demo/RPEXE_fitting.R

In RPEXE.RPEXT: Reduced Piecewise Exponential Estimate/Test Software

require(RPEXE.RPEXT)
library(RPEXE.RPEXT)

# we load in the data2 dataset
data(data2)
times = data2[,1]
censor = data2[,2]
group = data2[,3]

ID_nan = which(is.na(times))
times = times[-ID_nan] 
censor = censor[-ID_nan]
group = group[-ID_nan]
armsA_ID = which(group == 1)
armsB_ID = which(group == 2)

# Plot the data
# figure(1)
km(times[armsA_ID], censor[armsA_ID], 0)
# figure(2)
km_red(times[armsA_ID], censor[armsA_ID], 1)
# figure(3)
km(times[armsB_ID], censor[armsB_ID], 0)
# figure(4)
km_red(times[armsB_ID], censor[armsB_ID], 0)

# The analysis
# consists of presenting the PFS rates at the two scan times, and
# calculating a P value based on the grouped data (Appendix). This
# two-point procedure, like the procedure that compares PFS rates at
# single time point, essentially eliminates any evaluation-time bias.
# However, unlike the single-point procedure, if the two scan times
# are chosen well, there is little risk of major power loss compared
# with using the actual reported progression times. In particular, we
# recommend choosing the two scan times to be approximately the
# median PFS and twice the median PFS of the control arm.

# The median survival at median and 2*median;
# 2.7438 and 5.4876, time (survival prob;std)
# Arm A: 2.7438(0.4828;0.0656) n=53, 5.4876 (0.3276;0.0616) n=53;
# Arm B: 2.7438(0.4738;0.0673) n=47, 5.4876 (0.3796;0.0658) n=47;

# z score for t = median surv
(0.4828-0.4738)/sqrt(0.4828*(1-0.4828)/53+0.4738*(1-0.4738)/47)
# z score for t = 2*median surv
(0.3276-0.3796)/sqrt(0.3276*(1-0.3276)/53+0.3796*(1-0.3796)/47)

# Fit the rpexe with monotonic order restriction;
pexeoutA     =  RPEXEv1_2(times[armsA_ID],censor[armsA_ID], monotone = 1,criticalp = 0.05)

pexeoutB     =  RPEXEv1_2(times[armsB_ID],censor[armsB_ID], monotone = 1,criticalp = 0.05)

# combined
pexeout = RPEXEv1_2(times,censor, monotone = 1,criticalp = 0.05)

# calculate the ttot and n from a), 0-2.777, b), 2.777-8.959, c), 8,959-end;
#
# a), 0-2.777
returnvA=totaltest(times[armsA_ID],censor[armsA_ID]) #returnv=list(time_die,ttot,deaths),the variables owns the same length
m=dim(returnvA)[2]/3

time_dieA=returnvA[,1:m]
ttotA=returnvA[,(m+1):(2*m)]
deathsA=returnvA[,(2*m+1):3*m]

returnvB=totaltest(times[armsB_ID],censor[armsB_ID]) #returnv=list(time_die,ttot,deaths),the variables owns the same length
m=dim(returnvB)[2]/3

time_dieB=returnvB[,1:m]
ttotB=returnvB[,(m+1):(2*m)]
deathsB=returnvB[,(2*m+1):3*m]


ttotA1 = 0
ttotA2 = 0
ttotA3 = 0
dA1 = 0
dA2 = 0
dA3 = 0
for (i in 1:length(time_dieA))
{
  if ( time_dieA[i]<=2.777)
  {
    ttotA1 = ttotA1+ttotA[i]
    dA1    = dA1+deathsA[i]
  }else if (time_dieA[i]<=8.959)
  {
    ttotA2 = ttotA2+ttotA[i]
    dA2    = dA2+deathsA[i]
  } else 
  {
    ttotA3 = ttotA3+ttotA[i]
    dA3    = dA3+deathsA[i]
  }
     
}
      

ttotB1 = 0
ttotB2 = 0
ttotB3 = 0
dB1 = 0
dB2 = 0
dB3 = 0
for (i in 1:length(time_dieB))
{
  if ( time_dieB[i]<=2.777)
  {
    ttotB1 = ttotB1+ttotB[i]
    dB1    = dB1+deathsB[i]
  }else if (time_dieB[i]<=8.959)
  {
    ttotB2 = ttotB2+ttotB[i]
    dB2    = dB2+deathsB[i]
  } else 
  {
    ttotB3 = ttotB3+ttotB[i]
    dB3    = dB3+deathsB[i]
  }
}

# max(times(armsA_ID))
# max(times(armsB_ID))
# [times(armsA_ID) censor(armsA_ID)]


# test the two side hypothesis;
# first piece
result = exact_pvalue(ttotA1,ttotB1,dA1,dB1,0)
a21 = result[1]
p1 = result[2]

# second piece
result=exact_pvalue(ttotA2,ttotB2,dA2,dB2,0)
a22 = result[1]
p2 = result[2]

# third piece
result=exact_pvalue(ttotA3,ttotB3,dA3,dB3,0)
a23 = result[1]
p3 = result[2]

# first piece
result=exact_pvalue(ttotA1,ttotB1,dA1,dB1,1)
a21 = result[1]
p1 = result[2]

# second piece
result=exact_pvalue(ttotA2,ttotB2,dA2,dB2,1)
a22 = result[1]
p2 = result[2]

# third piece
result=exact_pvalue(ttotA3,ttotB3,dA3,dB3,1)
a23 = result[1]
p3 = result[2]

# first piece
result=exact_pvalue(ttotA1,ttotB1,dA1,dB1,2)
a21 = result[1]
p1 = result[2]

# second piece
result=exact_pvalue(ttotA2,ttotB2,dA2,dB2,2)
a22 = result[1]
p2 = result[2]

# third piece
result=exact_pvalue(ttotA3,ttotB3,dA3,dB3,2)
a23 = result[1]
p3 = result[2]