Isavucanazole Potential Option for Prophylaxis Against Invasive Fungal Infections in alloSCT Patients

In a recent poster session at the BMT Tandem Meetings in Salt Lake City, Utah, researchers presented findings from a recent study that explored the use of isavuconazole for prophylaxis against invasive fungal infections in allogeneic stem cell transplant patients.

Isavucanazole, is a broad-spectrum triazole antifungal that was approved by the US Food and Drug Administration back in March 2015 for the treatment of invasive aspergillosis and invasive mucormycosis—life-threatening fungal infections that primarily occur in patients who are immunocompromised.

Although the antifungal is known to have a favorable side effect profile, not much is known about how effective it is as an antifungal prophylaxis after allogeneic stem cell transplants (alloSCT).

To fill in this knowledge gap, researchers launched a study dedicated to reporting real-world experience with isavucanazole prophylaxis. Researchers performed a retrospective chart review on adult alloSCT recipients of the prophylaxis between November 2015 and September 2017.

For the study, researchers collected data pertaining to demographics, type of transplant, the reasons for selecting isavucanazole, breakthrough invasive fungal infections, and isavucanazole steady-state concentrations, according to the study abstract.

“Descriptive data were expressed as mean± SD or frequencies. Multivariate logistic regression adjusted for graft vs. host disease (GVHD) was performed to estimate odds of breakthrough IFIs with isavuconazole compared to historical data,” the authors write.

The study looked at a total of 25 adult patients with a mean age of 56±17 years; the majority or 80% of them had received a haploidentical alloSCT. About half, or 52%, of the patients developed adverse effects with posaconazole or voriconazole and were switched to isavuconazole; of these patients, 61.5% had LFT elevation with half of those having a diagnosis of GVHD of the gastrointestinal tract, half having QTc prolongation, and 1 of the participants experiencing hallucinations with voriconazole.

Of note, LFTs remained elevated in 62.5% of 8 patients despite switching over to isavuconazole. Two of the big reasons for selecting isavuconazole were secondary prophylaxis (32%) and cost issues (16%).

Compared with the historical cohort, a significant difference in cumulative incidence of a breakthrough of invasive fungal infections was not noted, with an odds ratio of 1.5.

Therefore, according to the study authors, isavuconazole could be a potential option for prophylaxis, although “larger studies are needed to establish its efficacy and discern whether therapeutic drug monitoring is warranted to optimize response,” the authors conclude.