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New IDSA aspergillosis guidelines endorse galactomannan for diagnosis


 

FROM CLINICAL INFECTIOUS DISEASES

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New aspergillosis guidelines from the Infectious Diseases Society of America recommend serum and bronchoalveolar lavage galactomannan as a marker for the diagnosis of invasive Aspergillus in adult and pediatric patients who have hematologic malignancies or have undergone hematopoietic stem cell transplants.

Serial monitoring of serum galactomannan (GM) is also useful to monitor disease progression, therapeutic response, and prognosis in hematologic malignancy and hematopoietic stem cell transplant (HSCT) patients who have elevated baseline GM (Clin Infect Dis. 2016 Jun 29. doi: 10.1093/cid/ciw326).

Serum beta-D-glucan assays also are recommended for diagnosing invasive Aspergillus (IA) in high-risk hematologic malignancy and allogeneic HSCT patients, although these tests are not very specific for the infection.

The advice illustrates the Society’s emphasis on early diagnosis in its new guidelines, which supplant the group’s 2008 guidance. There are almost 100 recommendations covering – in depth – the management of invasive, allergic, and chronic Aspergillus infections in all their manifestations. It’s a step-by-step, how-to manual for handling the problem.

Dr. Thomas Patterson
Dr. Thomas Patterson

“Aspergillosis mortality rates have decreased significantly in recent years, but there is still significant mortality from the infection, and we have a ways to go. We felt that early diagnosis was key, which is why it’s such an important part of these guidelines,” said lead author Thomas Patterson, MD, chief of the Division of Infectious Diseases at the University of Texas Health Science Center, San Antonio. He highlighted the most important developments in a recent interview.

“We know a lot more since 2008 about the benefits of using biomarkers like GM in bronchoalveolar lavage samples, which could be highly useful for diagnosis. However, biomarkers have not been as well validated for biologic response and are not recommended” in most cases for monitoring how well patients are doing. Also, “biomarkers are not as useful in solid organ transplants; we discuss that” in the guidelines, Dr. Patterson said.

The society came out against routine polymerase chain reaction (PCR) testing of blood samples for diagnosis. Although there has been a lot of work on the technique, the evidence isn’t strong enough yet to establish overall clinical benefit, but there is emerging evidence for the diagnostic use of PCR in conjunction with radiologic findings.

For treatment, voriconazole remains the go-to drug, but the guidelines make room for more recently approved therapies. “We now have isavuconazole, which may be better tolerated,” but it’s recommended only as an alternative to voriconazole because evidence comes mostly from a single clinical trial, he said.

Posaconazole extended-release tablets are strongly recommended as prophylaxis based on high-quality evidence from studies in neutropenic patients. Posaconazole extended-release tablets result in significantly higher antifungal blood levels than those seen with voriconazole, and “it certainly has been useful in some patients”; however, posaconazole is not approved for primary therapy in the United States, Dr. Patterson said.

A large clinical trial that tested voriconazole plus an echinocandin against voriconazole alone found that in patients diagnosed using serum galactomannan – especially those with hematologic malignancies – outcomes were better with the combination. “The panel felt combinations could be considered in some patients” but didn’t recommend them for routine use because [again,] there’s not strong evidence,” he said.

For now, it seems that higher-risk patients with hematologic malignancies and those with more widespread disease might be the ones who benefit most from combination therapy.

“We also discussed allergic and saprophytic diseases. We know that some patients with allergic bronchopulmonary aspergillosis will respond to antifungal therapy, and perhaps reduce their need for steroids, so that’s now part of the suggestions, as well,” he said.

The IDSA funded the work. Dr. Patterson receives research funding from Astellas, Merck, and Revolution Medicines, and has been an adviser to numerous drug companies.

aotto@frontlinemedcom.com

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