Vaxcyte Advances to Second Stage of Ongoing Phase 2 Study Evaluating VAX-31 for the Prevention of Invasive Pneumococcal Disease in Infants

Rhea-AI Summary

Vaxcyte (PCVX) has advanced to Stage 2 of its Phase 2 study for VAX-31, a 31-valent pneumococcal conjugate vaccine (PCV), following a successful review of Stage 1 safety and tolerability data. The study evaluates VAX-31's effectiveness in preventing invasive pneumococcal disease in healthy infants.

VAX-31 is designed to provide coverage for approximately 94% of invasive pneumococcal disease and 93% of acute otitis media in U.S. children under five. The company expects to announce topline safety, tolerability, and immunogenicity data from the primary immunization series in mid-2026, with booster dose data following nine months later.

Additionally, Vaxcyte remains on schedule to announce VAX-24 Phase 2 infant study topline data by the end of Q1 2025. Both VAX-31 and VAX-24 aim to provide enhanced protection against current and historically prevalent strains compared to standard-of-care vaccines.

Positive

• Advancement to Stage 2 of Phase 2 study following successful safety review
• VAX-31 targets 94% coverage of invasive pneumococcal disease in children under five
• VAX-31 aims for 93% coverage of acute otitis media in U.S. children under five
• Development of both VAX-31 and VAX-24 progressing on schedule

Negative

• Extended timeline for results - primary immunization data not expected until mid-2026
• Additional nine-month wait for booster dose data after primary results

Insights

Clinical Research Analyst

The advancement of VAX-31 to Stage 2 in infant trials marks a pivotal milestone in Vaxcyte's pneumococcal vaccine development program. The 31-valent vaccine candidate demonstrates superior theoretical coverage compared to current market leaders, targeting approximately 94% of invasive pneumococcal disease and 93% of acute otitis media in U.S. children under five.

The carrier-sparing platform technology represents a significant technical advantage, potentially enabling broader serotype coverage while maintaining robust immune responses - a historical challenge in PCV development. This technological edge could be particularly valuable given the complex manufacturing requirements of pneumococcal vaccines.

The timing of data readouts is strategically positioned, with VAX-24's Phase 2 infant data expected by Q1 2025 and VAX-31's primary immunization series data in mid-2026. This staggered approach allows for risk mitigation and potential market positioning strategies. The successful advancement through safety review suggests promising early signals, though it's important to note that immunogenicity data will be the key determinant of competitive viability.

The parallel development of both VAX-24 and VAX-31 demonstrates a sophisticated market strategy, potentially allowing Vaxcyte to address different market segments and compete effectively against established players. The broader coverage could provide significant competitive advantages, particularly in tender-based markets where coverage breadth often influences purchasing decisions.

Market Research Analyst

The pneumococcal conjugate vaccine market represents a substantial commercial opportunity, with current global sales exceeding $6 billion annually. VAX-31's advancement in infant trials is particularly significant given that the pediatric segment constitutes the majority of the PCV market volume.

The expanded serotype coverage of VAX-31 positions it favorably against current market standards. While existing vaccines cover 13-20 serotypes, VAX-31's 31-valent formulation could potentially capture additional market share by addressing unmet medical needs. The carrier-sparing platform could also provide manufacturing efficiency advantages, potentially improving margins in a cost-sensitive market.

The strategic development timeline, with data readouts through 2026, aligns well with market dynamics and potential competitor product cycles. The parallel development of VAX-24 and VAX-31 creates multiple commercial opportunities and risk mitigation pathways. Success in the infant market could provide a strong foundation for expansion into adult indications, where pricing dynamics are typically more favorable.

-- Advancement to Stage 2 of Infant Study Supported by Review of Stage 1 Safety and Tolerability Data --

-- Company Expects to Announce VAX-31 Infant Study Topline Safety, Tolerability and Immunogenicity Data from Primary Immunization Series in Mid-2026, Followed by Topline Data from the Booster Dose Approximately Nine Months Later --

-- VAX-31 is Designed to Cover Approximately 94% of Invasive Pneumococcal Disease and Approximately 93% of Acute Otitis Media in U.S. Children Under Five --

-- Company Remains on Track to Announce VAX-24 Phase 2 Infant Study Topline Data from Primary Immunization Series by End of First Quarter of 2025 --

-- VAX-31 and VAX-24 Offer Potential to Protect Vulnerable Population by Providing Greater Coverage Against Both Currently Circulating and Historically Prevalent Strains Relative to Standard-Of-Care Pneumococcal Conjugate Vaccines --

SAN CARLOS, Calif., Feb. 05, 2025 (GLOBE NEWSWIRE) -- Vaxcyte, Inc. (Nasdaq: PCVX), a clinical-stage vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases, today announced that the first study participants have been dosed in the second and final stage of the ongoing Phase 2 study of VAX-31 in healthy infants. Advancement to Stage 2 follows a blinded assessment of the Stage 1 safety and tolerability data per the study protocol. This study is evaluating the safety, tolerability and immunogenicity of VAX-31, a 31-valent pneumococcal conjugate vaccine (PCV) candidate designed to prevent invasive pneumococcal disease (IPD), in healthy infants. The Company expects to share topline data from the primary three-dose immunization series of the study in mid-2026, followed by topline data from the booster dose approximately nine months later.

“Advancing to Stage 2 of the VAX-31 infant Phase 2 study represents a significant step forward in evaluating the broadest vaccine candidate in the clinic today for this vulnerable population,” said Grant Pickering, Chief Executive Officer and Co-Founder of Vaxcyte. “PCVs have been a bedrock of the vaccination schedule for decades, providing critical protection against invasive pneumococcal disease for our communities. With our PCV franchise, VAX-24 and VAX-31, we are working to set a new standard that expands protection against currently and historically circulating strains while maintaining strong immune responses. We look forward to sharing topline data for safety, tolerability and immunogenicity from the VAX-31 infant study primary immunization series in mid-2026, and from the booster dose approximately nine months later.”

“PCVs have demonstrated the ability to deliver herd immunity to protect against devastating diseases caused by Streptococcus pneumoniae bacteria, and our technology has the potential to deliver best-in-class PCVs with broader coverage for both infants and adults,” said Jim Wassil, Executive Vice President and Chief Operating Officer of Vaxcyte. “Based on the body of positive evidence from the VAX-31 and VAX-24 adult Phase 1/2 programs, we believe our carrier-sparing platform has the potential to set a new standard in disease coverage.”

About the VAX-31 Infant Phase 2 Study
The VAX-31 infant Phase 2 study is a randomized, double-blind, active controlled, dose-finding, two-stage clinical study evaluating the safety, tolerability and immunogenicity of VAX-31 compared to Prevnar 20 (PCV20) in healthy infants.

• Stage 1 of the study evaluated the safety and tolerability of VAX-31 after the first vaccination at each of three ascending dose levels (low, middle and high) in 48 infants who received VAX-31 or PCV20 in one of three dose-escalating cohorts. In the low, middle and high doses, all serotypes were dosed at 1.1mcg, 2.2mcg and 3.3mcg, respectively, except serotypes 1, 5 and 22F, which were dosed at 1.65mcg, 3.3mcg, and 4.4mcg, respectively. Participants who received VAX-31 in Stage 1 will continue the standard dosing regimen as part of Stage 2 and will be included in the safety, tolerability and immunogenicity analysis of the study.
• Stage 2 of the study is evaluating the safety, tolerability and immunogenicity of VAX-31 at the same three dose levels and compared to PCV20 in approximately 750 infants.
• In line with recommendations from the Advisory Committee on Immunization Practices (ACIP), the study design includes a primary immunization series consisting of three doses given at two months, four months and six months of age, followed by a subsequent booster dose at 12-15 months of age.
• The key prespecified immunogenicity study endpoints include an assessment of immune responses for each of the VAX-31 dose levels in comparison with PCV20 for the 20 common and 11 unique serotypes in VAX-31. Post-primary series (post-dose 3 or PD3) immune responses will be assessed based on serotype-specific immunoglobulin G (IgG) seroconversion rates (proportion of participants achieving the accepted IgG threshold value of ≥0.35mcg/mL) at 30 days PD3. IgG geometric mean titers will be assessed at 30 days PD3 and post-dose 4 (PD4), along with other key immunogenicity endpoints.
• All participants in the study will be evaluated for safety through six months following the booster dose.
• The study is being conducted at approximately 50 sites in the United States.

About Pneumococcal Disease
Pneumococcal disease (PD) is an infection caused by Streptococcus pneumoniae bacteria. It can result in invasive pneumococcal disease (IPD), including meningitis and bacteremia, and non-invasive PD, including pneumonia, otitis media and sinusitis. In the United States, pneumococcal pneumonia is estimated to result in approximately 150,000 hospitalizations each year. Streptococcus pneumoniae is among the World Health Organization’s top antibiotic-resistant pathogens to be urgently addressed, and the U.S. CDC lists drug-resistant Streptococcus pneumoniae as a “serious threat.” In children under five, Streptococcus pneumoniae is the leading cause of vaccine-preventable deaths globally. Pneumococci also cause over 50% of all cases of bacterial meningitis in the United States. Antibiotics are used to treat PD, but some strains of the bacteria have developed resistance to treatments. The morbidity and mortality due to PD are significant, particularly for young children and older adults, underscoring the need for a broader-spectrum vaccine.

About VAX-31
VAX-31, a 31-valent PCV candidate advancing to a Phase 3 adult clinical program and currently being evaluated in a Phase 2 infant clinical program, is designed to prevent IPD, which is especially serious in infants, young children, older adults and those with immune deficiencies or certain chronic health conditions. IPD is associated with high case-fatality rates, antibiotic resistance and meningitis. VAX-31 is the broadest-spectrum PCV in the clinic and has the potential to provide protection against both currently circulating and historically prevalent serotypes. VAX-31 was designed to increase coverage, in a single vaccine, to more than 95% of IPD circulating in adults in the United States aged 50 and older, with the potential to provide an incremental 12-40% of coverage over current standard-of-care adult PCVs. In infants, it was designed to cover approximately 94% of IPD and approximately 93% of acute otitis media due to Streptococcus pneumoniae in children under five years of age in the United States.

In November 2024, Vaxcyte announced that the FDA granted Breakthrough Therapy designation to VAX-31 for the prevention of IPD in adults. The Breakthrough Therapy designation process is designed to expedite the development and review of drugs that are intended to treat a serious or life-threatening condition.

About Vaxcyte
Vaxcyte is a vaccine innovation company engineering high-fidelity vaccines to protect humankind from the consequences of bacterial diseases. The Company is developing broad-spectrum conjugate and novel protein vaccines to prevent or treat bacterial infectious diseases. VAX-31 is a 31-valent, carrier-sparing PCV being developed for the prevention of IPD in adults and infants and is the broadest-spectrum PCV candidate in the clinic today. VAX-24, the Company’s 24-valent PCV candidate, is designed to cover more serotypes than any infant PCV on-market and is currently being evaluated in a Phase 2 infant study. Both VAX-31 and VAX-24 are designed to improve upon the standard-of-care PCVs by covering the serotypes in circulation that are responsible for a significant portion of IPD and are associated with high case-fatality rates, antibiotic resistance and meningitis, while maintaining coverage of previously circulating strains that are currently contained through continued vaccination practice.

Vaxcyte is re-engineering the way highly complex vaccines are made through modern synthetic techniques, including advanced chemistry and the XpressCF™ cell-free protein synthesis platform, exclusively licensed from Sutro Biopharma, Inc. Unlike conventional cell-based approaches, the Company’s system for producing difficult-to-make proteins and antigens is intended to accelerate its ability to efficiently create and deliver high-fidelity vaccines with enhanced immunological benefits. Vaxcyte’s pipeline also includes VAX-A1, a prophylactic vaccine candidate designed to prevent Group A Strep infections; VAX-PG, a therapeutic vaccine candidate designed to slow or stop the progression of periodontal disease; and VAX-GI, a vaccine candidate designed to prevent Shigella. Vaxcyte is driven to eradicate or treat invasive bacterial infections, which have serious and costly health consequences when left unchecked. For more information, visit www.vaxcyte.com.

Forward-Looking Statements 
This press release contains forward-looking statements within the meaning of The Private Securities Litigation Reform Act of 1995. These statements include, but are not limited to, statements related to the potential benefits of VAX-24 and VAX-31, including breadth of coverage, and the ability to deliver potentially best-in-class PCVs and improve upon the standard-of-care; the process and timing of anticipated future development of Vaxcyte’s vaccine candidates; the timing of data readouts for the VAX-31 and VAX-24 infant Phase 2 studies; the demand for Vaxcyte’s vaccine candidates; and other statements that are not historical fact. The words “anticipate,” “believe,” “could,” “expect,” “intend,” “may,” “on track,” “potential,” “should,” “would” and similar expressions (as well as other words or expressions referencing future events, conditions or circumstances) convey uncertainty of future events or outcomes and are intended to identify forward-looking statements, although not all forward-looking statements contain these identifying words. These forward-looking statements are based on Vaxcyte’s current expectations and actual results and timing of events could differ materially from those anticipated in such forward-looking statements as a result of risks and uncertainties, including, without limitation, risks related to Vaxcyte’s product development programs, including development timelines, success and timing of chemistry, manufacturing and controls and related manufacturing activities, potential delays or inability to obtain and maintain required regulatory approvals for its vaccine candidates, and the risks and uncertainties inherent with preclinical and clinical development processes; the success, cost and timing of all development activities and clinical trials; and sufficiency of cash and other funding to support Vaxcyte’s development programs and other operating expenses. These and other risks are described more fully in Vaxcyte’s filings with the Securities and Exchange Commission (SEC), including its Quarterly Report on Form 10-Q filed with the SEC on November 5, 2024 or in other documents Vaxcyte subsequently files with or furnishes to the SEC. All forward-looking statements contained in this press release speak only as of the date on which they were made and are based on management’s assumptions and estimates as of such date, and readers should not rely upon the information in this press release as current or accurate after its publication date. Vaxcyte undertakes no duty or obligation to update any forward-looking statements contained in this release as a result of new information, future events or changes in its expectations. Readers should not rely upon the information in this press release as current or accurate after its publication date.

Contacts:

Patrick Ryan, Executive Director, Corporate Communications
Vaxcyte, Inc.
415-606-5135
media@vaxcyte.com

Jennifer Zibuda, Senior Director, Investor Relations
Vaxcyte, Inc.
860-729-8902
investors@vaxcyte.com

FAQ

What are the coverage rates for Vaxcyte's VAX-31 vaccine in children under 5?

VAX-31 is designed to cover approximately 94% of invasive pneumococcal disease and 93% of acute otitis media in U.S. children under five years old.

When will Vaxcyte (PCVX) release VAX-31 Phase 2 infant study results?

Vaxcyte expects to announce topline data from the primary immunization series in mid-2026, with booster dose data following approximately nine months later.

What milestone did Vaxcyte's VAX-31 Phase 2 study reach in February 2024?

Vaxcyte advanced to Stage 2 of its Phase 2 study for VAX-31 following a successful review of Stage 1 safety and tolerability data.

When will Vaxcyte release VAX-24 Phase 2 infant study results?

Vaxcyte expects to announce VAX-24 Phase 2 infant study topline data by the end of the first quarter of 2025.

How does VAX-31 compare to current standard-of-care pneumococcal vaccines?

VAX-31 aims to provide greater coverage against both currently circulating and historically prevalent strains compared to standard-of-care pneumococcal conjugate vaccines.