Sander Bins

Individualized pazopanib dosing : A prospective feasibility study in cancer patients

Purpose: Pazopanib is a tyrosine kinase inhibitor approved for the treatment of renal cell carcinoma and soft tissue sarcoma. Retrospective analyses have shown that an increased median progression-free survival and tumor shrinkage appear in patients with higher plasma trough levels (Cmin). Therefore, patients with low Cmin might benefit from pharmacokinetically guided individualized dosing. Experimental Design: We conducted a prospective multicenter trial in 30 patients with advanced solid tumors. Pazopanib Cmin was measured weekly by LC-MS/MS. At weeks 3, 5, and 7, the pazopanib dose was increased if the measured Cmin was <20 mg/L and toxicity was <grade 3. Results: In total, 17 patients had at least one Cmin <20 mg/L at weeks 3, 5, and 7. Of these, 10 were successfully treated with a pharmacokinetically guided dose escalation, leading to daily dosages ranging from 1,000 to 1,800 mg. Cmin in these patients increased significantly from 13.2 (38.0%) mg/L [mean (CV%)] to 22.9 mg/L (44.9%). Thirteen patients had all Cmin levels ≥20.0 mg/L. Of these, 9 patients with a high Cmin of 51.3 mg/L (45.1%) experienced ≥grade 3 toxicity and subsequently required a dose reduction to 600 or 400 mg daily, yet in these patients, Cmin remained above the threshold at 28.2 mg/L (25.3%). Conclusions: A pharmacokinetically guided individualized dosing algorithm was successfully applied and evaluated. The dosing algorithm led to patients being treated at dosages ranging from 400 to 1,800 mg daily. Further studies are needed to show a benefit of individualized dosing on clinical outcomes, such as progression-free survival. Clin Cancer Res; 22(23); 5738–46. ©2016 AACR. See related commentary by Ornstein and Rini, p. 5626

Individualization of Irinotecan Treatment: A Review of Pharmacokinetics, Pharmacodynamics, and Pharmacogenetics

Since its clinical introduction in 1998, the topoisomerase I inhibitor irinotecan has been widely used in the treatment of solid tumors, including colorectal, pancreatic, and lung cancer. Irinotecan therapy is characterized by several dose-limiting toxicities and large interindividual pharmacokinetic variability. Irinotecan has a highly complex metabolism, including hydrolyzation by carboxylesterases to its active metabolite SN-38, which is 100- to 1000-fold more active compared with irinotecan itself. Several phase I and II enzymes, including cytochrome P450 (CYP) 3A4 and uridine diphosphate glucuronosyltransferase (UGT) 1A, are involved in the formation of inactive metabolites, making its metabolism prone to environmental and genetic influences. Genetic variants in the DNA of these enzymes and transporters could predict a part of the drug-related toxicity and efficacy of treatment, which has been shown in retrospective and prospective trials and meta-analyses. Patient characteristics, lifestyle and comedication also influence irinotecan pharmacokinetics. Other factors, including dietary restriction, are currently being studied. Meanwhile, a more tailored approach to prevent excessive toxicity and optimize efficacy is warranted. This review provides an updated overview on today’s literature on irinotecan pharmacokinetics, pharmacodynamics, and pharmacogenetics.

Implementation of a Multicenter Biobanking Collaboration for Next‐Generation Sequencing‐Based Biomarker Discovery Based on Fresh Frozen Pretreatment Tumor Tissue Biopsies

BACKGROUND The discovery of novel biomarkers that predict treatment response in advanced cancer patients requires acquisition of high-quality tumor samples. As cancer evolves over time, tissue is ideally obtained before the start of each treatment. Preferably, samples are freshly frozen to allow analysis by next-generation DNA/RNA sequencing (NGS) but also for making other emerging systematic techniques such as proteomics and metabolomics possible. Here, we describe the first 469 image-guided biopsies collected in a large collaboration in The Netherlands (Center for Personalized Cancer Treatment) and show the utility of these specimens for NGS analysis. PATIENTS AND METHODS Image-guided tumor biopsies were performed in advanced cancer patients. Samples were fresh frozen, vital tumor cellularity was estimated, and DNA was isolated after macrodissection of tumor-rich areas. Safety of the image-guided biopsy procedures was assessed by reporting of serious adverse events within 14 days after the biopsy procedure. RESULTS Biopsy procedures were generally well tolerated. Major complications occurred in 2.1%, most frequently consisting of pain. In 7.3% of the percutaneous lung biopsies, pneumothorax requiring drainage occurred. The majority of samples (81%) contained a vital tumor percentage of at least 30%, from which at least 500 ng DNA could be isolated in 91%. Given our preset criteria, 74% of samples were of sufficient quality for biomarker discovery. The NGS results in this cohort were in line with those in other groups. CONCLUSION Image-guided biopsy procedures for biomarker discovery to enable personalized cancer treatment are safe and feasible and yield a highly valuable biobank. The Oncologist 2017;22:33-40Implications for Practice: This study shows that it is safe to perform image-guided biopsy procedures to obtain fresh frozen tumor samples and that it is feasible to use these biopsies for biomarker discovery purposes in a Dutch multicenter collaboration. From the majority of the samples, sufficient DNA could be yielded to perform next-generation sequencing. These results indicate that the way is paved for consortia to prospectively collect fresh frozen tumor tissue.

Development and clinical validation of an LC–MS/MS method for the quantification of pazopanib in DBS

BACKGROUND Pazopanib is approved for the treatment of renal cell carcinoma and soft tissue sarcoma. Analyses show increased benefit in patients with plasma trough concentrations ≥20.5 μg/ml compared with patients with lower concentrations. METHODS & RESULTS We developed a DBS assay as a patient friendly approach to guide treatment. The method was validated according to US FDA and EMA guidelines and European Bioanalysis Forum recommendations. Influence of spot homogeneity, spot volume and hematocrit were shown to be within acceptable limits. Analysis of paired clinical samples showed a good correlation between the measured plasma and DBS concentrations (R(2) of 0.872). CONCLUSION The method was successfully validated, applied to paired clinical samples and is suitable for application to therapeutic drug monitoring of pazopanib.

The time to progression ratio: a new individualized volumetric parameter for the early detection of clinical benefit of targeted therapies

BACKGROUND Early signs of efficacy are critical in drug development. Response Evaluation Criteria in Solid Tumors (RECIST) are commonly used to determine the efficacy of anti-cancer therapy in clinical trials. RECIST, however, emphasizes the value of tumor shrinkage, while many targeted agents induce prolonged tumor growth arrest. This limits its use for the detection of treatment efficacy for these more cytostatic regimens. Therefore, we designed an individualized variant of a time to progression (TTP) end point based on prospective volumetric measurements and an intra-patient control, the TTP ratio. PATIENTS AND METHODS Patients with any metastatic malignancy, without regular treatment options, were treated with the mTOR inhibitor everolimus. Treatment response was determined using both RECIST and the TTP ratio. The TTP ratio was defined as the volumetric pretreatment TTP divided by the volumetric on-treatment TTP. A patient was classified as a responder if the TTP ratio was <0.7. Consistency and reproducibility of volumetric measurements were determined. RESULTS Seventy-three patients were included of whom 59 started treatment. A TTP ratio could be established in 73% (n = 43) of the treated patients. The inter-observer agreement for volumetric progression was 0.78 (95% confidence interval 0.70-0.87) (Krippendorffs α-coefficient). According to RECIST, 35 patients (59%) had stable disease (SD) and 1 patient demonstrated a partial response (PR), whereas only 21 patients (36%) met the prespecified criteria for treatment efficacy according to the TTP ratio. Treatment response according to both the TTP ratio and RECIST (SD + PR) correlated with overall survival (OS) [P(log-rank) < 0.001]. The TTP ratio, however, was also able to differentiate which patients had a better OS within the RECIST SD group [P(log-rank) = 0.0496]. CONCLUSION The TTP ratio had a high inter-observer agreement, correlated with OS and identified which patients within the RECIST SD group had a longer OS. CLINICALTRIALSGOV IDENTIFIER NCT01566279.

Influence of OATP1B1 Function on the Disposition of Sorafenib‐β‐D‐Glucuronide

The oral multikinase inhibitor sorafenib undergoes extensive UGT1A9‐mediated formation of sorafenib‐β‐D‐glucuronide (SG). Using transporter‐deficient mouse models, it was previously established that SG can be extruded into bile by ABCC2 or follow a liver‐to‐blood shuttling loop via ABCC3‐mediated efflux into the systemic circulation, and subsequent uptake in neighboring hepatocytes by OATP1B‐type transporters. Here we evaluated the possibility that this unusual process, called hepatocyte hopping, is also operational in humans and can be modulated through pharmacological inhibition. We found that SG transport by OATP1B1 or murine Oatp1b2 was effectively inhibited by rifampin, and that this agent can significantly increase plasma levels of SG in wildtype mice, but not in Oatp1b2‐deficient animals. In human subjects receiving sorafenib, rifampin acutely increased the systemic exposure to SG. Our study emphasizes the need to consider hepatic handling of xenobiotic glucuronides in the design of drug–drug interaction studies of agents that undergo extensive phase II conjugation.

Capecitabine and the Risk of Fingerprint Loss

Capecitabine and the Risk of Fingerprint Loss Anticancer treatments are frequently accompanied by cutaneous adverse effects: capecitabine treatment induces handfoot syndrome (HFS) in approximately 50% to 60% of patients, whereas hand-foot skin reaction (HFSR) has been reported in 19% to 34% of patients treated with the tyrosine kinase inhibitors (TKIs) sunitinib malate or sorafenib tosylate.1 Ultimately, these cutaneous adverse events are believed to result in the loss of fingerprints, which, to our knowledge, has been described anecdotally for patients treated with capecitabine2-6 and can cause serious identification problems. We assessed the association of HFS and HFSR with fingerprint quality.

Association between single-nucleotide polymorphisms and adverse events in nivolumab-treated non-small cell lung cancer patients

BackgroundTreatment with PD-1 inhibitors can be hampered by severe auto-immune-related toxicities. Our objective was to identify single-nucleotide polymorphisms (SNPs) in genes previously associated with auto-immunity, which are associated with toxicities in nivolumab-treated NSCLC patients. This was in order to identify patients prone to develop severe toxicities and to gain more insight into the underlying pathobiology.MethodsWe analysed 322 nivolumab-treated patients and assessed the association with toxicities for seven SNPs in four genes, which are considered contributors to PD-1-directed T-cell responses, i.e., PDCD1, PTPN11, ZAP70 and IFNG. Every SNP was tested for its association with toxicity endpoints. Significant associations were tested in a validation cohort.ResultsA multivariable analysis in the exploration cohort showed that homozygous variant patients for PDCD1 804C>T (rs2227981) had decreased odds for any grade treatment-related toxicities (n = 96; OR 0.4; 95% CI 0.2–1.0; p = 0.039). However, this result could not be validated (n = 85; OR 0.9; 95% CI 0.4–1.9; p = NS).ConclusionsOur results show that it is unlikely that the investigated SNPs have a clinical implication in predicting toxicity. A finding, even though negative, that is considered timely and instructive towards further research in biomarker development for checkpoint inhibitor treatments.

Predicting clinical benefit from everolimus in patients with advanced solid tumors, the CPCT-03 study

BACKGROUND In this study, our aim was to identify molecular aberrations predictive for response to everolimus, an mTOR inhibitor, regardless of tumor type. METHODS To generate hypotheses about potential markers for sensitivity to mTOR inhibition, drug sensitivity and genomic profiles of 835 cell lines were analyzed. Subsequently, a multicenter study was conducted. Patients with advanced solid tumors lacking standard of care treatment options were included and underwent a pre-treatment tumor biopsy to enable DNA sequencing of 1,977 genes, derive copy number profiles and determine activation status of pS6 and pERK. Treatment benefit was determined according to TTP ratio and RECIST. We tested for associations between treatment benefit and single molecular aberrations, clusters of aberrations and pathway perturbation. RESULTS Cell line screens indicated several genes, such as PTEN (P = 0.016; Wald test), to be associated with sensitivity to mTOR inhibition. Subsequently 73 patients were included, of which 59 started treatment with everolimus. Response and molecular data were available from 43 patients. PTEN aberrations, i.e. copy number loss or mutation, were associated with treatment benefit (P = 0.046; Fishers exact test). CONCLUSION Loss-of-function aberrations in PTEN potentially represent a tumor type agnostic biomarker for benefit from everolimus and warrants further confirmation in subsequent studies.Background In this study, our aim was to identify molecular aberrations predictive for response to everolimus, an mTOR inhibitor, regardless of tumor type. Methods To generate hypotheses about potential markers for sensitivity to mTOR inhibition, drug sensitivity and genomic profiles of 835 cell lines were analyzed. Subsequently, a multicenter study was conducted. Patients with advanced solid tumors lacking standard of care treatment options were included and underwent a pre-treatment tumor biopsy to enable DNA sequencing of 1,977 genes, derive copy number profiles and determine activation status of pS6 and pERK. Treatment benefit was determined according to TTP ratio and RECIST. We tested for associations between treatment benefit and single molecular aberrations, clusters of aberrations and pathway perturbation. Results Cell line screens indicated several genes, such as PTEN (P = 0.016; Wald test), to be associated with sensitivity to mTOR inhibition. Subsequently 73 patients were included, of which 59 started treatment with everolimus. Response and molecular data were available from 43 patients. PTEN aberrations, i.e. copy number loss or mutation, were associated with treatment benefit (P = 0.046; Fishers exact test). Conclusion Loss-of-function aberrations in PTEN potentially represent a tumor type agnostic biomarker for benefit from everolimus and warrants further confirmation in subsequent studies.

Effects of budesonide on cabazitaxel pharmacokinetics and cabazitaxel-induced diarrhea: A randomized, open-label multicenter phase II study.

Purpose: Forty-seven percent of patients in the pivotal trial of cabazitaxel reported diarrhea of any grade. Aiming to reduce the incidence of diarrhea, we studied the effects of budesonide on the grade of cabazitaxel-induced diarrhea during the first two treatment cycles. Experimental Design: Between December 2011 and October 2015, 246 metastatic castration-resistant prostate cancer patients were randomized to receive standard-of-care cabazitaxel 25 mg/m2 every 3 weeks plus prednisone 10 mg/day (group CABA) or same dose/schedule of cabazitaxel with concomitant budesonide 9 mg daily during the first two treatment cycles (group BUD). The occurrence of diarrhea was reported by physicians and by patients in a diary. χ2 tests were used to compare incidence numbers. An intention-to-treat principle was used. Results: In the phase II trial, 227 patients were evaluable. Grade 2–3 diarrhea occurred in 35 patients (15%) and grade 4 diarrhea was not reported. The incidence of grade 2–3 diarrhea was comparable in both treatment groups: 14 of 113 patients in group CABA (12%) versus 21 of 114 patients in group BUD (18%; P = 0.21). Seven patients were admitted to the hospital with diarrhea (n = 5 group CABA vs. n = 2 group BUD). PSA response was seen in 30% of patients and was not affected by budesonide coadministration (P = 0.29). Also, other toxicities were not affected by budesonide coadministration. Conclusions: The incidence of cabazitaxel-induced diarrhea was notably lower than reported in the TROPIC trial and appears manageable in routine clinical practice. Budesonide coadministration did not reduce the incidence or severity of cabazitaxel-induced diarrhea. Clin Cancer Res; 23(7); 1679–83. ©2016 AACR.