Astellas, Affinivax’s vaccine against streptococcus pneumoniae wins breakthrough therapy status

WORLD – Astellas Pharma, a Japanese multinational pharmaceutical company, and Affinivax, a clinical stage biopharmaceutical company, have been granted a breakthrough therapy designation by the US Food and Drug Administration (FDA) for their vaccine candidate ASP3772.

ASP3772 is a novel vaccine candidate designed to provide B-cell and T-cell immune protection against Streptococcus pneumoniae.

The vaccine contains 24 pneumococcal polysaccharides as well as two conserved pneumococcal proteins.

Pneumococcal disease is a name for any infection caused by bacteria called Streptococcus pneumoniae or pneumococcus.

Streptococcus pneumoniae are lancet-shaped, gram-positive, facultative anaerobic bacteria with 100 known serotypes. Most S. pneumoniae serotypes can cause disease, but only a minority of serotypes produce the majority of pneumococcal infections.

Pneumococci are common inhabitants of the respiratory tract. The bacteria may be isolated from the nasopharynx of 5–90% of healthy persons, depending on the population and setting.

The duration of carriage varies and is generally longer in children than adults. In addition, researchers do not clearly understand the relationship of carriage to the development of natural immunity.

Its treatment is commonly through antibiotics although some bacteria are resistant to certain antibiotics used to treat it.

Antibiotic treatment for serious pneumococcal infections typically includes ‘broad-spectrum’ antibiotics until results of antibiotic sensitivity testing are available.

Antibiotic sensitivity testing shows which antibiotics will be most successful at treating a bacterial infection. Broad-spectrum antibiotics work against a wide range of bacteria.

Once the sensitivity of the bacteria is known, clinicians may choose a more targeted (or ‘narrow-spectrum’) antibiotic.

Prior to this designation, two vaccines were available for use against the disease and they included Pneumococcal conjugate vaccine (PCV13) and Pneumococcal polysaccharide vaccine (PPSV23).

These vaccines are used to prevent severe pneumococcal disease, which often require treatment in the hospital and can be deadly. However, these vaccines do not prevent all infections.

ASP3772 is hopeful to join the CDC listing of vaccines that can be used within the USA and the globe at large.

Its designation comes at the same time when, Affinivax and Astellas revealed results from the Phase II trial of ASP3772.

In the Phase II trial, the primary objective was to evaluate the safety, tolerability and reactogenicity of ASP3772 compared to Pfizer’s Prevnar13.

The secondary objective was to evaluate the immunogenicity of ASP3772 compared to Prevnar13 or Pneumovax.

In the trial ASP3772 was found to be well tolerated, with mild and self-limited injection site and systemic reactions similar to those seen in the Prevnar13 group.

At the three dose levels studied, ASP3772 exhibiting an antibody response to each of the 24 polysaccharides and to the conserved pneumococcal proteins.

In comparison to Prevnar13 alone, ASP3772 also demonstrated a similar or better IgG and OPA immune response to the 13 share serotypes.

In particular, ASP3772 demonstrated a statistically higher immune response to serotype 3 at all dose levels, as well as a higher immune response to serotypes 5 and 19F at the highest doses tested.

On top of that, when compared to Prevnar13 plus Pneumovax23, ASP3772 demonstrated a similar or better IgG and OPA immune response to the 13 shared serotypes with Prevnar13.

ASP3772 also demonstrated a similar – and in most cases statistically higher – immune response for all remaining 11 serotypes.