X0306 4 2021-03-29 0 0001183765 Molecular Templates, Inc. MTEM 0001259870 BIOTECH TARGET N V ARA HILL TOP BUILDING, UNIT A-5, PLETTERIJWEG OOST 1 CURACAO P8 00000 NETHERLANDS ANTILLES 0 0 1 0 0000924223 BB BIOTECH AG SCHWERTSTRASSE 6 SCHAFFHAUSEN V8 CH-8200 SWITZERLAND 0 0 1 0 Common Stock 2021-03-29 4 P 0 80000 11.4481 A 8116105 D Biotech Target N.V. is a wholly-owned subsidiary of BB Biotech AG. Accordingly, BB Biotech AG may be deemed to be the indirect beneficial owner of the securities of Molecular Templates, Inc. held directly or indirectly by Biotech Target N.V. This Form 4 is filed jointly by BB Biotech AG and Biotech Target N.V. /s/ Ivo Betschart 2021-03-31 /s/ Martin Gubler 2021-03-31