Develop a musical composition by integrating the alphabetically represented musical pattern and the supplied melodic theme.
X:1
L:1/8
M:2/4
K:A
['A>B cB ce']  
X:1
L:1/8
M:2/4
K:A
 A>B cB | ce f/g/a/f/ | ec c/B/A/c/ | cBBe | A>B cB | ce f/g/a/e/ | f/g/a/e/ f/a/e/d/ | cAAe | 
 a>bc'a | bee c/e/ | fbb a/b/ | c'afe | ac'a>f | eca>e | f/g/a/e/ f/a/e/d/ | cAAe |]  