Towards Rational Cancer Therapeutics: Optimizing Dosing, Delivery, Scheduling, and Combinations

Association of ADME gene polymorphisms on toxicity to CDK4/6 inhibitors in patients with HR+ HER2- metastatic breast cancer

A wide interindividual variability in therapeutic response to cyclin-dependent kinases 4 and 6 inhibitors (CDKis) palbociclib, ribociclib and abemaciclib, among patients with HR+/HER2- metastatic breast cancer has been reported. This study explored the impact of genetic polymorphisms in ADME genes (responsible for drug absorption, distribution, metabolism, and elimination) on CDKis safety profiles in 230 patients. Selected endpoints include grade 3/4 neutropenia at day 14 of the first treatment cycle, early dose-limiting toxicities (DLTs), and dose reductions within the initial three cycles. Our analysis revealed associations between these endpoints and polymorphisms in CYP3A4, CYP3A5, ABCB1, and ABCG2 genes. Their impact on CDKis plasma concentrations (Ctrough) was also examined. Specifically, ABCB1 c.1236C>T and c.2677C>T polymorphisms correlated significantly with grade 3/4 neutropenia at day 14 (OR 3.94, 95% CI 1.32-11.75; p = 0.014 and OR 3.32, 95% CI 1.12-9.85; p = 0.030). Additionally, ABCB1 c.3435C>T was associated with an elevated risk of early DLTs and dose reductions (OR 3.28, 95% CI 1.22-8.84, p = 0.019; OR 2.60, 95% CI 1.20-5.60, p = 0.015). Carriers of the CYP3A4*22 allele also demonstrated in univariate a higher risk of early DLTs (OR 3.10, 95% CI 1.01-9.56, p = 0.049). Furthermore, individuals with the ABCB1 1236T-3435T-2677T(A) variant haplotype exhibited significant associations with grade 3/4 neutropenia at day 14 (OR 3.36, 95% CI 1.20-9.41; p = 0.021) and early DLTs in univariate (OR 3.08, 95% CI 1.19-7.95; p = 0.020). Homozygous carriers of the ABCB1 T-T-T(A) haplotype tended to have a higher mean ribociclib Ctrough (934.0 ng/mL vs. 752.0 ng/mL and 668.0 ng/mL). Regardless preliminary, these findings offer promising insights into the role of pharmacogenetic markers in CDKis safety profiles, potentially contributing to address the interindividual variability in CDKis responses.

Treatment of evolving cancers will require dynamic decision support

Cancer research has traditionally focused on developing new agents, but an underexplored question is that of the dose and frequency of existing drugs. Based on the modus operandi established in the early days of chemotherapies, most drugs are administered according to predetermined schedules that seek to deliver the maximum tolerated dose and are only adjusted for toxicity. However, we believe that the complex, evolving nature of cancer requires a more dynamic and personalized approach. Chronicling the milestones of the field, we show that the impact of schedule choice crucially depends on processes driving treatment response and failure. As such, cancer heterogeneity and evolution dictate that a one-size-fits-all solution is unlikely-instead, each patient should be mapped to the strategy that best matches their current disease characteristics and treatment objectives (i.e. their 'tumorscape'). To achieve this level of personalization, we need mathematical modeling. In this perspective, we propose a five-step 'Adaptive Dosing Adjusted for Personalized Tumorscapes (ADAPT)' paradigm to integrate data and understanding across scales and derive dynamic and personalized schedules. We conclude with promising examples of model-guided schedule personalization and a call to action to address key outstanding challenges surrounding data collection, model development, and integration.

Copper(ii) and silver(i) complexes with dimethyl 6-(pyrazine-2-yl)pyridine-3,4-dicarboxylate (py-2pz): the influence of the metal ion on the antimicrobial potential of the complex

Dimethyl 6-(pyrazine-2-yl)pyridine-3,4-dicarboxylate (py-2pz) was used as a ligand for the synthesis of new copper(ii) and silver(i) complexes, [CuCl2(py-2pz)]2 (1), [Cu(CF3SO3)(H2O)(py-2pz)2]CF3SO3·2H2O (2), [Ag(py-2pz)2]PF6 (3) and {[Ag(NO3)(py-2pz)]·0.5H2O} n (4). The complexes were characterized by spectroscopic and electrochemical methods, while their structures were determined by single crystal X-ray diffraction analysis. The X-ray analysis revealed the bidentate coordination mode of py-2pz to the corresponding metal ion via its pyridine and pyrazine nitrogen atoms in all complexes, while in polynuclear complex 4, the heterocyclic pyrazine ring of one py-2pz additionally behaves as a bridging ligand between two Ag(i) ions. DFT calculations were performed to elucidate the structures of the investigated complexes in solution. The antimicrobial potential of the complexes 1-4 was evaluated against two bacterial (Pseudomonas aeruginosa and Staphylococcus aureus) and two Candida (C. albicans and C. parapsilosis) species. Silver(i) complexes 3 and 4 have shown good antibacterial and antifungal properties with minimal inhibitory concentration (MIC) values ranging from 4.9 to 39.0 μM (3.9-31.2 μg mL-1). All complexes inhibited the filamentation of C. albicans and hyphae formation, while silver(i) complexes 3 and 4 had also the ability to inhibit the biofilm formation process of this fungus. The binding affinity of the complexes 1-4 with calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) was studied by fluorescence emission spectroscopy to clarify the mode of their antimicrobial activity. Catechol oxidase biomimetic catalytic activity of copper(ii) complexes 1 and 2 was additionally investigated by using 3,5-di-tert-butylcatechol (3,5-DTBC) and o-aminophenol (OAP) as substrates.

Impact of pharmacogenetics on variability in exposure to oral vinorelbine among pediatric patients: a model-based population pharmacokinetic analysis

PURPOSE

Better understanding of pharmacokinetics of oral vinorelbine (VNR) in children would help predicting drug exposure and, beyond, clinical outcome. Here, we have characterized the population pharmacokinetics of oral VNR and studied the factors likely to explain the variability observed in VNR exposure among young patients.

DESIGN/METHODS

We collected blood samples from 36 patients (mean age 11.6 years) of the OVIMA multicentric phase II study in children with recurrent/progressive low-grade glioma. Patients received 60 mg/m² of oral VNR on days 1, 8, and 15 during the first 28-day treatment cycle and 80 mg/m², unless contraindicated, from cycle 2-12. Population pharmacokinetic analysis was performed using nonlinear mixed-effects modeling within the Monolix^® software. Fifty SNPs of pharmacokinetic-related genes were genotyped. The influence of demographic, biological, and pharmacogenetic covariates on pharmacokinetic parameters was investigated using a stepwise multivariate procedure.

RESULTS

A three-compartment model, with a delayed double zero-order absorption and a first-order elimination, best described VNR pharmacokinetics in children. Typical population estimates for the apparent central volume of distribution (V_c/F) and elimination rate constant were 803 L and 0.60 h^-1, respectively. Following covariate analysis, BSA, leukocytes count, and drug transport ABCB1-rs2032582 SNP showed a dramatic impact on V_c/F. Conversely, age and sex had no significant effect on VNR pharmacokinetics.

CONCLUSION

Beyond canonical BSA and leukocytes, ABCB1-rs2032582 polymorphism showed a meaningful impact on VNR systemic exposure. Simulations showed that the identified covariates could have an impact on both efficacy and toxicity outcomes. Thus, a personalized dosing strategy, using those covariates, could help to optimize the efficacy/toxicity balance of VNR in children.

Zinc(II) Complexes with Dimethyl 2,2′-Bipyridine-4,5-dicarboxylate: Structure, Antimicrobial Activity and DNA/BSA Binding Study

Two zinc(II) complexes with dimethyl 2,2′-bipyridine-4,5-dicarboxylate (py-2py) of the general formula [Zn(py-2py)X2], X = Cl− (1) and Br− (2) were synthesized and characterized by NMR, IR and UV-Vis spectroscopy and single-crystal X-ray diffraction analysis. Complexes 1 and 2 are isostructural and adopt a slightly distorted tetrahedral geometry with values of tetrahedral indices τ4 and τ’4 in the range of 0.80–0.85. The complexes were evaluated for their in vitro antimicrobial activity against two bacterial (Pseudomonas aeruginosa and Staphylococcus aureus) and two fungal strains (Candida albicans and Candida parapsilosis), while their cytotoxicity was tested on the normal human lung fibroblast cell line (MRC-5) and the model organism Caenorhabditis elegans. Complex 1 showed moderate activity against both Candida strains. However, this complex was twofold more cytotoxic compared to complex 2. The complexes tested had no effect on the survival rate of C. elegans. Complex 2 showed the ability to inhibit filamentation of C. albicans, while complex 1 was more effective than complex 2 in inhibiting biofilm formation. The interactions of complexes 1 and 2 with calf thymus DNA (ct-DNA) and bovine serum albumin (BSA) were studied to evaluate their binding affinity toward these biomolecules.

Comparison of a newly developed high performance liquid chromatography method with diode array detection to a liquid chromatography tandem mass spectrometry method for the quantification of cabozantinib, dabrafenib, nilotinib and osimertinib in human serum - Application to therapeutic drug monitoring

OBJECTIVE

Liquid chromatography tandem mass spectrometry (LC-MS/MS) is a highly selective and sensitive method for the quantification of kinase inhibitors, yet not widely available in clinical routine for therapeutic drug monitoring (TDM). To provide a more accessible alternative, a high-performance liquid chromatography method with ultraviolet/diode array detection (HPLC-UV/DAD) to quantify cabozantinib, dabrafenib, nilotinib and osimertinib, was developed and validated. Results were compared to LC-MS/MS.

METHOD

After liquid-liquid-extraction and reconstitution of the residue in 20 mM potassium dihydrogen phosphate (KH2PO4) (pH4.6), acetonitrile and methanol (50:25:25,v/v/v), chromatographic separation was achieved in 20.0 min using a Luna® C18(2)-HST column (100 × 2 mm, 2.5 μm), protected by a C18 guard column (4 × 2 mm) (column temperature: 30 °C, autosampler: 10 °C). Mobile phase A and B consisted of 20 mM KH2PO4 (pH4.9) and acetonitrile (9:1,v/v) and acetonitrile:20 mM KH2PO4 (pH4.9) (7:3,v/v), respectively. Gradient elution was performed at 200 µL/min. Analytes were quantified at 250, 280 and 330 nm, using sorafenib as internal standard.

RESULTS

Calibration curves were linear (35-2,000 ng/mL). Method validation assays met requirements by U.S. Food and Drug Administration and European Medicines Agency. Compared to the more sensitive and specific LC-MS/MS, HPLC-UV/DAD showed a good correlation and a strong positive association (Kendall's tau 0.811¬-0.963, p < 0.05). Bland-Altman-plots revealed 100% (cabozantinib), 98.6% (dabrafenib), 98.6% (nilotinib) and 96.2% (osimertinib) of relative differences inside the limits of agreement. Regulatory agency criteria for sample reanalysis and cross validation were met (±20%-criterion:100% (cabozantinib), 94.3% (dabrafenib), 92% (nilotinib) and 84.6% (osimertinib).

CONCLUSION

The developed HPLC-UV/DAD method is "fit-for-TDM" in clinical routine and serves as a genuine alternative to LC-MS/MS.

Adaptive dosing of sunitinib in a metastatic renal cell carcinoma patient: when in silico modeling helps to go quicker to the point

PURPOSE

Adaptive dosing strategy with oral targeted therapies in oncology is mostly based upon clinical signs. Using pharmacokinetics (PK) models to customize dosing could help saving time, i.e., by predicting clinical outcome through early monitoring of drug levels.

CASE REPORT

We present the case of a metastatic renal cell carcinoma patient treated with standard Sunitinib dosing (i.e., 50 mg QD). Clinical signs suggested lack of efficacy. Therapeutic Drug Monitoring (TDM) confirmed that exposure was below the expected target exposure. PK modeling suggested that dosing could be increased safely to 75 mg QD. Sunitinib dosing was instead changed empirically to 62.5 mg only, increasing drug exposure to the lower part of the therapeutic window. Resolution of bone pains plus Stable Disease were observed. Even though further modeling suggested to increase Sunitinib dosing to 75 mg again, the intermediate dosing was maintained for the subsequent cycles to preserve the safety. Unfortunately, severe pains plus degradation of the general state were reported and imaging showed Progressive Disease. The patient was finally switched to alternative therapy, without being treated at the 75 mg level of Suntitinib.

CONCLUSIONS AND DISCUSSION

This case suggests that model-based adaptive dosing could have allowed to reach quicker the best dosing with Sunitinib, thus possibly ensuring a better management of this patient. Model-informed dosing should be used instead of empirical search for the most appropriate dosing to ensure a good benefit/risk ratio with Sunitinib, especially in the context of such aggressive disease.

Evaluation of solid tumor response to sequential treatment cycles via a new computational hybrid approach

The development of an in silico approach that evaluates and identifies appropriate treatment protocols for individuals could help grow personalized treatment and increase cancer patient lifespans. With this motivation, the present study introduces a novel approach for sequential treatment cycles based on simultaneously examining drug delivery, tumor growth, and chemotherapy efficacy. This model incorporates the physical conditions of tumor geometry, including tumor, capillary network, and normal tissue assuming real circumstances, as well as the intravascular and interstitial fluid flow, drug concentration, chemotherapy efficacy, and tumor recurrence. Three treatment approaches-maximum tolerated dose (MTD), metronomic chemotherapy (MC), and chemo-switching (CS)-as well as different chemotherapy schedules are investigated on a real tumor geometry extracted from image. Additionally, a sensitivity analysis of effective parameters of drug is carried out to evaluate the potential of using different other drugs in cancer treatment. The main findings are: (i) CS, MC, and MTD have the best performance in reducing tumor cells, respectively; (ii) multiple doses raise the efficacy of drugs that have slower clearance, higher diffusivity, and lower to medium binding affinities; (iii) the suggested approach to eradicating tumors is to reduce their cells to a predetermined rate through chemotherapy and then apply adjunct therapy.

Pharmacokinetics and pharmacogenetics of liposomal cytarabine in AML patients treated with CPX-351

CPX-351 is a liposome encapsulating cytarabine and daunorubicin for treating Acute Myeloid Leukemia (AML) patients. To what extent differences in cytidine deaminase (CDA) activity, the enzyme that catabolizes free cytarabine in the liver, can affect the pharmacokinetics of liposomal cytarabine as well, is unknown. We have studied the pharmacokinetics (PK) of released, liposomal and total cytarabine using a population-modeling approach in 9 adult AML patients treated with liposomal CPX-351. Exposure levels and PK parameters were compared with respect to the patient's CDA status (i.e., Poor Metabolizer (PM) vs. Extensive Metabolizer (EM)). Overall response rate was 75%, and 56% of patients had non-hematological severe toxicities, including one lethal toxicity. All patients had febrile neutropenia. A large (>60%) inter-individual variability was observed on pharmacokinetics parameters and subsequent drug levels. A trend towards severe toxicities was observed in patients with higher exposure of cytarabine. Results showed that liposomal CPX-351 led to sustained exposure with reduced clearance (Cl = 0.16 L/h) and prolonged half-life (T_1/2 = 28 h). Liposomal nanoparticles were observed transiently in bone marrow with cytarabine levels 2.3-time higher than in plasma. Seven out of 9 patients were PM with a strong impact on the PK parameters, i.e., PM patients showing higher cytarabine levels as compared with EM patients (AUC: 5536 vs. 1784 ng/mL.h), sustained plasma exposure (T_1/2: 33.9 vs. 13.7 h), and reduced clearance (Cl: 0.12 vs. 0.29 L/h). This proof-of-concept study suggests that CDA status has a major impact on cytarabine PK and possibly safety in AML patients even when administered as a liposome.

Unraveling the complexity of therapeutic drug monitoring for monoclonal antibody therapies to individualize dose in oncology

Monoclonal antibodies (Mabs) have become key drugs in cancer treatment, either as targeted therapies or more recently as immune checkpoint inhibitors (ICIs). The fact that only some patients benefit from these drugs poses the usual question in the field of onco-hematology: that of the benefit of individual dosing and the potential of therapeutic drug monitoring (TDM) to carry out this individualization. However, Mabs present unique pharmacological characteristics for TDM, and the pharmacokinetic-pharmacodynamic relationship observed should be interpreted differently than that observed for conventional drugs and small molecules. This pharmacology practice review has been summarized from a public debate between the authors at the International TDM and Clinical Toxicology meeting in Banff, 2020, regarding the potential roles of TDM in the Mab/ICI setting.

Overcoming barriers to implementing precision dosing with 5-fluorouracil and capecitabine

Despite advances in targeted cancer therapy, the fluoropyrimidines 5-fluorouracil (5FU) and capecitabine continue to play an important role in oncology. Historically, dosing of these drugs has been based on body surface area. This approach has been demonstrated to be an imprecise way to determine the optimal dose for a patient. Evidence in the literature has demonstrated that precision dosing approaches, such as DPD enzyme activity testing and, in the case of intravenous 5FU, pharmacokinetic-guided dosing, can reduce toxicity and yield better patient outcomes. However, despite the evidence, there has not been uniform adoption of these approaches in the clinical setting. When a drug such as 5FU has been used clinically for many decades, it may be difficult to change clinical practice. With the aim of facilitating change of practice, issues and barriers to implementing precision dosing approaches for 5FU and capecitabine are identified and discussed with possible solutions proposed.