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SOC-1

Secondary cytoreduction followed by chemotherapy versus chemotherapy alone in platinum-sensitive relapsed ovarian cancer (SOC-1): a multicentre, open-label, randomised, phase 3 trial

Phase 3N = 357NCT01611766

Population
Platinum-sensitive relapsed epithelial ovarian cancer predicted to be resectable by iMODEL score and PET-CT
Design
Open-label trial at four academic centres in China. Patients with platinum-sensitive relapsed epithelial ovarian cancer (platinum-free interval of at least 6 months) predicted to have potentially resectable disease by the iMODEL score (4.7 or lower) and PET-CT were randomly assigned 1:1 to secondary cytoreductive surgery followed by six cycles of intravenous chemotherapy, or chemotherapy alone. By protocol amendment patients with an iMODEL score above 4.7 could enter if serum CA-125 was above 105 U/mL and the principal investigators judged the disease resectable by PET-CT. Primary endpoints were progression-free survival and overall survival; this report gives the final progression-free survival analysis and a prespecified interim overall survival analysis.
Primary endpoint
PFS, OS
Arms
  • Surgery plus chemotherapy (experimental, n = 182): Secondary cytoreductive surgery followed by intravenous paclitaxel or docetaxel with carboplatin
  • Chemotherapy alone (control, n = 175): Intravenous paclitaxel or docetaxel with carboplatin alone
People
Shi T
PFSHR 0.58 (95% CI 0.45–0.74)Δ median PFS+5.5 monthsOSHR 0.82 (95% CI 0.57–1.19)Δ median OS+4.2 months
Show the numbers
Results reported for SOC-1
EndpointAnalysisSurgery plus chemotherapyChemotherapy aloneEffect
PFSIntention-to-treat population (all participants randomly assigned)finalmedian follow-up 36 monthsShi 2021median 17.4 months (15.0–19.8)median 11.9 months (10.0–13.8)HR 0.58 (95% CI 0.45–0.74)P<0.0001Median follow-up 36.0 months (IQR 18.1 to 58.3). In the no-surgery group 11 of 175 participants (6%) had secondary cytoreduction during second-line therapy.
OSIntention-to-treat population (all participants randomly assigned)interimmedian follow-up 36 monthsShi 2021median 58.1 monthsmedian 53.9 months (42.2–65.5)HR 0.82 (95% CI 0.57–1.19)Prespecified interim analysis; the 95% CI for the surgery-group median was not estimable. Of 130 participants in the no-surgery group who had disease progression, 48 (37%) crossed over to surgery at a subsequent recurrence.
Results reported for SOC-1
EndpointAnalysisSurgery plus chemotherapyChemotherapy aloneEffect
PFSIntention-to-treat population (all participants randomly assigned)finalmedian follow-up 36 monthsShi 2021median 17.4 months (15.0–19.8)median 11.9 months (10.0–13.8)HR 0.58 (95% CI 0.45–0.74)P<0.0001Median follow-up 36.0 months (IQR 18.1 to 58.3). In the no-surgery group 11 of 175 participants (6%) had secondary cytoreduction during second-line therapy.
OSIntention-to-treat population (all participants randomly assigned)interimmedian follow-up 36 monthsShi 2021median 58.1 monthsmedian 53.9 months (42.2–65.5)HR 0.82 (95% CI 0.57–1.19)Prespecified interim analysis; the 95% CI for the surgery-group median was not estimable. Of 130 participants in the no-surgery group who had disease progression, 48 (37%) crossed over to surgery at a subsequent recurrence.
Hazard ratio (95% CI) by endpoint. Values below 1 favour the experimental arm.
PFSOS0.512◀ experimentalcontrol ▶
Data table
EndpointHR95% CI
PFS0.580.45–0.74
OS0.820.57–1.19
Illustrative — modelled from reported values, not trial data. PFS, final.
0%25%50%75%100%010203040Months (modelled)
  • Surgery plus chemotherapy (experimental)
  • Chemotherapy alone (control)

Median-only curves assume a constant hazard (exponential) and fit plateaus, as seen with some immunotherapies, poorly.

Data table (modelled values)
MonthsSurgery plus chemotherapyChemotherapy alone
0100.0%100.0%
1164.5%52.7%
2241.6%27.8%
3326.9%14.6%
4417.3%7.7%
Illustrative — modelled from reported values, not trial data. OS, interim.
0%25%50%75%100%020406080100120140Months (modelled)
  • Surgery plus chemotherapy (experimental)
  • Chemotherapy alone (control)

Median-only curves assume a constant hazard (exponential) and fit plateaus, as seen with some immunotherapies, poorly.

Data table (modelled values)
MonthsSurgery plus chemotherapyChemotherapy alone
0100.0%100.0%
3665.1%62.9%
7341.9%39.1%
10927.2%24.6%
14517.7%15.5%
Primary publication: Shi T, Zhu J, Feng Y, Tu D, Zhang Y, Zhang P, et al. Secondary cytoreduction followed by chemotherapy versus chemotherapy alone in platinum-sensitive relapsed ovarian cancer (SOC-1): a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol. 2021;22(4):439-449. PubMedDOI

Appears in

Sources

  1. Shi T, Zhu J, Feng Y, Tu D, Zhang Y, Zhang P, et al. Secondary cytoreduction followed by chemotherapy versus chemotherapy alone in platinum-sensitive relapsed ovarian cancer (SOC-1): a multicentre, open-label, randomised, phase 3 trial. Lancet Oncol. 2021;22(4):439-449.

    PubMedDOI