Clinical Pharmacology for Dalvance
Mechanism Of Action
Dalbavancin is an antibacterial drug [see Microbiology].
Pharmacodynamics
The antibacterial activity of dalbavancin appears to best correlate with the ratio of area under the concentration-time curve to minimal inhibitory concentration (AUC/MIC) for Staphylococcus aureus based on animal models of infection. An exposure-response analysis of a single study in patients with complicated skin and skin structure infections supports the two-dose regimen [see DOSAGE AND ADMINISTRATION, Pharmacokinetics].
Cardiac Electrophysiology
In a randomized, positive-and placebo-controlled, thorough QT/QTc study, 200 healthy subjects received dalbavancin 1000 mg IV, dalbavancin 1500 mg IV, oral moxifloxacin 400 mg, or placebo. Neither dalbavancin 1000 mg nor dalbavancin 1500 mg had any clinically relevant adverse effect on cardiac repolarization.
Pharmacokinetics
General Pharmacokinetic Properties
Dalbavancin pharmacokinetic parameters have been characterized in healthy subjects, patients, and specific populations. Pharmacokinetic parameters following administration of single intravenous 1000 mg and 1500 mg doses were as shown in Table 4. The pharmacokinetics of dalbavancin can be described using a three-compartment model.
Table 4. Dalbavancin Pharmacokinetic Parameters in Healthy Subjects
| Parameter |
Single 1000 mg Dose |
Single 1500 mg Dose |
| Cmax (mg/L) |
287 (13.9)1 |
423 (13.2)4 |
| AUC0-24 (mg•h/L) |
3185 (12.8)1 |
4837 (13.7)4 |
| AUC0-Day7 (mg•h/L) |
11160 (41.1)2 |
ND |
| AUC0-inf (mg•h/L) |
23443 (40.9)2 |
ND |
| Terminal t½ (h) |
346 (16.5)2,3 |
ND |
| CL (L/h) |
0.0513 (46.8)2 |
ND |
All values are presented as mean (% coefficient of variation)
1 Data from 50 healthy subjects.
2 Data from 12 healthy subjects.
3 Based upon population pharmacokinetic analyses of data from patients, the effective half-life is approximately 8.5 days (204 hours).
4 Data from 49 healthy subjects.
Abbreviation: ND – not determined |
In healthy subjects, dalbavancin AUC0-24h and Cmax both increased proportionally to dose following single IV dalbavancin doses ranging from 140 mg to 1500 mg, indicating linear pharmacokinetics.
The mean plasma concentration-time profile for dalbavancin following the recommended two-dose regimen of 1000 mg followed one week later by 500 mg is shown in Figure 2.
Figure 2. Mean (± standard deviation) dalbavancin plasma concentrations versus time in healthy subjects (n=10) following IV administration over 30 minutes of 1000 mg dalbavancin (Day 1) and 500 mg dalbavancin (Day 8).
No apparent accumulation of dalbavancin was observed following multiple IV infusions administered once weekly for up to eight weeks, with 1000 mg on Day 1 followed by up to seven weekly 500 mg doses, in healthy adults with normal renal function.
Distribution
Dalbavancin is reversibly bound to human plasma proteins, primarily to albumin. The plasma protein binding of dalbavancin is approximately 93% and is not altered as a function of drug concentration, renal impairment, or hepatic impairment. The mean concentrations of dalbavancin achieved in skin blister fluid remain above 30 mg/L up to 7 days (approximately 146 hours) post dose, following 1000 mg IV dalbavancin. The mean ratio of the AUC0-144 hrs in skin blister fluid/AUC0-144 hrs in plasma is 0.60 (range 0.44 to 0.64).
Metabolism
In vitro studies using human microsomal enzymes and hepatocytes indicate that dalbavancin is not a substrate, inhibitor, or inducer of CYP450 isoenzymes. A minor metabolite of dalbavancin (hydroxy-dalbavancin) has been observed in the urine of healthy subjects. Quantifiable concentrations of the hydroxy-dalbavancin metabolite have not been observed in human plasma (lower limit of quantitation = 0.4 μg/mL) [see DRUG INTERACTIONS].
Excretion
Following administration of a single 1000 mg dose in healthy subjects, 20% of the dose was excreted in feces through 70 days post dose. An average of 33% of the administered dalbavancin dose was excreted in urine as unchanged dalbavancin and approximately 12% of the administered dose was excreted in urine as the metabolite hydroxy-dalbavancin through 42 days post dose.
Specific Populations
Renal Impairment
The pharmacokinetics of dalbavancin were evaluated in 28 subjects with varying degrees of renal impairment and in 15 matched control subjects with normal renal function.
Following a single dose of 500 mg or 1000 mg dalbavancin, the mean plasma clearance (CLT) was reduced 11%, 35%, and 47% in subjects with CLcr 50 to 79 mL/min, CLcr 30 to 49 mL/min), and CLcr less than 30 mL/min, respectively, compared to subjects with normal renal function. The clinical significance of the decrease in mean plasma CLT, and the associated increase in AUC0-∞ noted in these pharmacokinetic studies of dalbavancin in subjects with CLcr less than 30 mL/min has not been established [see DOSAGE AND ADMINISTRATION, Use In Specific Populations].
Dalbavancin pharmacokinetic parameters in subjects with end-stage renal disease receiving regularly scheduled hemodialysis (three times/week) are similar to those observed in subjects with mild to moderate renal impairment, and less than 6% of an administered dose is removed after three hours of hemodialysis.
Therefore, no dosage adjustment is recommended for patients receiving regularly scheduled hemodialysis, and dalbavancin may be administered without regard to the timing of hemodialysis in such patients [see DOSAGE AND ADMINISTRATION, OVERDOSE].
Hepatic Impairment
The pharmacokinetics of dalbavancin were evaluated in 17 subjects with mild, moderate, or severe hepatic impairment (Child-Pugh class A, B or C) and compared to those in nine matched healthy subjects with normal hepatic function. The mean AUC0-336 hrs was unchanged in subjects with mild hepatic impairment compared to subjects with normal hepatic function; however, the mean AUC0-336 hrs decreased 28% and 31% in subjects with moderate and severe hepatic impairment respectively, compared to subjects with normal hepatic function. The clinical significance of the decreased AUC0-336 hrs in subjects with moderate and severe hepatic function is unknown.
No dosage adjustment is recommended for patients with mild hepatic impairment. Caution should be exercised when prescribing dalbavancin to patients with moderate or severe hepatic impairment as no data are available to determine the appropriate dosing.
Gender
Clinically significant gender-related differences in dalbavancin pharmacokinetics have not been observed either in healthy subjects or in patients with infections. No dosage adjustment is recommended based on gender.
Geriatric Patients
Clinically significant age-related differences in dalbavancin pharmacokinetics have not been observed in patients with infections. No dosage adjustment is recommended based solely on age.
Pediatric Patients
The pharmacokinetics of dalbavancin has been evaluated in 211 individual pediatric patients [4 days to 17.9 years of age, including a preterm neonate (gestational age 36 weeks; n=1) and term neonates (gestational age 37 to 40 weeks; n=4)] with CLcr 30 mL/min/1.73 m2 and above. There is insufficient information to assess the exposure of DALVANCE in the pediatric patients with CLcr less than 30 mL/min/1.73 m2. No clinically important differences in drug exposure between pediatric age groups (including preterm neonates) and adults are expected following administration of the age-dependent recommended single dose of DALVANCE. The median plasma AUC from 0 to 120 hours (AUC0-120h) of dalbavancin in pediatric patient age groups from term neonates at birth to less than 18 years is expected to be comparable to that in adult patients (AUC0-120h, 10400 mg*h/L). The expected median plasma AUC0-120h of dalbavancin in preterm neonates at birth (gestational age 26 weeks to <37 weeks) was approximately 62% of that in adult patients. The expected median maximum plasma concentrations (Cmax) of dalbavancin for pediatric patient age groups ranged between approximately 53% to 73% of that in adult patients (Cmax, 412 mg/L). However, in all pediatric age groups, the percentage of patients attaining PK/PD targets related to in vivo drug activity were above 90% or higher for MICs up to 0.25 mg/L.
Drug Interactions
Nonclinical studies demonstrated that dalbavancin is not a substrate, inhibitor, or inducer of CYP450 isoenzymes. In a population pharmacokinetic analysis, dalbavancin pharmacokinetics were not affected by co-administration with known CYP450 substrates, inducers or inhibitors, nor by individual medications including acetaminophen, aztreonam, fentanyl, metronidazole, furosemide, proton pump inhibitors (omeprazole, esomeprazole, pantoprazole, lansoprazole), midazolam, and simvastatin.
Microbiology
Mechanism Of Action
Dalbavancin, a semisynthetic lipoglycopeptide, interferes with cell wall synthesis by binding to the D-alanyl-D-alanine terminus of the stem pentapeptide in nascent cell wall peptidoglycan, thus preventing cross-linking. Dalbavancin is bactericidal in vitro against Staphylococcus aureus and Streptococcus pyogenes at concentrations similar to those sustained throughout treatment in humans treated according to the recommended dosage regimen.
Resistance
The development of bacterial isolates resistant to dalbavancin has not been observed, either in vitro, in studies using serial passage, or in animal infection experiments.
Interaction With Other Antimicrobials
When tested in vitro, dalbavancin demonstrated synergistic interactions with oxacillin and did not demonstrate antagonistic or synergistic interactions with any of the following antibacterial agents of various classes: gentamicin, vancomycin, levofloxacin, clindamycin, quinupristin/dalfopristin, linezolid, aztreonam, rifampin or daptomycin. The clinical significance of these in vitro findings is unknown.
Antimicrobial Activity
Dalbavancin has been shown to be active against the following microorganisms, both in vitro and in clinical infections [see INDICATIONS].
Aerobic bacteria
Gram-positive bacteria
Staphylococcus aureus (including methicillin-resistant isolates)
Streptococcus pyogenes
Streptococcus agalactiae
Streptococcus dysgalactiae
Streptococcus anginosus group (including S. anginosus, S. intermedius, S. constellatus)
Enterococcus faecalis (vancomycin-susceptible isolates only)
The following in vitro data are available, but their clinical significance is unknown. At least 90 percent of the following bacteria exhibit an in vitro minimum inhibitory concentration (MIC) less than or equal to the susceptible breakpoint for dalbavancin against isolates of similar genus or organism group. However, the efficacy of dalbavancin in treating clinical infections caused by these bacteria has not been established in adequate well-controlled clinical trials.
Aerobic bacteria
Gram-positive bacteria
Enterococcus faecium (vancomycin-susceptible isolates only)
Susceptibility Testing
For specific information regarding susceptibility test interpretive criteria and associated test methods and quality control standards recognized by FDA for this drug, please see: https://www.fda.gov/STIC.
Animal Toxicology And/Or Pharmacology
Increases in serum levels of liver enzymes (ALT, AST), associated with microscopic findings in the liver were noted in toxicology studies in rats and dogs where dalbavancin was administered daily for 28 to 90 days. Hepatocellular necrosis was observed in dogs dosed at ≥10 mg/kg/day for longer than 2 months, i.e., at approximately 5 to 7 times the expected human dose on an exposure basis. Histiocytic vacuolation and hepatocyte necrosis were observed in rats dosed daily at 40 and 80 mg/kg/day, respectively, for 4 weeks, (approximately 3 and 6 times the expected human dose on an exposure basis, respectively). In addition, renal toxicity characterized by increases in serum BUN and creatinine and microscopic kidney findings was observed in rats and dogs at doses 5 to 7 times the expected human dose on an exposure basis. The relationship between these findings in the animal toxicology studies after 28 and 90 consecutive days of dosing to the indicated clinical dosing of 2 doses 7 days apart are unclear.
Clinical Studies
Clinical Studies Of DALVANCE In Adult Patients With Acute Bacterial Skin And Skin Structure Infections
DALVANCE Two-dose Regimen (1000 mg Day 1; 500 mg Day 8)
Adult patients with ABSSSI were enrolled in two Phase 3, randomized, double-blind, double-dummy clinical trials of similar design (Trial 1 and Trial 2). The Intent-to-Treat (ITT) population included 1,312 randomized patients. Patients were treated for two weeks with either a two-dose regimen of intravenous DALVANCE (1000 mg followed one week later by 500 mg) or intravenous vancomycin (1000 mg or 15 mg/kg every 12 hours, with the option to switch to oral linezolid after 3 days). DALVANCE-treated patients with creatinine clearance of less than 30 mL/min received 750 mg followed one week later by 375 mg. Approximately 5% of patients also received a protocol-specified empiric course of treatment with intravenous aztreonam for coverage of Gram-negative pathogens.
The specific infections in these trials included cellulitis (approximately 50% of patients across treatment groups), major abscess (approximately 30%), and wound infection (approximately 20%).
The median lesion area at baseline was 341 cm2. In addition to local signs and symptoms of infection, patients were also required to have at least one systemic sign of disease at baseline, defined as temperature 38°C or higher (approximately 85% of patients), white blood cell count greater than 12,000 cells/mm3 (approximately 40%), or 10% or more band forms on white blood cell differential (approximately 23%). Across both trials, 59% of patients were from Eastern Europe and 36% of patients were from North America. Approximately 89% of patients were Caucasian and 58% were males. The mean age was 50 years and the mean body mass index was 29.1 kg/m2.
The primary endpoint of these two ABSSSI trials was the clinical response rate where responders were defined as patients who had no increase from baseline in lesion area 48 to 72 hours after initiation of therapy, and had a temperature consistently at or below 37.6° C upon repeated measurement. Table 5 summarizes overall clinical response rates in these two ABSSSI trials using the pre-specified primary efficacy endpoint in the ITT population.
Table 5. Clinical Response Rates in ABSSSI Trials at 48-72 Hours after Initiation of Therapy1,2
|
DALVANCE
n/N (%) |
Vancomycin/Linezolid
n/N (%) |
Difference
(95% CI)3 |
| Trial 1 |
240/288 (83.3) |
233/285 (81.8) |
1.5 (-4.6, 7.9) |
| Trial 2 |
285/371 (76.8) |
288/368 (78.3) |
-1.5 (-7.4, 4.6) |
1 There were 7 patients who did not receive treatment and were counted as non-responders: 6 DALVANCE patients (3 in each trial) and one vancomycin/linezolid patient in Trial 2.
2 Patients who died or used non-study antibacterial therapy or had missing measurements were classified as non-responders.
3 The 95% Confidence Interval (CI) is computed using the Miettinen and Nurminen approach, stratified by baseline fever status. |
A key secondary endpoint in these two ABSSSI trials evaluated the percentage of ITT patients achieving a 20% or greater reduction in lesion area from baseline at 48-72 hours after initiation of therapy. Table 6 summarizes the findings for this endpoint in these two ABSSSI trials.
Table 6. Patients in ABSSSI Trials with Reduction in Lesion Area of 20% or Greater at 48-72 Hours after Initiation of Therapy1,2
|
DALVANCE
n/N (%) |
Vancomycin/Linezolid
n/N (%) |
Difference (95% CI)3 |
| Trial 1 |
259/288 (89.9) |
259/285 (90.9) |
-1.0 (-5.7, 4.0) |
| Trial 2 |
325/371 (87.6) |
316/368 (85.9) |
1.7 (-3.2, 6.7) |
1 There were 7 patients (as described in Table 5) who did not receive treatment and were counted as non-responders.
2 Patients who died or used non-study antibacterial therapy or had missing measurements were classified as non-responders.
3 The 95% CI is computed using the Miettinen and Nurminen approach, stratified by baseline fever status. |
Another secondary endpoint in these two ABSSSI trials was the clinical success rate assessed at a follow-up visit occurring between Days 26 to 30. Clinical Success at this visit was defined as having a decrease in lesion size (both length and width measurements), a temperature of 37.6° C or lower, and meeting pre-specified criteria for local signs: purulent discharge and drainage absent or mild and improved from baseline, heat/warmth & fluctuance absent, swelling/induration & tenderness to palpation absent or mild.
Table 7 summarizes clinical success rates at a follow-up visit for the ITT and clinically evaluable population in these two ABSSSI trials. Note that there are insufficient historical data to establish the magnitude of drug effect for antibacterial drugs compared with placebo at the follow-up visits. Therefore, comparisons of DALVANCE to vancomycin/linezolid based on clinical success rates at these visits cannot be utilized to establish non-inferiority.
Table 7. Clinical Success Rates in ABSSSI Trials at Follow-Up (Day 26 to 30) 1,2
|
DALVANCE
n/N (%) |
Vancomycin/Linezolid
n/N (%) |
Difference (95% CI)3 |
| Trial 1 |
| ITT |
241/288 (83.7%) |
251/285 (88.1%) |
-4.4% (-10.1, 1.4) |
| CE |
212/226 (93.8%) |
220/229 (96.1%) |
-2.3% (-6.6, 2.0) |
| Trial 2 |
| ITT |
327/371 (88.1%) |
311/368 (84.5%) |
3.6% (-1.3, 8.7) |
| CE |
283/294 (96.3%) |
257/272 (94.5%) |
1.8% (-1.8, 5.6) |
1 There were 7 patients (as described in Table 5) who did not receive treatment and were counted as failures in the analysis.
2 Patients who died, used non-study antibacterial therapy, or had an unplanned surgical intervention 72 hours after the start of therapy were classified as Clinical Failures.
3 The 95% CI is computed using the Miettinen and Nurminen approach, stratified by baseline fever status. |
Table 8 shows outcomes in patients with an identified baseline pathogen, using pooled data from Trials 1 and 2 in the microbiological ITT (microITT) population. The outcomes shown in the table are clinical response rates at 48 to 72 hours and clinical success rates at follow-up (Day 26 to 30), as defined above.
Table 8. Outcomes by Baseline Pathogen (Trial 1, 2; MicroITT) 1
|
Early Clinical Response at 48-72 hours |
| Early Responder2 |
≥ 20% reduction in lesion size |
Clinical Success at Day 26 to 30 |
| Pathogen |
DALVANCE
n/N (%) |
Comparator
n/N (%) |
DALVANCE
n/N (%) |
DALVANCE
n/N (%) |
DALVANCE
n/N (%) |
Comparator
n/N (%) |
| Staphylococcus aureus |
206/257 (80.2) |
219/256 (85.5) |
239/257 (93.0) |
232/256 (90.6)x |
217/257 (84.4) |
229/256 (89.5) |
| Methicillin-susceptible |
134/167 (80.2) |
134/167 (80.2) |
83/90 (92.2) |
59/67 (88.1) |
75/90 (83.3) |
57/67 (85.1) |
| Methicillin-resistant |
72/90 (80.0) |
56/67 (83.6) |
83/90 (92.2) |
59/67 (88.1) |
75/90 (83.3) |
57/67 (85.1) |
| Streptococcus agalactiae |
6/12 (50.0) |
11/14 (78.6) |
10/12 (83.3) |
10/14 (71.4) |
10/12 (83.3) |
11/14 (78.6) |
| Streptococcus pyogenes |
28/37 (75.7) |
24/36 (66.7) |
32/37 (86.5) |
27/36 (75.0) |
33/37 (89.2) |
32/36 (88.9) |
| Streptococcus anginosus group |
18/22 (81.8) |
23/ 25 (92.0) |
21/22 (95.5) |
21/22 (95.5) |
21/22 (95.5) |
23/25 (92.0) |
| Enterococcus faecalis |
8/12 (66.7) |
10/13 (76.9) |
12/12 (100.0) |
12/13 (92.3) |
12/12 (100.0) |
12/12 (100.0) |
All DALVANCE dosing regimens in Trials 1 and 2 consisted of two doses.
1 There were 2 patients in the DALVANCE arm with methicillin-susceptible S. aureus at baseline who did not receive treatment and were counted as non-responders/failures.
2 Early Responders are patients who had no increase from baseline in lesion area 48 to 72 hours after initiation of therapy, and had a temperature consistently at or below 37.6 C upon repeated measurement. |
DALVANCE 1500 mg Single Dose Regimen
Adult patients with ABSSSI were enrolled in a Phase 3, double-blind, clinical trial. The ITT population included 698 patients who were randomized to DALVANCE treatment with either a single 1500 mg dose or a two-dose regimen of 1000 mg followed one week later by 500 mg (Trial 3). Patients with creatinine clearance less than 30 mL/min had their dose adjusted (Section 2.2). Approximately 5% of patients also received a protocol-specified empiric course of treatment with intravenous aztreonam for coverage of Gram-negative pathogens. The specific infections and other patient characteristics in this trial were similar to those described above for previous ABSSSI trials.
The primary endpoint in this ABSSSI trial was the clinical response rate where responders were defined as patients who had at least a 20% decrease from baseline in lesion area 48 to 72 hours after randomization without receiving any rescue antibacterial therapy. The secondary endpoint was the clinical success rate at a follow-up visit occurring between Days 26 and 30, with clinical success defined as having at least a 90% decrease from baseline in lesion size, a temperature of 37.6 C or lower, and meeting pre-specified criteria for local signs: purulent discharge and drainage absent or mild and improved from baseline (for patients with wound infections), heat/warmth and fluctuance absent, swelling/induration and tenderness to palpation absent or mild. Table 9 summarizes results for these two endpoints in the ITT population. Note that there are insufficient historical data to establish the magnitude of drug effect for antibacterial drugs compared with placebo at the follow-up visit. Therefore, comparisons between treatment groups based on clinical success rates at this visit cannot be utilized to establish non-inferiority.
Table 9. Primary and Secondary Efficacy Results in ABSSSI Patients (Trial 3) 1,2
|
DALVANCE, n/N (%) |
|
| Single Dose (1500 mg) |
Two doses
(1000 mg Day 1/500 mg Day 8) |
Difference (95% CI)3 |
| Clinical Responders at 48-72 Hours (ITT) |
284/349 (81.4) |
294/349 (84.2) |
-2.9 (-8.5, 2.8) |
| Clinical Success at Day 26-30 (ITT) |
295/349 (84.5) |
297/349 (85.1) |
-0.6 (-6.0, 4.8) |
| Clinical Success at Day 26-30 (CE) |
250/271 (92.3) |
247/267 (92.5) |
-0.3 (-4.9, 4.4) |
1 There were 3 patients in the two-dose group who did not receive treatment and were counted as non-responders.
2 Patients who died or used non-study antibacterial therapy or had missing measurements were classified as non-responders.
3 The 95% Confidence Interval (CI) is computed using the Miettinen and Nurminen approach.
Abbreviations: ITT-intent to treat; CE-clinically evaluable |
Table 10 shows outcomes in patients with an identified baseline pathogen from Trial 3 in the microbiological ITT (microITT) population. The outcomes shown in the table are clinical response rates at 48 to 72 hours and clinical success rates at follow-up (Day 26 to 30), as defined above.
Table 10. Outcomes by Baseline Pathogen (Trial 3; MicroITT)
|
Early Clinical Response at 48-72 hours |
|
| ≥ 20% reduction in lesion size |
Clinical Success at Day 26 to 30 |
| Pathogen |
Single dose
(1500 mg)
n/N (%) |
Two doses
(1000 mg Day 1/ 500 mg Day 8)
n/N (%) |
Single dose
(1500 mg)
n/N (%) |
Two doses
(1000 mg Day 1/ 500 mg Day 8)
n/N (%) |
| Staphylococcus aureus |
123/139 (88.5) |
133/156 (85.3) |
124/139 (89.2) |
140/156 (89.7) |
| Methicillin-susceptible |
92/103 (89.3) |
89/96 (89.6) |
93/103 (90.3) |
86/96 (89.6) |
| Methicillin-resistant |
31/36 (86.1) |
48/61 (78.7) |
31/36 (86.1) |
55/61 (90.2) |
| Streptococcus agalactiae |
6/6(100.0) |
4/6 (66.7) |
5/6 (83.3) |
5/6 (83.3) |
| Streptococcus anginosus group |
31/33 (93.9) |
19/19 (100.0) |
29/33 (87.9) |
17/19 (89.5) |
| Streptococcus pyogenes |
14/14 (100.0) |
18/22 (81.8) |
18/22 (81.8) |
19/22 (86.4) |
| Enterococcus faecalis |
4/4 (100.0) |
8/10 (80.0) |
4/4 (100.0) |
9/10 (90.0) |
In Trials 1, 2, and 3, all patients had blood cultures obtained at baseline. A total of 40 ABSSSI patients who received DALVANCE had bacteremia at baseline caused by one or more of the following bacteria: 26 S. aureus (21 MSSA and 5 MRSA), 6 S. agalactiae, 7 S. pyogenes, 2 S. anginosus group, and 1 E. faecalis. In patients who received DALVANCE, a total of 34/40 (85%) were clinical responders at 48-72 hours and 32/40 (80%) were clinical successes at Day 26 to 30.
Clinical Study Of DALVANCE In Pediatric Patients With Acute Bacterial Skin And Skin Structure Infections
The pediatric trial was a multicenter, open-label, randomized, actively controlled trial (NCT02814916, Trial 4 ) conducted in pediatric patients 3 months of age to less than 18 years with ABSSSI, not known or expected to be caused exclusively by Gram-negative organisms. Patients were randomized in a 3:3:1 ratio to receive either DALVANCE single-dose regimen, DALVANCE two-dose regimen, or comparator. The comparator regimens included IV vancomycin for methicillin-resistant Gram-positive infections, or IV oxacillin or flucloxacillin for methicillin-susceptible Gram-positive infections. Patients in the comparator arm received IV treatment for a minimum of 72 hours before an optional switch to oral therapy to complete a total of 10-14 days of antibacterial drug therapy. Additional 5 patients from birth to < 3 months of age were enrolled and assigned to the DALVANCE single-dose regimen.
A study population of 191 pediatric patients received study medication (DALVANCE single dose regimen n=83, DALVANCE two-dose regimen n=78, comparator n=30); 62% of the patients were male and 89% were white, and 83% were from Eastern Europe. The pediatric age groups who received DALVANCE were as follows: 12 to < 18 years (n=58), 6 to < 12 years (n=49), 2 to < 6 years (n=35), 3 months to < 2 years (n=14), and birth < 3 months (n=5). Patients had diagnoses of major cutaneous abscess (53%), cellulitis (29%), or surgical site/traumatic wound infection (18%). The predominant pathogen at baseline was Staphylococcus aureus (84%)
The primary objective was to evaluate the safety and tolerability of DALVANCE. The trial was not powered for a comparative inferential efficacy analysis. Efficacy was assessed in the modified intent-totreat population (n=183) which included all randomized patients who received any dose of study drug and had a diagnosis of ABSSSI caused by Gram-positive organism(s). Patients with ABSSSI only caused by Gram-negative organisms were excluded. The five patients in the age group birth to < 3 months of age were not included in efficacy analyses since they were enrolled with expanded inclusion criteria and only received the single dose DALVANCE regimen. An early clinical response at 48–72 hours was defined as ≥ 20% reduction in lesion size compared to baseline and no receipt of rescue antibacterial therapy. The proportion of patients with early clinical response, was 97.3% (73/75) in the DALVANCE single-dose arm, 93.6% (73/78) in the DALVANCE two-dose arm, and 86.7% (26/30) in the comparator arm. The difference in responder rates between the dalbavancin single-dose and comparator arms was 10.7%, with an exact 97.5% confidence interval (CI) of (-1.7%, 31.6%). The difference in responder rates between the dalbavancin two-dose and comparator arms was 6.9%, with an exact 97.5% CI of (-6.4%, 27.7%).
Clinical cure was defined as resolution of the clinical signs and symptoms of infection, when compared to baseline, and no additional antibacterial treatment for the disease under study. In patients, 3 months of age or older in the mITT population, the clinical cure rate at the test of cure (TOC) visit (28 ± 2 days) was 94.7% (71/75) in the DALVANCE single-dose arm, 92.3% (72/78) in the DALVANCE two-dose arm and 100% (30/30) in the comparator arm. The difference in cure rates between the dalbavancin single-dose and comparator arms was -5.3%, with an exact 97.5% CI of (-15.1%, 10.5%). The difference in cure rates between the dalbavancin two-dose and comparator arms was -7.7%, with an exact 97.5% CI of (-17.9%, 8.3%)