Patients with chronic lymphocytic leukaemia (CLL) are a “special case” that should be granted priority access to newly-approved COVID pre-exposure prophylaxis therapy, international experts say.
The combination of tixagevimab and cilgavimab antibodies (Evusheld) was recently given provisional approval by the TGA as pre-exposure prevention of COVID-19 in people who have moderate-to-severe immune compromise due to a medical condition or receipt of immunosuppressive medications.
Professor Paul Moss, a haematologist at the University of Birmingham and lead of the UK Coronavirus Immunology Consortium, told the the British Society of Haematology (BSH) 2022 meeting last week that the profound immune suppression that is associated with CLL has produced specific challenges for those patients during the pandemic.
At the start of the pandemic it came as no surprise to clinicians that CLL patients were incredibly vulnerable, with few therapeutic options and high rates of death. Patients were shielding and there were tricky decisions to make around use of CLL treatments, he added.
Now the situation is much brighter with vaccines and antiviral medicines but people with CLL continue to be a vulnerable group, he noted, particularly those on certain treatments.
Data from the UK CLL-VR study of 500 patients presented at the conference found that, while after three vaccines 80% of patients had an antibody response, this does not improve with further doses and 20% of patients remain antibody-refractory.
Further analysis showed that those about to start therapy, taking BTK inhibitors or with low serum immunoglobulins are the most vulnerable groups.
Follow-up data up from as recent as last week presented by Dr Helen Parry, Associate Professor at The University of Birmingham, showed that 78 of 486 patients still being followed had had COVID-19 and 39 of those were in the past three months.
And while Omicron causes more breakthrough infections in everyone, these vulnerable patients were benefiting from vaccine cross protection and from antivirals and monoclonal antibody treatment; 36% had received these outpatient treatments in the current wave and no patient had been hospitalised.
Associate Professor Parry did note that CLL patients seemed vulnerable to reinfection. “It’s important we make our patients aware of the access to monoclonal antibody and antiviral therapy, when they’re testing positive and make sure they get access to that very quickly,” she said.
Professor Moss told the conference that vaccines were important and must be encouraged but were not the answer for everybody.
Speaking with the limbic he noted that Evusheld had been used successfully in several countries but the question of its rollout centred around which populations would be eligible.
“One of the issues is the group of immune suppressed patients in the UK is really big — half a million,” he said.
He explained he believed there was a real case for CLL patients to be prioritised for this treatment which is given as two injections to patients who have not mounted a vaccine response before they have been exposed to COVID-19.
A trial showed it reduced the risk of symptomatic COVID by 77% and lasted for at least six months.
“CLL patients have a real problem by the very nature of their disease and treatment, they are exemplary and we need to lobby to ensure they have access to this.”
According to the TGA approval decision, the long-acting monoclonal antibodies, tixagevimab and cilgavimab, bind to the spike protein of the SARS-CoV-2 virus at two different sites to stop the virus from entering the body’s cells and causing infection.
The TGA said it had based the provisional approval on data from the PROVENT Phase III pre-exposure prevention trial, which demonstrated that Evusheld significantly reduces the risk of developing symptomatic COVID-19 with protection from the virus continuing for at least six months.
However it cautioned that pre-exposure prevention with Evusheld is not a substitute for vaccination in individuals for whom COVID-19 vaccination is recommended.