Study to Investigate the Safety, Tolerability, and Pharmacokinetics of DSTA4637S in Participants With Staphylococcus Aureus Bacteremia Receiving Standard-of-Care (SOC) Antibiotics

Study Overview
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Brief Summary
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This is a Phase Ib, randomized double-blind, placebo-controlled multiple-ascending dose study to investigate the safety, tolerability, and pharmacokinetics of multiple doses of DSTA4637S when given in addition to anti-staphylococcal SOC antibiotics to participants with methicillin-resistant staphylococcus aureus (MRSA) and methicillin-sensitive staphylococcus aureus (MSSA) bacteremia requiring at least 4 weeks of anti-staphylococcal SOC antibiotics.

Official Title
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A Phase IB, Randomized, Double-Blind, Placebo-Controlled, Multiple-Ascending Dose Study to Investigate the Safety, Tolerability, and Pharmacokinetics of DSTA4637S in Patients With Staphylococcus Aureus Bacteremia Receiving Standard-of-Care Antibiotics

Conditions
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Bacteremia

Intervention / Treatment
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* Drug: DSTA4637S
* Drug: Placebo
* Drug: SOC


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Body mass index greater than or equal (>/=) 18 to less than or equal to (</=) 40 kg/m^2 At randomization, participants must have >/=1 blood culture or molecular diagnostic that is positive for Staphylococcal aureus (S. aureus) collected in the previous 120 hours In the investigator's judgment, an expected treatment duration for S. aureus intravenous infection with anti-staphylococcal SOC antibiotics >/= 4 weeks Exclusion Criteria: The presence of an intravascular catheter that is not planned to be removed within 96 hours of study randomization S. aureus bacteremia associated with an intracardiac device and/or intravascular prosthetic material (including hemodialysis access graft) In the investigator's judgement, S. aureus bacteremia involving infection of a prosthetic joint or vertebral hardware In participants with cirrhosis, a Child-Pugh Score of Class B or C Known rifampicin-resistant S. aureus Anticipated receipt of a rifamycin class (excluding rifaxamin) antibiotic from Day 1 to study completion/discontinuation In the investigator's judgment, the need for emergent valve surgery at the time of randomization or a high likelihood of cardiac surgery within 3 days after randomization Polymicrobial bacteremia Participants with significant immune suppression Participants with evidence of liver disease History or presence of an abnormal electrocardiogram (ECG) Exposure to any biological therapy or investigational biological agent within 90 days prior to the screening evaluation or have received any other investigational treatment 30 days prior to the screening evaluation

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: DSTA4637S low dose level + SOC<br>DSTA4637S low dose level intravenous (IV) infusion will be administered within 24 hours of randomization on Day 1 and then every 7 days up to 6 doses of study drug in addition to anti-staphylococcal SOC antibiotics. | Drug: DSTA4637S<br>* DSTA4637S will be administered as an IV infusion at 3 dose levels.<br>Drug: SOC<br>* Anti-staphylococcal SOC antibiotics dosage and duration of therapy will be based on relevant health-authority approved indications and local and national treatment guidelines.<br>|
| Experimental: DSTA4637S intermediate dose level+ SOC<br>DSTA4637S intermediate dose level IV infusion will be administered within 24 hours of randomization on Day 1 and then every 7 days up to 6 doses of study drug in addition to anti-staphylococcal SOC antibiotics. | Drug: DSTA4637S<br>* DSTA4637S will be administered as an IV infusion at 3 dose levels.<br>Drug: SOC<br>* Anti-staphylococcal SOC antibiotics dosage and duration of therapy will be based on relevant health-authority approved indications and local and national treatment guidelines.<br>|
| Experimental: DSTA4637S high dose level+ SOC<br>DSTA4637S high dose level IV infusion will be administered within 24 hours of randomization on Day 1 and then every 7 days up to 6 doses of study drug in addition to anti-staphylococcal SOC antibiotics. | Drug: DSTA4637S<br>* DSTA4637S will be administered as an IV infusion at 3 dose levels.<br>Drug: SOC<br>* Anti-staphylococcal SOC antibiotics dosage and duration of therapy will be based on relevant health-authority approved indications and local and national treatment guidelines.<br>|
| Placebo Comparator: Placebo + SOC<br>Placebo matched to DSTA4637S IV infusion will be administered within 24 hours of randomization on Day 1 and then every 7 days up to 6 doses of study drug in addition to anti-staphylococcal SOC antibiotics. | Drug: Placebo<br>* Placebo matched to DSTA4637S IV infusion will be administered as specified.<br>Drug: SOC<br>* Anti-staphylococcal SOC antibiotics dosage and duration of therapy will be based on relevant health-authority approved indications and local and national treatment guidelines.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Participants With Adverse Events (AEs) |  | Baseline up to approximately 156 Days | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Measure of Antibody-Conjugated 4-Dimethylamino Piperidino-Hydroxybenzoxazino Rifamycin (dmDNA31) measured by Plasma |  | Baseline up to approximately 156 Days | 
| Measure of DSTA4637S Total Antibody measured by Serum |  | Baseline up to approximately 156 Days | 
| Measure of Unconjugated dmDNA31 measured by Plasma |  | Baseline up to approximately 156 Days | 
| Percentage of Participants With Anti-Therapeutic Antibodies (ATAs) to DSTA4637S |  | Baseline up to approximately 156 Days |