Background

Troxacitabine is a novel L-nucleoside analogue. Preclinical studies showed improved activity with infusions of at least 3 days compared with bolus regimens, especially at concentrations >20 ng/ml. This phase I study tested the feasibility of achieving a troxacitabine steady-state concentration of 20 ng/ml for at least 72 h in patients with solid tumors.

Patients and methods

Patients with solid tumors received troxacitabine as a progressively longer infusion on days 1–4 of a 28-day cycle. The initial length of infusion and infusion rate were 48 h and 3 mg/m2/day.

Results

Twenty-one patients were treated at infusion lengths that increased from 48 to 72 h and then 96 h. The infusion rate was decreased from 3 to 1.88 mg/m2/day due to toxicity. Dose-limiting toxicities consisted of grade 4 neutropenia (three) and grade 3 constipation (one). The maximum tolerated dose of continuous infusion troxacitabine in patients with solid tumors is 7.5 mg/m2 administered over 96 h. This dose level resulted in steady-state drug concentration of at least 20 ng/ml for 72 h.

Conclusions

Administration of troxacitabine by continuous infusion achieved the prospectively defined target plasma concentration. Pharmacokinetics (PK) modeling coupled with real-time PK assessment was an efficient approach to conduct hypothesis-driven phase I trials.

Background

Pancreatic carcinoma remains a treatment-refractory cancer with a poor prognosis. Here, we compared anti-EGF receptor and anti-HER2 monoclonal antibodies (2mAbs) injections with standard gemcitabine treatment on human pancreatic carcinoma xenografts.

Materials and Methods

Nude mice, bearing human pancreatic carcinoma, xenografts, were treated with either combined anti-EGFR (cetuximab) and anti-HER2 (trastuzumab), or gemcitabine and tumor growth were observed.

Results and Conclusion

In first-line therapy, mice survival was significantly longer in 2mAbs groups compared to gemcitabine (p<0.0001: BxPC-3; p=0.0679: MiaPaCa-2; p=0.0019: Capan-1) and to controls (p<0.0001). In second-line therapy tumor regressions were observed after replacing gemcitabine by 2mAbs treatment, resulting in significantly longer animal survival, compared with mice receiving continuous gemcitabine injections (p=0.008, BxPC-3; p=0.05; MiaPaCa-2; p<0.001, Capan-1). Therapeutic benefit of 2mAbs was observed, despite K-Ras mutation. Interestingly, concerning the mechanism of action, coinjection of F(ab)′2 fragments from 2mAbs induced significant tumor growth inhibition, compared to controls (p=0.001), indicating that the 2mAbs had an, Fc-independent, direct action on tumor cells.

This pre-clinical study demonstrated a significant improvement of survival and tumour regression in mice treated with anti-EGFR/anti-HER2 2mAbs in first and second-line treatments, compared to gemcitabine, independently of the K-Ras status.

The epithelial-mesenchymal transition (EMT) describes a rapid and often reversible modulation of phenotype by epithelial cells. EMT was originally defined in the context of developmental stages, including heart morphogenesis, mesoderm and neural crest formation. Epithelial cells loosen cell-cell adhesion structures throughout EMT. They modulate their polarity, cytoskeleton organization and typically express vimentin filaments and downregulate cytokeratins. They become isolated, mobile and resistant to anoikis. The epithelial-mesenchymal transition at least superficially resembles the evolution from normal to transformed cell phenotype during carcinoma progression. The relevance of the concept of epithelial-mesenchymal transition in this context was suggested by in vitro models using transformed epithelial cells. Transduction pathways typical for embryogenic EMT in vivo were also found to be activated during cancer progression. More recently, it has been found that such pathways suggest an increased plasticity linked to cellular stemness and ability to generate tumors. However, in the absence of direct evidence, a number of oncologists and pathologists remain skeptical about applying the EMT concept to human tumor progression. In fact, EMT concept appears to be fully relevant in some situations, but the concept has to be adjusted in other situations to reflect tumor cell renewal and plasticity during carcinoma progression and metastasis.

Background

Low tumour expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) have been linked with improved outcome for colorectal cancer (CRC) patients treated with 5-fluorouracil (5-FU). It is unclear whether this occurs because such tumours have better prognosis or they are more sensitive to 5-FU treatment.

Patients and methods

Associations between TS, DPD and TP levels, determined by tissue microarrays and immunohistochemistry, and survival was evaluated in 945 CRC patients according to treatment status.

Results

Low TS and DPD expression associated with worse prognosis in stage II [hazard ratio (HR) = 1.69, 95% confidence interval (CI) (1.09–2.63) and HR = 1.92 (95% CI 1.23–2.94), respectively] and stage III CRC patients treated by surgery alone [HR = 1.39 (95% CI 0.92–2.13) and HR = 1.49 (95% CI 1.02–2.17), respectively]. Low TS, DPD and TP associated with trends for better outcome in stage III patients treated with 5-FU [HR = 0.81 (95% CI 0.49–1.33), HR = 0.70 (95% CI 0.42–1.15) and HR = 0.66 (95% CI 0.39–1.12), respectively].

Conclusion

Low TS and DPD expression are prognostic for worse outcome in CRC patients treated by surgery alone, whereas low TS, DPD and TP expression are prognostic for better outcome in patients treated with 5-FU chemotherapy. These results provide indirect evidence that low TS, DPD and TP protein expression are predictive of good response to 5-FU chemotherapy.

Background: To determine the maximum tolerated dose (MTD), safety, potential pharmacokinetic (PK) interactions, and effect on liver histology of trabectedin in combination with pegylated liposomal doxorubicin (PLD) for advanced malignancies.

Patients and methods: Entry criteria for the 36 patients included normal liver function, prior doxorubicin exposure <250 mg/m2, and normal cardiac function. A 1-h PLD (30 mg/m2) infusion was followed immediately by one of six trabectedin doses (0.4, 0.6, 0.75, 0.9, 1.1, and 1.3 mg/m2) infused over 3 h, repeated every 21 days until evidence of complete response (CR), disease progression, or unacceptable toxicity. Plasma samples were obtained to assess PK profiles.

Results: The MTD of trabectedin was 1.1 mg/m2. Drug-related grade 3 and 4 toxic effects were neutropenia (31%) and elevated transaminases (31%). Six patients responded (one CR, five partial responses), with an overall response rate of 16.7%, and 14 had stable disease (less than a 50% reduction and less than a 25% increase in the sum of the products of two perpendicular diameters of all measured lesions and the appearance of no new lesions) >4 months (39%). Neither drug had its PK affected significantly by concomitant administration compared with trabectedin and PLD each given as a single agent.

Conclusion: Trabectedin combined with PLD is generally well tolerated at therapeutic doses of both drugs in pretreated patients with diverse tumor types and appears to provide clinical benefit. These results support the need for additional studies of this combination in appropriate cancer types.

SUMMARY

Background

To determine the maximum tolerated dose (MTD), safety, potential pharmacokinetic (PK) interactions, and effect on liver histology of trabectedin in combination with pegylated liposomal doxorubicin (PLD) for advanced malignancies.

Patients and Methods

Entry criteria for the 36 patients included normal liver function, prior doxorubicin exposure <250 mg/m2, and normal cardiac function. A 1-hour PLD (30 mg/m2) infusion was followed immediately by 1 of 6 trabectedin doses (0.4, 0.6, 0.75, 0.9, 1.1, and 1.3 mg/m2) infused over 3 hours, repeated every 21 days until evidence of complete response (CR), disease progression, or unacceptable txicity. Plasma samples were obtained to assess PK profiles.

Results

The MTD of trabectedin was 1.1 mg/m2. Drug-related grade 3 and 4 toxicities were neutropenia (31%) and elevated transaminases (31%). Six patients responded (1 CR, 5 partial responses), with an overall response rate of 16.7%, and 14 had stable disease >4 months (39%). Neither drug had its PK affected significantly by concomitant administration compared to trabectedin and PLD each given as a single agent.

Conclusion

Trabectedin combined with PLD is generally well tolerated at therapeutic doses of both drugs in pretreated patients with diverse tumor types, and appears to provide clinical benefit. These results support the need for additional studies of this combination in appropriate cancer types.