Preliminary experience of tigecycline treatment for infection in children with hematologic malignancies

Tigecycline-Induced Tooth Discoloration in Children Younger than Eight Years

Tetracycline may cause tooth discoloration when used in young children during tooth development. Whether tigecycline, a tetracycline derivative, has either a similar adverse event or not remains unclear. We assessed the discoloration of the permanent teeth of patients <8 years old after tigecycline exposure. These patients were identified through a retrospective chart review in a Chinese children's hospital. Those who had at least one erupted permanent tooth after tigecycline exposure were interviewed, examined, and photographed by an experienced pediatric dentist and independently assessed by another senior dentist to detect tetracycline-like tooth discoloration. We identified 101 patients who were exposed to tigecycline, 12 of whom were included. The mean daily dose of tigecycline was 2.3 mg/kg of body weight (standard deviation, 0.6), and the median duration was 12.5 days (interquartile range [IQR], 8.0 to 19.3). The median age of exposure was 5.2 years (IQR, 4.5 to 7.4), and the median age of dental examination was 9.1 years (IQR, 9.0 to 10.3). Two patients (16.7%) developed yellow discoloration: a girl having yellow discoloration with white-to-yellow opacities in the upper lateral incisors and lower incisors and a boy with a suspicious buccal yellow discoloration and enamel dysplasia in the second molars. The incidence and extent of tigecycline-associated dental adverse events remain unclear due to the small sample size and inadequate follow-up period.

Dose optimisation based on pharmacokinetic/pharmacodynamic target of tigecycline

Tigecycline, a new first-in-class glycylcycline antibiotic, has shown promising efficacy against a broad range of micro-organisms. It is widely prescribed for various infections, with most prescriptions being considered for off-label use. However, only a few years after its approval by the US Food and Drug Administration (FDA), tigecycline is suspected of increasing all-cause mortality. Some clinicians have suggested such unfavourable outcomes correlate with inadequate drug exposure at the infection site. The pharmacokinetic/pharmacodynamic (PK/PD) profile of a drug plays an important role in predicting its antibiotic effect, which for tigecycline is determined as the ratio of area under the concentration-time curve (AUC) to minimum inhibitory concentration (MIC). In this study, PK/PD targets based on infection sites, bacterial isolates and patient populations are discussed. Generally, a higher dosage of tigecycline for the treatment of serious infections has been recommended in previous reports. However, the latest finding of tigecycline's atypical protein binding property requires consideration when recommending further use. In addition, combination therapy with other antibiotics provides another option by potentially lowering the MICs of multidrug-resistant bacteria.

Overcoming Glucocorticoid Resistance in Acute Lymphoblastic Leukemia: Repurposed Drugs Can Improve the Protocol

Glucocorticoids (GCs) are a central component of multi-drug treatment protocols against T and B acute lymphoblastic leukemia (ALL), which are used intensively during the remission induction to rapidly eliminate the leukemic blasts. The primary response to GCs predicts the overall response to treatment and clinical outcome. In this review, we have critically analyzed the available data on the effects of GCs on sensitive and resistant leukemic cells, in order to reveal the mechanisms of GC resistance and how these mechanisms may determine a poor outcome in ALL. Apart of the GC resistance, associated with a decreased expression of receptors to GCs, there are several additional mechanisms, triggered by alterations of different signaling pathways, which cause the metabolic reprogramming, with an enhanced level of glycolysis and oxidative phosphorylation, apoptosis resistance, and multidrug resistance. Due to all this, the GC-resistant ALL show a poor sensitivity to conventional chemotherapeutic protocols. We propose pharmacological strategies that can trigger alternative intracellular pathways to revert or overcome GC resistance. Specifically, we focused our search on drugs, which are already approved for treatment of other diseases and demonstrated anti-ALL effects in experimental pre-clinical models. Among them are some “truly” re-purposed drugs, which have different targets in ALL as compared to other diseases: cannabidiol, which targets mitochondria and causes the mitochondrial permeability transition-driven necrosis, tamoxifen, which induces autophagy and cell death, and reverts GC resistance through the mechanisms independent of nuclear estrogen receptors (“off-target effects”), antibiotic tigecycline, which inhibits mitochondrial respiration, causing energy crisis and cell death, and some anthelmintic drugs. Additionally, we have listed compounds that show a classical mechanism of action in ALL but are not used still in treatment protocols: the BH3 mimetic venetoclax, which inhibits the anti-apoptotic protein Bcl-2, the hypomethylating agent 5-azacytidine, which restores the expression of the pro-apoptotic BIM, and compounds targeting the PI3K-Akt-mTOR axis. Accordingly, these drugs may be considered for the inclusion into chemotherapeutic protocols for GC-resistant ALL treatments.

Tigecycline therapy in pediatric patients with multidrug resistant bacteremia

INTRODUCTION

Multidrug resistance among bacteria increases the need for new therapeutic options. Tigecycline is one candidate drug, due to property of a wider anti-bacterial spectrum to multi-drug resistant (MDR) pathogens. However, it has still not been approved for use in pediatric patients.

METHODS

In this study the effectiveness and safety of tigecycline in children was assessed retrospectively.

RESULTS

A total of 36 pediatric patients, received tigecycline therapy with a median of 13 days (2-32 days). Tigecycline was used as a combination therapy in all cases. Microbiological eradication was achieved in 27 patients (75%) and clinical response was observed in 30 patients (83%). There were six cases (17%) of relapse.

CONCLUSION

Our findings suggest that tigecycline may be an option for children with severe infections due to multidrug resistant bacteria.