Aug 16 (Reuters) - Pfizer ( PFE ) and BioNTech

said a late-stage trial of their experimental mRNA

vaccine to protect against influenza and COVID-19 found the

combination shot failed to meet one of the study's two main

goals and they are evaluating next steps.

The drugmakers said on Friday the Phase 3 trial showed the

vaccine elicited a robust influenza A immune response, compared

to a standard flu vaccine, but showed weaker results against the

influenza B strain.

The formulation showed similar responses against SARS-CoV-2

as the companies' COVID-19 vaccine.

"We remain optimistic about our combination COVID-19 and

influenza program, for which we are evaluating the next steps,"

Annaliesa Anderson, Pfizer's ( PFE ) head of vaccine research and

development, said in a statement.

The companies said they are discussing the findings with

health authorities and evaluating adjustments to the candidate.

The trial, which compared the experimental vaccine to a

licensed influenza vaccine and the companies' COVID-19 vaccine

given at the same visit, enrolled 8,000 healthy adults.

The drugmakers said no safety issues with the combination

vaccine have been identified.

Pfizer ( PFE ) also said a Phase 2 trial of its second-generation

mRNA flu vaccine candidate showed that the formulation elicited

robust influenza A and B responses, with no safety issues

reported.

It said data from the 450-patient flu vaccine trial would be

made available at a later date.