First-Line Data

The safety and efficacy of paclitaxel followed by cisplatin in patients with advanced ovarian cancer and no prior chemotherapy were evaluated in 2, Phase 3 multicenter, randomized, controlled trials. In an Intergroup study led by the European Organization for Research and Treatment of Cancer involving the Scandinavian Group NOCOVA, the National Cancer Institute of Canada, and the Scottish Group, 680 patients with Stage IIB–C, III, or IV disease (optimally or non-optimally debulked) received either paclitaxel 175 mg/m2 infused over 3 hours followed by cisplatin 75 mg/m2 (Tc) or cyclophosphamide 750 mg/m2 followed by cisplatin 75 mg/m2 (Cc) for a median of 6 courses. Although the protocol allowed further therapy, only 15% received both drugs for 9 or more courses. In a study conducted by the Gynecological Oncology Group (GOG), 410 patients with Stage III or IV disease (>1 cm residual disease after staging laparotomy or distant metastases) received either paclitaxel 135 mg/m2 infused over 24 hours followed by cisplatin 75 mg/m2 or cyclophosphamide 750 mg/m2 followed by cisplatin 75 mg/m2 for 6 courses.

In both studies, patients treated with paclitaxel in combination with cisplatin had significantly higher response rate, longer time to progression, and longer survival time compared with standard therapy. These differences were also significant for the subset of patients in the Intergroup study with non-optimally debulked disease, although the study was not fully powered for subset analyses (TABLES 2A and 2B). Kaplan- Meier survival curves for each study are shown in FIGURES 1 and 2.

TABLE 2A. EFFICACY IN THE PHASE 3 FIRST-LINE OVARIAN CARCINOMA STUDIES   


TABLE 2B. EFFICACY IN THE PHASE 3 FIRST-LINE OVARIAN CARCINOMA INTERGROUP STUDY   


Figure 1. Survival: Cc Versus Tc (Intergroup)

Figure 2. Survival: Cc Versus Tc (GOG-111)

The adverse event profile for patients receiving paclitaxel in combination with cisplatin in these studies was qualitatively consistent with that seen for the pooled analysis of data from 812 patients treated with single-agent paclitaxel in 10 clinical studies. These adverse events and adverse events from the Phase 3 first-line ovarian carcinoma studies are described in the ADVERSE REACTIONS section in tabular (TABLES 10 and 11) and narrative form.

Second-Line Data

Data from 5, Phase 1 and 2 clinical studies (189 patients), a multicenter randomized Phase 3 study (407 patients), as well as an interim analysis of data from more than 300 patients enrolled in a treatment referral center program were used in support of the use of paclitaxel in patients who have failed initial or subsequent chemotherapy for metastatic carcinoma of the ovary. Two of the Phase 2 studies (92 patients) utilized an initial dose of 135 to 170 mg/m2 in most patients (>90%) administered over 24 hours by continuous infusion. Response rates in these 2 studies were 22% (95% CI, 11 to 37%) and 30% (95% CI, 18 to 46%) with a total of 6 complete and 18 partial responses in 92 patients. The median duration of overall response in these 2 studies measured from the first day of treatment was 7.2 months (range, 3.5 to 15.8 months) and 7.5 months (range, 5.3 to 17.4 months), respectively. The median survival was 8.1 months (range, 0.2 to 36.7 months) and 15.9 months (range, 1.8 to 34.5+ months).

The Phase 3 study had a bifactorial design and compared the efficacy and safety of paclitaxel, administered at 2 different doses (135 or 175 mg/m2) and schedules (3- or 24-hour infusion). The overall response rate for the 407 patients was 16.2% (95% CI, 12.8 to 20.2%), with 6 complete and 60 partial responses. Duration of response, measured from the first day of treatment was 8.3 months (range, 3.2 to 21.6 months). Median time to progression was 3.7 months (range, 0.1+ to 25.1+ months). Median survival was 11.5 months (range, 0.2 to 26.3+ months).

Response rates, median survival, and median time to progression for the 4 arms are given in the following table.

TABLE 3. EFFICACY IN THE PHASE 3 SECOND-LINE OVARIAN CARCINOMA STUDY

Analyses were performed as planned by the bifactorial study design described in the protocol, by comparing the 2 doses (135 or 175 mg/m2) irrespective of the schedule (3 or 24 hours) and the 2 schedules irrespective of dose. Patients receiving the 175 mg/m2 dose had a response rate similar to that for those receiving the 135 mg/m2 dose: 18% versus 14% (p=0.28). No difference in response rate was detected when comparing the 3-hour with the 24-hour infusion: 15% versus 17% (p=0.50). Patients receiving the 175 mg/m2 dose of paclitaxel had a longer time to progression than those receiving the 135 mg/m2 dose: median 4.2 versus 3.1 months (p=0.03). The median time to progression for patients receiving the 3-hour versus the 24-hour infusion was 4 months versus 3.7 months, respectively. Median survival was 11.6 months in patients receiving the 175 mg/m2 dose of paclitaxel and 11 months in patients receiving the 135 mg/m2 dose (p=0.92). Median survival was 11.7 months for patients receiving the 3-hour infusion of paclitaxel and 11.2 months for patients receiving the 24-hour infusion (p=0.91). These statistical analyses should be viewed with caution because of the multiple comparisons made. 

Paclitaxel remained active in patients who had developed resistance to platinum-containing therapy (defined as tumor progression while on, or tumor relapse within 6 months from completion of, a platinum-containing regimen) with response rates of 14% in the Phase 3 study and 31% in the Phase 1 and 2 clinical studies.

The adverse event profile in this Phase 3 study was consistent with that seen for the pooled analysis of data from 812 patients treated in 10 clinical studies. These adverse events and adverse events from the Phase 3 second-line ovarian carcinoma study are described in the ADVERSE REACTIONS section in tabular (TABLES 10 and 12) and narrative form.

The results of this randomized study support the use of paclitaxel at doses of 135 to 175 mg/m2, administered by a 3-hour intravenous infusion. The same doses administered by 24-hour infusion were more toxic. However, the study had insufficient power to determine whether a particular dose and schedule produced superior efficacy.