Factors influencing delayed clearance of high dose methotrexate (HDMTX) in pediatric, adolescent, and young adult oncology patients

Purpose

To identify modifiable risk factors associated with prolonged clearance of methotrexate in pediatric, adolescent, and young adult (AYA) oncology patients receiving high dose methotrexate (HDMTX).

Design/Method

A single institution, retrospective chart review of patients receiving HDMTX between 2010-2017. Patients had a diagnosis of either leukemia or osteosarcoma. Data included demographics, concurrent intravenous (IV) medications, IV fluids (IVF) administered, urine output (UO), and rises in serum creatinine (RSC) reflective of renal toxicity (RT). Outcome measures included 1) delayed targeted MTX clearance (DC), 2) actual time to clearance (TTC) and 3) length of stay (LOS).

Results

Data from 447 HDMTX administrations were analyzed. The sample consisted of 241 (54%) osteosarcoma encounters, and 206 (46%) leukemia encounters, with an average patient age of 12.7 years. Multivariate analysis showed that DC was associated with the diagnosis of leukemia (OR 7.64, p <.0001), and less UO on day 1 (OR 0.76, p=0.005). Increased TTC was associated with increasing age (RR 1.02, p<0.0001), higher 24-hour MTX levels (RR 1.001, p=0.012) and 48-hour MTX levels (RR 1.02, p<0.0001), RT (RR 1.004, p<0.0001), use of IV lorazepam (RR 1.08, p=0.001) and IV metoclopramide (RR 1.08, p<0.001) both on day 3. Like TTC, LOS was affected by MTX levels at 24 (RR 1.001, p=0.025) and 48 hours (RR 1.03, p<0.0001), RT (RR 1.006, p<0.0001), total IV medications on day 3 (RR 1.042, p<0.0001), and the use of leucovorin on day 2 (RR 0.93, p=0.002).

Conclusion

Multiple modifiable risk factors were identified which can be leveraged to improve HDMTX clearance. Subsequent efforts will assess whether acting on such risk factors can improve MTX clearance and shorten LOS.

The clinical and immunological characteristics of COVID-19 patients with delayed SARS-CoV-2 virus clearance

BACKGROUND

The outbreak of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed a great threat to human health. Some severe COVID-19 patients still carried detectable levels of SARS-CoV-2 even after prolonged intensive care unit treatment. However, the immunological features of these COVID-19 patients with delayed virus clearance (CDVC) are still unclear.

METHODS

We retrospectively reviewed the clinical and immunological data of 13 CDVC cases, who were admitted into one hospital in Wuhan from February to April 2020. These data were also compared to those of perished (n = 9) and recovered (n = 52) cases. The expression of the exhaustion marker PD-1 on circulating T cells of these patients was measured by flow cytometry.

RESULTS

High levels of serum interleukin-6 (IL-6), IL-1β, IL-8, as well as other inflammatory mediators, were seen in CDVC cases. Severe lymphopenia was observed in CDVC patients with the counts of total lymphocytes (0.9 × 109 /L), CD4+ T cells (0.35 × 109 /L), and CD8+ T cells (0.28 × 109 /L) below their corresponding lower limits of normal range. Similar to the perished group, CDVC cases have higher percentages of CD25+ Foxp3+ regulatory T cells (Treg) in circulation. Moreover, enhanced expression of the exhaustion marker PD-1 on CCR7- CD45RA+ effector, CCR7+ CD45RA- central memory, and CCR7- CD45RA- effector memory CD4+ and CD8+ T cells were also observed in CDVC cases.

CONCLUSION

CDVC patients still have SARS-CoV-2 and these cases manifest with severe clinical symptoms due to persistent inflammation. Augmentation of the frequency of circulating Treg, severe lymphopenia, and functional exhaustion of T cells might lead to inefficient clearance of SARS-CoV-2. Therefore, enhancing lymphocyte counts and reversing T-cell exhaustion might be key methods to boost immune responses and eliminate SARS-CoV-2 in CDVC patients.

Unusual blood smear with multiple stages of plasmodium falciparum infection and intraleukocytic malaria pigments in an expatriate with severe malaria and delayed clearance of parasites

A French expatriate in Ethiopia presented with severe Plasmodium falciparum infection. The blood smear was remarkable associating multiple stages of parasites including circulating schizonts with a high rate of intraleukocytic malaria pigments. Under artesunate treatment, without polymorphism in PfK13 gene, delayed clearance of parasites occurred, probably following the massive merogony.

Detection of Respiratory Syncytial Virus or Rhinovirus Weeks After Hospitalization for Bronchiolitis and the Risk of Recurrent Wheezing

BACKGROUND

In severe bronchiolitis, it is unclear if delayed clearance or sequential infection of respiratory syncytial virus (RSV) or rhinovirus (RV) is associated with recurrent wheezing.

METHODS

In a 17-center severe bronchiolitis cohort, we tested nasopharyngeal aspirates (NPA) upon hospitalization and 3 weeks later (clearance swab) for respiratory viruses using PCR. The same RSV subtype or RV genotype in NPA and clearance swab defined delayed clearance (DC); a new RSV subtype or RV genotype at clearance defined sequential infection (SI). Recurrent wheezing by age 3 years was defined per national asthma guidelines.

RESULTS

Among 673 infants, RSV DC and RV DC were not associated with recurrent wheezing, and RSV SI was rare. The 128 infants with RV SI (19%) had nonsignificantly higher risk of recurrent wheezing (hazard ratio [HR], 1.31; 95% confidence interval [CI], .95-1.80; P = .10) versus infants without RV SI. Among infants with RV at hospitalization, those with RV SI had a higher risk of recurrent wheezing compared to children without RV SI (HR, 2.49; 95% CI, 1.22-5.06; P = .01).

CONCLUSIONS

Among infants with severe bronchiolitis, those with RV at hospitalization followed by a new RV infection had the highest risk of recurrent wheezing.

Pharmacokinetic Model of the Transport of Fast-Acting Insulin From the Subcutaneous and Intradermal Spaces to Blood

Pharmacokinetic (PK) models describing the transport of insulin from the injection site to blood assist clinical decision making and are part of in silico platforms for developing and testing of insulin delivery strategies for treatment of patients with diabetes. The ability of these models to accurately describe all facets of the in vivo insulin transport is therefore critical for their application. Here, we propose a new model of fast-acting insulin analogs transport from the subcutaneous and intradermal spaces to blood that can accommodate clinically observed biphasic appearance and delayed clearance of injected insulin, 2 phenomena that are not captured by existing PK models. To develop the model we compare 9 insulin transport PK models which describe hypothetical insulin delivery pathways potentially capable of approximating biphasic appearance of exogenous insulin. The models are tested with respect to their ability to describe clinical data from 10 healthy volunteers which received 1 subcutaneous and 2 intradermal insulin injections on 3 different occasions. The optimal model, selected based on information and posterior identifiability criteria, assumes that insulin is delivered at the administrative site and is then transported to the bloodstream via 2 independent routes (1) diffusion-like process to the blood and (2) combination of diffusion-like processes followed by an additional compartment before entering the blood. This optimal model accounts for biphasic appearance and delayed clearance of exogenous insulin. It agrees better with the clinical data as compared to commonly used models and is expected to improve the in silico development and testing of insulin treatment strategies, including artificial pancreas systems.