This is an open-label study to evaluate the immunogenicity and safety of raxibacumab in healthy adult male and female subjects. Subjects who have received raxibacumab \>= 4 months ago will be enrolled and dosed as follows: A maximum of 25 subjects (to include 3 evaluable female subjects) will receive a second dose of raxibacumab equal to that of the previous dose \>= 4 months following the first dose. Subjects will remain in house from Day 0 until Day 1 and will be followed for 70 days after receiving the second dose of raxibacumab. Raxibacumab has been shown to provide improved survival in rabbit and monkey anthrax spore challenge studies. Preliminary data from our rabbit pivotal efficacy study showed significant survival benefit for raxibacumab over placebo. Exposure to anthrax and resulting clinical disease can occur more than once, especially in individuals who do not develop protective immunity. Hence, if clinically indicated for the treatment of anthrax, there may be a requirement for the repeat administration of raxibacumab. The rationale of the study is to evaluate the immunogenicity and safety of repeat administration of raxibacumab with a \>= 4 month interval between dosing.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
20
Raxibacumab will be supplied in 50 milliliter (mL) sterile, single-use vials containing 34.9 mL of liquid formulation per vial. Each vial contains 50 milligram (mg)/mL raxibacumab in 0.13 mg/mL citric acid, 2.8 mg/mL sodium citrate, 10 mg/mL sucrose, 18 mg/mL glycine, 0.2 mg/mL polysorbate 80, pH 6.5
Number of Participants Who Developed a Positive Anti-raxibacumab Antibody Response
Number of participants who developed an positive anti-raxibacumab antibody response during the study were assessed.The antibody response to raxibacumab was assessed using a screening assay (i.e. by electrochemiluminescence counts). Positive samples would be further tested in an inhibition of binding assay to confirm the specificity of binding.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Any Adverse Event (AE) or Any Serious Adverse Event (SAE) During the Treatment Period
An AE is defined as any untoward medical occurrence in a participant or clinical investigation participant, temporally associated with the use of a medicinal product, whether or not considered related to the medicinal product. This includes worsening (eg, increase in frequency or severity) of pre-existing conditions. A serious adverse event (SAE) is defined as any untoward medical occurrence that, at any dose, results in death, is life threatening, requires hospitalization or prolongation of existing hospitalization, results in disability/incapacity, or is a congenital anomaly/birth defect. Medical or scientific judgment should be exercised in deciding whether reporting is appropriate in other situations. Refer to the General Adverse AE/SAE module for a complete list of AEs and SAEs.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Hematological Toxicities of the Indicated Grade
Clinical hematological parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With at Least a 2-grade Worsening From Baseline in Hematological Toxicities
The number of participants with at least a 2-grade worsening from Baseline in hematological toxicities is presented. Clinical hematological parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable. Baseline is defined as the value of the variable measured at Day 0 prior to dosing.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Liver Toxicities of the Indicated Grade
Liver function parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With at Least a 2-grade Worsening From Baseline in Liver Toxicities
The number of participants with at least a 2-grade worsening from Baseline in liver toxicities is presented. Liver function parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable. Baseline is defined as the value of the variable measured at Day 0 prior to dosing.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Electrolyte Toxicities of the Indicated Grade
Electrolyte function parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With at Least a 2-grade Worsening From Baseline in Electrolyte Toxicities
The number of participants with at least a 2-grade worsening from Baseline in electrolyte toxicities is presented. Electrolyte function parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0.Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable. Baseline is defined as the value of the variable measured at Day 0 prior to dosing.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Other Chemistry Toxicities of the Indicated Grade
Other chemistry parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With at Least a 2-grade Worsening From Baseline in Other Chemistry Toxicities
The number of participants with at least a 2-grade worsening from Baseline in other chemistry toxicities is presented. Other clinical chemistry parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.Baseline is defined as the value of the variable measured at Day 0 prior to dosing.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With Urinalysis Toxicities of the Indicated Grade
Urinaysis parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Number of Participants With at Least a 2-grade Worsening From Baseline in Urinalysis Toxicities
Urinalysis parameters were assessed using the modified Division of Microbiology and Infectious Diseases (DMID) toxicity tables, version 2.0. Grade 1 (Mild): Transient or mild discomfort (\< 48 hours); no medical intervention or therapy required. Grade 2 (Moderate): Mild to moderate limitation in activity, some assistance may be needed; no or minimal medical intervention or therapy required. Grade 3 (Severe): Marked limitation in activity, some assistance usually required; medical intervention or therapy required, hospitalizations possible. Grade 4 (Life-threatening): Extreme limitation in activity, significant assistance required; significant medical intervention or therapy required, hospitalization or hospice care probable.Baseline is defined as the value of the variable measured at Day 0 prior to dosing.
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 70
Mean Raxibacumab Concentration-time Following an IV Infusion Raxibacumab Dose
Blood was collected from each participant at the selected times: pre-dose (Day 0), 0.00347 hours (Day 0), 0.3333 hours (Day 0), Day 1, Day 3, Day 7, Day 14, Day 21, Day 28, Day 42, and Day 56 post-dose. Serum specimens were analyzed for raxibacumab using a validated electrochemiluminescense-based assay. The individual serum raxibacumab concentration data were summarized by nominal collection time and treatment group using descriptive statistics
Time frame: From the date of the dose administration of study agent for this study (Day 0) until Day 56
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