ABSTRACT
1
Comp. Study [Year] Treatment assignments at randomization Sampl e size Regimen type Strate gy study 1 Design 2 1 C97-3 [1997] C: FOLFIRIFOLFOX6; E: FOLFOX6FOLFIRI 220 NT Y NI 2 N9741 [1999] C: IFL; E: FOLFOX 531 NT N Sup 3 C: IFL; E: IROX 528 NT N Sup 4 C: rIFL; E: FOLFOX 304 NT N Sup 5 C: rIFL; E: IROX 269 NT N Sup 6 FOCUS [2000] C: FUIRI; E: FU+IRI 1058 NT Y Sup 7 C: FUIRI; E: FU+OX 1057 NT Y Sup 8 AVF2192g [2000] C: 5FULV+Placebo; E: 5FULV+Bev 209 ANG N Sup 9 AVF2107g [2000] C: IFL+Placebo; E: IFL+Bev 813 ANG N Sup 10 C: IFL+Placebo; E: 5FULV+Bev 220 ANG N Sup 11 HORG [2000] C: FOLFIRI; E: FOLFOXIRI 283 NT N Sup 12 GONO [2001] C: FOLFIRI; E: FOLFOXIRI 244 NT N Sup 13 03-TTD-01 [2002] C: FUOX; E: XELOX 348 NT N NI 14 AIO22 [2002] C: CAPOX; E: FUFOX 474 NT N NI 15 HORIZON II [2005] C: FOLFOX/CAPOX+placebo E: FOLFOX/CAPOX+Cediranib20mg 860 ANG N Sup 16 C: FOLFOX/CAPOX+placebo E: FOLFOX/CAPOX+Cediranib30mg 432 ANG N Sup 17 CAIRO1 [2003] C: CapIRICap+Bev; E: Cap+IRICap+Bev 803 ANG Y Sup 18 BICC-C [2003] C: FOLFIRI; E: mIFL 285 NT N NI 19 C: FOLFIRI+Bev; E: mIFL+Bev 117 ANG N NI 20 C: FOLFIRI; E: CapeIRI 289 NT N NI 21 FOCUS2 [2004] C: 5FULV; E: 5FULV+OX 230 NT N Sup 22 C: Cap; E: Cap+OX 229 NT N Sup 23 NO16966 [2003] C: FOLFOX4; E: XELOX 634 NT N NI 24 C: FOLFOX4+placebo; E: XELOX+placebo 701 NT N NI 25 C: FOLFOX4+Bev; E: XELOX+Bev 699 ANG N NI 26 C: XELOX+placebo; E: XELOX+Bev 700 ANG N Sup 27 C: FOLFOX4+placebo; E: FOLFOX4+Bev 700 ANG N Sup 28 FIRE II [2004] C: Cetuximab+CAPIRI; E: Cetuximab+CAPOX 177 EGFR N NI 29 PACCE [2005] C: Bev+OX (KRAS WT); E: Bev+OX+Pmab (KRAS WT) 408 ANG + EGFR N Sup 30 C: Bev+OX (KRAS MT) E: Bev+OX+Pmab (KRAS MT) 262 ANG + EGFR N Sup 31 C: Bev+IRI (KRAS WT) E: Bev+IRI+Pmab (KRAS WT) 116 ANG + EGFR N Sup 32 C: Bev+IRI (KRAS MT) E: Bev+IRI+Pmab (KRAS MT) 89 ANG + EGFR N Sup 33 COIN [2005] C: 5FULv/Cap+OX (KRAS WT) E: 5FULv/Cap+OX+Cetuximab (KRAS WT) 729 EGFR N Sup 34 C: 5FULv/Cap+OX (KRAS MT) E: 5FULv/Cap+OX+Cetuximab (KRAS MT) 565 EGFR N Sup 35 CAIRO2 [2005] C: Cap+OX+Bev (KRAS WT) E: Cap+OX+Bev+Cetuximab (KRAS WT) 316 ANG + EGFR N Sup 36 C: Cap+OX+Bev (KRAS MT) E: Cap+OX+Bev+Cetuximab (KRAS MT) 204 ANG + EGFR N Sup 37 MAX [2005] C: Cap; E: Cap+Bev 313 ANG N Sup 38 C: Cap; E: Cap+Bev+Mitomycin 314 ANG N Sup 39 Macro [2006] C: XELOX+BevXELOX+Bev E: XELOX+BevBev 480 ANG N NI 40 PRIME [2006] C: FOLFOX4 (KRAS WT) E: FOLFOX4+Pmab (KRAS WT) 656 EGFR N Sup 41 C: FOLFOX4 (KRAS MT) E: FOLFOX4+Pmab (KRAS MT) 440 EGFR N Sup ABSTRACT METHODS HYPOTHESES FINDINGS Background: Progression-free survival (PFS) has previously been established as a surrogate for overall survival (OS) based on individual patient data (IPD) from 1 st line metastatic colorectal cancer )mCRC) trials conducted before 1999. As mCRC treatment (trt) has advanced in the last decade and OS has increased from 1 to 2 years, this surrogacy required re-examination. Methods: IPD from 16,762 pts, median age 62, 62% male, 53% ECOG PS 0 were available from 22 1 st line mCRC studies conducted from 1997-2006; 12 tested targeted (anti-angiogenic and/or anti- EGFR) regimens. The relationship between PFS (first event of progression or death) and OS was evaluated at patient-, trt-arm-, and trial-levels using correlation (corr.) coefficients and R 2 (closer to 1 the better) from weighted least square (WLS) regression of arm-specific survival rates and trial-specific hazard ratios (HRs), estimated using Cox and Copula bivariate models. The concordance of significance (CoS) of the treatment effects (TEs) on both endpoints was calculated. Results: 44% pts received a targeted regimen. Median PFS was 8 and OS was18 months. The corr. between PFS and OS was modest at all three levels with low CoS in TE comparisons (see Table). Analyses limited to trials testing targeted trts, non-strategy trials, or superiority trials did not improve surrogacy. Conclusion: In modern mCRC trials, where survival post- first progression exceeds time to first progression, PFS TEs do not reliably predict TEs on OS. Nonetheless, until alternative endpoints of clinical benefit can be validated, PFS remains a relevant primary endpoint for 1 st line mCRC trials, as our data demonstrate that the ability for any agent to produce an OS benefit from a single line of therapy is challenging. • Short-term PFS predicts the clinical benefit on long-term OS at the patient-level • Treatment effect measured on PFS predicts the treatment effect on OS at trial-level • Type of treatment (targeted vs. non-targeted) affects the predictive relationship between PFS and OS • Superiority trials will have RESULTS Trial Selection and Patient Characteristics •22 trials and 43 comparisons were included • Two of 24 1st line trials in ARCAD with regimens identical in both arms before 1st PD were excluded • Trials with multiple arms were prospectively defined to generate two-arms comparisons • Where KRAS available, KRAS wildtype vs. mutated patients were treated as 2 separate comparisons • Trials with regimens identical in both arms before 1st progressive disease (PD) were excluded • The non-reported cohorts were included and treated as separate comparisons •Total of 16,762 patients were included • Age: 14% < 50; 26% 50 – 59; 35% 60 – 69; 25% ≥ 70 • ECOG PS: 53% 0; 42% 1; 5% 2+ • Gender: 61% male; 39% female • Regimen: 44% targeted; 56% non- targeted Endpoint Definitions •OS – Time from randomization to death due to any cause •PFS – Time from randomization to 1 st PD or death due to any cause • When possible, PFS centrally redefined to allow consistent calculations across trials Statistical Methods •Patient level • Landmark analysis (evaluating prognostic value of PFS at 6 and 12 months for OS) • Rank correlation coefficient, ρ, between PFS and OS (Copula bivariate survival model) •Treatment arm level • Correlation between short-term (6 DISCUSSION • Although early PFS rate is a strong predictor of long-term OS (patient level landmark analysis), treatment effects observed on PFS at the trial- level do not provide sufficiently accurate prediction of treatment effect on OS in the first-line advanced CRC trials. • Trials testing targeted therapies demonstrated only modestly higher PFS/OS correlations at patient-, treatment arm, and trial-level between PFS and OS than non- targeted trials. • Restricting to non-strategy trials, overall results remain: correlation measures between PFS and OS by treatment arm and at trial-level improved by ~ 0.1 in absolute values. • Restricting trials with superiority design, the above results remain. • Excluding one outlier improved the correlation measures only slightly Individual Patient Data Analysis of Progression-Free versus Overall Survival as an Endpoint for Metastatic Colorectal Cancer in Modern Trials: Findings from the 16,700 Patient ARCAD Database Q Shi 1 , A de Gramont 2 , M Buyse 3 , A Grothey 1 , H-J Schmoll 4 , MT Seymour 5 , R Adams 6 , L Saltz 7 , RM Goldberg 8 , CJA Punt 9 , J-Y Douillard 10 , JR Hecht 11 , H Hurwitz 12 , E Diaz-Rubio 13 , Pr R Proschen 14 , NC Tebbutt 15 , C Fuchs 16 , J Souglakos 17 , A Falcone 18 , DJ Sargent 1 , For the ARCAD Group 1 Mayo Clinic, Rochester MN; 2 Hospital Saint Antoine, Paris, France; 3 International Drug Development Institute, Louvain-la-Neuve, Belgium; 4 Martin-Luther University, Halle, Germany; 5 Cancer Rsrch UK Clinical Ctr, Leeds, UK; 6 Cardiff University, Cardiff, UK; 7 Memory Sloan Kettering Cancer Center, New York, NY; 8 Ohio State University Comprehensive Cancer Center, Columbus, OH; 9 Academic Medical Center, Amsterdam, Netherlands; 10 Centre R Gauducheau, St Herblain, France; 11 David Geffen School of Medicine at UCLA, Los Angeles, CA; 12 Duke University Medical Center, Durham, NC; 13 Hospital Clinico San Carlos, Madrid, Spain; 14 Klinikum Bremen-Ost, Bremen, Germany; 15 Austin Health, Australia; 16 Dana Farber Cancer Institution, Boston, MA; 17 University of Crete, School of Medicine, Heraklion, Greece; 18 University Hospital “S. Chiara”, Pisa, Italy Table 2: Surrogacy Estimation Figure 1: Overall Treatment arm and Trial- level Surrogacy Table 1: Trials Included Class (n. of Comp.) Overall (22) Targeted (12) Non-strategy (18) Superiority (16) Patient level Rank corr. ρ .51 (.50 - .52) .55 (.54 - .56) .53 (.52 - .54) .51 (.50 - .52) Treatment arm level [6m PFS vs. 12m OS rates] r 2 WLS .69 (.58 - .79) .70 (.48 - .91) .73 (.62 - .83) .71 (.59 - .83) Trial level [HR PFS vs. HR OS ] R 2 WLS .54 (.33 - .75) .52 (.24 - .80) .54 (.32 - .76) .51 (.24 - .77) Abbreviations: C, control arm; E, experimental arm; IRI, irinotecan; OX, oxaliplatin; LV, leucovorin; Bev, bevacizumab; Cap, capecitabine; Pmab, Pamtumumab; WT, wild type; MT, mutated; T, targeted; NT, non-targeted; ANG, Anti-angiogenic regimen; EGFR, Anti-EGFR regimen; OS, overall survival; PFS, progression-free survival; HR, hazard ratio; PD, progressive disease 1. Cross-over reflects the actual cross-over from one arm to another due to toxicity, PD and other reasons. 2 Strategy trial refers more treatment specified by protocol beyond the first per protocol regimen. For example, a sequence of treatment was specified per protocol (i.e., the treatment effect of a whole strategy of experimental arm is compared to the control arm), or cross over after PD was specified per protocol. For these studies, the PFS (1 st PD-PFS) with the 1 st PD occurred during study follow-up as one of the events may not be the appropriate endpoint if the regimen before 1 st PD was same for both experimental and control arms. 3 The design refers to the intended primary comparison between arms, i.e., non-inferiority (NI) or superiority (Sup) comparison. The statistical sample size/power consideration section may not reflect NI or Sup design. • PFS has its own merits as an endpoint, and is considered by some a clinical benefit endpoint. However, based on modern trials, PFS treatment effects do not reliably translate into treatment effects on OS. • The lack of association between PFS and OS in modern trials is likely due to extensive use of later-line therapies. • The lack of ability for PFS to predict OS emphasizes rather than detracts from its importance as a clinical trials endpoint to demonstrate activity of a new agent. • PFS remains a relevant primary
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Individual Patient Data Analysis of Progression-Free versus Overall Survival as an Endpoint for Metastatic Colorectal Cancer in Modern Trials: Findings from the 16,700 Patient ARCAD Database - PowerPoint PPT Presentation
Transcript of ABSTRACT
Comp. Study [Year] Treatment assignments at randomizationSample
size Regimen typeStrategy study1 Design2
1 C97-3 [1997]C: FOLFIRIFOLFOX6; E: FOLFOX6FOLFIRI
220 NT Y NI
2
N9741 [1999]
C: IFL; E: FOLFOX 531 NT N Sup3 C: IFL; E: IROX 528 NT N Sup4 C: rIFL; E: FOLFOX 304 NT N Sup5 C: rIFL; E: IROX 269 NT N Sup6
FOCUS [2000]C: FUIRI; E: FU+IRI 1058 NT Y Sup
7 C: FUIRI; E: FU+OX 1057 NT Y Sup8 AVF2192g [2000] C: 5FULV+Placebo; E: 5FULV+Bev 209 ANG N Sup9
AVF2107g [2000]C: IFL+Placebo; E: IFL+Bev 813 ANG N Sup
10 C: IFL+Placebo; E: 5FULV+Bev 220 ANG N Sup11 HORG [2000] C: FOLFIRI; E: FOLFOXIRI 283 NT N Sup12 GONO [2001] C: FOLFIRI; E: FOLFOXIRI 244 NT N Sup13 03-TTD-01 [2002] C: FUOX; E: XELOX 348 NT N NI14 AIO22 [2002] C: CAPOX; E: FUFOX 474 NT N NI
15HORIZON II[2005]
C: FOLFOX/CAPOX+placeboE: FOLFOX/CAPOX+Cediranib20mg
860 ANG N Sup
16C: FOLFOX/CAPOX+placeboE: FOLFOX/CAPOX+Cediranib30mg
432 ANG N Sup
17 CAIRO1 [2003]C: CapIRICap+Bev; E: Cap+IRICap+Bev
803 ANG Y Sup
18BICC-C [2003]
C: FOLFIRI; E: mIFL 285 NT N NI19 C: FOLFIRI+Bev; E: mIFL+Bev 117 ANG N NI20 C: FOLFIRI; E: CapeIRI 289 NT N NI21
FOCUS2 [2004]C: 5FULV; E: 5FULV+OX 230 NT N Sup
22 C: Cap; E: Cap+OX 229 NT N Sup23
NO16966 [2003]
C: FOLFOX4; E: XELOX 634 NT N NI
24 C: FOLFOX4+placebo; E: XELOX+placebo 701 NT N NI
25 C: FOLFOX4+Bev; E: XELOX+Bev 699 ANG N NI26 C: XELOX+placebo; E: XELOX+Bev 700 ANG N Sup
27 C: FOLFOX4+placebo; E: FOLFOX4+Bev 700 ANG N Sup
28 FIRE II [2004]C: Cetuximab+CAPIRI; E: Cetuximab+CAPOX
177 EGFR N NI
29
PACCE [2005]
C: Bev+OX (KRAS WT); E: Bev+OX+Pmab (KRAS WT)
408 ANG + EGFR N Sup
30C: Bev+OX (KRAS MT)E: Bev+OX+Pmab (KRAS MT)
262 ANG + EGFR N Sup
31C: Bev+IRI (KRAS WT)E: Bev+IRI+Pmab (KRAS WT)
116 ANG + EGFR N Sup
32C: Bev+IRI (KRAS MT)E: Bev+IRI+Pmab (KRAS MT)
89 ANG + EGFR N Sup
33COIN [2005]
C: 5FULv/Cap+OX (KRAS WT)E: 5FULv/Cap+OX+Cetuximab (KRAS WT)
729 EGFR N Sup
34C: 5FULv/Cap+OX (KRAS MT)E: 5FULv/Cap+OX+Cetuximab (KRAS MT)
565 EGFR N Sup
35CAIRO2 [2005]
C: Cap+OX+Bev (KRAS WT)E: Cap+OX+Bev+Cetuximab (KRAS WT)
316 ANG + EGFR N Sup
36C: Cap+OX+Bev (KRAS MT)E: Cap+OX+Bev+Cetuximab (KRAS MT)
204 ANG + EGFR N Sup
37MAX [2005]
C: Cap; E: Cap+Bev 313 ANG N Sup
38 C: Cap; E: Cap+Bev+Mitomycin 314 ANG N Sup
39 Macro [2006]C: XELOX+BevXELOX+BevE: XELOX+BevBev
480 ANG N NI
40PRIME [2006]
C: FOLFOX4 (KRAS WT)E: FOLFOX4+Pmab (KRAS WT)
656 EGFR N Sup
41C: FOLFOX4 (KRAS MT)E: FOLFOX4+Pmab (KRAS MT)
440 EGFR N Sup
42HORIZON III[2006]
C: mFOLFOX6+BevE: mFOLFOX6+Cediranib20mg
1409 ANG N Sup
43C: mFOLFOX6+Bev E: mFOLFOX6+Cediranib30mg
380 ANG N Sup
ABSTRACT METHODS
HYPOTHESES
FINDINGS
Background:Progression-free survival (PFS) has previously been established as a surrogate for overall survival (OS) based on individual patient data (IPD) from 1st line metastatic colorectal cancer )mCRC) trials conducted before 1999. As mCRC treatment (trt) has advanced in the last decade and OS has increased from 1 to 2 years, this surrogacy required re-examination. Methods:IPD from 16,762 pts, median age 62, 62% male, 53% ECOG PS 0 were available from 22 1st line mCRC studies conducted from 1997-2006; 12 tested targeted (anti-angiogenic and/or anti-EGFR) regimens. The relationship between PFS (first event of progression or death) and OS was evaluated at patient-, trt-arm-, and trial-levels using correlation (corr.) coefficients and R2 (closer to 1 the better) from weighted least square (WLS) regression of arm-specific survival rates and trial-specific hazard ratios (HRs), estimated using Cox and Copula bivariate models. The concordance of significance (CoS) of the treatment effects (TEs) on both endpoints was calculated. Results:44% pts received a targeted regimen. Median PFS was 8 and OS was18 months. The corr. between PFS and OS was modest at all three levels with low CoS in TE comparisons (see Table). Analyses limited to trials testing targeted trts, non-strategy trials, or superiority trials did not improve surrogacy. Conclusion:In modern mCRC trials, where survival post-first progression exceeds time to first progression, PFS TEs do not reliably predict TEs on OS. Nonetheless, until alternative endpoints of clinical benefit can be validated, PFS remains a relevant primary endpoint for 1st line mCRC trials, as our data demonstrate that the ability for any agent to produce an OS benefit from a single line of therapy is challenging.
• Short-term PFS predicts the clinical benefit on long-term OS at the patient-level
• Treatment effect measured on PFS predicts the treatment effect on OS at trial-level
• Type of treatment (targeted vs. non-targeted) affects the predictive relationship between PFS and OS
• Superiority trials will have stronger PFS/OS surrogacy than strategy/non-inferiority trials
RESULTS
Trial Selection and Patient Characteristics•22 trials and 43 comparisons were included• Two of 24 1st line trials in ARCAD with regimens
identical in both arms before 1st PD were excluded• Trials with multiple arms were prospectively defined
to generate two-arms comparisons• Where KRAS available, KRAS wildtype vs. mutated
patients were treated as 2 separate comparisons• Trials with regimens identical in both arms before 1st
progressive disease (PD) were excluded• The non-reported cohorts were included and treated as
separate comparisons •Total of 16,762 patients were included • Age: 14% < 50; 26% 50 – 59; 35% 60 – 69; 25% ≥ 70• ECOG PS: 53% 0; 42% 1; 5% 2+• Gender: 61% male; 39% female• Regimen: 44% targeted; 56% non-targeted
Endpoint Definitions•OS – Time from randomization to death due to any cause•PFS – Time from randomization to 1st PD or death due to any cause• When possible, PFS centrally redefined to allow
consistent calculations across trialsStatistical Methods•Patient level• Landmark analysis (evaluating prognostic value of
PFS at 6 and 12 months for OS)• Rank correlation coefficient, ρ, between PFS and OS
(Copula bivariate survival model)•Treatment arm level• Correlation between short-term (6 months) PFS rates
and long-term (12 & 18 months) OS rates• Estimated based on Kaplan-Meier estimates• Coefficient of determination from weighted least
square (WLS) linear regression, r2WLS
•Trial (i.e. comparison) level • Correlation between hazard ratios (HRs) on PFS and
OS – Coefficient of determination from linear regression based on HRs estimated by• Cox model (& WLS regression), R2
WLS
• Copula bivariate survival model, R2Copula
• Concordance of significance of the treatment effect
DISCUSSION
• Although early PFS rate is a strong predictor of long-term OS (patient level landmark analysis), treatment effects observed on PFS at the trial-level do not provide sufficiently accurate prediction of treatment effect on OS in the first-line advanced CRC trials.
• Trials testing targeted therapies demonstrated only modestly higher PFS/OS correlations at patient-, treatment arm, and trial-level between PFS and OS than non-targeted trials.
• Restricting to non-strategy trials, overall results remain: correlation measures between PFS and OS by treatment arm and at trial-level improved by ~ 0.1 in absolute values.
• Restricting trials with superiority design, the above results remain.
• Excluding one outlier improved the correlation measures only slightly
Individual Patient Data Analysis of Progression-Free versus Overall Survival as an Endpoint for Metastatic Colorectal Cancer in Modern Trials: Findings from the 16,700 Patient ARCAD Database
Q Shi1, A de Gramont2, M Buyse3, A Grothey1, H-J Schmoll4, MT Seymour5, R Adams6, L Saltz7, RM Goldberg8, CJA Punt9, J-Y Douillard10, JR Hecht11, H Hurwitz12,
E Diaz-Rubio13, Pr R Proschen14, NC Tebbutt15, C Fuchs16, J Souglakos17, A Falcone18, DJ Sargent1, For the ARCAD Group1Mayo Clinic, Rochester MN; 2Hospital Saint Antoine, Paris, France; 3International Drug Development Institute, Louvain-la-Neuve, Belgium; 4Martin-Luther University, Halle, Germany; 5Cancer Rsrch UK Clinical Ctr, Leeds, UK; 6Cardiff University, Cardiff, UK; 7Memory Sloan Kettering Cancer Center, New
York, NY; 8Ohio State University Comprehensive Cancer Center, Columbus, OH; 9Academic Medical Center, Amsterdam, Netherlands; 10Centre R Gauducheau, St Herblain, France; 11David Geffen School of Medicine at UCLA, Los Angeles, CA; 12Duke University Medical Center, Durham, NC; 13Hospital Clinico San Carlos, Madrid, Spain; 14Klinikum Bremen-Ost, Bremen, Germany; 15Austin Health, Australia; 16Dana Farber Cancer Institution, Boston, MA; 17 University of Crete, School of Medicine, Heraklion, Greece; 18University Hospital “S. Chiara”, Pisa, Italy
Table 2: Surrogacy Estimation
Figure 1: Overall Treatment arm and Trial-level SurrogacyTable 1: Trials Included
Class (n. of Comp.) Overall (22) Targeted (12) Non-strategy (18) Superiority (16) Patient level Rank corr. ρ .51 (.50 - .52) .55 (.54 - .56) .53 (.52 - .54) .51 (.50 - .52)Treatment arm level [6m PFS vs. 12m OS rates]
r2WLS .69 (.58 - .79) .70 (.48 - .91) .73 (.62 - .83) .71 (.59 - .83)
Trial level [HRPFS vs. HROS]
R2WLS .54 (.33 - .75) .52 (.24 - .80) .54 (.32 - .76) .51 (.24 - .77)
R2Copula .46 (.24 - .68) .45 (.16 - .75) .48 (.24 - .71) .54 (.31 - .78)
Concordance of conclusions 67% 64% 68% 63%
Abbreviations: C, control arm; E, experimental arm; IRI, irinotecan; OX, oxaliplatin; LV, leucovorin; Bev, bevacizumab; Cap, capecitabine; Pmab, Pamtumumab; WT, wild type; MT, mutated; T, targeted; NT, non-targeted; ANG, Anti-angiogenic regimen; EGFR, Anti-EGFR regimen; OS, overall survival; PFS, progression-free survival; HR, hazard ratio; PD, progressive disease1.Cross-over reflects the actual cross-over from one arm to another due to toxicity, PD and other reasons.2Strategy trial refers more treatment specified by protocol beyond the first per protocol regimen. For example, a sequence of treatment was specified per protocol (i.e., the treatment effect of a whole strategy of experimental arm is compared to the control arm), or cross over after PD was specified per protocol. For these studies, the PFS (1st PD-PFS) with the 1st PD occurred during study follow-up as one of the events may not be the appropriate endpoint if the regimen before 1st PD was same for both experimental and control arms.3The design refers to the intended primary comparison between arms, i.e., non-inferiority (NI) or superiority (Sup) comparison. The statistical sample size/power consideration section may not reflect NI or Sup design.
• PFS has its own merits as an endpoint, and is considered by some a clinical benefit endpoint. However, based on modern trials, PFS treatment effects do not reliably translate into treatment effects on OS.
• The lack of association between PFS and OS in modern trials is likely due to extensive use of later-line therapies.
• The lack of ability for PFS to predict OS emphasizes rather than detracts from its importance as a clinical trials endpoint to demonstrate activity of a new agent.
• PFS remains a relevant primary endpoint for 1st line mCRC trials, as our data demonstrate that the ability for any agent to produce an OS benefit from a single line of therapy is challenging.
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