J&J single-shot COVID-19 vaccine shows early promise

J&J has announced early trial results that suggest its single-shot coronavirus vaccine provides a sustained response against the virus ahead of a phase 3 trial readout due later this month.

The UK has caused controversy in recent weeks by tinkering with the dosing regimens for coronavirus vaccines from AstraZeneca and Pfizer/BioNTech, which are being rolled as part of the country’s mass vaccination programme.

Both of these vaccines require two doses, as does the most recently approved shot from Moderna, which is due to arrive in the UK in the spring.

In order to make the best use of scarce vaccine resources the UK has opted to extend the time between doses to up to 12 weeks, a strategy that has been criticised by some scientists who are fearful that it could cause vaccine-tolerant strains of the virus to emerge.

Johnson & Johnson's Janssen pharma unit is further behind in the development of its vaccine, which has the crucial advantage of being administered in a single shot.

The UK government has an order of 30 million doses of the vaccine from J&J and an option for an additional 22 million doses in an agreement signed last summer.

Latest data give hope that the vaccine could be added to the campaign after phase 1/2a data showed that the shot provided an immune response that lasted for at least 71 days, the duration of time measured in the study involving patients aged 18-55 years.

The phase 1/2a interim analysis showed that the Company’s COVID-19 vaccine candidate induced an immune response and was generally well-tolerated across all study participants.

Data demonstrated that, after a single vaccination, neutralising antibodies against COVID-19 were detected in over 90% of study participants at day 29 and 100% of participants aged 18-55 years at day 57.

These neutralising antibodies remained stable through day 71, currently the latest timepoint available in this ongoing study.

Data on durability of immune responses in trial participants aged over 65 years will be available in late January and longer-term follow-up to one year is planned.

Top line data from a phase 3 study is due later this month, although this timing may change due to disease events.

J&J expects to file with the FDA first, followed by other regulators. The European Medicines Agency is conducting a rolling review of the vaccine to speed up the process.