BE-proff
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2015-08-17 13:59
(3173 d 20:55 ago)

Posting: # 15279
Views: 4,387
 

 Indications for different BE-designs [Design Issues]

Hi All!

Could anybody explain "indications", advantages and disadvantages of the following BE-designs:
  • 3×3 Latin Squares
  • 6 sequence Williams’ design
  • 4×4 Latin Squares, Williams’ design
  • 2×4×4 fully replicated design
Thanks to everyone!
Helmut
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2015-08-17 16:55
(3173 d 17:58 ago)

@ BE-proff
Posting: # 15283
Views: 3,586
 

 Effects and adverse effects

BE-proff,

for effects and adverse effects ask your physician or pharmacist. See f.i. this presentation. Some more:
  • 2×2×3 Full replicate design (RTR|TRT)
    • Estimation of CVwR and CVwT.
      Suitable for both ABEL (EMA) / RSABE (FDA) and ABE.
      Less sampled blood volume compared to RTRT|TRTR and lower chance of dropouts.
    • The EMA requires ≥12 evaluable subjects in sequence RTR. Practically not relevant (see this post).
  • 2×3×3 Partial replicate design (RRT|RTR|TRR)
    • Suitable for both ABEL (EMA) / RSABE (FDA) and ABE.
      Less sampled blood volume compared to RTRT|TRTR and lower chance of dropouts.
    • Allows only estimation of CVwR.
      Sometimes convergence issues if evaluated by FDA’s method for ABE.
  • 2×4×2 Balaam’s design (RT|TR|RR|TT)
    • Allows estimation of CVwR and CVwT.
      Suitable for both ABEL (EMA) / RSABE (FDA) and ABE.
      Less sampled blood volume compared to 3-period replicate designs and lower chance of dropouts.
    • Very (!) low power compared to 3- and 4-period replicate designs. Only ½ of the subjects are used to assess BE; CVwR and CVwT are estimated from ¼ of the subjects.
  • Balanced Incomplete Block Designs (BIBD)
    • Suitable for ABE.
      Generally only used in pilot or dose proportionality studies if >4 treatments are tested and >4 periods cannot be used due to blood volume restrictions and/or expected dropout-rate.
      Number of periods < number of treatments.
    • Lower power compared to higher-order crossovers (Latin Squares or William’s designs, where number of periods = number of treatments).
Notes:
  1. Balaam’s design and the 4-sequence 4-period replicate designs (2×4×2 RTTR|TRRT|RRTT|TTRR) are cur­rent­ly (v1.2-08 of 2015-07-10) not implemented in PowerTOST’s functions for ABEL and RSABE.
  2. The completely randomized 4-period replicate (RTTR|TRRT|RRTT|TTRR|RTRT|TRTR) is not im­ple­mented at all. Doesn’t matter – haven’t seen one in ages.

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BE-proff
●    

2015-08-18 10:26
(3173 d 00:28 ago)

@ Helmut
Posting: # 15293
Views: 3,567
 

 Effects and adverse effects

Dear Helmut,

Thank you very much for your help!
I do appreciate it :-)
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