Case report: Pharmacokinetics of pembrolizumab in a patient with stage IV non-small cell lung cancer after a single 200 mg administration

Polymyalgia Rheumatica (PMR) and Polymyalgia Rheumatica-like (PMR-like) Manifestations in Cancer Patients Following Treatment with Nivolumab and Pembrolizumab: Methodological Blurred Points Identified Through a Systematic Review of Published Case Reports

Background: Among rheumatologic diseases following therapy with immune checkpoint inhibitors (ICIs), the cases of cancer patients diagnosed as having polymyalgia rheumatica (PMR), particularly with nivolumab and pembrolizumab, has been steadily rising in published reports. Objectives: We performed a systematic review of published case reports with the aim of answering these questions: (1) Is PMR following therapy with nivolumab and pembrolizumab an adverse drug reaction (ADR)? (2) Is there a difference between cases of PMR following therapy with nivolumab and those following therapy with pembrolizumab? Methods: Based on Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines, a comprehensive literature search in three main bibliographic databases: MEDLINE (Ovid interface), EMBASE, and COCHRANE Library was carried out on 27 December 2024. This systematic review has no registration number. Results: Data were extracted from 12 patients. Namely, 5 cases followed treatment with nivolumab and 7 with pembrolizumab. Validated scales for ADR assessment-such as Naranjo's scale-were not used in 10 out of the 12 patients. Additionally, validated diagnostic or classification criteria for PMR were used in the majority of case reports related to nivolumab. On the contrary, clinical judgment alone was the rule in almost all case reports on pembrolizumab. Finally, the time interval between PMR manifestations and nivolumab/pembrolizumab therapy ranged from one to 14 cycles (fully compatible with pharmacokinetics). Conclusions: Our literature review highlighted significant methodological blurred lines in the categorization of PMR following therapy with nivolumab or pembrolizumab.

Evaluation and validation of a clinical decision support system for dose optimisation in hospitalized patients with (morbid) obesity - a retrospective, observational study

BACKGROUND

Obesity changes a patient's pharmacokinetics and pharmacotherapeutic advices should be personalized to ensure proper treatment. Currently, implementations of advices regarding the obese population are lacking and weight and body mass index (BMI) are rarely monitored. The Maasstad Hospital built a clinical decision support system (CDSS) for pharmacists, based on current Dutch guidelines, to supply therapeutic advices for (morbidly) obese patients based on patient characteristics. In this study we evaluated whether patients receiving inadequate pharmacotherapy are indeed identified via this CDSS and to which extent irrelevant alerts are generated. Moreover, it is investigated to which extent pharmacists carry on the generated advices and to which extent physicians act upon these.

METHODS

The research concerned a retrospective observational study performed at the Maasstad Hospital in Rotterdam, the Netherlands between January 2021 and august 2021. The drugs included were dalteparin, apixaban, dabigatran, edoxaban, rivaroxaban, vancomycin and ciprofloxacin. Dispensing data, patient characteristics and CDSS processing were collected. Dispensing data was included when the patient's weight or BMI could potentially lead to dose adjustments via the CDSS. The CDSS was evaluated for sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV). Additionally, excess alerts, defined as irrelevant alerts on the moment of assessment, of the CDSS and adherence to the CDSS were investigated.

RESULTS

1218 alerts over 3735 drug dispenses were generated. 568 alerts (46.6%) resulted in a pharmacotherapeutic advice by the pharmacist to the physician. In most cases, the sensitivity, specificity, PPV and NPV were 100.0% with varying 95% CIs. For some drugs technical adjustments were needed, including the initially incorrect BMI setting of vancomycin within the CDSS, resulting in a high excess alerts of 56.9%. Dabigatran had a NPV of 22.2% 95% CI [6.3-54.7] and a sensitivity of 56.3% 95% CI [33.2-76.9]. Overall excess alerts varied from 22.2% to 56.9%. Depending on the drug, the advices resulted in 6.9-100.0% real pharmacotherapy adjustments in practise.

CONCLUSION

The (morbid) obesity CDSS functions as expected and identifies the (morbidly) obese patients with inadequate pharmacotherapy. The adherence of physicians and the follow-up in practise varies widely and requires further investigation.

TRIAL REGISTRATION

Non-WMO research W21.218.

Life-threatening toxicities upon Pembrolizumab intake: could pharmacokinetics be the bad guy?

PURPOSE

We report the case of an adult patient diagnosed with Hodgkin's lymphoma who was scheduled for Pembrolizumab after failure of standard therapy. After three well-tolerated courses of Pembrolizumab, a PET scan showed a favorable outcome and a fourth course of Pembrolizumab was started. Unexpectedly, extremely severe toxicities (i.e., autoimmune peripheral hypothyroidism, rhabdomyolysis and severe acute renal failure) occurred after this last course, requiring transfer to the intensive care unit.

METHODS

Therapeutic drug monitoring was performed to measure residual Pembrolizumab levels at intervals from the last dose (i.e., 120 and then 170 days), as well as pharmacogenetics investigations on the FCγR gene.

RESULTS

Pembrolizumab plasma concentrations that were still pharmacologically active months after the last administration, suggesting impaired elimination of Pembrolizumab in this patient. Further pharmacokinetic modeling based on the population approach showed that both half-life (47.8 days) and clearance (0.12 L/day) values were significantly different from the standard values usually reported in patients. Further in silico simulations showed that pharmacologically active concentrations of Pembrolizumab were maintained for up to 136 days after the last dose. The search for possible polymorphisms affecting the genes coding for FCγR (i.e., rs1801274 on FCGR2A and rs396991 on FCGR3A gene) was negative. Further TDM showed that Pembrolizumab could be detected up to 263 days after the last administration.

CONCLUSION

This case report suggests that persistent overexposure in plasma could lead to life-threatening toxicities with Pembrolizumab.

Mitigating non-genetic resistance to checkpoint inhibition based on multiple states of immune exhaustion

Despite the revolutionary impact of immune checkpoint inhibition on cancer therapy, the lack of response in a subset of patients, as well as the emergence of resistance, remain significant challenges. Here we explore the theoretical consequences of the existence of multiple states of immune cell exhaustion on response to checkpoint inhibition therapy. In particular, we consider the emerging understanding that T cells can exist in various states: fully functioning cytotoxic cells, reversibly exhausted cells with minimal cytotoxicity, and terminally exhausted cells. We hypothesize that inflammation augmented by drug activity triggers transitions between these phenotypes, which can lead to non-genetic resistance to checkpoint inhibitors. We introduce a conceptual mathematical model, coupled with a standard 2-compartment pharmacometric (PK) model, that incorporates these mechanisms. Simulations of the model reveal that, within this framework, the emergence of resistance to checkpoint inhibitors can be mitigated through altering the dose and the frequency of administration. Our analysis also reveals that standard PK metrics do not correlate with treatment outcome. However, we do find that levels of inflammation that we assume trigger the transition from the reversibly to terminally exhausted states play a critical role in therapeutic outcome. A simulation of a population that has different values of this transition threshold reveals that while the standard high-dose, low-frequency dosing strategy can be an effective therapeutic design for some, it is likely to fail a significant fraction of the population. Conversely, a metronomic-like strategy that distributes a fixed amount of drug over many doses given close together is predicted to be effective across the entire simulated population, even at a relatively low cumulative drug dose. We also demonstrate that these predictions hold if the transitions between different states of immune cell exhaustion are triggered by prolonged antigen exposure, an alternative mechanism that has been implicated in this process. Our theoretical analyses demonstrate the potential of mitigating resistance to checkpoint inhibitors via dose modulation.

Low-Dose Immunotherapy: Is It Just an Illusion?

The development and use of immunotherapy in the last decade have led to a drastic improvement in results in the onco-haematological field. This has implied, on the one hand, the need for clinicians to manage a new type of adverse event and, on the other hand, a significant increase in costs. However, emerging scientific evidence suggests that, as with other drugs in the recent past, the registry dosage can be drastically reduced for immunotherapies without penalizing their effectiveness. This would also lead to an important reduction in costs, expanding the audience of cancer patients who could access immunotherapy-based treatments. In this “Commentary”, we analyze the available evidence of pharmacokinetics and pharmacodynamics and the most recent literature in favor of low-dose immunotherapy.