Patients with chronic lymphocytic leukaemia (CLL) who are hospitalised with COVID-19 have a high risk of mortality whether they are being treated for their cancer or not, a large international study has reported.

Analysis of data from 198 CLL patients with COVID-19 across 43 centres found that 90% were admitted to hospital and after a median follow up of 16 days 33% had died and 25% had not been discharged suggesting the mortality rate may increase.

Those who were under a ‘watch and wait’ strategy for their CLL had similar outcomes to those who were being actively treated, independent of their disease stage.

The results showed comparable rates of admission (89% vs. 90%), ICU admission (35% vs. 36%), intubation (33% vs. 25%), and mortality (37% vs. 32%) for watch and wait and treatment groups.

The international team of researchers also found no impact, protective or otherwise, of treatment with BTK inhibitors, despite suggestions that they may modulate the immune response by blocking of pro-inflammatory and chemo-attractant cytokines in lung tissue.

Writing in the journal Blood the researchers said data on outcomes for CLL patients who have developed symptomatic COVID-19, particularly the effect of cancer treatment on outcomes, “are likely to fundamentally shape how we manage CLL patients as the pandemic continues and evolves”.

They pointed it that it had been suggested that the immune dysfunction related to CLL may put “watch and wait” patients at particular risk but their data suggested patients who had not received therapy did not suffer a more aggressive disease course with COVID-19

Speaking with The Limbic, study author Dr Toby Eyre, Haematology Consultant at Oxford University Hospitals NHS Foundation Trust said the results highlighted the importance of risk factors that had already been characterised in the general population, such as age.

“I think it probably suggests that individual risk factors that are know about for COVID-19 patients apply for CLL patients as well, and are probably more dominant than the treatment stage of the disease per se.”

He added: “I think the suggestion that patients on watch and wait having similar outcomes to those on treatment was a bit surprising, but of course this paper was examining a subgroup of patients with severe disease, and it is hard to make very strong statements about risk without an accurate patient denominator; and as the discussion of the paper highlights, this can only be accurately done with widespread community testing.”