Phase II trial of docetaxel (Taxotere) for untreated advanced colorectal carcinoma

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Gastrointestinal Malignancy: Genetic Implications to Clinical Applications

Advances in molecular genetics have revolutionized our understanding of the pathogenesis, progression, and therapeutic options for treating gastrointestinal (GI) cancers. This chapter provides a comprehensive overview of the molecular landscape of GI cancers, focusing on key genetic alterations implicated in tumorigenesis across various anatomical sites including GIST, colon and rectum, and pancreas. Emphasis is placed on critical oncogenic pathways, such as mutations in tumor suppressor genes, oncogenes, chromosomal instability, microsatellite instability, and epigenetic modifications. The role of molecular biomarkers in predicting prognosis, guiding treatment decisions, and monitoring therapeutic response is discussed, highlighting the integration of genomic profiling into clinical practice. Finally, we address the evolving landscape of precision oncology in GI cancers, considering targeted therapies and immunotherapies.

Drug-repurposing screen on patient-derived organoids identifies therapy-induced vulnerability in KRAS-mutant colon cancer

Patient-derived organoids (PDOs) are widely heralded as a drug-screening platform to develop new anti-cancer therapies. Here, we use a drug-repurposing library to screen PDOs of colorectal cancer (CRC) to identify hidden vulnerabilities within therapy-induced phenotypes. Using a microscopy-based screen that accurately scores drug-induced cell killing, we have tested 414 putative anti-cancer drugs for their ability to switch the EGFRi/MEKi-induced cytostatic phenotype toward cytotoxicity. A majority of validated hits (9/37) are microtubule-targeting agents that are commonly used in clinical oncology, such as taxanes and vinca-alkaloids. One of these drugs, vinorelbine, is consistently effective across a panel of >25 different CRC PDOs, independent of RAS mutational status. Unlike vinorelbine alone, its combination with EGFR/MEK inhibition induces apoptosis at all stages of the cell cycle and shows tolerability and effective anti-tumor activity in vivo, setting the basis for a clinical trial to treat patients with metastatic RAS-mutant CRC.

Novel octapeptide-DTX prodrugs targeting MMP-7 as effective agents for the treatment of colorectal cancer with lower systemic toxicity

Colorectal cancer (CRC) is the third most common cancer and the fourth leading cause of cancer death around the world. The current treatments of CRC exhibited high occurrence rate of side effects. Docetaxel (DTX), an important drug widely used in cancer chemotherapy, showed serious toxicity in CRC. Reducing toxicity of DTX could be a feasible and promising way to achieve the new indication of DTX for CRC. In this study, a series of MMP-7 activated octapeptide-DTX/4FDT prodrugs (6a-10a and 6b-10b) were designed and synthesized based on the features of MMP-7 which is highly expressed in CRC and could specially recognize octapeptides with specific sequences. Among them, 9a and 9b, both possessing an octapeptide Gly-Pro-Gln-Gly-Ile-Ala-Met-Gln moiety, were the most potent prodrugs. Compounds 9a and 9b were also tested their release rate in HCT116 cell culture fluids and tumor homogenate along with in vivo anti-CRC activity and systemic toxicity. Since 9a showed better anti-CRC activity and lower systemic toxicity than 9b in CRC tumor bearing mice, it was further evaluated for its acute toxicity, pharmacokinetics and tissue distribution in comparison with its parent drug DTX. These results revealed that 9a possessed good systemic stability, rapid release rate in CRC and reduced systemic toxicity, while retaining similar anti-CRC activity to its parent drug DTX. Thus, 9a, an MMP-7 polypeptide prodrug of DTX, has been identified as a promising candidate for the treatment of CRC.

Pharmacoethnicity of docetaxel-induced severe neutropenia: integrated analysis of published phase II and III trials

BACKGROUND

Ethnic differences in drug susceptibility and toxicity are a major concern, not only in drug development but also in the clinical setting. We review the toxicity profiles of docetaxel according to dose and ethnicity.

METHODS

We analyzed phase II and III clinical trials that included a once-every-3-weeks single-agent docetaxel arm. Logistic regression analysis was applied to identify the significant variables affecting the reported incidence of docetaxel-induced severe neutropenia.

RESULTS

Multivariate logistic regression analysis identified studies conducted in Asia [odds ratio (OR) 19.0; 95% confidence interval (95% CI) 3.64-99.0] and docetaxel dose (OR 1.08; 95% CI 1.03-1.13) as independent variables for the incidence of grade 3/4 neutropenia.

CONCLUSIONS

There is a significant difference in the incidence of docetaxel-induced severe neutropenia between Asian and non-Asian clinical studies. Physicians and pharmacists should consider ethnic diversity in docetaxel toxicity when interpreting the results of clinical trials.

Transcatheter arterial chemoembolization with docetaxel-loaded microspheres controls heavily pretreated unresectable liver metastases from colorectal cancer: a case study

This is the first case report describing transcatheter arterial chemoembolization (TACE) with docetaxel-loaded microspheres which was successful in controlling liver metastases. We report on a 50-year-old woman with unresectable liver metastases from colorectal cancer. Since November 2007, the patient had received 12 courses of mFOLFOX6 (LV/5-FU/L-OHP) as the 1st line therapy, 18 courses of LV/5-FU as the 2nd line therapy, 16 courses of FOLFIRI (LV/5-FU/CPT-11) + bevacizumab as the 3rd line therapy, and 32 courses of cetuximab as the 4th line therapy. All treatments had been conducted after confirmation of the disease progression. The patient experienced hepatic dysfunction, upper abdominal pain and malaise due to the growth of metastatic liver tumors. Since December 2009, the patient received 3 courses of TACE with docetaxel-loaded microspheres in combination with hepatic arterial infusion of 20 mg cisplatin (CDDP) in a palliative setting for the treatment of liver metastases, which resulted in a reduction or necrosis of liver metastases and improvement in hepatic function and symptoms. TACE with docetaxel-loaded microspheres may be a palliative therapy for patients with colorectal cancer who are refractory to the current standard systemic chemotherapy and have predominant liver metastases.

A phase I clinical and pharmacokinetic study of tipifarnib in combination with docetaxel in patients with advanced solid malignancies

PURPOSE

This phase I study assessed the maximum tolerated doses (MTDs), safety, pharmacokinetics, and efficacy of combined tipifarnib and docetaxel treatment in patients with advanced solid malignancies.

EXPERIMENTAL DESIGN

The study protocol was sensitive to myelosuppression, as both drugs have been associated with this adverse event. Due to myelosuppression incidence, and in order to determine the MTD of docetaxel, multiple treatment regimens were employed. Tipifarnib was administered orally at 200 or 300 mg, twice daily (BID) for 21 days, 14 days, or 7 days for multiple 21-day cycles; intravenous (i.v.) docetaxel was administered on day 1 of each cycle at 60, 75, or 85 mg/m2.

RESULTS

A total of 36 patients entered into the study. For each drug, MTDs were identified (tipifarnib: 300 mg BID for 14 days with 60 mg/m2 docetaxel; tipifarnib: 200 mg BID for 14 days with 75 mg/m2 docetaxel). The major dose-limiting toxicity was myelosuppression, particularly febrile neutropenia (44%). Mutual pharmacokinetic interactions (the effect of docetaxel on tipifarnib pharmacokinetics and the effect of tipifarnib on docetaxel pharmacokinetics) were not evident, as maximum plasma concentration (Cmax) and the area under the serum concentration-time curve (AUC) values of both tipifarnib and docetaxel were similar (p > or = 0.43) whether the two drugs were concomitantly administered or not. Seven of 31 evaluable patients (23%) had an objective response, 11 (35%) had stable disease (six > or = 24 weeks), and the overall clinical benefit rate (objective response and/or stable disease > or = 24 weeks) was 42%.

CONCLUSIONS

Although the high incidence of febrile neutropenia necessitated a multiple scheduling adaptation of tipifarnib compared to the original protocol, the apparent lack of mutual pharmacokinetic interactions, the ability to coadminister tipifarnib and docetaxel near single-agent MTDs, and suggestive evidence of efficacy make this drug combination attractive for further examination.

Blockade of Wnt-1 signaling induces apoptosis in human colorectal cancer cells containing downstream mutations

Aberrant Wnt signaling, mainly through mutations of APC and in some cases of CTNNB1 or AXIN2, has been found in the majority of colorectal cancers. Recently, frequent promoter hypermethylation was identified to cause silencing of the secreted frizzled-related protein (sFRP) family in colorectal cancer. Restoration of sFRP in colorectal cancer cells attenuates Wnt signaling even in the presence of downstream mutations. Here we show that Wnt inhibitory factor-1 (WIF-1), a different secreted antagonist of Wnt signaling, is also silenced by promoter hypermethylation in colorectal cancer cells. Restoration of WIF-1 function, Wnt-1 siRNA, or a monoclonal anti-Wnt-1 antibody that we developed attenuates Wnt-1 signaling and induces significant apoptosis in these cells containing downstream mutations and expressing Wnt-1. In addition, this monoclonal anti-Wnt-1 antibody showed synergistic effects with docetaxel in treating these colorectal cancer cells and great efficacy in treating primary colorectal cancer cultures freshly prepared from patients. Therefore, our data support the hypothesis that constitutive Wnt signaling may be required to complement downstream mutations in the evolution of colorectal cancer. Furthermore, our results suggest that blockade of the Wnt signal may have a therapeutic role in the treatment of colorectal cancer.

Pharmacobiologically based scheduling of capecitabine and docetaxel results in antitumor activity in resistant human malignancies

PURPOSE

Capecitabine and docetaxel have demonstrated preclinical antitumor synergy. This synergy is thought to occur from docetaxel-mediated upregulation of thymidine phosphorylase (dThdPase), an enzyme responsible for the relative tumor selectivity of capecitabine. On the basis of the time-dependency and transiency for this upregulation, we performed a phase I study of capecitabine in combination with weekly docetaxel. We hypothesized that weekly docetaxel would result in sustained dThdPase expression and that capecitabine administration at times of maximum dThdPase upregulation would increase the therapeutic index for this combination.

PATIENTS AND METHODS

Patients with advanced solid malignancies received docetaxel on days 1, 8, and 15, and capecitabine bid on days 5 to 18, every 4 weeks. Docetaxel was fixed at 36 mg/m(2)/wk, whereas capecitabine was escalated in successive patients cohorts.

RESULTS

Sixteen patients received 77 courses at capecitabine doses from 950 to 1,500 mg/m(2)/d. The most common toxicities were hand-foot syndrome, diarrhea, nausea/vomiting, and asthenia. Grades 3 to 4 hematologic toxicities were infrequent and no treatment-related hospitalizations occurred. Three of three patients treated at 1,500/36 mg/m(2) capecitabine/docetaxel developed grade 3 hand-foot syndrome or diarrhea during either their first or second course, whereas only two of 13 patients at 1,250/36 mg/m(2) doses developed significant toxicity. Antitumor responses (n = 7) occurred in patients with hepatocellular, non-small-cell lung, and chemotherapy-refractory breast, bladder, and colorectal carcinomas. Prolonged stabilizations occurred in patients with metastatic mesothelioma (n = 2), chemorefractory non-small-cell lung carcinoma, and bronchioloalveolar carcinoma.

CONCLUSION

Capecitabine in combination with weekly docetaxel is well tolerated. Recommended doses are capecitabine 1,250 mg/m(2)/d (625 mg/m(2) bid) with docetaxel 36 mg/m(2)/wk. The acceptable toxicity profile in this dose schedule, and the antitumor activity observed, warrant further evaluation of this regimen.