A comparison of antibiotic release between a cement scaffold, a perforated cement scaffold and a cement scaffold mixed to calcium sulphate: in vitro study

One of the most dangerous possible complications in joint replacement is infection due to bacteria adhere to prosthesis surface making biofilm difficult to erase. The gold standard treatment consists in prosthesis removal, placement of antibiotic-impregnated cement spacer and systemic antibiotics therapy. When the infection heals a new prosthesis is implanted. The antibiotic-impregnated spacer is important to maintain the prosthesis space and to guarantee a local high concentration of antibiotics. The release of the antibiotic by the cement happens at its surface so that, increasing this, the concentration of antibiotic should be increased as well. The aim of the present study is to verify the different release of antibiotic in plasma by different groups of scaffolds to identify the best solution to make the antibiotic spacer in septic prosthesis revision. Six groups of three antibiotic impregnated cement cube-shaped have been done. The first, made by only antibiotic and cement, the second by a double concentration of the antibiotic and cement, the third made by the antibiotic cement and perforated in every surface with a needle before hardening, the fourth similar to the previous but with a double concentration of antibiotic, the fifth by antibiotic-impregnated cement mixed with calcium sulphate pellets, the sixth similar to the previous with a double concentration of antibiotic. The cubes were immersed in plasma and the concentration of antibiotic released valued at specific times. The perforated cement scaffold demonstrated the best result during the first four weeks.

Analysis of phase I pharmacokinetic studies with targeted molecules based on gender and age

2521

Background: Pharmacokinetic parameters are usually not sufficiently correlated with patient characteristics, such as age, gender, or excretory organ function, and with outcome measures. Female sex has been shown to be a risk factor for clinically relevant adverse drug reactions and acting as a predictive/prognostic factor. Methods: We analyzed Phase I/II oncology trials of solid tumors with targeted agents enrolling Male and Female population (age>18yrs), reporting pharmacokinetic analysis, published between 2000 and 2007. We excluded trials involving Radiation therapy alone, Hematological malignancies, and trials of Gender related pathology (ovarian, prostate and breast cancer). Standard descriptive statistics was used. Results: 160 phase I and II trials involving 48 targeted agents has been selected. 44%, 37% and 19% of the population enrolled for PK analysis is respectively male, female or unknown gender. 65% of the trials have male preponderance. Authors did not specified number of male and female if only a group of patients enrolled in the trial was submitted to pharmacokinetic analysis. 95% of the trials enrolled patients > 65years, while 16% of the trials enrolled patients >80years. But only 3% of studies specified individual patient age and less than 6% of papers showed the number of male and female for each dose level, while about 10% of studies considered ethnicity as a characteristic. Conclusions: What emerged from our analysis is the irregularity and the lack of important informations when reported for publication. Knowing the impact of important prognostic/predictive factor of such clinical parameter (age, gender) we believe that more informations should be reported in the trials in order to evaluate if Toxicity and Efficacy could be gender or age related. Definitive data will be presented at the meeting.

No significant financial relationships to disclose.

Dose-escalating study of continuative low dose of oral vinorelbine in patients with advanced breast cancer

1128

Background: Low and continuative dose of antineoplastic drugs has been shown to have an antiangiogenic activity. The rapid absorption and relatively short half-life of the oral formulation of vinorelbine are favorable pharmacokinetic characteristics to test a continuative low-dose schedule. Methods: Patients with measurable metastatic breast cancer were treated with escalating dose of oral vinorelbine from 50 mg/m2 per week to 90 mg/m2 per week until progressive disease or unacceptable toxicity. These patients were administered one third of the total weekly dose 3 times per week, every other day. A pharmacokinetic analysis was planned at the first 3 weeks of drug assumption. Results: Of twenty-two patients included in the study, 3 were treated at 50 mg/m2/w (level 1), 5 at 60 mg/m2/w (level 2), 3 at 70 mg/m2/w (level 3), 8 at 80 mg/m2/w (level 4), and 3 at 90 mg/m2/w (level 5); we are still enrolling patients at this level. The median age was 59 years (range 23–75). The median number of prior lines of chemotherapy and hormonal therapy was 2 (range 0–4 for CT and 0–5 for OT). Fifteen of 22 patients had visceral metastasis. No dose-limiting toxicities have been observed until now. The main toxicities were: asymptomatic neutropenia grade 4 in two patients (1 in level 4 and 1 in level 5), asthenia grade 3 in 7 patients (1 at level 1, 2 at level 2, 1 at level 3, 3 at level 4), neurotoxicity grade 3 in two patients (one at level 2 and one at level 4). One patient experienced an intestinal sub-occlusion and hospitalization was required with no permanent side effects. One patient had a partial response, five a stable disease, fourteen progressed and two are not evaluated yet. At 1 year, five of the twenty evaluable patients are died by disease. Samples of twenty patients were collected for pharmacokinetic analysis that will be presented at the meeting. Conclusions: The continuative split 3 times per week oral vinorelbine is feasible, and at 90 mg/m2/w we have not reached yet the maximum tolerated dose.

No significant financial relationships to disclose.

Dose scheduling and pharmacokinetic (PK) study of trastuzumab in patients (pts) with HER2/neu overexpressing breast cancer?

1109

Has been demonstrated that 10–20 μg/mL is the minimum serum trough concentration (Cmin) of trastuzumab that causes maximal tumor growth inhibition. This concentration was shown to be achievable using a weekly (4 mg/kg loading dose followed by 2 mg/kg weekly) and a three-weekly (8 mg/kg loading dose followed by 6 mg/kg) schedule, but only indirect comparisons of the two schedule have been performed. We prospectively analysed the PK distribution of trastuzumab in three different schedules, as follows: weekly (cohort I), bi-weekly (trastuzumab 6 mg/kg loading dose followed by 4 mg/kg, cohort II) and three-weekly schedule (cohort III). The PK analysis was performed in 18 pts (4 pts receiving the loading dose of cohort III, 8 pts receiving the maintenance dose of cohort III, 3 pts receiving the maintenance dose of cohort II, and 3 pts receiving loading dose of cohort I). Of the 18 pts analyzed, 9 were metastatic. The median age was 54 years (range 39–76), the median weight was 61,5 kg (range 53–80). At diagnoses, 10 pts had stage I disease, 5 and 3 pts had stage II and III respectively, ER was negative in 10 pts and PgR was negative in 12 pts; Ki67 was highly expressed in 14 pts; Her/neu was overexpressed and amplified in 16 and 2 pts respectively. To evaluate preliminary interpatient variability, 3 pts receiving 6mg/kg of trastuzumab repeated the PK analysis after four cycles: the comparison between two groups was not statistically significative. Comparison of Cmax and AUC mean between groups was statistically significative (P<0.05, Bonferroni test) except for 8 mg/kg vs 6 mg/kg AUC.All the doses and schedules analysed are able to reach the minimum serum concentration of trastuzumab that causes the maximal tumor growth inhibition.

[Table: see text]

No significant financial relationships to disclose.