Could the best chemotherapy be an antimicrobial drug?

Marking the beginning of World Antimicrobial Awareness Week, Anna Zorzet and Scott Howard make the case that often the most important treatment for people with cancer are the drugs that cure their infections.

The discovery of antimicrobials is one of the greatest advances of our time. Being able to treat a multitude of different infections has saved countless lives. This is certainly true for people living with cancer, who rely on antimicrobials for the prevention and treatment of infections. Antimicrobials are also crucial for safe cancer surgery. However, global action to address drug resistant infections has not kept pace with the number or organisms that have developed resistance. Watching a person with curable cancer succumb to infection while on the road to cure is truly heartbreaking.

Case of aspergilliosis in AML

To highlight the impact of effective antimicrobials, consider acute myeloid leukemia (AML). Standard care for people with AML includes four or five cycles of intensive chemotherapy that severely suppresses patients’ immune systems and increases their likelihood of developing bacterial and fungal infections.

For example, approximately 10% of people with AML develop the fungal infection invasive aspergillosis due to exposure to spores in their environment. Aspergillosis infections in the 1980s had an overwhelmingly negative impact on patient survival: half of people with AML complicated by aspergillosis died from infection. In addition to increasing rates of mortality, these types of infections commonly caused delays and interruption to chemotherapy treatment, which increased the likelihood of relapse, so drug-resistant aspergillus had a double impact on survival. 

From 1991 to 2001, cure rates for AML did not improve. But then since 2001, survival for children with AML has increased by a whopping 14%. The surprise was that this increase came despite using the same chemotherapy as before. The difference resulted from controlling aspergillus fungus infection, which had been resistant to the commonly used amphotericin but was sensitive to the newly approved anti-fungal drug voriconazole.

In the 1990s, aspergillus was resistant to the existing treatments, which led to prolonged infections, delayed chemotherapy, and increased relapse. The new antifungal drugs had a game-changing impact on outcomes for people receiving cancer therapy. 

Antimicrobial resistance and lack of access to cancer care and antibiotics: a triple burden for low- and middle-income countries

Unfortunately, many patients in LMICS have not benefited from these remarkable improvements and their related increased survival. Despite their inclusion on the WHO’s Model List of Essential Medicines, most of these life-saving drugs are either not licensed or inaccessible due to prohibitive costs and inadequate supply chains.

Thus, people with cancer in LMICs carry the triple burden of lacking access to cancer medicines and antibiotics as well as being more exposed to resistant infections. This has had devastating consequences for cancer patient outcomes. 

Dr Scott Howard, one of the UICC AMR and cancer care task force members, recently consulted on a young girl in Myanmar who developed a fungal mass in her lungs during treatment for acute leukemia that has a 90% cure rate in high-income countries. Unfortunately, voriconazole was not available to her, and her prolonged high fevers and lung damage meant that she could no longer safely receive chemotherapy. The lack of chemotherapy led to a delay in her remission, and the persistent leukemia compounded the damage from the aspergillus infection.

This inequity also leads to impossible ethical dilemmas. In India, doctors have realised that treating cancer patients exposed them to the risk of dying with an untreatable, resistant infection. What do you choose in such a situation?

Why the cancer community needs to act on antimicrobial resistance

With the number of drug-resistant infections increasing worldwide, the cancer community needs to act. Cancer physicians are concerned – as many as 95 % of polled oncologists in the UK worry about increasing drug resistance and its consequences on future cancer care. 

The COVID-19 pandemic has highlighted the need for resilient health systems, reinforced the importance of managing infections that occur in people fighting cancer and resulted in an unprecedented rate of collaboration. Antimicrobials are crucial to all health systems, so we must consider how to keep them effective and sustain a high level of global collaboration to fight infections with every means at our disposal. 

The creation of an AMR task force at the UICC is a welcome step but more action is needed. Cancer societies, patients and physicians need to join the debate to make the issue a political priority. Without the effectiveness of these treatments, doctors and patients risk regressing decades back to the poor survival rates of the 1970s. 

Helle Aagaard, Deputy Director, ReAct, and Tina Chong, Vice President, Resonance, also contributed to this article.