Manufactured in Livingston, West Lothian, it was set to be the only Covid vaccine on order from the UK Government made in Scotland.
But the government cancelled an order of 100 million doses of the vaccine last month.
At the time Valneva said it had been served notice over allegations of a breach of contract, which it “strenuously” denied.
In new phase three results reported on Monday, the firm said the vaccine – VLA2001 – had successfully met its measurement points, and was well-tolerated in subjects.
The “very encouraging” results suggest it will be at least as effective, and potentially more so, than the AstraZenea vaccine, said Adam Finn, Professor of Paediatrics at Bristol University and Trial Chief Investigator.
Professor Finn said he is “cautiously optimistic” that the vaccine will be approved by the Medicines and Healthcare products Regulatory Agency (MHRA).
In September UK health secretary Sajid Javid told MPs it was clear to the UK Government that Valneva’s vaccine candidate “would not get approval” from the MHRA. This statement was later amended to say that the vaccine had “not yet gained approval”.
Valneva Chief Medical Officer Juan Carlos Jaramillo said on Monday that the company aims to send a final submission to the MHRA in November, and “potentially expects an initial approval” by the end of the year.
Dr Jaramillo refused to comment on contract negotiations with the UK Government, but said further updates would be given in the coming days.
He added that regardless of contract negotiations, the manufacturing operation in Scotland will continue.
Professor Penny Ward, a pharmaceutical expert at King’s College London, said the UK Government’s decision “might yet be regretted” following the positive results.
Unlike phase three trials for the Pfizer and AstraZeneca vaccines, the Valneva candidate was not compared against a placebo, as the trial was undertaken while vaccines were already available on the NHS for older adults, and this was considered unethical.
Instead it was compared to the already-approved AstraZeneca vaccine, with the benchmark that it must prove to be just as effective or better.
Professor Finn said: “The low levels of reactogenicity and high functional antibody responses alongside broad T-cell responses seen with this adjuvanted inactivated whole virus vaccine are both impressive and extremely encouraging.
“This is a much more traditional approach to vaccine manufacture than the vaccines so far deployed in the UK, Europe and North America and these results suggest this vaccine candidate is on track to play an important role in overcoming the pandemic.”
Thomas Lingelbach, chief executive officer of Valneva, said he believes the vaccine will make “an important contribution to the global fight against the Covid-19 pandemic.”
Commenting on the results from Valneva, Prof Ward said: “As we know the UK government is in dispute with Valneva having cancelled the UK’s order of up to 100 million doses, placed by the Vaccines Taskforce in 2020, in September.
"The results today suggest that this decision might yet be regretted, but because of it Valneva might be able to provide an immediate supply of this vaccine for other countries struggling with the freezer shipping requirements of other, more expensive, vaccines.
"Good news for Covax and countries still awaiting supplies.”