Sanofi and GlaxoSmithKline Reenter COVID-19 Vaccine Race With Phase 2 Results

Sanofi and GlaxoSmithKline (GSK) have reemerged as COVID-19 vaccine contenders after their reformulated candidate delivered a strong immune response across all age groups in a phase 2 study.

The adjuvanted vaccine suffered a serious setback in December when a phase 1/2 trial showed the candidate delivered only a weak response in older adults (DID, Dec. 14, 2020). But the companies said their refined antigen formulation induced a strong immune response in individuals ages 18 to 95, with neutralizing antibodies comparable to those found in patients after recovery from SARS‑CoV‑2 infection. The interim phase 2 results will be published in a peer-reviewed journal, the companies said.

The mid-stage study enrolled 722 volunteers aged 18 years and older in the U.S. and Honduras to evaluate the two-dose regimen given 21 days apart (DID, Feb. 23).

Sanofi and GSK now plan to enroll more than 35,000 participants in a phase 3 study to evaluate the vaccine’s efficacy against the original SARS‑CoV‑2 virus and the variant first identified in South Africa. And if the results are positive, the companies expect to seek approval from regulators in the fourth quarter.

Although wealthy territories like the U.S. and EU have already ordered enough vaccines to inoculate their entire populations, Sanofi and GSK are betting that the world will need multiple vaccines to combat emerging variants.

Sanofi has also entered into vaccine manufacturing partnerships to help produce the Pfizer/BioNTech, Moderna and Johnson & Johnson shots (DID, April 13), and it is developing a messenger RNA-based vaccine candidate with Translate Bio. The mRNA candidate is currently being assessed in a phase 1/2 study. Preliminary results from that trial are expected in the third quarter (DID, March 15). ― Jason Scott