Viral infections have overtaken bacterial infections as the dominant microbiologically-confirmed infections in multiple myeloma patients treated with newer agents.
And they’re nasty for vulnerable patients – associated with high rates of hospitalisation (58.0%) and ICU admission (17.2% of hospital-admitted patients).
A Melbourne study comprised 148 patients treated with second generation therapies and/or monoclonal antibodies between January 2013 and December 2018 and followed up for infection for a median of 13.2 months.
The study identified 345 infection episodes – an overall incidence rate of infection was 1.7 per patient-year. Almost 60% of the infection episodes occurred within the first 12 months of commencement of new generation MM therapies.
“The risk for infection appears to decrease with increasing duration of therapy in patients with newly diagnosed disease, a reflection of immune recovery following disease control,” the study said.
“However, the relatively late risk period for infection identified in our study could reflect slower immune reconstitution in a relapsed and refractory patient population.”
The study found viral infections, particularly of the respiratory tract, were the largest group of microbiologically-confirmed infections. The most common causes were respiratory syncytial virus (24.0%), rhinovirus (16.0%), and influenza (14.0%).
It also found receipt of proteasome inhibitor-based therapy and more than four lines of therapy were the risk factors associated with a higher risk for infection.
The researchers from the Peter MacCallum Cancer Centre, Royal Melbourne and St Vincent’s hospitals, said infection remains a significant contributor to morbidity in patients with myeloma.
“In this study, high-grade infection (CTCAE grade 3 or above) associated with hospitalisation was observed in nearly one-third of patients overall and comprised of 41.7% of all infection episodes.”
“Novel agents such as IMiD and PI have increased progression-free-survival, resulting in more cumulative drug exposure and longer periods at risk for acquiring vRTI in the community.”
“Based on viral pathogens identified, improved infection prevention measures including social distancing, hand hygiene and vaccination could assist with reducing burden of infection.”
The most common bacterial pathogens identified in the study were E.coli and C. difficile.
“Interestingly, encapsulated bacteria such as S. pneumoniae, a classic pathogen in patients with MM was not detected in our study. This could reflect improved supportive care measures utilised in recent years such as a comprehensive approach to post-transplant vaccination,” the study said.
Isolated fungal pathogens were Cryptococcus neoformans and Candida krusei.
The study was published in Clinical Lymphoma, Myeloma and Leukaemia.