Translational Pharmacokinetic/Pharmacodynamic Modeling and Simulation of Oxaliplatin and Irinotecan in Colorectal Cancer

Despite the recent advances in this field, there are limited methods for translating organoid-based study results to clinical response. The goal of this study was to develop a pharmacokinetic/pharmacodynamic (PK/PD) model to facilitate the translation, using oxaliplatin and irinotecan treatments with colorectal cancer (CRC) as examples. The PK models were developed using qualified oxaliplatin and irinotecan PK data from the literature. The PD models were developed based on antitumor efficacy data of SN-38 and oxaliplatin evaluated in vitro using tumor organoids. To predict the clinical response, translational scaling of the models was established by incorporating predicted ultrafiltration platinum in plasma or SN-38 in tumors to PD models as the driver of efficacy. The final PK/PD model can predict PK profiles and responses following treatments with oxaliplatin or irinotecan. After generation of virtual patient cohorts, this model simulated their tumor shrinkages following treatments, which were used in analyzing the efficacies of the two treatments. Consistent with the published clinical trials, the model simulation suggested similar patient responses following the treatments of oxaliplatin and irinotecan with regards to the probabilities of progression-free survival (HR = 1.05, 95%CI [0.97;1.15]) and the objective response rate (OR = 1.15, 95%CI [1.00;1.32]). This proposed translational PK/PD modeling approach provides a significant tool for predicting clinical responses of different agents, which may help decision-making in drug development and guide clinical trial design.

Genipin Enhances the Therapeutic Effects of Oxaliplatin by Upregulating BIM in Colorectal Cancer

Despite an increase in the survival rate of patients with cancer owing to the use of current chemotherapeutic agents, adverse effects of cancer therapies remain a concern. Combination therapies have been developed to increase efficacy, reduce adverse effects, and overcome drug resistance. Genipin is a natural product derived from Gardenia jasminoides, which has been associated with anti-inflammatory, anti-angiogenic, and anti-proliferative effects; hypertension; and anti-ischemic brain injuries. However, the enhancement of oxaliplatin sensitivity by genipin remains unexplored. Our study showed that a combination of genipin and oxaliplatin exerts synergistic antitumor effects in vitro and in vivo in colorectal cancer cell lines through the reactive oxygen species (ROS)/endoplasmic reticulum (ER) stress/BIM pathway. Importantly, the combination did not affect normal colon cells. BIM knockdown markedly inhibited apoptosis induced by the combination. In addition, genipin induced ROS by inhibiting superoxide dismutase 3 activity. These findings suggest that genipin may be a novel agent for increasing the sensitivity of oxaliplatin against colorectal cancer. The combination of oxaliplatin and genipin hold significant therapeutic potential with minimal adverse effects.

Efficacy and Toxicity of Low-Dose versus Conventional-Dose Chemotherapy for Malignant Tumors: a Meta-Analysis of 6 Randomized Controlled Trials

Low-dose chemotherapy has emerged as a new strategy for control of cancer. However, there is a controversy as to whether low-dose chemotherapy is an effective way to manage many human malignancies. To shed light on this controversy, we performed a meta-analysis of relative merits between low-dose and conventional-dose chemotherapy in different carcinomas. Studies published before February 29, 2016 were reviewed for the meta-analysis and selected according to defined criteria. The effect levels of low-dose chemotherapy regarding overall survival (OS), progression-free survival (PFS) and severe adverse events (SAEs) (Grade≥3) were calculated as risk ratios (ORs) or adjusted hazard ratios (HRs). Six randomized controlled studies (RCTs) have provided data for low-dose chemotherapy versus conventional-dose chemotherapy for 838 cases and 833 cases, respectively. Interestingly, low-dose chemotherapy achieved the same desired potency as conventional-dose chemotherapy, with no differences in pooled ORR (RR=1.00, 95%CI [0.89, 1.13]; (P=0.97), OS (HR=1.07, 95%CI [0.90, 1.26]; P=0.44) and PFS (HR=1.02, 95%CI [0.84, 1.23]; P=0.87) values. Furthermore, pooled data for common SAEs showed that, compared with conventional-dose chemotherapy regimen, low-dose chemotherapy regimen resulted in significant less mucositis (P<0.0001), thrombocytopenia (P<0.00001), anemia (P=0.0001) and febrile neutropenia (P=0.004). At the same time, no statistically significant differences were observed with regard to treatment-related death (P=0.36), diarrhea (P=0.49), leucopenia (P=0.11), neutropenia (P=0.74) and nausea/vomiting (ʺPʺ=0.21). Publication bias was assessed by Egger’s test and the funnel plot. In conclusion, the meta-analysis seems to support the idea that low-dose chemotherapy may play an important role in achieving the same desired potency as conventional-dose chemotherapy in managing malignant tumors. Moreover, low-dose regimen seems to possess positive advantages of lower toxicity which is a particular concern for most patients.

Cytotoxic effects of the newly-developed chemotherapeutic agents 17-AAG in combination with oxaliplatin and capecitabine in colorectal cancer cell lines

The use of heat shock protein 90 inhibitors like 17-allylamino-17-demethoxy-geldanamycin (17-AAG) has been recently introduced as an attractive anticancer therapy. It has been shown that 17-AAG may potentiate the inhibitory effects of some classical anticolorectal cancer (CRC) agents. In this study, two panels of colorectal carcinoma cell lines were used to evaluate the effects of 17-AAG in combination with capecitabine and oxaliplatin as double and triple combination therapies on the proliferation of CRC cell lines. HT-29 and all HCT-116 cell lines were seeded in culture media in the presence of different doses of the mentioned drugs in single, double, and triple combinations. Water-soluble tetrazolium-1 (WST-1) assay was used to investigate cell proliferation 24 h after treatments. Then, dose-response curves were plotted using WST-1outputs, and IC₅₀ values were determined. For double and triple combinations respectively 0.5 × IC₅₀ and 0.25 × IC₅₀ were used. Data was analyzed with the software CompuSyn. Drug interactions were analyzed using Chou-Talalay method to calculate the combination index (CI).The data revealed that 17-AAG shows a potent synergistic interaction (CI < 1) with oxaliplatin and capecitabine in double combinations (0.5 × IC₅₀) in both cell lines. In the case of triple combinations, the findings showed an antagonistic interaction (CI > 1) in HT-29 and a synergistic effect (CI < 1) in HCT-116 (0.25 × IC₅₀) cell lines. It was concluded that double combinations of 17-AAG with oxaliplatin or capecitabine might be effective against HCT-116 and HT-29 cell lines. However, in triple combinations, positive results were seen only against HCT-116. Further investigation is suggested to confirm the effectiveness of these combinations in clinical trials.

Management of advanced colorectal cancer, Part 1

PURPOSE

Important developments in chemotherapy for advanced colorectal cancer over the past 15 years are reviewed, with an emphasis on the most recently published data from clinical trials of newer multidrug regimens, administration techniques, and dosing schedules.

SUMMARY

Eight agents are approved by the Food and Drug Administration (FDA) for use in treating patients with advanced colorectal cancer. Fluorouracil and leucovorin still constitute the foundation of most chemotherapy regimens for this population; combination fluorouracil-leucovorin therapy plus either irinotecan (the FOLFIRI regimen) or oxaliplatin (the FOLFOX regimen) are two firmly established first-line treatments shown to produce similar outcomes. In Phase III trials conducted over the past six to seven years, regimens of capecitabine plus oxaliplatin (CapeOx) were demonstrated to have clinical effectiveness comparable to that of FOLFOX therapy. Response rates of 35-55% and median overall survival of ≥20 months have been documented with some of the newer regimens. Research to define the optimal role of the three monoclonal antibody agents approved by FDA for use in managing advanced colorectal cancer is ongoing; bevacizumab has been shown to confer significant survival benefits when added to certain chemotherapy regimens, and other monoclonal antibodies (cetuximab and panitumumab) also appear to offer significant benefits in select patients as first- or second-line therapies.

CONCLUSION

Over the past 15 years, a shift toward multiagent treatment strategies including a variety of chemotherapy agents and monoclonal antibodies has yielded improved rates of response and prolonged survival among patients with advanced colorectal cancer. The CapeOx, FOLFOX, and FOLFIRI regimens are currently among the most widely used first-line treatments.

Biweekly XELOX (capecitabine and oxaliplatin) as first-line treatment in elderly patients with metastatic colorectal cancer

OBJECTIVE

The combination of oxaliplatin and oral capecitabine (XELOX) has shown to be an active regimen in metastatic colorectal cancer (MCRC). However, the experience with XELOX in elderly patients is limited. This study aimed to evaluate the efficacy and safety of XELOX as first-line treatment in elderly patients with MCRC.

PATIENTS AND METHODS

Patients aged ≥70years with previously untreated MCRC received oxaliplatin 85mg/m(2) on day 1, every 2weeks plus capecitabine 1000mg/m(2) (or capecitabine 750mg/m(2) if creatinine clearance was 30-50mL/min) twice daily on days 1-7, every 2weeks. Treatment was continued until progression, intolerable toxicity, or for a maximum of 12cycles.

RESULTS

Thirty-five patients were enrolled. Median age was 78years (range, 70-83). Patients received a median of 11cycles of treatment. The objective response rate (ORR) was 49% and the tumor control rate was 86%. Median time to progression and overall survival were 8.6 (95% CI: 5.5-11.7) and 15.5 (95% CI: 9.6-21.3) months, respectively. Toxicities were generally mild to moderate. Major grade 1-2 toxicities were asthenia (40%), nausea (43%), and diarrhea (40%). No grade 4 toxicity was detected and grade 3 toxicities were reported in 17% of patients. There was no treatment-related death.

CONCLUSION

Our findings show that the biweekly XELOX regimen represents an effective and tolerable first-line treatment option for elderly patients with MCRC.

Ideal vial size for bortezomib: real-world data on waste and cost reduction in treatment of multiple myeloma in Brazil

OBJECTIVES

Single-size vials of drugs may be a source of waste and increase in treatment costs. Bortezomib, indicated for multiple myeloma (MM) treatment, is available in 3.5-mg vials, a quantity higher than the average dose commonly prescribed. This analysis aimed to demonstrate, through real-world data, which would be the optimal vial presentation for bortezomib in Brazil and quantify the reduction in medication waste related to this option.

METHODS

From November 2007 to October 2009 all patients with MM treated with bortezomib were identified via the Evidências database. Analysis of prescribed, dispensed, and wasted doses, their costs and projections of the ideal vial size were performed.

RESULTS

Thirty-five patients (mean body surface area of 1.73 m(2)) received 509 infusions in 131 cycles of treatment (average of 3.77 cycles per patient). The average dose prescribed was 2.1 mg per infusion (95% confidence interval [CI] 1.97-2.26) with average waste of 39.5% of the vial content (95% CI 35.35-43.76). The mean waste per patient per day was 1.38 mg (95% CI 1.24-1.52). If a 3-mg vial were available, the average drug waste per patient per day would be 0.88 mg (95% CI 0.74-1.03) or 36.2% less. With a 2.5-mg vial the waste would be 1.05 mg (95% CI 0.81-1.29) or 23.9% less. If two presentations were available (2.5 mg and 0.5 mg), the waste would be 0.52 mg (95% CI 0.4-0.63) or 62.5% less. Considering the price of the different vials to be proportional to the original 3.5-mg vial, the cost would be also reduced by the same rates described above.

CONCLUSIONS

A simple adjustment in vial size may reduce the waste of bortezomib by 36% to 62% and can also reduce the cost of treatment.

XELOX in colorectal cancer: a convenient option for the future?

XELOX is a 3-weekly chemotherapy combination of oral capecitabine and intravenous oxaliplatin. The central hypothesis that led to its development was that it would provide a convenient and cost-effective alternative to intravenous fluorouracil-based chemotherapy doublets, without compromising on anti-tumor efficacy. Recently its role in colorectal cancer has become more established in both the metastatic and adjuvant setting. Ongoing investigation of XELOX continues in a number of directions: its combination with novel biological agents, its efficacy and safety in the elderly, and the development of biomarkers that can predict its anti-tumor effect. This article provides a comprehensive and up-to-date synopsis of all pertinent clinical studies detailing this regimen and its promise for the future.

Thymidine phosphorylase expression in metastatic sites is predictive for response in patients with colorectal cancer treated with continuous oral capecitabine and biweekly oxaliplatin

The primary objective of this study was to determine the activity and safety profile of biweekly oxaliplatin combined with continuous oral capecitabine in the first-line treatment of metastatic colorectal cancer. A secondary endpoint was to investigate the correlation between thymidylate synthase and thymidine phosphorylase (TP) expression in metastatic tissues and tumor response. Forty-one patients received oral capecitabine 1331 mg/m every day combined with intravenous oxaliplatin 85 mg/m every 2 weeks. The overall response rate was 58.5% [95% confidence interval (CI): 43.3-73.6%], the median progression-free survival 9.4 months (95% CI: 7.7-11.2 months) and the median survival 22.3 months (95% CI: 16.1-27.5 months). There were no grade 4 toxicities, and grade 3 toxicity was also uncommon. High TP expression in metastatic tissue was significantly associated with response to treatment (P=0.019), and also with a trend towards a better median progression-free survival and overall survival compared with patients expressing low TP (P=0.056; P=0.073). This study suggests that biweekly oxaliplatin and continuous oral capecitabine is an active and well-tolerated chemotherapy regimen in the first-line treatment of metastatic colorectal cancer. Moreover, these findings add to a growing body of evidence that patients with high levels of intratumoral TP expression are the ideal candidates for capecitabine-based chemotherapy.

Drug waste minimisation and cost-containment in Medical Oncology: two-year results of a feasibility study

BACKGROUND

Cost-containment strategies are required to face the challenge of rising drug expenditures in Oncology. Drug wastage leads to economic loss, but little is known about the size of the problem in this field.

METHODS

Starting January 2005 we introduced a day-to-day monitoring of drug wastage and an accurate assessment of its costs. An internal protocol for waste minimisation was developed, consisting of four corrective measures: 1. A rational, per pathology distribution of chemotherapy sessions over the week. 2. The use of multi-dose vials. 3. A reasonable rounding of drug dosages. 4. The selection of the most convenient vial size, depending on drug unit pricing.

RESULTS

Baseline analysis focused on 29 drugs over one year. Considering their unit price and waste amount, a major impact on expense was found to be attributable to six drugs: cetuximab, docetaxel, gemcitabine, oxaliplatin, pemetrexed and trastuzumab. The economic loss due to their waste equaled 4.8% of the annual drug expenditure. After the study protocol was started, the expense due to unused drugs showed a meaningful 45% reduction throughout 2006.

CONCLUSION

Our experience confirms the economic relevance of waste minimisation and may represent a feasible model in addressing this issue.A centralised unit of drug processing, the availability of a computerised physician order entry system and an active involvement of the staff play a key role in allowing waste reduction and a consequent, substantial cost-saving.