Despite the fact that pharmacokinetic exposure of kinase inhibitors (KIs) is highly variable and clear relationships exist between exposure and treatment outcomes, fixed dosing is still standard ...practice. This review aims to summarize the available clinical pharmacokinetic and pharmacodynamic data into practical guidelines for individualized dosing of KIs through therapeutic drug monitoring (TDM). Additionally, we provide an overview of prospective TDM trials and discuss the future steps needed for further implementation of TDM of KIs.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Preclinical data suggest that EGFR tyrosine kinase inhibitors (TKIs) plus MET TKIs are a possible treatment for EGFR mutation-positive lung cancers with MET-driven acquired resistance. Phase 1 safety ...data of savolitinib (also known as AZD6094, HMPL-504, volitinib), a potent, selective MET TKI, plus osimertinib, a third-generation EGFR TKI, have provided recommended doses for study. Here, we report the assessment of osimertinib plus savolitinib in two global expansion cohorts of the TATTON study.
In this multi-arm, multicentre, open-label, phase 1b study, we enrolled adult patients (aged ≥18 years) with locally advanced or metastatic, MET-amplified, EGFR mutation-positive non-small-cell lung cancer, who had progressed on EGFR TKIs. We considered two expansion cohorts: parts B and D. Part B consisted of three cohorts of patients: those who had been previously treated with a third-generation EGFR TKI (B1) and those who had not been previously treated with a third-generation EGFR TKI who were either Thr790Met negative (B2) or Thr790Met positive (B3). In part B, patients received oral osimertinib 80 mg and savolitinib 600 mg daily; after a protocol amendment (March 12, 2018), patients who weighed no more than 55 kg received a 300 mg dose of savolitinib. Part D enrolled patients who had not previously received a third-generation EGFR TKI and were Thr790Met negative; these patients received osimertinib 80 mg plus savolitinib 300 mg. Primary endpoints were safety and tolerability, which were assessed in all dosed patients. Secondary endpoints included the proportion of patients who had an objective response per RECIST 1.1 and was assessed in all dosed patients and all patients with centrally confirmed MET amplification. Here, we present an interim analysis with data cutoff on March 29, 2019. This study is registered with ClinicalTrials.gov, NCT02143466.
Between May 26, 2015, and Feb 14, 2019, we enrolled 144 patients into part B and 42 patients into part D. In part B, 138 patients received osimertinib plus savolitinib 600 mg (n=130) or 300 mg (n=8). In part D, 42 patients received osimertinib plus savolitinib 300 mg. 79 (57%) of 138 patients in part B and 16 (38%) of 42 patients in part D had adverse events of grade 3 or worse. 115 (83%) patients in part B and 25 (60%) patients in part D had adverse events possibly related to savolitinib and serious adverse events were reported in 62 (45%) patients in part B and 11 (26%) patients in part D; two adverse events leading to death (acute renal failure and death, cause unknown) were possibly related to treatment in part B. Objective partial responses were observed in 66 (48%; 95% CI 39–56) patients in part B and 23 (64%; 46–79) in part D.
The combination of osimertinib and savolitinib has acceptable risk–benefit profile and encouraging antitumour activity in patients with MET-amplified, EGFR mutation-positive, advanced NSCLC, who had disease progression on a previous EGFR TKI. This combination might be a potential treatment option for patients with MET-driven resistance to EGFR TKIs.
AstraZeneca.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Pazopanib is an inhibitor of the vascular endothelial growth factor receptor, platelet-derived growth factor receptor, fibroblast growth factor receptor and stem cell receptor c-Kit, and has been ...approved for the treatment of renal cell carcinoma and soft tissue sarcoma. The pharmacokinetics of pazopanib are complex and are characterized by pH-dependent solubility, large interpatient variability and low, non-linear and time-dependent bioavailability. Exposure to pazopanib is increased by both food and coadministration of ketoconazole, but drastically reduced by proton pump inhibitors. Studies have demonstrated relationships between systemic exposure to pazopanib and toxicity, such as hypertension. Furthermore, a strong relationship between pazopanib trough level ≥20 mg/L and both tumor shrinkage and progression-free survival has been established. At the currently approved daily dose of 800 mg, approximately 20% of patients do not reach this threshold and may be at risk of suboptimal treatment. As a result of this, clinical trials have explored individualized pazopanib dosing, which demonstrate the safety and feasibility of individualized pazopanib dosing based on trough levels. In summary, we provide an overview of the complex pharmacokinetic and pharmacodynamic profiles of pazopanib and, based on the available data, we propose optimized dosing strategies.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Papillary renal cell carcinoma (PRCC) is the most common type of non-clear cell RCC. Because some cases of PRCC are MET-driven, MET inhibition could be a targeted treatment approach. In previous ...studies, savolitinib (AZD6094, HMPL-504, volitinib), a highly selective MET-tyrosine kinase inhibitor, demonstrated antitumor activity in this patient group.
To determine whether savolitinib is a better treatment option for this patient population, vs standard of care, sunitinib.
The SAVOIR phase 3, open-label, randomized clinical trial was a multicenter study carried out in 32 centers in 7 countries between July 2017 and the data cutoff in August 2019. Overall, 360 to 450 patients were to be screened to randomize approximately 180 patients. Patients were adults with MET-driven (centrally confirmed), metastatic PRCC, with 1 or more measurable lesions. Exclusion criteria included prior receipt of sunitinib or MET inhibitor treatment. Overall, 254 patients were screened.
Patients received 600 mg of savolitinib orally once daily (qd), or 50 mg of sunitinib orally qd for 4 weeks, followed by 2 weeks without treatment.
The primary end point was progression-free survival (PFS, assessed by investigator and confirmed by blinded independent central review). Secondary end points included overall survival (OS), objective response rate (ORR), duration of response, and safety/tolerability.
At data cutoff, 60 patients were randomized (savolitinib n = 33; sunitinib n = 27); most patients had chromosome 7 gain (savolitinib, 30 91%; sunitinib, 26 96%) and no prior therapy (savolitinib, 28 85%; sunitinib, 25 93%). For savolitinib and sunitinib, 4 (12%) and 10 (37%) patients were women, and the median (range) age was 60 (23-78) and 65 (31-77) years, respectively. Following availability of external data on PFS with sunitinib in patients with MET-driven disease, study enrollment was closed. Progression-free survival, OS, and ORR were numerically greater with savolitinib vs sunitinib. Median PFS was not statistically different between the 2 groups: 7.0 months (95% CI, 2.8-not calculated) for savolitinib and 5.6 months (95% CI, 4.1-6.9) for sunitinib (hazard ratio HR, 0.71; 95% CI, 0.37-1.36; P = .31). For savolitinib and sunitinib respectively, grade 3 or higher adverse events (AEs) were reported in 14 (42%) and 22 (81%) of patients and AE-related dose modifications in 10 (30%) and 20 (74%). After discontinuation, 12 (36%) and 5 (19%) of patients on savolitinib and sunitinib respectively, received subsequent anticancer therapy.
Although patient numbers and follow-up were limited, savolitinib demonstrated encouraging efficacy vs sunitinib, with fewer grade 3 or higher AEs and dose modifications. Further investigation of savolitinib as a treatment option for MET-driven PRCC is warranted.
ClinicalTrials.gov Identifier: NCT03091192.
Fixed dosing of oral targeted therapies is inadequate in the era of precision medicine. Personalized dosing, based on pharmacokinetic (PK) exposure, known as therapeutic drug monitoring (TDM), is ...rational and supported by increasing evidence. The purpose of this perspective is to discuss whether randomized studies are needed to confirm the clinical value of precision dosing in oncology. PK-based dose adjustments are routinely made for many drugs and are recommended by health authorities, for example, for patients with renal impairment or for drug-drug interaction management strategies. Personalized dosing simply extrapolates this paradigm from selected patient populations to each individual patient with suboptimal exposure, irrespective of the underlying cause. If it has been demonstrated that exposure is related to a relevant clinical outcome, such as efficacy or toxicity, and that exposure can be optimized by PK-guided dosing, it could be logically assumed that PK-guided dosing would result in better treatment outcomes without the need for randomized confirmatory trials. We propose a path forward to demonstrate the clinical relevance of individualized dosing of molecularly-targeted anticancer drugs.
Oral anticancer drugs show a high interpatient variability in pharmacokinetics (PK), leading to large differences in drug exposure. For many of these drugs, exposure has been linked to efficacy and ...toxicity. Despite this knowledge, these drugs are still administered in a one-size-fits-all approach. Consequently, individual patients have a high probability to be either underdosed, which can lead to decreased antitumor efficacy, or overdosed, which could potentially result in increased toxicity. Therapeutic drug monitoring (TDM), personalized dosing based on measured drug levels, could be used to circumvent underdosing and overdosing and thereby optimize treatment outcomes.
In this prospective clinical study (www.trialregister.nl; NL6695), the feasibility, tolerability, and efficacy of TDM of oral anticancer drugs will be evaluated. In total, at least 600 patients will be included for (at least) 23 different compounds. Patients starting regular treatment with one of these compounds at the approved standard dose can be included. PK sampling will be performed at 4, 8, and 12 weeks after the start of treatment and every 12 weeks thereafter. Drug concentrations will be measured, and trough concentrations (Cmin) will be calculated. In cases where Cmin falls below the predefined target and acceptable toxicity, a PK-guided intervention will be recommended. This could include emphasizing compliance, adapting concomitant medication (due to drug-drug interactions), instructing to take the drug concomitant with food, splitting intake moments, or recommending a dose increase.
Despite a strong rationale for the use of TDM for oral anticancer drugs, this is currently not yet widely adopted in routine patient care. This prospective study will be a valuable contribution to demonstrate the additional value of dose optimization on treatment outcome for these drugs.
Oral anti-hormonal drugs are essential in the treatment of breast and prostate cancer. It is well known that the interpatient variability in pharmacokinetic exposure is high for these agents and ...exposure-response relationships exist for many oral anti-hormonal drugs. Yet, they are still administered at fixed doses. This could lead to underdosing and thus suboptimal efficacy in some patients, while other patients could be overdosed resulting in unnecessary side effects. Therapeutic drug monitoring (TDM), individualized dosing based on measured blood concentrations of the drug, could therefore be a valid option to further optimize treatment. In this review, we provide an overview of relevant clinical pharmacokinetic and pharmacodynamic characteristics of oral anti-hormonal drugs in oncology and translate these into practical guidelines for TDM. For some agents, TDM targets are not well established yet and as a reference the median pharmacokinetic exposure could be targeted (exemestane: minimum plasma concentration (C
) 4.1 ng/mL and enzalutamide: C
11.4 mg/L). However, for most drugs, exposure-efficacy analyses could be translated into specific targets (abiraterone: C
8.4 ng/mL, anastrozole: C
34.2 ng/mL, and letrozole: C
85.6 ng/mL). Moreover, prospective clinical trials have shown TDM to be feasible for tamoxifen, for which the exposure-efficacy threshold of its active metabolite endoxifen is 5.97 ng/mL. Based on the available data, we therefore conclude that individualized dosing based on drug concentrations is feasible and promising for oral anti-hormonal drugs and should be developed further and implemented into clinical practice.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Summary
Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are recommended first-line treatments in EGFR-mutated (EGFRm) non-small-cell lung cancer (NSCLC). However, acquired ...resistance (e.g. MET amplification) is frequently observed. Savolitinib (volitinib, HMPL-504, AZD6094) is an oral, potent, and highly selective MET-TKI. In this phase Ib, open-label, multicenter study, we enrolled Chinese patients with EGFRm advanced NSCLC, whose disease progressed following prior EGFR-TKI treatment. In the safety run-in, patients received savolitinib 600 or 800 mg plus gefitinib 250 mg orally once daily, and dose-limiting toxicities were recorded. In the expansion phase, patients with MET amplification received savolitinib plus gefitinib. The primary endpoint was safety/tolerability. Secondary endpoints included antitumor activity. Thirteen patients were enrolled in the safety phase (median age 52 years, 46% female) and 51 enrolled in the expansion phase (median age 61 years, 67% female). No dose-limiting toxicities were reported in either dose group during the safety run-in. Adverse events of grade ≥ 3 in the safety run-in and expansion phases (
n
= 57) were reported in 21 (37%) patients. The most frequently reported adverse events (all grades) were: vomiting (
n
= 26, 46%), nausea (
n
= 23, 40%), increased aspartate aminotransferase (
n
= 22, 39%). Of four deaths, none were treatment-related. The objective response rates in EGFR T790M-negative, −positive, and -unknown patients were 52% (12/23), 9% (2/23), and 40% (2/5), respectively. Savolitinib 600 mg plus gefitinib 250 mg once daily had an acceptable safety profile and demonstrated promising antitumor activity in EGFRm, MET-amplified advanced NSCLC patients who had disease progression on EGFR-TKIs. NCT02374645, Date of registration: March 2nd 2015.
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CEKLJ, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Savolitinib is an oral, potent, and highly selective MET-tyrosine kinase inhibitor under investigation in various tumor types. A thorough QT study evaluated effects on QT interval after a 600-mg ...single savolitinib dose in healthy subjects. We report exposure-response (E-R) modeling from this study to characterize the effects of savolitinib and its metabolites, M2 and M3, on QTc changes. In a novel application,
in vitro
potencies against hERG current provided mechanistic support to model the metabolites’ effects. The hERG IC50 estimates (95% CI) were 25.8 (22.2–29.9) and 22.6 (14.7–34.6) μM for parent and M2, respectively. The E-R was described by both linear and
E
max
models, with exposure captured by an active moiety that consisted of savolitinib and M2 concentrations, weighted by the hERG IC50 ratio (1.14). The maximal increase in ΔΔQTcF and EC50 estimates (95% CI) was 18.5 (9.2–27.7) ms and 5709 (2889–8529) nM, respectively. Ignoring M2 contribution resulted in under prediction of QTcF prolongation in the hypothetical case of inhibited M2 clearance; at 300 mg
C
max
, the mean (90% CI) of ∆∆QTcF was 9.0 (5.7–12.6) and 5.9 (2.9–8.9) ms using the hERG-informed and parent-only linear models, respectively. Simulations in normal setting confirmed modest QTcF prolongation with 600 mg, but not 300 mg. Using the linear model, the mean (90% CI) maximum ΔΔQTcF were 12.3 (8.6–16.2) and 5.5 (2.6–8.5) ms for 600 and 300 mg, respectively. Further clinical studies will monitor cardiac safety to assess the clinical significance of QT-interval prolongation with savolitinib.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
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