Pharmacokinetic Simulation Analysis of Less Frequent Nivolumab and Pembrolizumab Dosing: Pharmacoeconomic Rationale for Dose Deescalation

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.

Phase 1 first-in-human dose-escalation study of ANV419 in patients with relapsed/refractory advanced solid tumors

Patients with advanced cancer, previously treated with immune checkpoint blockade therapy, may retain residual treatment when undergoing the initial infusion of experimental monotherapy in phase 1 clinical trials. ANV419, an antibody-cytokine fusion protein, combines interleukin-2 (IL-2) with an anti-IL-2 monoclonal antibody, aiming to stimulate the expansion of CD8 T and natural killer lymphocytes while restricting regulatory T lymphocytes. In the recent publication of the phase 1 dose escalation study of ANV419, a notable gap exists in detailed information regarding patients' prior antitumoral treatments, specifically programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) targeted monoclonal antibodies. Some patients likely retained residual anti-PD-1/PD-L1 monoclonal antibodies, potentially influencing the outcomes of ANV419. In a separate clinical cohort, we retrospectively measured the residual concentration of nivolumab and pembrolizumab, revealing persistent serum concentrations of anti-PD-1/PD-L1 antibodies even months after treatment cessation. This underscores the importance of comprehensively documenting prior immunotherapy details in clinical trials. Such information is crucial for understanding potential interactions that may impact both immunological and clinical effects.

Extending the dosing intervals of nivolumab: model-based simulations in unselected cancer patients

BACKGROUND

Reducing nivolumab dose intensity could increase patients' life quality and decrease the financial burden while maintaining efficacy. The aims of this study were to develop a population PK model of nivolumab based on data from unselected metastatic cancer patients and to simulate extended-interval regimens allowing to maintain minimal effective plasma concentrations (MEPC).

METHODS

Concentration-time data (992 plasma nivolumab concentrations, 364 patients) were modeled using a two-compartment model with linear elimination clearance in Monolix software. Extended-interval regimens allowing to maintain steady-state trough concentrations (Cmin,ss) above the MEPC of 2.5 mg/L or 1.5 mg/L in >90% of patients were simulated.

RESULTS

Increasing 3-times the dosing interval from 240 mg every two weeks (Q2W) to Q6W and 2-times from 480 mg Q4W to Q8W resulted in Cmin,ss above 2.5 mg/L in 95.8% and 95.4% of patients, respectively. 240 mg Q8W and 480 mg Q10W resulted in Cmin,ss above 1.5 mg/L in 91.0% and 91.8% of patients, respectively. Selection of a 240 mg Q6W regimen would decrease by 3-fold the annual treatment costs compared to standard regimen of 240 mg Q2W (from 78,744€ to 26,248€ in France).

CONCLUSIONS

Clinical trials are warranted to confirm the non-inferiority of extended-interval compared to standard regimen.

Cost-utility analysis of Pembrolizumab compared to other alternative immunotherapy and chemotherapy treatments for patients with advanced melanoma in Iran

OBJECTIVES

Immunotherapy drugs like Pembrolizumab have shown significant improvements in treatment outcomes of advanced melanoma. This study aimed to evaluate the cost-utility of Pembrolizumab compared to other immunotherapy and chemotherapy drugs in the first-line treatment of advanced melanoma in Iran.

METHODS

A partitioned-survival model, based on data from a recent randomized phase 3 study (KEYNOTE-006) and recent meta-analysis, was used to divide Overall survival (OS) time into Progression-free survival (PFS) and post-progression survival for Pembrolizumab, Nivolumab, Ipilimumab, Dacarbazine, Temozolomide, Carboplatin, and Paclitaxel combination. Quality Life Years (QALY) and Incremental Cost-Effectiveness Ratio (ICER) were considered as the final outcome.

RESULTS

The ICER of Ipilimumab, Nivolumab, Nivolumab & Ipilimumab, and Pembrolizumab compared to Temozolomide was calculated as $40,365.53, $19,591.13, $24,578, and $47,324.2 per QALY, respectively. Scenario analysis demonstrated if the price of one vial of Nivolumab 100 is $90.51, each vial of Pembrolizumab is $119.20, and each vial of Ipilimumab is $101.54, they will be cost-effective in Iran.

CONCLUSION

None of the immunotherapy drugs studied were found to be cost-effective when considering the cost-effectiveness threshold of $3,532. Therefore, a cost reduction of more than 90% in the prices of immunotherapy drugs would be necessary for them to be considered cost-effective in Iran.

Interventional pharmacoeconomics for immune checkpoint inhibitors through alternative dosing strategies

Immune checkpoint inhibitors (ICIs) are approved for the treatment of a variety of cancer types. The doses of these drugs, though approved by the Food and Drug Administration (FDA), have never been optimised, likely leading to significantly higher doses than required for optimal efficacy. Dose optimisation would hypothetically decrease the risk, severity, and duration of immune-related adverse events, as well as provide an opportunity to reduce costs through interventional pharmacoeconomic strategies such as off-label dose reductions or less frequent dosing. We summarise existing evidence for ICI dose optimisation to advocate for the role of interventional pharmacoeconomics.

Therapeutic drug monitoring of immune checkpoint inhibitors: based on their pharmacokinetic properties and biomarkers

As a new means of oncology treatment, immune checkpoint inhibitors (ICIs) can improve survival rates in patients with resistant or refractory tumors. However, there are obvious inter-individual differences in the unsatisfactory response rate, drug resistance rate and the occurrence of immune-related adverse events (irAE). These questions have sparked interest in researchers looking for a way to screen sensitive populations and predict efficacy and safety. Therapeutic drug monitoring (TDM) is a way to ensure the safety and effectiveness of medication by measuring the concentration of drugs in body fluids and adjusting the medication regimen. It has the potential to be an adjunctive means of predicting the safety and efficacy of ICIs treatment. In this review, the author outlined the pharmacokinetic (PK) characteristics of ICIs in patients. The feasibility and limitations of TDM of ICIs were discussed by summarizing the relationships between the pharmacokinetic parameters and the efficacy, toxicity and biomarkers.

Pembrolizumab for the adjuvant treatment of IIB or IIC melanoma

INTRODUCTION

Up to 30% of patients with stage IIB and 50% of stage IIC melanoma experience recurrence within 5 years after radical surgery. Adjuvant treatment is expected to improve this prognosis.

AREAS COVERED

Pembrolizumab (MK-3475) is a humanized monoclonal antibody that acts against the programmed cell death 1 (PD-1) receptor. Pembrolizumab was first approved in monotherapy for the treatment of unresectable/metastatic melanoma based on the results of the prospective KEYNOTE-001, KEYNOTE-002, and KEYNOTE-006 trials. KEYNOTE-716 is the randomized phase III trial of pembrolizumab treatment in resected stage II melanoma. Treatment with pembrolizumab is statistically significant, reducing the risk of recurrence as well as distant metastases risk after primary tumor resection. Pembrolizumab treatment has a 24-month RFS rate of 81.2% (HR 0.64 vs placebo) and a DMFS rate of 88.1%.

EXPERT OPINION

1-year adjuvant pembrolizumab treatment of stage IIB/C melanoma patients significantly reduces recurrence or death risk. The safety profile of adjuvant treatment is not different from previously reported and is manageable. Longer follow-up is required to fully understand the efficacy and safety of adjuvant therapy for stage II melanoma, as the number of patients needed to treat is twice as high as for stage III patients.

In Silico Re-Optimization of Atezolizumab Dosing Using Population Pharmacokinetic Simulation and Exposure-Response Simulation

Atezolizumab, a humanized monoclonal antibody against programmed cell death ligand 1 (PD-L1), was initially approved in 2016, around the same time that the sponsor published the minimum serum concentration to maintain the saturation of receptor occupancy (6 μg/mL). The initially approved dose regimen of 1200 mg every 3 weeks (q3w) was subsequently modified to 840 mg q2w or 1680 mg q4w through pharmacokinetic simulations. Yet, each standard regimen yields steady-state trough concentrations (CMIN,SS ) far exceeding (≈ 40-fold) the stated target concentration. Additionally, the steady-state area under the plasma drug concentration-time curve (AUCSS ) at 1200 mg q3w was significantly (P = .027) correlated with the probability of adverse events of special interest (AESIs) in patients with non-small cell lung cancer (NSCLC) and, coupled with excess exposure, this provides incentive to explore alternative dose regimens to lower the exposure burden while maintaining an effective CMIN,SS . In this study, we first identified 840 mg q6w as an extended-interval regimen that could robustly maintain a serum concentration of 6 μg/mL (≥99% of virtual patients simulated, n = 1000), then applied this regimen to an approach that administers 2 "loading doses" of standard-interval regimens for a future clinical trial aiming to personalize dose regimens. Each standard dose was simulated for 2 loading doses, then 840 mg q6w thereafter; all yielded cycle-7 CMIN,SS values of >6 μg/mL in >99% of virtual patients. Further, the AUCSS from 840 mg q6w resulted in a flattening (P = .63) of the exposure-response relationship with adverse events of special interest (AESIs). We next aim to verify this in a clinical trial seeking to validate extended-interval dosing in a personalized approach using therapeutic drug monitoring.

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

Background

Pembrolizumab is a well-tolerated biologic agent with a potentially stable and durable anti-tumor response. Unfortunately, discontinuation of therapy can occur as a consequence of immune-related adverse effects (irAEs). These irAEs appear independent of dose and exposure. However, such irAEs might also result from pembrolizumab's highly specific mechanism of action and current dosing regimens. However, the currently available pharmacokinetic (PK) and pharmacodynamic (PD) data to reassess dosing strategies are insufficient.To highlight the importance of additional PK/PD studies, we present a case describing the complexity of pembrolizumab's PK/PD after a single 200 mg pembrolizumab dose in a treatment-naive patient with non-small cell lung cancer (NSCLC).

Case description

A 72-year-old man with stage IV NSCLC presented hepatotoxic symptoms 19 days after receiving the first 200 mg pembrolizumab dose. Hence, pembrolizumab therapy was paused, and prednisolone therapy was initiated, which successfully inhibited the toxic effect of pembrolizumab. However, repeated flare-ups due to prednisolone tapering suggest that the toxic effect of pembrolizumab outlasts the presence of pembrolizumab in the bloodstream. This further suggests that the T-cell-mediated immune response outlasts the programmed cell death protein 1 (PD-1) receptor occupancy by pembrolizumab, which challenges the need for the current fixed-interval strategies and their stop criteria.Furthermore, a validated ELISA quantified pembrolizumab levels in 15 samples within 123 days after administration. A shift in the pembrolizumab clearance rate was evident ensuing day 77 (0.6 µg/mL) after administration. Pembrolizumab levels up to day 77 (9.1-0.6 µg/mL) strongly exhibited a linear, first-order clearance (R² = 0.991), whereas after day 77, an accelerated non-linear clearance was observed. This transition from a linear to non-linear clearance was most likely a result of full target receptor saturation to non-full target receptor saturation, in which the added effect of target-mediated drug disposition occurs. This suggests that pembrolizumab's targets were fully saturated at levels above 0.6 µg/mL, which is 43 to 61 times lower than the steady-state trough levels (C_trough,ss) of the currently registered fixed-dosing regimens (3-5).

REFINE (REduced Frequency ImmuNE checkpoint inhibition in cancers): A multi-arm phase II basket trial testing reduced intensity immunotherapy across different cancers

BACKGROUND

Immune checkpoint inhibitors (ICI) have revolutionised treating advanced cancers. ICI are administered intravenously every 2-6 weeks for up to 2 years, until cancer progression/unacceptable toxicity. Physiological efficacy is observed at lower doses than those used as standard of care (SOC). Pharmacodynamic studies indicate sustained target occupancy, despite a pharmacological half-life of 2-3 weeks. Reducing frequency of administration may be possible without compromising outcomes. The REFINE trial aims to limit individual patient exposure to ICI whilst maintaining efficacy, with potential benefits in quality of life and reduced drug treatment/attendance costs.

METHODS/DESIGN

REFINE is a randomised phase II, multi-arm, multi-stage (MAMS) adaptive basket trial investigating extended interval administration of ICIs. Eligible patients are those responding to conventionally dosed ICI at 12 weeks. In stage I, patients (n = 160 per tumour-specific cohort) will be randomly allocated (1:1) to receive maintenance ICI at SOC vs extended dose interval. REFINE is currently recruiting UK patients with locally advanced or metastatic renal cell carcinoma (RCC) who have tolerated and responded to initial nivolumab/ipilimumab, randomised to receive maintenance nivolumab SOC (480 mg 4 weekly) vs extended interval (480 mg 8 weekly). Additional tumour cohorts are planned. Subject to satisfactory outcomes (progression-free survival) stage II will investigate up to 5 different treatment intervals. Secondary outcome measures include overall survival, quality-of-life, treatment-related toxicity, mean incremental pathway costs and quality-adjusted life-years per patient. REFINE is funded by the Jon Moulton Charity Trust and Medical Research Council, sponsored by University College London (UCL), and coordinated by the MRC CTU at UCL. Trial Registration ISRCTN79455488. NCT04913025 EUDRACT #: 2021-002060-47. CTA 31330/0008/001-0001; MREC approval: 21/LO/0593. REFINE Protocol version 4.0.

Dosing Regimens of Immune Checkpoint Inhibitors: Attempts at Lower Dose, Less Frequency, Shorter Course

Immune checkpoint inhibitors (ICIs) are a revolutionary breakthrough in the field of cancer by modulating patient's own immune system to exert anti-tumor effects. The clinical application of ICIs is still in its infancy, and their dosing regimens need to be continuously adjusted. Pharmacokinetic/pharmacodynamic studies showed a significant plateau in the exposure-response curve, with high receptor occupancy and plasma concentrations achieved at low dose levels. Coupled with concerns about drug toxicity and heavy economic costs, there has been an ongoing quest to reevaluate the current ICI dosing regimens while preserving maximum clinical efficacy. Many clinical data showed remarkable anticancer effects with ICIs at the doses far below the approved regimens, indicating the possibility of dose reduction. Our review attempts to summarize the clinical evidence for ICIs regimens with lower-dose, less-frequency, shorter-course, and provide clues for further ICIs regimen optimization.