A Study of MK-6072 and MK-3415A in Participants Receiving Antibiotic Therapy for Clostridium Difficile Infection (MK-3415A-002)

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile after clinical cure of the initial CDI episode. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen.

An adverse event (AE) is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the medicinal product, whether or not considered related to the use of the product. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the medicinal product, is also an adverse event.

An adverse event (AE) is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the medicinal product, whether or not considered related to the use of the product. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the medicinal product, is also an adverse event. A drug-related adverse event is determined by the investigator to be related to the drug.

A serious adverse event (SAE) is any AE occurring at any dose or during any use of the medicinal product that results in death; or is life threatening; or results in a persistent or significant disability/incapacity; or results in or prolongs an existing inpatient hospitalization; or is a congenital anomaly/birth defect; or other important medical events. A serious drug-related adverse event is determined by the investigator to be related to the drug.

An adverse event (AE) is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the medicinal product, whether or not considered related to the use of the product. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the medicinal product, is also an adverse event.

An adverse event (AE) is defined as any unfavorable and unintended change in the structure, function, or chemistry of the body temporally associated with the use of the medicinal product, whether or not considered related to the use of the product. Any worsening (i.e., any clinically significant adverse change in frequency and/or intensity) of a preexisting condition which is temporally associated with the use of the medicinal product, is also an adverse event.

Global cure is defined as the clinical cure of the initial CDI episode with no CDI recurrence through Week 12. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen. The 027 ribotype is a more virulent, epidemic strain responsible for several outbreaks of disease associated with an increased risk of severity and mortality.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen. An epidemic strain includes ribotypes 027, 014, 002, 001, 106 or 020.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen. Participants with clinically severe CDI have a Zar Score greater than or equal to 2 points based on the presence of 1 or more of the following: 1) age >60 years old (1 point); 2) body temperature >38.3°C (>100°F) (1 point); 3) albumin level ˂2.5 mg/dl (1 point); 4) peripheral white blood cell count >15,000 cells/mm^3 within 48 hours (1 point); 5) endoscopic evidence of pseudomembranous colitis (2 points); and 6) treatment in Intensive Care Unit (2 points).

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen.

CDI recurrence is defined as the development of a new episode of diarrhea (3 or more loose stools in 24 or fewer hours) and a positive lab stool test (local or central) for toxigenic C. difficile. Clinical cure is defined as no diarrhea [2 or fewer loose stools per 24 hours] for 2 consecutive days following completion of SOC therapy for the initial CDI episode in participants who received =< 14 day regimen. Compromised immunity is an active hematological malignancy (including leukemia, lymphoma, multiple myeloma), an active malignancy requiring recent cytotoxic chemotherapy, receipt of a prior hematopoietic stem cell transplant, receipt of a prior solid organ transplant, asplenia, or neutropenia/pancytopenia due to other conditions.