Table 3.
Number of Responders by Randomized Treatment Group for Two-Stage Group Sequential Design
| Stage and Response | TOPO (n = 30 at stage 1; n = 59 at stage 2) | TOPO/CTX (n = 30 at stage 1; n = 57 at stage 2) | Difference in No. of CR + PR Responders (R = R(TOPO/CTX)–R(TOPO)) | Decision Boundary | Decision |
|---|---|---|---|---|---|
| Stage 1, n = 60 | 0 | R ≥ 7: stop (success) | Continue to stage 2 | ||
| CR + PR | 6 | 6 | –2 < R < 7: continue | ||
| CR + PR + MR | 10 | 13 | R ≤ –2: stop (futile) | ||
| Stage 2, n = 116 | 7 | ≥ 8: success | Insufficient evidence of benefit | ||
| CR + PR | 11 | 18 | < 8: insufficient | ||
| CR + PR + MR | 19 | 26 | evidence of benefit |
Abbreviations: TOPO, topotecan alone; TOPO/CTX, topotecan plus cyclophosphamide; CR, complete response; PR, partial response; R, responders.