How antimicrobial resistance is risking blood cancer treatment

Cancer care has entered a new era of innovation. Advances in immunotherapy, targeted treatments and cellular therapies are transforming patient outcomes. Yet all these breakthroughs rest on a fragile foundation: antimicrobials.

Without effective infection prevention and treatment, chemotherapy cannot be delivered safely, stem cell transplants cannot proceed, immune-based therapies become less feasible, clinical trials face disruption and oncology pipelines risk losing momentum.

The scale of the challenge is sobering. Antimicrobial resistance was associated with nearly 4.95 million deaths worldwide in 2019.

Forecasts now warn of 39 million cumulative deaths over the next 25 years. Despite this scale, resistant infections remain almost invisible in oncology trials. This is a blind spot that threatens patient outcomes, the resilience of global cancer innovation and the sustainability of future markets.

Infection is already the second leading cause of death in patients with cancer, after progression of the disease itself. Recent multicentre studies in the United States highlight how antimicrobial resistance compounds this risk.

In outpatients with cancer, resistant pathogens were up to three times more common than in non-cancer populations. Among hospitalized patients, antimicrobial resistance rates for key pathogens were 1.5 to 2 times higher than those in patients without cancer.

For patients with haematological malignancies, the risks are especially acute. These cancers account for 6.6% of all diagnoses and 7.2% of cancer-related deaths globally. In the United States alone, someone is diagnosed with a blood cancer every three minutes.

Both the disease and its treatments leave patients profoundly immunosuppressed, making survival heavily dependent on timely access to effective antimicrobials.

Our review of haematology-oncology studies revealed inconsistent and incomplete reporting of infections, with microbiological and resistance data largely absent. In the literature, bloodstream infections have featured prominently, with prevalence ranging from 22% to 45%, depending on the patient population, treatment type and clinical setting.

Multidrug-resistant gram-negative pathogens were a recurring theme, particularly extended-spectrum beta-lactamase-producing enterobacteriaceae, and vancomycin-resistant enterococci in heavily pre-treated populations – these can lead to serious, difficult-to-treat infections.

However, trial data painted a different picture. Analysis of 27 haematology-oncology trials found infections to be among the most frequent adverse events but with reporting concentrated on respiratory infections (50.6% of cases) and sepsis-related complications (16.2%).

Across drug classes, respiratory infections were consistently the most common, while sepsis-related events ranked among the top three categories for cytotoxic chemotherapy, combination regimens and targeted therapies. Targeted therapies carried the highest burden, affecting more than 40% of participants, while monoclonal antibodies were associated with lower infection rates.

These discrepancies reflect systematic differences in reporting between clinical trials and real-world studies. Critically, trials seldom demonstrated whether infections contributed to death or treatment discontinuation, obscuring the true clinical impact. Most significantly, antimicrobial resistance data were absent altogether as no trial systematically captured resistance or colonization information, leaving the role of multidrug-resistant pathogens invisible.

The gaps are not only in data collection but also in geography. Clinical trials are concentrated in Europe, North America and East Asia. In contrast, real-world studies reviewed include high-burden settings, such as Argentina, India, Turkey, Pakistan and China, regions where antimicrobial resistance prevalence is highest and where demand for oncology treatments is expected to grow most rapidly.

The result is a disconnect between the evidence base and real-world conditions. For patients, this translates into higher non-relapse mortality, treatment interruptions and reduced feasibility of immunosuppressive therapies.

For clinical trials, it creates the risk of attrition, delays and protocol failure in high-resistance settings. For pharmaceutical companies, it means the emergence of blind spots. Underestimating antimicrobial resistance is to underestimate disruption risk.

The consequences of these blind spots extend well beyond patient care. If left unaddressed, antimicrobial resistance could erode the safety and feasibility of breakthrough therapies, compromise clinical trial outcomes and diminish the commercial sustainability of oncology portfolios.

Frequent, severe and treatment-resistant infections are no longer a tolerable side effect but a direct threat to patient survival and to the resilience of the innovation ecosystem.

For pharmaceutical companies, the impact is strategic. Failure to integrate antimicrobial resistance into oncology development risks patient safety and market viability. Costs will be measured not only in terms of patient outcomes but also in terms of lost revenue, slower market access and diminished treatment effectiveness.

Antimicrobial resistance is both a clinical and commercial disruptor for oncology. To future-proof innovation, companies, regulators and policymakers must act decisively across several priority areas:

Without action, antimicrobial resistance threatens patient survival and undermines the sustainability of oncology innovation. The costs of inaction will be measured in lives lost, stalled pipelines and diminished market potential.

Decisive action today can secure the long-term impact of innovation across global cancer care. Leaders who embed antimicrobial resistance readiness into oncology trials, portfolios and policies will protect patients and ensure trial feasibility, as well as sustain the resilience of global cancer innovation.

The fight against antimicrobial resistance is inextricably linked to the future of oncology and the time to act is now.

Daniel Mora-Brito, EMEA Thought Leadership, Global Health, IQVIA, also contributed to this article.