Promising Early Trial Results for Dynavax’s Shingles Vaccine
Dynavax’s high hopes of challenging Shingrix began on strong footing, as its experimental shingles shot matched up well against GSK’s blockbuster in the opening segment of a phase 1/2 trial.
The study assessed multiple versions and dosing schedules of the recombinant subunit candidate, named Z-1018, in comparison with Shingrix among healthy participants aged 50 to 69. The regimen Dynavax has chosen to advance into the trial’s second stage delivered a 100% humoral response rate (indicating antibody generation) one month after the second dose, versus nearly 97% for patients on Shingrix.
Comparative Efficacy and Tolerability
In terms of gE-sfocused CD4+ T-cell activity, Dynavax reported that nearly 90% of patients in the Z-1018 arm gave a cellular immune response, compared with 93.5% in the Shingrix arm, according to its August 21 update.
The company also noted that its candidate was generally well tolerated, with investigators recording only low incidences of grade 2 and 3 local or systemic post-injection responses across all tested doses, formulations, and schedules.
In the formulation selected for advancement, almost 13% of participants in the Dynavax arm experienced grade 2 or 3 local post-injection reactions, while 27.5% were found to have grade 2 or 3 systemic reactions. By comparison, rates in the Shingrix group were notably higher, reaching above 52% and 63%, respectively.
A Turning Point for Dynavax
Dynavax CEO Ryan Spencer remarked in the release that the encouraging trial results represent a critical turning point for the company’s shingles vaccine program. He explained that the goal is to create a vaccine candidate with a potentially superior profile, positioning it to challenge the billion dollar shingles vaccine market, which is largely controlled by a single product.
Spencer noted that the study had successfully met its objective, with results demonstrating immune responses on par with Shingrix while also showing a favorable tolerability profile. He emphasized that these findings provided the foundation for determining the appropriate dose and regimen to move into later stages of development.
Future Development and Market Opportunity
He further explained that, based on the data, preparations were already in motion to launch the second part of the phase 1/2 trial in participants aged 70 and above, offering an opportunity to further reduce risk before moving into phase 3 development.
Shingrix first secured FDA approval in 2017, and in the second quarter of 2025, GSK generated $1.1 billion in sales from the vaccine.
While Shingrix remains firmly in position as the market leader, Dynavax’s CMO, Robert Janssen, M.D., said the company sees an opening to capture market share by leveraging Z-1018’s immune response profile and favorable tolerability results.
Janssen expressed optimism about the strength and consistency of the immune responses seen in the trial, emphasizing that Z-1018 showed notably strong CD4⁺ T cell activity when compared with Shingrix. He remarked that a vaccine capable of delivering a robust immune response while also maintaining good tolerability, relative to the existing standard of care, could represent a valuable new option for safeguarding against the illness.
