FDA Grants Breakthrough Therapy Designation to Novel 24-Valent Pneumococcal Vaccine ASP3772 Developed by Affinivax and Astellas

On July 13, 2021, Affinivax and Astellas Pharma announced that their co-developed innovative pneumococcal vaccine, ASP3772, achieved positive results in a Phase 2 clinical trial. ASP3772 utilizes Affinivax’s proprietary Multiple Antigen Presentation System (MAPS) technology platform, which can simultaneously present polysaccharide and protein antigens, thereby providing broader and more robust immune protection (B cell + T cell) against multiple pneumococcal serotypes. Phase 2 trial results indicated that ASP3772 was well tolerated. Furthermore, ASP3772 elicited antibody responses against 24 pneumococcal polysaccharide antigens, as well as against the two conserved pneumococcal protein antigens presented by the vaccine.

Based on the positive results from this Phase 2 trial, the U.S. FDA has granted Breakthrough Therapy Designation to ASP3772 for the prevention of pneumonia and invasive disease caused by the pneumococcal serotypes contained in the vaccine in adults aged 50 years and older.

The primary results of this Phase II clinical trial are as follows:

ASP3772 was well tolerated, with injection site and systemic reactions being mild and self-limiting, similar to those observed in the control 13-valent vaccine group.

1) Common local reactions were tenderness and pain, all occurring within the first 2–3 days after vaccination, with no significant difference compared to the 13-valent vaccine group.

2) During the safety assessment period up to 180 days post-vaccination, no vaccine-related serious adverse events or clinically significant abnormalities (vital signs, ECG, laboratory parameters) were observed, nor were any potential immune-mediated adverse events observed.

At the three dose levels studied, ASP3772 elicited robust immune responses against all 24 pneumococcal serotypes included in the vaccine.

1) Compared with the approved 13-valent active control vaccine, ASP3772 demonstrated similar or higher immune responses to the 13 serotypes shared between ASP3772 and the 13-valent vaccine.

2) At all ASP3772 dose levels, compared with the 13-valent vaccine or the 23-valent active control vaccine, ASP3772 demonstrated statistically significantly higher immune responses against serotypes 3, 4, 5, 6A, 7F, 9V, and 18C.

3) At the highest dose level of ASP3772, a statistically significantly higher immune response against serotypes 5 and 19F was demonstrated.

4) For the remaining 11 serotypes not included in the 13-valent vaccine, ASP3772 also demonstrated a statistically significant and favorable immune response.

ASP3772 also demonstrated a more than 2-fold increase in antibody responses against the two included conserved protein antigens, a phenomenon not observed in the 13-valent vaccine control group.

▲Affinivax's MAPS Technology Platform (Image source: Affinivax official website)

Note: The original text has been abridged.

References:

[1] Affinivax and Astellas Present Safety and Immunogenicity Data from Phase 2 Study of ASP3772, a Novel 24 valent MAPS™ Vaccine for Streptococcus pneumoniae. Retrieved July 13, 2021, from https://www.astellas.com/en/news/17066

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