ZQ|CERT#|COY|CLS|RGSTRY|ACCT#|TRANSTYPE|RUN#|TRANS# . COMMON STOCK PAR VALUE $0.001 COMMON STOCK THIS CERTIFICATE IS TRANSFERABLE IN CANTON, MA, JERSEY CITY, NJ AND COLLEGE STATION, TX Shares * * 000000 * * * * * * * * * * * * * * * * * * * * * 000000 * * * * * * * * * * * * * * * * * * * * * 000000 * * * * * * * * * * * * * * * * * * * * * 000000 * * * * * * * * * * * * * * * * * * * * * 000000 * * * * * * * * * * * * * * Certificate Number ZQ00000000 INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE ** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David THIS CERTIFIES THAT Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander Alexander David SamMple ***R* Mr. A.lexaSnderADavidMSampPle ***L* MrE. Alexan&der DavMid SamRple **S** Mr.. AleSxandeAr DaMvid SamPple *L*** MEr. Alex&ander David Sample **** David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample Sample **** Mr. AlexandeMr DaviRd Sam.ple S**** MAr. AleMxandePr DavLid SEample *&*** Mr. AMlexanRder DaSvid S.ampSle ***A* Mr.MAlexanPder DLavidESample **** Mr. Alexander **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David SEE REVERSE FOR CERTAIN DEFINITIONS David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Alexander David Sample **** Mr. Sample **** Mr. Sample is the owner of **000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares*** *000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares**** 000000**Shar*es****0*000Z00**SEhareRs****00O0000**ShHares**U**0000N00**SDhares*R***000E000**DShares**T**000H000**SOhares*U***000S000**AShareNs****00D0000**Shares****0 00000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****00 0000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000 000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****0000 00**Shares****0Z0000E0**ShRares***O*000000*H*ShareUs****0N00000D**SharRes****0E0000D0**ShareAs****0N00000D**SharesZ****00E0000R**SharOes****0*000*00**Shares****00000 0**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000 **Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000* *Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000** Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**Shares****000000**S FULLY PAID AND NON-ASSESSABLE SHARES OF THE COMMON STOCK, $0.001 PAR VALUE PER SHARE, OF CELLDEX THERAPEUTICS, INC. transferable on the books of the Corporation by the holder hereof in person or by duly authorized attorney, upon surrender of this Certificate properly endorsed. This Certificate is not valid unless countersigned by the Transfer Agent and registered by the Registrar. WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. DATED DD-MMM-YYYY COUNTERSIGNED AND REGISTERED: COMPUTERSHARE TRUST COMPANY, N.A. TRANSFER AGENT AND REGISTRAR, President and Chief Executive Officer By Senior Vice President and Chief Financial Officer AUTHORIZED SIGNATURE CUSIP Holder ID Insurance Value Number of Shares DTC Certificate Numbers 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 1234567890/1234567890 Total Transaction XXXXXX XX X XXXXXXXXXX 1,000,000.00 123456 12345678 123456789012345 PO BOX 43004, Providence, RI 02940-3004 Num/No. Denom. Total 1 2 3 4 5 6 7 1 2 3 4 5 6 1 2 3 4 5 6 MR A SAMPLE DESIGNATION (IF ANY) ADD 1 ADD 2 ADD 3 ADD 4 CUSIP 15117B 10 3

. (Cust) (Minor) (State) and not as tenants in common (Cust) (Minor) PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE For value received, hereby sell, assign and transfer unto (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP CODE, OF ASSIGNEE) Shares represented by the within Certificate, and do hereby irrevocably constitute and appoint Attorney to transfer the said shares on the books of the within-named Corporation with full power of substitution in the premises. Dated: 20 Signature: Signature: Notice: The signature to this assignment must correspond with the name as written upon the face of the certificate, in every particular, without alteration or enlargement, or any change whatever. Signature(s) Guaranteed: Medallion Guarantee Stamp THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (Banks, Stockbrokers, Savings and Loan Associations and Credit Unions) WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17Ad-15. The following abbreviations, when used in the inscription on the face of this certificate, shall be construed as though they were written out in full according to applicable laws or regulations: TEN COM - as tenants in commonUNIF GIFT MIN ACT-. . . . . . . . . .Custodian . . . . . . . . . . . . . . . TEN ENT - as tenants by the entiretiesunder Uniform Gifts to Minors Act . . . . . . . . . . . . . JT TEN-as joint tenants with right of survivorshipUNIF TRF MIN ACT . . . . . . . . . . . . . . .Custodian (until age. . . ). . . . . . . . . . . under Uniform Transfers to Minors Act. . . . . . . . . . (State) Additional abbreviations may also be used though not in the above list.