CClinicalTrials.gg
Sign In
CompletedNCT05266456Updated Apr 18, 2024Results posted

Safety, Tolerability, and Immunogenicity Study of a 24-Valent Pneumococcal Conjugate Vaccine (VAX-24) in Adults

A Phase 1/2 interventional study of 24 valent pneumococcal conjugate vaccine and 20 valent pneumococcal conjugate vaccine in Pneumococcal Vaccines, sponsored by Vaxcyte, Inc.. Completed at 13 sites in United States. Open to participants aged 18 Years to 64 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2024-04-18.

Sponsored by Vaxcyte, Inc. · Phase 1/2, Interventional, and Prevention

Phase
Phase 1/2
Study type
Interventional
Enrollment
835
Allocation
Randomized
Ages
18 Years to 64 Years
Sex
All
01

Study summary

The objective of the study is to evaluate the safety and tolerability of a single injection of VAX-24 at 3 dose levels compared to Prevnar 20™ (PCV20) in adults 18 to 49 years of age in Phase 1. The Phase 2 will evaluate the safety, tolerability, and immunogenicity of a single injection of VAX-24 at 3 dose levels compared to PCV20 in adults aged 50 to 64 years of age in Phase 2.

Read the detailed description

The objective of the study is to evaluate the safety and tolerability of a single injection of VAX-24 at 3 dose levels (Low: 1.1 mcg; Mid: 2.2 mcg; or Mixed: 2.2/4.4 mcg) compared to Prevnar 20™ (PCV20) in adults 18 to 49 years of age in Phase 1. The Phase 2 will evaluate the safety, tolerability, and immunogenicity of a single injection of VAX-24 at 3 dose levels (Low: 1.1 mcg; Mid: 2.2 mcg; or Mixed: 2.2/4.4 mcg) compared to PCV20 in adults aged 50 to 64 years of age.

02

Conditions studied

  • Pneumococcal Vaccines
03

In context

Lead sponsor

Vaxcyte, Inc. is the lead sponsor of 9 studies on the registry; 1 is open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 64 Years
Sexes eligible
All
Accepts healthy volunteers
Yes

Inclusion criteria

  • Male or female age 18 to 49 years (inclusive) for the Phase 1 group, or 50 to 64 years (inclusive) for the Phase 2 group at the time of enrollment into the study.
  • Able and willing to complete the informed consent process.
  • Available for clinical follow-up through the last study visit at 6 months after the study vaccination.
  • In good general health as determined by medical history, vital signs, physical examination, and clinical judgment of the investigator.
  • Screening laboratory values must be within the central laboratory normal limits prior to study enrollment. Minor abnormalities are considered acceptable if not clinically significant.
  • Willing to have blood samples collected, stored indefinitely, and used for research purposes.
  • Able to provide proof of identity to the satisfaction of the study staff completing the enrollment process.
  • Negative pregnancy test (urine and serum) for women of childbearing potential.

Exclusion criteria

Exclusion Criteria:

  • Previous pneumococcal disease (either confirmed or by self-reporting).
  • Previous receipt of a licensed or investigational pneumococcal vaccine.
  • Receipt of any investigational study product within 30 days prior to enrollment into the study, currently participating in another interventional investigational study, or having plans to receive another investigational product(s) while on study.
  • Planned or actual administration of any licensed vaccine during the period starting 30 days before enrollment into the study through Day 29.
  • Physical examination indicating any clinically significant medical condition.
  • Body Temperature > 38.0°C (> 100.4°F) or acute illness within 3 days prior to study vaccination (subject may be rescheduled).
  • Seropositive to HIV, HCV, or HBsAg.
  • History of severe allergic reaction with generalized urticaria, angioedema, or anaphylaxis.
  • Female who is breast-feeding or planning to become pregnant during study participation.
  • Bleeding disorder diagnosed by a doctor (eg, factor deficiency, coagulopathy, or platelet disorder requiring special precautions) or significant bruising or bleeding difficulties with IM injections or blood draws.
  • Any other chronic or clinically significant medical condition that, in the opinion of the investigator, would jeopardize the safety or rights of the subject or confound evaluation of the study vaccine.
  • Any medical, psychiatric, or social condition that, in the judgment of the investigator, is a contraindication to protocol participation or impairs a subject's ability to give informed consent.
  • Received blood or blood product (including Immune Globulin IV) within 90 days prior to enrollment into the study.
  • Received systemic corticosteroids for ≥ 14 consecutive days and has not completed treatment ≤30 days prior to enrollment into the study.
  • Receiving immunosuppressive therapy.
  • History of malignancy ≤5 years before enrollment, except for adequately treated basal cell or squamous cell skin cancer or in situ cervical cancer.
05

Study design

Phase
Phase 1 / Phase 2
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Parallel assignment
Masking
Quadruple (Participant, Care provider, Investigator, Outcomes assessor)
Enrollment
835 participants (actual)

Study arms

  • Experimental
    VAX-24 Low Dose

    Participants will receive a single dose of VAX-24 1.1 mcg administered as an intramuscular injection on Day 1.

    Biological: 24 valent pneumococcal conjugate vaccine

  • Experimental
    VAX-24 Mid Dose

    Participants will receive a single dose of VAX-24 2.2 mcg administered as an intramuscular injection on Day 1.

    Biological: 24 valent pneumococcal conjugate vaccine

  • Experimental
    VAX-24 Mixed Dose

    Participants will receive a single dose of VAX-24 2.2 mcg/4.4 mcg administered as an intramuscular injection on Day 1.

    Biological: 24 valent pneumococcal conjugate vaccine

  • Active comparator
    PCV20

    Participants will receive a single intramuscular injection of the standard dose of PCV20 on Day 1.

    Biological: 20 valent pneumococcal conjugate vaccine

Interventions

  • Biological24 valent pneumococcal conjugate vaccine

    0.5 ml dose of VAX-24 will be administered into the deltoid muscle at Day 1

  • Biological20 valent pneumococcal conjugate vaccine

    0.5 ml dose of PCV20 will be administered into the deltoid muscle at Day 1

06

What researchers measure

Primary outcomes

  1. Percentage of Participants Reporting Solicited Local Reactions Within 7 Days After Vaccination in Each Age Group

    Solicited local reactions include redness/erythema, swelling/induration, and pain at injection site within 7 days after vaccination in each age group

    Time frame: 7 days after vaccination

  2. Percentage of Participants Reporting Solicited Systemic Events Within 7 Days After Vaccination in Each Age Group

    Solicited systemic reactions include fever, headache, fatigue, muscle pain, and joint pain

    Time frame: 7 days after vaccination

  3. Percentage of Participants Reporting Unsolicited Adverse Events (AE) in Each Age Group

    Percentage of participants in each age group with adverse events (AEs) whose date of onset occurs after the study vaccine and within the 28 days after vaccination.

    Time frame: 1 month after vaccination

  4. Percentage of Participants Reporting SAEs and New Onset of Chronic Illnesses (NOCI)

    Percentage of participants with SAEs and NOCIs

    Time frame: 6 months after vaccination

Secondary outcomes

  1. Percentage of Participants With Laboratory Value Abnormalities and/or Potentially Clinically Significant Laboratory Values

    Shifts from Normal at Baseline to Abnormal on Day 29 in Clinical Chemistry Parameters Occurring in \>5% of Subjects Aged 50 to 64 Years

    Time frame: 1 month after vaccination

  2. VAX-24 Pneumococcal Serotype-specific Opsonophagocytic Assay (OPA) Geometric Mean Titer (GMTs)

    Antibody geometric mean titers as measured by OPA for the 24 pneumococcal serotypes in VAX-24

    Time frame: 1 month after vaccination

  3. VAX-24 Pneumococcal Serotype-specific Immunoglobulin G (IgG) Geometric Mean Concentration (GMCs)

    Antibody geometric mean concentrations as measured by IgG for the 24 pneumococcal serotypes in VAX-24

    Time frame: 1 month after vaccination

07

Results

Posted Apr 18, 2024
Limitations and caveats
Some limitations of this clinical study include the lack of a group, such as 3·3 µg or 4·4 µg, for all serotypes, aimed at understanding whether the dose response of polysaccharide can overcome carrier suppression. The relatively low ethnic diversity of participants is also a limitation, which will be addressed in larger phase 3 clinical trials.

Participant flow

First subject was enrolled 22-Feb-2022 and last subject randomized/vaccinated was 01-Jul-22. Study sites were medical clinics.

Phase 1, Adults 18-49 Years of Age
Participant flow — Phase 1, Adults 18-49 Years of Age
MilestoneVAX-24 Low DoseVAX-24 Mid DoseVAX-24 Mixed DosePCV20
Started16161616
Completed15151615
Not completed1101
Withdrew: Lost to follow-up1100
Withdrew: Withdrawal by subject0001
Phase 2, Adults 50-64 Years
Participant flow — Phase 2, Adults 50-64 Years
MilestoneVAX-24 Low DoseVAX-24 Mid DoseVAX-24 Mixed DosePCV20
Started193192192194
Completed186186187192
Not completed7652
Withdrew: Lost to follow-up6631
Withdrew: Withdrawal by subject0020
Withdrew: Unavailable for follow up1001

Outcome measures

PrimaryPercentage of Participants Reporting Solicited Local Reactions Within 7 Days After Vaccination in Each Age Group

Solicited local reactions include redness/erythema, swelling/induration, and pain at injection site within 7 days after vaccination in each age group

Time frame:
7 days after vaccination
Reported as:
Number · percentage of participants
Percentage of Participants Reporting Solicited Local Reactions Within 7 Days After Vaccination in Each Age Group
percentage of participantsVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsVAX24 Low Dose 18-64 YrsVAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Any solicited local AE; Overall, Any Grade56.381.381.393.873.671.777.571.972.272.577.873.6
Pain at injection site; Overall, Any Grade56.375.081.381.371.071.277.069.969.971.577.370.8
Erythema (redness) at injection site; Overall, Any Grade6.36.318.825.06.77.98.98.76.77.79.79.9
Edema (swelling) at injection site; Overall, Any Grade18.812.525.018.88.87.97.910.79.68.29.211.3
PrimaryPercentage of Participants Reporting Solicited Systemic Events Within 7 Days After Vaccination in Each Age Group

Solicited systemic reactions include fever, headache, fatigue, muscle pain, and joint pain

Time frame:
7 days after vaccination
Reported as:
Number · Percentage of participants
Percentage of Participants Reporting Solicited Systemic Events Within 7 Days After Vaccination in Each Age Group
Percentage of participantsVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsVAX-24 Low Dose 18-64 YrsVAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Any solicited systemic adverse event50.062.556.375.069.469.671.264.867.969.170.065.6
Fever (oral temperature >= 100.4ºF)6.36.30.012.51.00.52.11.01.41.01.91.9
Fatigue37.531.337.550.042.540.840.839.842.140.140.640.6
Headache31.337.525.037.530.628.830.430.130.629.530.030.7
Muscle Pain37.537.518.856.357.056.060.253.155.554.657.053.3
Joint Pain25.012.512.543.824.916.227.724.024.915.926.625.5
PrimaryPercentage of Participants Reporting Unsolicited Adverse Events (AE) in Each Age Group

Percentage of participants in each age group with adverse events (AEs) whose date of onset occurs after the study vaccine and within the 28 days after vaccination.

Time frame:
1 month after vaccination
Reported as:
Number · Percentage of participants
Percentage of Participants Reporting Unsolicited Adverse Events (AE) in Each Age Group
Percentage of participantsVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64VAX-24 Low Dose 18-64VAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Percentage of Participants Reporting Unsolicited Adverse Events (AE) in Each Age Group12.512.56.36.315.511.513.116.815.311.612.616.0
PrimaryPercentage of Participants Reporting SAEs and New Onset of Chronic Illnesses (NOCI)

Percentage of participants with SAEs and NOCIs

Time frame:
6 months after vaccination
Reported as:
Number · percentage of participants
Percentage of Participants Reporting SAEs and New Onset of Chronic Illnesses (NOCI)
percentage of participantsVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed DosePCV20 50-64 YrsVAX-24 Low Dose 18-64 YrsVAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Subjects with at least one SAE00001.01.60.52.01.01.40.51.9
Subjects with at least one NOCI00001.61.63.12.61.41.42.92.4
SecondaryPercentage of Participants With Laboratory Value Abnormalities and/or Potentially Clinically Significant Laboratory Values

Shifts from Normal at Baseline to Abnormal on Day 29 in Clinical Chemistry Parameters Occurring in \>5% of Subjects Aged 50 to 64 Years

Time frame:
1 month after vaccination
Reported as:
Number · percentage of participants
Percentage of Participants With Laboratory Value Abnormalities and/or Potentially Clinically Significant Laboratory Values
percentage of participantsVAX-24 Low DoseVAX-24 Mid DoseVAX-24 Mixed DosePCV20
Bicarbonate: Low14.418.415.011.8
Cholesterol: High7.27.78.78.5
Triglycerides: High9.18.29.710.8
Creatinine: High11.511.110.68.5
Glucose: High7.23.95.37.1
Uric Acid: High8.17.22.95.7
SecondaryVAX-24 Pneumococcal Serotype-specific Opsonophagocytic Assay (OPA) Geometric Mean Titer (GMTs)

Antibody geometric mean titers as measured by OPA for the 24 pneumococcal serotypes in VAX-24

Time frame:
1 month after vaccination
Reported as:
Geometric mean · Titer
VAX-24 Pneumococcal Serotype-specific Opsonophagocytic Assay (OPA) Geometric Mean Titer (GMTs)
TiterVAX-24 Low DoseVAX-24 Mid DoseVAX-24 Mixed DosePCV20
1190.08 (147.05 to 245.69)317.62 (246.32 to 409.56)228.09 (176.35 to 295.01)358.18 (278.29 to 461.00)
21371.45 (1135.70 to 1656.12)1698.18 (1409.82 to 2045.51)1822.43 (1509.74 to 2199.89)62.40 (51.85 to 75.08)
3319.33 (263.23 to 387.40)407.13 (336.51 to 492.56)497.72 (410.26 to 603.84)343.29 (283.99 to 414.96)
41229.24 (1070.97 to 1576.17)1717.83 (1419.20 to 2079.30)1326.49 (1093.40 to 1609.25)1414.77 (1169.79 to 1711.05)
5491.01 (370.31 to 651.05)546.38 (413.37 to 722.19)366.50 (276.39 to 485.99)691.28 (524.10 to 911.78)
6A3252.03 (2439.24 to 4335.64)3604.41 (2718.05 to 4779.81)3218.37 (2416.99 to 4285.44)3932.31 (2969.22 to 5207.78)
6B3506.32 (2730.26 to 4502.96)4646.32 (3630.07 to 5947.07)4867.77 (3792.29 to 6248.24)3783.96 (2961.89 to 4834.20)
7F3318.45 (2768.67 to 3977.40)4359.57 (3646.63 to 5211.90)5962.25 (4965.38 to 7159.25)3975.12 (3324.16 to 4753.56)
82344.26 (1954.41 to 2811.88)2483.57 (2075.88 to 2971.34)2668.87 (2224.94 to 3201.37)2267.98 (1897.25 to 2711.15)
9N8217.87 (6958.94 to 9704.54)9753.78 (8278.27 to 11492.29)9066.94 (7672.89 to 10714.27)1636.07 (1387.32 to 1929.41)
9V2596.46 (2006.38 to 3360.09)3028.18 (2348.52 to 3904.52)3757.52 (2903.40 to 4862.91)1733.44 (1345.08 to 2233.92)
10A4156.84 (3371.51 to 5125.10)5800.54 (4722.94 to 7124.01)5366.49 (4358.65 to 6607.37)5533.20 (4507.79 to 6791.86)
11A1117.61 (1044.46 to 1195.89)1076.79 (1007.27 to 1151.11)1064.03 (994.37 to 1138.58)1038.01 (971.15 to 1109.47)
12F1550.61 (1187.61 to 2024.56)2307.24 (1773.76 to 3001.15)1549.29 (1186.52 to 2022.97)1914.42 (1472.75 to 2488.55)
143398.89 (2686.58 to 4300.06)4282.68 (3393.98 to 5404.08)4107.89 (3246.39 to 5198.01)3634.47 (2885.63 to 4577.65)
15B2384.28 (1857.24 to 3060.89)3242.54 (2534.98 to 4147.58)2535.37 (1975.01 to 3254.71)3137.65 (2456.10 to 4008.34)
17F2317.55 (2037.96 to 2635.49)2301.19 (2027.23 to 2612.17)2290.15 (2013.79 to 2604.43)666.74 (586.52 to 757.92)
18C2735.58 (2198.02 to 3404.60)3435.80 (2770.54 to 4260.79)4103.02 (3298.26 to 5104.14)1963.65 (1584.40 to 2433.69)
19A4351.67 (3577.95 to 5292.72)5653.21 (4658.23 to 6860.70)6211.37 (5106.76 to 7554.90)4813.63 (3972.27 to 5833.20)
19F1928.24 (1669.54 to 2227.03)2347.67 (2036.83 to 2705.93)2453.82 (2124.54 to 2834.14)1419.27 (1232.17 to 1634.79)
20B8205.88 (6476.81 to 10396.54)8545.04 (6763.81 to 10795.35)7809.21 (6150.35 to 9915.50)140.23 (110.55 to 177.88)
22F6243.38 (4988.03 to 7814.68)7164.92 (5738.17 to 8946.42)4843.18 (3869.91 to 6061.23)7631.74 (6120.11 to 9516.73)
23F1000.62 (740.33 to 1352.43)1368.00 (1015.55 to 1842.76)857.41 (634.33 to 1158.95)962.52 (715.73 to 1294.42)
33F11672.18 (9582.40 to 14217.70)17099.25 (14061.56 to 20793.17)11856.15 (9732.71 to 14442.87)11030.39 (9085.39 to 13391.78)
SecondaryVAX-24 Pneumococcal Serotype-specific Immunoglobulin G (IgG) Geometric Mean Concentration (GMCs)

Antibody geometric mean concentrations as measured by IgG for the 24 pneumococcal serotypes in VAX-24

Time frame:
1 month after vaccination
Reported as:
Geometric mean · mcg/mL
VAX-24 Pneumococcal Serotype-specific Immunoglobulin G (IgG) Geometric Mean Concentration (GMCs)
mcg/mLVAX-24 Low DoseVAX-24 Mid DoseVAX-24 Mixed DosePCV20
12.85 (2.29 to 3.55)4.65 (3.75 to 5.77)4.01 (3.22 to 4.99)4.39 (3.54 to 5.45)
213.31 (10.99 to 16.11)16.37 (13.56 to 19.76)18.73 (15.47 to 22.68)1.02 (0.85 to 1.23)
30.41 (0.34 to 0.50)0.53 (0.44 to 0.64)0.79 (0.65 to 0.97)0.48 (0.40 to 0.59)
41.79 (1.45 to 2.21)2.52 (2.04 to 3.10)1.83 (1.48 to 2.26)2.02 (1.64 to 2.48)
52.13 (1.66 to 2.73)2.42 (1.90 to 3.10)1.78 (1.39 to 2.28)3.70 (2.90 to 4.73)
6A3.92 (3.00 to 5.11)4.66 (3.59 to 6.06)4.38 (3.36 to 5.71)4.62 (3.56 to 5.99)
6B2.83 (2.14 to 3.73)3.78 (2.87 to 4.97)4.43 (3.36 to 5.86)2.44 (1.85 to 3.20)
7F4.97 (4.10 to 6.04)6.29 (5.20 to 7.61)8.82 (7.26 to 10.70)4.74 (3.92 to 5.73)
88.94 (7.25 to 11.02)8.79 (7.15 to 10.81)8.94 (7.25 to 11.02)7.30 (5.95 to 8.97)
9N7.98 (6.72 to 9.48)10.78 (9.10 to 12.78)7.91 (6.66 to 9.40)2.52 (2.13 to 2.99)
9V3.93 (3.13 to 4.92)5.12 (4.10 to 6.40)7.15 (5.71 to 8.97)2.94 (2.36 to 3.67)
10A6.73 (5.30 to 8.54)7.90 (6.24 to 10.00)6.58 (5.18 to 8.36)9.38 (7.41 to 11.86)
11A5.62 (4.73 to 6.67)5.76 (4.86 to 6.83)4.87 (4.10 to 5.78)3.72 (3.14 to 4.40)
12F1.73 (1.40 to 2.15)2.13 (1.72 to 2.64)1.91 (1.54 to 2.38)1.15 (0.93 to 1.42)
148.62 (6.54 to 11.36)10.47 (7.97 to 13.75)10.47 (7.93 to 13.81)8.17 (6.23 to 10.72)
15B10.67 (8.61 to 13.23)14.09 (11.41 to 17.40)11.59 (9.36 to 14.36)14.81 (12.00 to 18.27)
17F9.57 (7.92 to 11.56)10.51 (8.72 to 12.67)9.89 (8.18 to 11.95)0.46 (0.38 to 0.55)
18C6.66 (5.10 to 8.70)8.50 (6.53 to 11.07)10.35 (7.92 to 13.53)6.67 (5.13 to 8.67)
19A7.35 (5.80 to 9.31)9.21 (7.29 to 11.64)11.50 (9.07 to 14.58)8.84 (7.01 to 11.16)
19F4.98 (3.80 to 6.52)8.92 (6.83 to 11.64)9.96 (7.60 to 13.04)4.34 (3.33 to 5.66)
20B19.53 (16.82 to 22.68)24.90 (21.49 to 28.84)19.40 (16.71 to 22.52)4.06 (3.50 to 4.70)
22F4.13 (3.41 to 5.00)5.45 (4.51 to 6.59)3.81 (3.15 to 4.61)7.32 (6.06 to 8.83)
23F4.60 (3.59 to 5.87)5.90 (4.63 to 7.52)5.27 (4.12 to 6.73)5.18 (4.07 to 6.59)
33F12.20 (10.11 to 14.72)17.58 (14.60 to 21.17)11.82 (9.77 to 14.30)9.73 (8.08 to 11.71)

Adverse events

Collected over 6 months. Non-serious events are listed at a 5% frequency threshold.

Adverse event summary by group
GroupDeathsSeriousOther
VAX-24 Low Dose 18-49 Yrs0/16 (0%)0/16 (0%)9/16 (56.3%)
VAX-24 Mid Dose 18-49 Yrs0/16 (0%)0/16 (0%)13/16 (81.3%)
VAX-24 Mixed Dose 18-49 Yrs0/16 (0%)0/16 (0%)14/16 (87.5%)
PCV20 18-49 Yrs0/16 (0%)0/16 (0%)16/16 (100%)
VAX-24 Low Dose 50-64 Yrs0/193 (0%)2/193 (1%)161/193 (83.4%)
VAX-24 Mid Dose 50-64 Yrs0/191 (0%)3/191 (1.6%)155/191 (81.2%)
VAX-24 Mixed Dose 50-64 Yrs0/191 (0%)1/191 (0.5%)164/191 (85.9%)
PCV20 50-64 Yrs0/196 (0%)4/196 (2%)163/196 (83.2%)
VAX-24 Low Dose 18-64 Yrs0/209 (0%)2/209 (1%)170/209 (81.3%)
VAX-24 Mid Dose 18-64 Yrs0/207 (0%)3/207 (1.4%)168/207 (81.2%)
VAX-24 Mixed Dose 18-64 Yrs0/207 (0%)1/207 (0.5%)178/207 (86%)
PCV20 18-64 Yrs0/212 (0%)4/212 (1.9%)179/212 (84.4%)
Most frequent serious events
Showing 10 of 15
Most frequent serious events
EventVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsVAX-24 Low Dose 18-64 YrsVAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Pulmonary embolismRespiratory, thoracic and mediastinal disorders0/160/160/160/160/1930/1910/1912/1960/2090/2070/2072/212
Colitis ulcerativeGastrointestinal disorders0/160/160/160/160/1931/1910/1910/1960/2091/2070/2070/212
Gastric ulcer haemorrhageGastrointestinal disorders0/160/160/160/160/1931/1910/1910/1960/2091/2070/2070/212
Toxic encephalopathyNervous system disorders0/160/160/160/160/1931/1910/1910/1960/2091/2070/2070/212
DepressionPsychiatric disorders0/160/160/160/160/1930/1911/1910/1960/2090/2071/2070/212
Acute kidney injuryRenal and urinary disorders0/160/160/160/160/1931/1910/1910/1960/2091/2070/2070/212
Invasive ductal breast carcinomaNeoplasms benign, malignant and unspecified (incl cysts and polyps)0/160/160/160/161/1930/1910/1910/1961/2090/2070/2070/212
PancreatitisGastrointestinal disorders0/160/160/160/161/1930/1910/1910/1961/2090/2070/2070/212
Acetabulum fractureInjury, poisoning and procedural complications0/160/160/160/160/1930/1910/1911/1960/2090/2070/2071/212
Bladder InjuryInjury, poisoning and procedural complications0/160/160/160/160/1930/1910/1911/1960/2090/2070/2071/212
Most frequent other events
Showing 10 of 17
Most frequent other events
EventVAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsVAX-24 Low Dose 18-64 YrsVAX-24 Mid Dose 18-64 YrsVAX-24 Mixed Dose 18-64 YrsPCV20 18-64 Yrs
Injection site painSkin and subcutaneous tissue disorders9/1612/1613/1613/16137/193136/191147/191137/196146/209148/207160/207150/212
Muscle painMusculoskeletal and connective tissue disorders6/166/163/169/16110/193107/191115/191104/196116/209113/207118/207113/212
FatigueGeneral disorders6/165/166/168/1682/19378/19178/19178/19688/20983/20784/20786/212
Joint painMusculoskeletal and connective tissue disorders4/162/162/167/1648/19331/19153/19147/19652/20933/20755/20754/212
HeadacheGeneral disorders5/166/164/166/1659/19355/19158/19159/19664/20961/20762/20765/212
ErythemaSkin and subcutaneous tissue disorders1/161/163/164/1613/19315/19117/19117/19614/20916/20720/20721/212
EdemaSkin and subcutaneous tissue disorders3/162/164/163/1617/19315/19115/19121/19620/20917/20719/20724/212
FeverGeneral disorders1/161/160/162/162/1931/1914/1912/1963/2092/2074/2074/212
Oropharyngeal painRespiratory, thoracic and mediastinal disorders0/160/160/161/161/1930/1910/1910/1961/2090/2070/2071/212
Nasal congestionRespiratory, thoracic and mediastinal disorders1/160/160/160/161/1930/1910/1910/1962/2090/2070/2070/212

Baseline characteristics

Baseline demographics include all randomized subjects from Phase 1 and Phase 2 by age group. The prespecified immunogenicity analysis and Laboratory Value Abnormalities and/or Potentially Clinically Significant Laboratory Values included only subjects 50-64 years old.

Age, Continuous
Age, Continuous(Years)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Median39.5 (35.0 to 46.5)34.0 (30.0 to 37.5)39.0 (28.5 to 43.0)37.0 (26.5 to 41.5)57.0 (53.0 to 60.0)57.0 (53.5 to 60.0)57.0 (53.0 to 60.0)57.0 (53.0 to 60.0)57.0 (53.0 to 60.0)
Sex: Female, Male
Sex: Female, Male(Participants)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Female7788110121134127522
Male998883715867313
Ethnicity (NIH/OMB)
Ethnicity (NIH/OMB)(Participants)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Hispanic or Latino45232218221793
Not Hispanic or Latino12101413171172168177737
Unknown or Not Reported010002205
Race (NIH/OMB)
Race (NIH/OMB)(Participants)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
American Indian or Alaska Native000010023
Asian000210238
Native Hawaiian or Other Pacific Islander000010001
Black or African American5741040322929156
White108124145157156154646
More than one race1000214311
Unknown or Not Reported0100321310
Region of Enrollment
Region of Enrollment(participants)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
United States16161616193192192194835
Height (cm)
Height (cm)(cm)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Median176.1 (166.3 to 183.3)170.1 (165.1 to 179.2)167.1 (161.2 to 188.0)170.8 (165.1 to 176.6)168.3 (162.6 to 176.5)167.6 (162.6 to 175.3)167.6 (160.6 to 173.0)167.6 (160.0 to 176.5)167.6 (161.3 to 175.8)
Weight (kg)
Weight (kg)(kg)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Median80.85 (69.91 to 96.16)92.10 (74.94 to 117.24)90.50 (71.96 to 103.65)78.07 (72.04 to 96.62)87.82 (71.85 to 103.42)86.72 (72.58 to 104.33)83.10 (70.46 to 97.39)82.83 (70.31 to 97.52)84.81 (71.67 to 99.97)
Body Mass Index (kg/m^2) Median, Q1 - Q3
Body Mass Index (kg/m^2) Median, Q1 - Q3(kg/m^2)VAX-24 Low Dose 18-49 YrsVAX-24 Mid Dose 18-49 YrsVAX-24 Mixed Dose 18-49 YrsPCV20 18-49 YrsVAX-24 Low Dose 50-64 YrsVAX-24 Mid Dose 50-64 YrsVAX-24 Mixed Dose 50-64 YrsPCV20 50-64 YrsTotal
Median26.99 (24.01 to 30.12)31.09 (26.20 to 36.81)29.16 (26.66 to 34.56)26.91 (23.95 to 31.83)29.87 (25.75 to 35.99)30.65 (26.15 to 35.88)29.34 (25.20 to 33.20)29.06 (25.41 to 34.28)29.49 (25.61 to 34.68)
08

Study locations

13 sites
  • CenExel RCA
    Hollywood, Florida 33024, United States
  • Precision Clinical Research
    Sunrise, Florida 33351, United States
  • Meridian Clinical Research
    Savannah, Georgia 31406, United States
  • Velocity Clinical Research
    Valparaiso, Indiana 46383, United States
  • Johnson County Clin-Trials
    Lenexa, Kansas 66219, United States
  • Benchmark Research
    Metairie, Louisiana 70006, United States
  • Alliance for Multispecialty Research
    Kansas City, Missouri 64114, United States
  • Rochester Clinical Research
    Rochester, New York 14609, United States
  • Acellacare of Wilmington
    Wilmington, North Carolina 28401, United States
  • Velocity Clinical Research
    Warwick, Rhode Island 02886, United States
  • Coastal Carolina Research
    North Charleston, South Carolina 29405, United States
  • Benchmark Research
    San Angelo, Texas 76904, United States
  • JBR Clinical Research
    Salt Lake City, Utah 84107, United States
09

References and documents

Publications

  • Wassil J, Sisti M, Fairman J, Davis M, Fierro C, Bennett S, Johnson D, Migone TS, Nguyen K, Sauer P, Currie M, Iki S, Simon JK. Evaluating the safety, tolerability, and immunogenicity of a 24-valent pneumococcal conjugate vaccine (VAX-24) in healthy adults aged 18 to 64 years: a phase 1/2, double-masked, dose-finding, active-controlled, randomised clinical trial. Lancet Infect Dis. 2024 Mar;24(3):308-318. doi: 10.1016/S1473-3099(23)00572-8. Epub 2023 Dec 4. PubMed 38061367 ↗

Study documents

  • Study protocol · May 31, 2022
  • Statistical analysis plan · Dec 29, 2022

Documents are hosted by the registry — open the source record to download them.

Individual participant data

Plan to share: Yes — Vaxcyte is committed to providing access to anonymized data from the company's clinical trials for the purpose of legitimate scientific research. Requests for data may be addressed to datasharing@vaxcyte.com. Requests must be accompanied by a detailed analysis plan and will be reviewed for scientific validity. Data will be made available after initial product approval. Sharing of data may require execution of a data-sharing agreement.

Supporting information: Study protocol

10

Updates

Tracking since Sep 25, 2026
No changes since tracking began. The registry record was last updated on Apr 18, 2024, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
11

Registry details

Key details

Study ID
NCT05266456
Lead sponsor
Vaxcyte, Inc.
Responsible party
Sponsor
First posted
Mar 4, 2022
Start date
Feb 22, 2022
Primary completion
Jan 10, 2023
Completion
Jan 10, 2023
Results posted
Apr 18, 2024
Last update
Apr 18, 2024

Study contacts

Clinical Development
study director · Vaxcyte, Inc.

Oversight

Data monitoring committee
Yes
FDA-regulated drug
Yes
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Mar 2024. You cannot join it, but the record below documents what was studied.

Follow this study

Get an email when the registry record changes — status, dates, results — or when someone posts here.

Sign in to follow

Discussion

Questions and observations about this study, from anyone following it. Not medical advice, and not a channel to the study team — their contact details are on the registry record.

Sign in to join the discussion. Reading takes no account; posting does. You choose a display name, and a pseudonym is the default.

Nothing here yet. If you are running this trial, taking part in it, or weighing whether to, this is the place to say so.

Other studies from this sponsor

Vaxcyte, Inc.

Start the discussion