Higher Systemic Exposure to Unbound Active Metabolites of Regorafenib Is Associated With Short Progression-Free Survival in Colorectal Cancer Patients

Regorafenib treatment improves survival of patients with metastatic colorectal cancer, but it is also characterized by detrimental side effects that may require modified dosing or interval schedules. Regorafenib is metabolized by cytochrome P450 3A4 in the liver to its active metabolites, M-2 and M-5. We examined area under the unbound plasma concentration-time curve (AUCu) to these compounds to establish pharmacokinetic bases for individualized dosing strategies. The plasma protein binding of M-2 and M-5 was approximately 10-fold lower than that of regorafenib, whereas AUCu values for active metabolites on both days 1 and 15 were significantly higher than that of regorafenib. Patients with higher AUCu values of M-2 or M-5 on day 1 showed significantly shorter progression-free survival than others, likely due, at least in part, to treatment discontinuation as a result of adverse events, especially occurred during first cycle.

Alteration in the Plasma Concentrations of Endogenous Organic Anion-Transporting Polypeptide 1B Biomarkers in Patients with Non-Small Cell Lung Cancer Treated with Paclitaxel

Paclitaxel has been considered to cause OATP1B-mediated drug-drug interactions at therapeutic doses; however, its clinical relevance has not been demonstrated. This study aimed to elucidate in vivo inhibition potency of paclitaxel against OATP1B1 and OATP1B3 using endogenous OATP1B biomarkers. Paclitaxel is an inhibitor of OATP1B1 and OATP1B3, with K_i of 0.579 ± 0.107 and 5.29 ± 3.87 μM, respectively. Preincubation potentiated its inhibitory effect on both OATP1B1 and OATP1B3, with K_i of 0.154 ± 0.031 and 0.624 ± 0.183 μM, respectively. Ten patients with non-small cell lung cancer who received 200 mg/m² of paclitaxel by a 3-hour infusion were recruited. Plasma concentrations of 10 endogenous OATP1B biomarkers-namely, coproporphyrin I, coproporphyrin III, glycochenodeoxycholate-3-sulfate, glycochenodeoxycholate-3-glucuronide, glycodeoxycholate-3-sulfate, glycodeoxycholate-3-glucuronide, lithocholate-3-sulfate, glycolithocholate-3-sulfate, taurolithocholate-3-sulfate, and chenodeoxycholate-24-glucuronide-were determined in the patients with non-small cell lung cancer on the day before paclitaxel administration and after the end of paclitaxel infusion for 7 hours. Paclitaxel increased the area under the plasma concentration-time curve (AUC) of the endogenous biomarkers 2- to 4-fold, although a few patients did not show any increment in the AUC ratios of lithocholate-3-sulfate, glycolithocholate-3-sulfate, and taurolithocholate-3-sulfate. Therapeutic doses of paclitaxel for the treatment of non-small cell lung cancer (200 mg/m²) will cause significant OATP1B1 inhibition during and at the end of the infusion. This is the first demonstration that endogenous OATP1B biomarkers could serve as surrogate biomarkers in patients. SIGNIFICANCE STATEMENT: Endogenous biomarkers can address practical and ethical issues in elucidating transporter-mediated drug-drug interaction (DDI) risks of anticancer drugs clinically. We could elucidate a significant increment of the plasma concentrations of endogenous OATP1B biomarkers after a 3-hour infusion (200 mg/m²) of paclitaxel, a time-dependent inhibitor of OATP1B, in patients with non-small cell lung cancer. The endogenous OATP1B biomarkers are useful to assess the possibility of OATP1B-mediated DDIs in patients and help in appropriately designing a dosing schedule to avoid the DDIs.

High-throughput method to analyze tegafur and 5-fluorouracil in human tears and plasma using hydrophilic interaction liquid chromatography/tandem mass spectrometry

RATIONALE

We developed a new high-throughput method to analyze tegafur (FT) and 5-fluorouracil (5-FU) in tear and plasma samples using hydrophilic interaction liquid chromatography (HILIC)/tandem mass spectrometry (MS/MS).

METHODS

The tear samples (10 μL) spiked with FT, 5-FU, and 5-chlorouracil (internal standard) were diluted using 40 μL of 2 M ammonium acetate and 250 μL of acetonitrile with 2% formic acid; 20 μL of plasma spiked with the two drugs and internal standard was diluted with 80 μL of 2 M ammonium acetate and 500 μL of acetonitrile with 2% formic acid. After centrifugation, the clear supernatant extract (15 μL) was directly injected into the HILIC/MS/MS instrument, and each drug was separated on a Unison UK-Amino column (50 mm × 3 mm i.d., 3 μm particle size) with a linear gradient elution system composed of 10 mM ammonium acetate (pH 6.8) and acetonitrile at a flow rate of 0.7 mL/min. We performed quantification by multiple reaction monitoring (MRM) with negative-ion atmospheric-pressure chemical ionization.

RESULTS

Distinct peaks were observed for the drugs on each MRM channel within 2 min. The regression equations showed good linearity within the range 0.04-4.0 μg/mL for the tear and plasma samples with detection limits at 0.02-0.04 μg/mL. Recoveries for target analytes (FT and 5-FU) for the tear and plasma samples were in the 94-128% and 94-104% ranges, respectively. The intra- and inter-day coefficients of variation for the two drugs were lower than 10.8%. The accuracies of quantitation were 97-115% for both samples.

CONCLUSIONS

We established a high-throughput, reproducible, and practical procedure for analyzing FT and 5-FU in human tear and plasma samples using HILIC/MS/MS analysis with an aminopropyl-bonded mixed-mode separation column. This method can be applied to the high-throughput routines used in clinical analyses.

Prophylactic effect of rikkunshito, an herbal medicine, for chemotherapy-induced nausea in thoracic cancer patients receiving carboplatin-based chemotherapy

Rikkunshito has been shown to improve upper gastrointestinal symptoms and anorexia. The aim of this study was to evaluate whether rikkunshito improves chemotherapy-induced nausea in thoracic cancer patients receiving carboplatin (CBDCA)-based chemotherapy. A retrospective before-and-after comparison study was conducted in patients with thoracic cancer receiving the first cycle of CBDCA-based chemotherapy. Among 61 eligible patients, 34 received standard antiemetic therapy with a combination of 5-hydroxytryptamine-3 receptor antagonist and dexamethasone from September 2012 and June 2013 (standard group), while the other 27 received the standard antiemetic therapy plus oral rikkunshito from July 2013 and December 2014 (rikkunshito group). The rates of no nausea showed no significant difference between the standard and rikkunshito group (Overall phase: 64.7 % for standard group vs 74.1 % for rikkunshito group, p = 0.579). Subgroup analysis indicated that, in female patients, the rates of no nausea in rikkunshito groups was significantly higher than in standard group (overall phase: 44.4 % vs 100 %, p = 0.034). Rikkunshito did not demonstrate an additional prophylactic effect on standard antiemetic therapy for nausea in patients with thoracic cancer receiving CBDCA-based chemotherapy, but showed a prophylactic effect of nausea in female patients.

Basic evaluation of a novel 4D target and human body phantom

Stereotactic body radiation therapy (SBRT) is usually verified with a dynamic phantom or solid phantom, but there is a demand for phantoms that can accurately simulate tumor dynamics within an individual that would allow customized validation in every patient. We developed a new 4D dynamic target phantom (multi-cell 4D phantom) that allows simulation of tumor movement in patients. The basic quality and dynamic reproducibility of this new phantom was verified in this investigation. The newly developed multi-cell 4D phantom comprises four main components: soft tissue, bones, lungs, and tumor (target). The phantom structure was based on computed tomography (CT) data of a male. In this study, we investigated the basic performance of a multi-cell 4D phantom. All the CT numbers of the phantom were very close to those of human data. The geometric maximum amplitudes were 4.57 mm in the lateral direction, 4.59 mm in the ventrodorsal direction, and 3.68 mm in the cranio-caudal direction. Geometric errors were 0.84, 0.58, and 0.40 mm, respectively. Movements of the abdominal surface were stable for 60 s. Repeated measurements show no actual differences in target movements between multiple measurements and indicated high reproducibility (r  >  0.97). End-to-end tests using Gafchromic film revealed a gamma pass rate of 98% or above (2 mm/3%). Although our phantom performed limited reproducibility in the movement of the patient tumor at present, a satisfactory level of precision was confirmed in general. This is a very promising device for use in the verification of radiation therapy for moving targets.

Abstract 3883: High unbound plasma concentration of M-2, an active metabolite, is associated with shorter survival in patients with metastatic colorectal cancer who received regorafenib

Background and Aims: Regorafenib is an oral multikinase inhibitor which showed survival advantage in the later-line chemotherapy in patients with metastatic colorectal cancer (mCRC). This anticancer drug is sequentially metabolized to pharmacologically active metabolites M-2 and M-5 by the hepatic CYP3A. A randomized phase II trial has recently revealed that initial dose of 80 mg/day followed by dose escalations (40 mg/week) was superior to the standard dosing strategy (160 mg/day) with respect to overall survival (OS), resulting in the NCCN guideline recommendation for this dose escalation strategy, although scientific index for rational dose estimation is still limited. The aim of this prospective study was to clarify the association of pharmacokinetics (PK) with clinical outcome of regorafenib in patients with mCRC.

Methods: Consecutive patients with mCRC administered regorafenib at Showa University Hospital were prospectively enrolled in this study. Patients received regorafenib 160 mg once daily for the first 3 weeks of each 4 weeks cycle. Blood samples for PK analysis were obtained on day1 (0-48 h) skipping the second dose on day2, and if possible day15 of treatment (0-24 h). Plasma concentrations of the regorafenib, M-2, and M-5 were analyzed by HPLC or LC-MS/MS. Unbound fraction of these compounds were measured by equilibrium dialysis method.

Results: A total of 36 patients were enrolled between October 2013 and June 2017. The median progression free survival (PFS) was 1.9 months, and the median OS was 6.4 months. Area under the total (protein bound plus unbound) plasma concentration-time curve (AUC) on day1 was the highest in regorafenib (88.5 ± 53.8 µM·h), followed by M-2 and M-5 (37.0 ± 32.9 and 5.9 ± 6.5 µM·h, respectively), whereas AUC calculated based on unbound plasma concentration (uAUC) of M-2 was the highest (9.8 ± 12.0 nM·h), followed by M-5 and regorafenib (2.5 ± 4.3 and 1.8 ± 1.7 nM·h, respectively), reflecting ~10-fold higher unbound fraction in M-2 and M-5 than regorafenib. uAUC of M-2 measured on day15 was also higher than those of M-5 and regorafenib. Patients with the M-2 uAUC of 9.8 nM·h or higher had significantly shorter PFS than those with the uAUC of lower than 9.8 nM·h (30 vs. 74 days, p=0.0092). The highest uAUC value of M-2 may be compatible with its association with PFS, implying that unbound form of M-2 could be primarily important for clinical response.

Conclusion: We thus found that uAUC of active M-2 was the highest as compared to those of regorafenib and M-5, which was associated with shorter PFS.

Citation Format: Yutaro Kubota, Ken-ichi Fujita, Takehiro Takahashi, Yu Sunakawa, Hiroo Ishida, Kazuyuki Hamada, Wataru Ichikawa, Takuya Tsunoda, Yusuke Masuo, Yukio Kato, Yasutsuna Sasaki. High unbound plasma concentration of M-2, an active metabolite, is associated with shorter survival in patients with metastatic colorectal cancer who received regorafenib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3883.

Does Industry-Conducted All-Case Surveillance of Newly Approved Oncology Drugs Contribute to the Revision of Package Inserts in Japan?

In Japan, the Pharmaceuticals and Medical Devices Agency requires all-case surveillance studies (ACSS) for many novel oncology drugs as a condition for approval. However, this is a major burden on the pharmaceutical industry and clinicians. The objective of this analysis was to investigate whether ACSS can contribute essential new information on severe adverse drug reactions, which are necessary to revise the package inserts of drugs. All oncology drugs for which ACSS were required from January 2006-September 2015 found on the Pharmaceuticals and Medical Devices Agency website were reviewed, and the influence of ACSS on the package insert content was evaluated. Most of the package insert revisions regarding serious treatment-related adverse events were based on spontaneous reports from clinicians. The contribution of ACSS results to the revision of package inserts is limited and comes at the cost of financial resources and labor. An alternative, more efficient adverse-event reporting system is necessary.

The ideal intercostal space for internal mammary vessel exposure during total rib-sparing microvascular breast reconstruction: A critical evaluation

BACKGROUND

Total rib-preserving free flap breast reconstruction (RP-FFBR) using internal mammary vessel (IMV) recipients usually involves vessel exposure in the second or third intercostal spaces (ICS). Although the third one is more commonly used, no direct comparisons between the two have hitherto been performed.

OBJECTIVES

To compare the in-vivo topography and vascular anatomy of second and third ICSs in patients undergoing FFBR using the rib-preservation technique of IMV exposure.

METHODS

An analysis of prospectively collected data on intercostal space distance (ISD), number and arrangement of IMVs, location of venous confluence, and vessel exposure time was conducted on a single surgeon's consecutive RP-FFBRs.

RESULTS

A total of 296 RP-FFBRs were performed in 246 consecutive patients. The second, third, or both second and third spaces were utilized in 282, 28, and 22 cases, respectively. The ISDs were 20.6 mm ± 3.52 for the second ICS and 14.0 mm ± 4.35 for the third ICS (p<0.0001, CI = 5.17-7.97, t-test). The second versus third ICS vein content was as follows: single 81.4% vs. 74%, dual 18.6% vs. 26%, and confluence 3.7% vs. 13%. The second ICS single vein was medial to the artery in 92.6%. The third ICS single vein was medial to the artery in 88.2% Vessel exposure times for second (47.2 mins ± 26.7) and third (46.5 mins ± 31.4) spaces were similar (p = 0.93). The overall intraoperative anastomotic revision rate was 9.1%, and the postoperative flap re-exploration rate was 4.0%, with 99.7% overall flap success.

DISCUSSION AND CONCLUSION

Preferential use of the second ICS is supported by its more predictable vascular anatomy, a broader space for performing the microanastomoses and a higher frequency of a single postconfluence (and thus larger) vein facilitating the microsurgery.

The critical role of urease in yogurt fermentation with various combinations of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus

The protocooperation between Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus relies on metabolite exchanges that accelerate acidification during yogurt fermentation. Conflicting results have been obtained in terms of the effect of the Strep. thermophilus urease and the NH₃ and CO₂ that it generates on the rate of acidification in yogurt fermentation. It is difficult to perform a systematic study of the effects of urease on protocooperation because it is necessary to distinguish among the direct, indirect, and strain-specific effects resulting from the combination of the strains of both species. To evaluate the direct effects of urease on protocooperation, we generated 3 urease-deficient mutants (ΔureC) of fast- and slow-acidifying Strep. thermophilus strains and observed the effects of NH₃ or CO₂ supplementation on acidification by the ΔureC strains. Further, we examined 5 combinations of 3 urease-deficient ΔureC strains with 2 CO₂-responsive or CO₂-unresponsive strains of L. bulgaricus. Urease deficiency induced a shortage of ammonia nitrogen and CO₂ for the fast- and slow-acidifying Strep. thermophilus and for the CO₂-responsive L. bulgaricus, respectively. Notably, the shortage of ammonia nitrogen had more severe effects than that of CO₂ on yogurt fermentation, even if coculture with L. bulgaricus masked the effect of urease deficiency. Our work established (1) that urease deficiency inhibits the fermentative acceleration of protocooperation regardless of the Strep. thermophilus and L. bulgaricus strain combinations, and (2) that urease is an essential factor for effective yogurt acidification.

Lack of correlation between the costs of anticancer drugs and clinical benefits in Japan

Both overall survival (OS) and progression-free survival (PFS) are primary endpoints of phase III studies of new anticancer drugs. Medical care expenditures, especially oncology drug prices, are rapidly increasing; however, the impact of oncology drug prices on OS and PFS is unclear. We analyzed the relationship between oncology drug prices and clinical outcomes in Japan. The costs of a full course or 1 year of treatment were estimated on the basis of the latest National Health Insurance Drug Price Standards, and the relationship between costs and improvements in OS or PFS obtained with each drug were analyzed. Cost-effectiveness was compared between new-class drugs and next-in-class drugs. We then developed a simple model for estimating the costs required to prolong OS and PFS by 1 day and used this model to compare cost-effectiveness. Drug costs were not significantly related to treatment outcomes in terms of PFS or OS. There was no significant difference in the median cost between novel drugs and the next-in-class drugs (P = 0.39). The oncology drug cost required to prolong PFS by 1 day was more expensive than the drug cost required for prolong OS by 1 day. Prices of oncology drugs should be decided on the basis of actual clinical benefits for cancer patients, and the drug price evaluation process should be disclosed in Japan.

Anisakiasis: The risks of seafood consumption

Context and Aims

Japanese cuisine is now popular worldwide, and consumption of raw fish has thus increased at sushi bars and Japanese restaurants outside Japan. Anisakiasis, also known as herring-worm disease, is caused by ingesting larval nematodes in raw seafood and is a common illness in Japan. However, due to the rising popularity of Japanese food, gastroenterologists outside Japan need to be familiar with this disease.

Subjects and Methods and Results

We treated 158 patients presenting with acute gastrointestinal manifestations caused by anisakiasis from April 1991 to April 2000. One or more nematodes were removed endoscopically within 48 h of presentation in 44% of these patients, which resulted in prompt resolution of symptoms. Major endoscopic findings were gastric ulcer accompanied by hemorrhage, erosion, redness, and edema of the gastric mucosa in areas penetrated by larvae and other areas.

Conclusions

Endoscopy was valuable for the diagnosis and treatment of anisakiasis. We recommend endoscopy in suspected cases of anisakiasis. Moreover, it is desirable to combine complementary tests such as immunological tests/IgE measurement. As the popularity of Japanese cuisine increases, reports of anisakiasis are likely to be more frequent in countries other than Japan.

Prognostic nutritional index and early mortality with percutaneous endoscopic gastrostomy

BACKGROUND

Although percutaneous endoscopic gastrostomy (PEG) is a well-accepted and less invasive method of feeding tube placement in patients with swallowing difficulties, complications and early death after PEG have been reported.

AIM

This study aimed to evaluate predictive factors associated with 30-day mortality after PEG, and to assess the utility of nutritional supporting period before PEG in reducing early mortality following PEG.

DESIGN

An observational study.

METHODS

We retrospectively analyzed 268 patients who underwent PEG at Sapporo Shirakaba-dai Hospital from 2006 to 2010, using clinical and laboratory data to analyze predictive factors associated with early death after PEG. Then, we prospectively assessed 152 consecutive patients assessed for eligibility for PEG from 2011 to 2014. We assessed the patients' nutritional condition using Onodera's prognostic nutritional index (PNI), and supported nutrition for more than 10 days before PEG in patients with a poor nutritional index (PNI < 37).

RESULTS

In both univariate and multivariate analyses in the retrospective study, Onodera's PNI of less than 37 was the only predictive factor for early mortality. In the second study, among the 115 patients who finally underwent PEG, early mortality rates improved to 1.7% from 5.2% in the first study. Conversely, 32% of patients with malnutrition who did not undergo PEG died within 30 days.

CONCLUSION

Nutritional status might be a predictive factor for early mortality after PEG. In patients with poor nutritional status, nutritional supporting period before PEG might improve the outcomes and reduce unnecessary PEG.