GSK-Sanofi COVID-19 Vaccine Shows Insufficient Immunity, Late-Stage Trials Delayed

Sanofi SA SNY and GlaxoSmithKline plc GSK on Friday reported a delay in their COVID-19 vaccine program as interim results from Phase 1 and 2 trials indicate a low immune response in older adults.

What Happened: The drugmakers said in a statement that early-stage vaccine trials indicate a low immune response in older adults — most likely caused by an insufficient concentration of the antigen.

The results show that while patients aged 18 to 49 years showed an immune response comparable to patients who recovered from COVID-19, the response was lower in older adults.

The vaccine platform uses Sanofi’s recombinant technology and GlaxoSmithKline’s pandemic adjuvant.

Roger Connor, president of GlaxoSmithKline said, “The results of the study are not as we hoped. Based on previous experience and other collaborations, we are confident that GSK’s pandemic adjuvant system, when coupled with a COVID-19 antigen, can elicit a robust immune response with an acceptable reactogenicity profile.”

Thomas Triomphe, executive vice president of Sanofi said, “No single pharma company can make it alone; the world needs more than one vaccine to fight the pandemic.”

Why It Matters: The drugmakers said that their vaccine is now likely to be delayed until the fourth quarter of next year, contingent on the successful completion of its development plan.

The companies said it would launch a study in February with the help of the Biomedical Advanced Research and Development Authority as a part of Operation Warp Speed which would include a comparison with an authorized COVID-19 vaccine.

See Also: Pfizer-BioNTech COVID-19 Vaccine Gets FDA Advisors' Nod

Sanofi and GlaxoSmithKline have informed governments — including the European Commission — with whom the companies have a commitment to supply the vaccine. 

Price Action: Sanofi shares closed nearly 0.3% higher at $49.74 on Thursday. On the same day, GlaxoSmithKline shares closed 0.34% higher at $37.97 and gained 0.21% in the after-hours session.

See Also: Bill Gates Says 6 COVID-19 Vaccines Likely To Get Regulatory Approval By Q1