MAST THERAPEUTICS INC

CUSIP: 576314108 Class: COM

DEERFIELD MANAGEMENT COMPANY, L.P.'s Holding History (CIK: 0001009258)

Note: Option positions (PUT/CALL) are excluded.

Q4 2014
Shares 700,000 Value ($000) $392 Avg Close — Range —
Q4 2013
Shares 1,466,249 Value ($000) $678 Avg Close — Range —
Q3 2013
Shares 2,634,221 Value ($000) $1,156 Avg Close — Range —
Q2 2013
Shares 3,948,302 Value ($000) $1,695 Avg Close — Range —