumor Grade Grade 3 | 12 participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 25 / 25 |
| serious Total, serious adverse events | 9 / 25 |
Outcome results
Primary
Fasting F-18 Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET/CT) Imaging Complete Metabolic Response, Reported Following National Cancer Institute (NCI) and European Organization for Research and Treatment of Cancer (EORTC) Guidelines.
To quantitate change in pre-treatment standard uptake value (SUV) on PET/CT and posttreatment PET/CT or disease progression PET/CT. Change in PET/CT SUV will be associated with 3-month best overall clinical response.
Time frame: post therapy at 3 months
Population: 1 patient was non-compliant and received no therapy. Pt was excluded from analyses. 1 patient died from an unrelated health event after completing radiation and experimental chemotherapy and did not undergo 3-month F-18 FDG study.
| Arm | Measure | Group | Value (MEDIAN) |
|---|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Fasting F-18 Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET/CT) Imaging Complete Metabolic Response, Reported Following National Cancer Institute (NCI) and European Organization for Research and Treatment of Cancer (EORTC) Guidelines. | Pretherapy SUV | 14.6 Standard uptake value (SUV) |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Fasting F-18 Fluorodeoxyglucose (FDG) Positron Emission Tomography (PET/CT) Imaging Complete Metabolic Response, Reported Following National Cancer Institute (NCI) and European Organization for Research and Treatment of Cancer (EORTC) Guidelines. | Posttherapy SUV | 2.6 Standard uptake value (SUV) |
Secondary
Change in Sexual Function, Assessed Using the Sexual Function-Vaginal Changes Questionnaire
Time frame: Baseline to up to 5 years
Population: Data were not collected as the study was terminated prior to the time period for collection.
Secondary
Change in Smoking Behavior, Assessed Using the Smoking Questionnaire and Cessation Counseling
Time frame: 18 months from study entry
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Change in Smoking Behavior, Assessed Using the Smoking Questionnaire and Cessation Counseling | Non-Smokers | 9 participants |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Change in Smoking Behavior, Assessed Using the Smoking Questionnaire and Cessation Counseling | Smokers that quit while on study | 11 participants |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Change in Smoking Behavior, Assessed Using the Smoking Questionnaire and Cessation Counseling | Current smokers | 5 participants |
Secondary
Clinical and Objective Response Assignment
Number of patients with a complete clinical responses defined as disappearance of all target lesions. A complete metabolic response on PET/CT will be defined as absence of abnormal FDG uptake at sites of abnormal FDG uptake noted on pre-treatment FDG-PET study.
Time frame: three month follow up assessment
Population: Patients that completed the the 3-month 18F-FDG PET/CT. One patient died from an unrelated health event after completing radiation and experimental chemotherapy and was excluded from analyse.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Clinical and Objective Response Assignment | 23 participants |
Secondary
Clinical and Objective Response Assignment
Number of patients with a complete clinical responses defined as disappearance of all target lesions. A complete metabolic response on PET/CT will be defined as absence of abnormal FDG uptake at sites of abnormal FDG uptake noted on pre-treatment FDG-PET study.
Time frame: one month follow up assessment
Population: Patients that completed the the 3-month 18F-FDG PET/CT. One patient died from an unrelated health event after completing radiation and experimental chemotherapy and was excluded from analyse.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Clinical and Objective Response Assignment | 23 participants |
Secondary
Clinical and Objective Response Assignment
Number of patients with a complete clinical responses defined as disappearance of all target lesions. A complete metabolic response on PET/CT will be defined as absence of abnormal FDG uptake at sites of abnormal FDG uptake noted on pre-treatment FDG-PET study.
Time frame: post therapy at 3 months
Population: Patients that completed the 3-month F-18 FDG study.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Clinical and Objective Response Assignment | 21 participants |
Secondary
Percent of Patients With Incidence of Grade 2 or Higher Gastrointestinal and Genitourinary Toxicity, Assessed Using CTCAE v3.0 Until December 31, 2010 and CTCAE v4.0 Beginning January 1, 2011
Information will include the type, severity, time of onset, time of resolution, and the probable association with the study regimen. Frequency tables will be constructed to summarize observed incidence by severity and type of toxicity.
Time frame: After 5 weeks of radiation therapy
Population: All patients who receive at least one dose of Triapine® and cisplatin treatment.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Percent of Patients With Incidence of Grade 2 or Higher Gastrointestinal and Genitourinary Toxicity, Assessed Using CTCAE v3.0 Until December 31, 2010 and CTCAE v4.0 Beginning January 1, 2011 | 0 percentage of patients |
Secondary
PET/CT Scan Metabolic Activity
Descriptive tabular data reporting mean, standard deviation, minimum, maximum provided by metabolic response cohort. Status of 3-month post-treatment metabolic response associated with clinical response measured by RECIST criteria and with overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation used. Tests of equivalence of the estimates compared using the Wilcoxon long-rank test using P 0.05. Cox proportional hazards regression models used in multivariate analyses.
Time frame: Baseline (pre-therapy)
Population: Patients that completed the 3-month 18F-FDG PET/CT
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | PET/CT Scan Metabolic Activity | 14.6 Standard Uptake Value (SUV) |
Secondary
PET/CT Scan Metabolic Activity
Descriptive tabular data reporting mean, standard deviation, minimum, maximum provided by metabolic response cohort. Status of 3-month post-treatment metabolic response associated with clinical response measured by RECIST criteria and with overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation used. Tests of equivalence of the estimates compared using the Wilcoxon long-rank test using P 0.05. Cox proportional hazards regression models used in multivariate analyses.
Time frame: 3 months post-treatment
Population: Patients that completed 3-month 18F-FDG PET/CT
| Arm | Measure | Value (MEDIAN) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | PET/CT Scan Metabolic Activity | 2.6 Standard Uptake Value (SUV) |
Secondary
PET/CT Scan Metabolic Activity
Descriptive tabular data reporting mean, standard deviation, minimum, maximum provided by metabolic response cohort. Status of 3-month post-treatment metabolic response associated with clinical response measured by RECIST criteria and with overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation used. Tests of equivalence of the estimates compared using the Wilcoxon long-rank test using P 0.05. Cox proportional hazards regression models used in multivariate analyses.
Time frame: Up to 5 years
Population: Data were not collected as the study was terminated prior to the time period for collection.
Secondary
Progression-free Survival
Percentage of patients that did not have disease progression. Estimates of progression-free survival will be computed using the product-limit estimate of Kaplan and Meier.
Time frame: at 18 months from study entry
Population: Patients that completed the the 3-month 18F-FDG PET/CT.
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression-free Survival | 67 percentage of patients |
Secondary
Progression Free Survival by HPV Subtype
Tabular descriptive data will be presented. HPV sub-type will be associated with treatment related toxicity, clinical response, PET metabolic response, and overall clinical outcome. Kaplan-Meier (product-limit) method of survival estimation will be used. Tests of equivalence of the estimates will be compared using the Wilcoxon long-rank test using a threshold for statistical significance of P 0.05. Cox proportional hazards regression models will be used in multivariate analyses.
Time frame: Baseline
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression Free Survival by HPV Subtype | HPV16/18 | 74 percentage of patients |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression Free Survival by HPV Subtype | HPV-naive tumors | 83 percentage of patients |
Post Hoc
Progression Free Survival by Smoking Status
Percent of patients that were progression free by smoking status
Time frame: at 18 months from study entry
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression Free Survival by Smoking Status | Non-Smokers | 76 percentage of paticipants |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression Free Survival by Smoking Status | Smokers that quit while on study | 89 percentage of paticipants |
| Treatment (Cisplatin, Triapine, Radiation Therapy) | Progression Free Survival by Smoking Status | Smokers | 50 percentage of paticipants |