A randomized, placebo-controlled phase I study assessing the safety and immunogenicity of a Pseudomonas aeruginosa hybrid outer membrane protein OprF/I vaccine (IC43) in healthy volunteers

Figures & data

Figure 1. Study design. Subjects were randomly allocated in a 1:1:1:1:1 ratio to one of five treatment groups: 50, 100, or 200 µg IC43 with adjuvant, 100 µg IC43 without adjuvant, or placebo (0.9% sodium chloride) and two intramuscular injections were given in the deltoid region 7 d apart. Note: Vaccinations were given on day 0 and day 7. R, randomization; w/o adj, without aluminum hydroxide adjuvant. ^aPlacebo = 0.9% sodium chloride.

Figure 2. OprF/I-specific IgG antibody geometric mean titer by treatment group (per protocol population). The primary immunogenicity analysis of OprF/I-specific IgG antibody titer on day 14 (7 d after the second vaccination) demonstrated significant differences between treatment groups (P < 0.0001) with a significant study center effect (P = 0.0200) in the per protocol population and a non-significant study center effect (P = 0.0716) in the intention to treat population. Note: Statistically significant P values for pairwise comparisons of GMT ratio estimates are shown (analysis of variance with treatment group and study center as fixed factors, adjusted for multiple comparisons by Tukey’s Honestly Significant Difference test). D, day; GMT, geometric mean titer; IgG, immunoglobulin G; OprF/I, outer membrane protein OprF/I hybrid vaccine; w/o, without adjuvant.

Table 1. Number and percentage of subjects with a ≥4-fold increase in OprF/I-specific IgG antibody geometric mean titer from day 0 (first vaccination) to day 14 (7 d after second vaccination) (per-protocol-population)

Treatment group		Number of subjects with ratio day 14/day 0 ≥ 4	% (95% CI)^a
IC43 100 µg	(n = 30)	29	96.7% (83.3%, 99.4%)
IC43 100 µg w/o	(n = 30)	29	96.7% (83.3%, 99.4%)
IC43 200 µg	(n = 30)	29	96.7% (83.3%, 99.4%)
IC43 50 µg	(n = 11)	10	90.9% (62.3%, 98.4%)
Placebo	(n = 32)	0	0.0% (0.0%, 10.7%)

^a 95% Confidence intervals were calculated according to the Wilson method recommended by Altman.¹⁷ CI, confidence interval; IgG, immunoglobulin G; OprF/I, outer membrane protein OprF/I hybrid vaccine; w/o, without adjuvant.

Table 2. Number and percentage of subjects with a ≥4-fold increase in OprF/I-specific IgG antibody geometric mean titer from day 0 (first vaccination) to day 180 (6 mo after first vaccination) (per protocol population)

Treatment group		Number of subjects with ratio day 180/day 0 ≥4	% (95% CI) ^a
IC43 100 µg	(n = 30)	18	60.0% (42.3%, 75.4%)
IC43 100 µg w/o	(n = 30)	18	60.0% (42.3%, 75.4%)
IC43 200 µg	(n = 30)	16	53.3% (36.1%, 69.8%)
IC43 50 µg	(n = 11)	8	72.7% (43.4%, 90.3%)
Placebo	(n = 32)	0	0.0% (0.0%, 10.7%)

^a 95% Confidence intervals were calculated according to the Wilson method recommended by Altman.¹⁷ CI, confidence interval; IgG, immunoglobulin G; OprF/I, outer membrane protein OprF/I hybrid vaccine; w/o, without adjuvant.

Figure 3. Median OPA ratio (change in OPA titer from day 0 to day 14) by treatment group (per protocol population). From day 0 to day 14, a ≥2-fold increase in OPA titer was observed in 54.5% of all subjects who received IC43 (range 46.7%−63.3% across all IC43 treatment groups; PP population) and 1 subject (3.1%) in the placebo group. Note: P values from Wilcoxon test for unpaired observations on OPA ratio (day 14/day 0) are statistically significant for comparisons between each IC43 treatment group and placebo, and between IC43 100 μg and IC43 200 μg. OPA, opsonophagocytic assay; w/o, without adjuvant.

Table 3. Avidity index of OprF/I-specific IgG antibodies at day 7 and day 14 by treatment group (per protocol population; subgroup of subjects with detectable OprF/I-specific IgG antibodies at day 7 and day 14)

Day	Statistic	IC43 100 µg (n = 5)	IC43 100 µg w/o (n = 11)	IC43 200 µg (n = 7)	IC43 50 µg (n = 3)
7	Median	0.64	0.93	1.49	0.10
	IQR	0.59 − 1.87	0.71 − 1.23	1.12 − 2.72	0.10 − 2.03
14	Median	1.56	1.45	2.55	0.10
	IQR	0.85 − 2.43	0.89 − 2.19	1.91 − 3.16	0.10 − 2.82

Note: An index of low (defined as >50% stripping with a concentration of 0.5 M ammonium thiocyanate) was set to 0.1 M; an index of high (<50% stripping with 4 M ammonium thiocyanate) was set to 4.5 M. IgG, immunoglobulin G; IQR, interquartile range; OprF/I, outer membrane protein OprF/I hybrid vaccine; w/o, without adjuvant.

Figure 4. Median OprF/I-specific ASC response (%) vs. OprF/I-specific IgG geometric mean titer (U/mL) on days 0, 7, 14, and 180 (PP population). For median OprF/I-specific ASC response, the number of observations was n = 10 (100 μg), n = 9–10 (100 μg w/o), n = 9–11 (200 μg), n = 10–11 (50 μg), and n = 11–12 (placebo). For OprF/I-specific IgG geometric mean titer, the number of observations was n = 30 (100 μg), n = 30–31 (100 μg w/o), n = 30–31 (200 μg), n = 11 (50 μg), and n = 32 (placebo). OprF/I, outer membrane protein; OprF/I, hybrid vaccine; w/o, without adjuvant.

Table 4. Overall incidence of TEAEs and treatment-related TEAEs, and TEAEs for which there was a statistically significant difference among treatment groups^a (safety population)

MedDRA system organ class	Number (%) of subjects ^b (95% confidence interval)					P value ^c
Preferred term	IC43 100 µg (n = 33)	IC43 100 µg w/o (n = 32)	IC43 200 µg (n = 33)	IC43 50 µg (n = 32)	Placebo (n = 33)
Subjects with ≥ 1 TEAE	32 (97) (85, 100)	30 (94) (80, 98)	29 (88) (73, 95)	30 (94) (80, 98)	26 (79) (62, 89)	0.1448
Subjects with ≥ 1 treatment-related TEAE	29 (88) (73, 95)	21 (66) (48, 80)	28 (85) (69, 93)	26 (81) (65, 91)	10 (30) (17, 47)	<0.0001*
General disorders and administration site conditions	26 (79) (62, 89)	20 (63) (45, 77)	27 (82) (66, 91)	25 (78) (61, 89)	9 (27) (15, 44)	<0.0001*
Injection site pain	19 (58) (41, 73)	15 (47) (31, 64)	21 (64) (47, 78)	21 (66) (48, 80)	1 (3) (1, 15)	<0.0001*
Injection site induration	4 (12) (5, 27)	1 (3) (1, 16)	8 (24) (13, 41)	2 (6) (2, 20)	1 (3) (1, 15)	0.0308*
Infections and infestations	20 (61) (44, 75)	20 (63) (45, 77)	17 (52) (35, 68)	13 (41) (26, 58)	17 (52) (35, 68)	0.4174
Bronchitis	4 (12) (5, 27)	0 (0) (0, 11)	2 (6) (2, 20)	0 (0) (0, 11)	0 (0) (0, 10)	0.0232*
Musculo-skeletal and connective tissue disorders	20 (61) (44, 75)	9 (28) (16, 45)	14 (42) (27, 59)	14 (44) (28, 61)	4 (12) (5, 27)	0.0006*
Myalgia	8 (24) (13, 41)	5 (16) (7, 32)	9 (27) (15, 44)	9 (28) (16, 45)	1 (3) (1, 15)	0.0292*
Pain in extremity	7 (21) (11, 38)	0 (0) (0, 11)	4 (12) (5, 27)	4 (13) (5, 28)	1 (3) (1, 15)	0.0209*
Injury, poisoning and procedural complications	1 (3) (1, 15)	3 (9) (3, 24)	4 (12) (5, 27)	3 (9) (3, 24)	3 (9) (3, 24)	0.7666
Joint sprain	0 (0) (0, 10)	0 (0) (0, 11)	3 (9) (3, 24)	0 (0) (0, 11)	0 (0) (0, 10)	0.0371*
Surgical and medical procedures	0 (0) (0, 10)	1 (3) (1, 16)	1 (3) (1, 15)	4 (13) (5, 28)	0 (0) (0, 10)	0.0445*

^a MedDRA preferred terms are included if there was a statistically significant difference among treatment groups, together with the corresponding MedDRA system organ class. Additionally, MedDRA system organ classes are provided on their own if there was a statistically significant difference among treatment groups. ^bSubjects are counted only once per system organ class or preferred term. Percentages and confidence intervals are based on the number (n) in each group and rounded to nearest integer. ^cP values were calculated according to Fisher”Freeman”Halton test. Two-sided 95% confidence intervals were calculated according Altman.¹⁷ *Statistically significant difference among treatment groups. MedDRA, Medical Dictionary for Regulatory Activities; TEAE, treatment-emergent adverse event; w/o, without adjuvant.

Table 5. Incidence of local and systemic tolerability symptoms recorded in the subject diary in the 7-d periods after the first and second vaccinations (safety population)

Symptom^a	Vacc	Number (%) of subjects with symptom present					P value^b
		IC43 100 µg (n = 33)	IC43 100 µg w/o (n = 32)	IC43 200 µg (n = 33)	IC43 50 µg (n = 32)	Placebo (n = 33)
Erythema/ redness	1	2 (6.1)	3 (9.4)	2 (6.1)	1 (3.2)	0	0.5071
	2	0	2 (6.5)	3 (10.0)	0	0	0.0395*
Induration	1	3 (9.1)	1 (3.1)	6 (18.2)	1 (3.2)	1 (3.0)	0.1238
	2	2 (6.1)	0	4 (13.3)	0	0	0.0137*
Itching	1	0	0	0	1 (3.2)	1 (3.0)	0.5066
	2	1 (3.0)	0	0	0	0	1.0000
Pain	1	17 (51.5)	9 (28.1)	17 (51.5)	15 (48.4)	1 (3.0)	<0.0001*
	2	16 (48.5)	4 (12.9)	18 (60.0)	8 (26.7)	2 (6.3)	<0.0001*
Swelling	1	3 (9.1)	3 (9.4)	0	2 (6.5)	1 (3.0)	0.3783
	2	1 (3.0)	0	0	0	0	1.0000
Tender- ness	1	11 (33.3)	9 (28.1)	13 (39.4)	13 (41.9)	1 (3.0)	0.0009*
	2	11 (33.3)	8 (25.8)	14 (46.7)	13 (43.3)	1 (3.1)	0.0003*
Excessive fatigue	1	8 (24.2)	6 (18.8)	7 (21.2)	4 (12.9)	2 (6.1)	0.2649
	2	4 (12.1)	4 (12.9)	5 (16.7)	4 (13.3)	2 (6.3)	0.8025
Fever	1	0	0	1 (3.0)	0	0	1.0000
	2	0	0	1 (3.3)	1 (3.3)	0	0.4214
Flu-like symptoms	1	3 (9.1)	2 (6.3)	2 (6.1)	2 (6.5)	1 (3.0)	0.9247
	2	3 (9.1)	4 (12.9)	4 (13.3)	3 (10.0)	1 (3.1)	0.6375
Headache	1	9 (27.3)	4 (12.5)	6 (18.2)	8 (25.8)	7 (21.2)	0.5896
	2	9 (27.3)	8 (25.8)	7 (23.3)	10 (33.3)	3 (9.4)	0.2053
Muscle pain	1	12 (36.4)	4 (12.5)	11 (33.3)	9 (29.0)	1 (3.0)	0.0016*
	2	11 (33.3)	4 (12.9)	8 (26.7)	7 (23.3)	0	0.0017*
Nausea	1	1 (3.0)	3 (9.4)	1 (3.0)	0	1 (3.0)	0.4254
	2	2 (6.1)	2 (6.5)	3 (10.0)	3 (10.0)	1 (3.1)	0.7759
Other symptoms	1	11 (33.3)	3 (9.4)	6 (18.2)	5 (16.1)	6 (18.2)	0.2205
	2	9 (27.3)	9 (29.0)	2 (6.7)	6 (20.0)	5 (15.6)	0.1384
Rash	1	0	0	1 (3.0)	0	1 (3.0)	1.0000
	2	0	0	0	0	0	NC
Vomiting	1	0	0	1 (3.0)	0	0	1.0000
	2	0	0	2 (6.7)	1 (3.3)	0	0.0792

^a Local tolerability symptoms = erythema/redness, induration, itching, pain, swelling, and tenderness. Systemic tolerability symptoms = excessive fatigue, fever, flu-like symptoms, headache, muscle pain, nausea, other symptoms, rash, and vomiting. ^bP values were calculated according to Fisher-Freeman-Halton test. *Statistically significant difference among treatment groups. NC, not calculable; Vacc, vaccination; w/o, without adjuvant.

Mansouri E, Gabelsberger J, Knapp B, Hundt E, Lenz U, Hungerer KD, Gilleland HE Jr., Staczek J, Domdey H, von Specht BU. Safety and immunogenicity of a Pseudomonas aeruginosa hybrid outer membrane protein F-I vaccine in human volunteers. Infect Immun 1999; 67:1461 - 70; PMID: 10024596

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