“Reassuring” data on immune responses to COVID-19 vaccine in patients on methotrexate or targeted biological monotherapies have been published by UK researchers.
A study of 84 patients with psoriasis who were treated with methotrexate or an IL-17 or IL-23 inhibitor and 17 healthy controls showed some differences in neutralising antibodies but that cellular immune responses were induced across the board.
The findings have implications across rheumatology, the researchers said, but more studies are being done on specific aspects and longevity of the immune response.
Overall seroconversion rates were lower in patients receiving immunosuppressants after having the Pfizer vaccine (60 of 77 or 78%) than in controls (100%), with the lowest rate observed in those receiving methotrexate (7 of 15 or 47%).
Writing in The Lancet Rheumatology, the researchers reported that neutralising activity against wild-type SARS-CoV-2 was significantly lower in patients receiving methotrexate than in controls but was preserved in those on targeted biologics.
They also found that neutralising activity against the B117 alpha variant was uniformly low among all participants, including the healthy controls.
But cellular immune responses, measured by spike-specific T-cell responses were induced in all groups, and were the same in patients receiving methotrexate or targeted biologics compared with controls.
The researchers concluded that the data on those receiving biologics was encouraging but the results highlighted a disparity between humoral and cellular immune responses after vaccination in those taking methotrexate.
It is not yet clear what clinical significance that difference may have, they added, and one avenue that should be explored is whether temporarily stopping methotrexate at the time of vaccination would be worthwhile.
Study co-author Dr James Galloway, clinical lecturer at King’s College London and an honorary consultant in rheumatology at King’s College Hospital, said people taking these medications had “definitely had real anxiety” about whether the vaccines would work.
Speaking with the limbic, he said it was relevant to a large population of people on these treatments for auto-immune disease.
“We know that immune responses are complex so this was not just looking at antibody response but also T-cell response.
“The findings are very reassuring with regards the biologics we booked at as there really wasn’t any obvious signal the vaccine was impeded,” he said.
Dr Galloway added there were still lots of unanswered questions and they were doing more work.
“The sample size was small and we are following up on it looking at longevity. We didn’t look at the Delta variant and only one of the vaccines. Over the next year more answers will start to emerge but its optimistic that the impacts were really very limited.”
He said that it made sense from a mechanism of action point of view that methotrexate would produce different results to the more targeted treatments.
“One thing we need to look at for methotrexate is whether interrupting treatment for a couple of weeks after vaccination allows a better vaccine response and that’s definitely something other studies are looking into but that has to be weighed up against the risk of disease flare.”