Paclitaxel and docetaxel are approved drugs for metastatic
breast cancer patients. Clinical and laboratory studies suggested that these
drugs had different effects in metastatic breast cancer patients. Both drugs
have similar chemical structure. In early stage of clinical studies docetaxel
demonstrated linear pharmacokinetics and less schedule dependence than
paclitaxel. For both drugs dose limiting toxicity is neutropenia. Indirect
clinical comparison was performed between these two drugs and there was
imprecise because of difference in patient population. Hence head to head
comparison of these two drugs was done to compare safety and efficacy.
Therefore randomised phase III study is designed to compare paclitaxel and
docetaxel at approved doses and schedule.
Study design is randomised, multicenter, controlled
and open label phase III study to compare antitumor activity and toxicity of docetaxel of dose
100mg/m2 per hour
intravenous infusion for every 21 days verses paclitaxel 175mg/m3 for 3 hours intravenous
infusion for every 21 days. Premedication for docetaxel patients consists of dexamethasone
8 mg by mouth twice daily starting one day before intravenous infusion and
continuing for 5 days. Premedication for paclitaxel patients is dexamethasone
20mg by mouth administered 12 and 6 hours before the paclitaxel infusion,
Ranitidine 50mg or cimetidine 300mg IV and diphenhydramine 50 mg IV
administered 30 to 60 minutes before intravenous infusion. Treatment continued
up to unacceptable toxicity or tumour progression or withdrawal of consent.
53 Institutions between October 1994 and October 2001 449 subjects were
randomly assigned for study. 225 subjects were randomly assigned for docetaxel
arm and 224 subjects were randomly assigned for paclitaxel arm. From these, 211
subjects in the docetaxel arm and 214 subjects in the paclitaxel arm were eligible
and 189 docetaxel subjects and 205 subjects paclitaxel subjects were considered
assessable for efficacy. In the intent-to-treat population, both the
median overall survival (OS, 15.4 v 12.7 months; hazard ratio HR,
1.41; 95% CI, 1.15 to 1.73; P _ .03) and the median time to progression (TTP,
5.7 months v 3.6 months; HR, 1.64; 95% CI, 1.33 to 2.02; P _ .0001)
for docetaxel was significantly longer than for paclitaxel, and the overall
response rate (ORR, 32% v 25%; P _ .10) was higher for docetaxel.
These results were confirmed by multivariate analyses. The incidence of
treatment-related hematologic and nonhematologic toxicities was greater for
docetaxel than for paclitaxel. Hence quality-of-life scores were not
statistically different between treatment groups over time.