UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

ANAPTYSBIO, INC.

(Exact name of Registrant as Specified in Its Charter)

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

Securities registered pursuant to Section 12(b) of the Act:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 1.01 Entry into a Material Definitive Agreement.

On June 15, 2026, AnaptysBio, Inc. (the “Company”), entered into a Sublease Agreement (the “Sublease”) with First Tracks Biotherapeutics, Inc., a Delaware corporation (“First Tracks”), pursuant to which the Company agreed to sublease to First Tracks approximately 45,057 rentable square feet of space located at 10770 Wateridge Circle, San Diego, California 92121 (the “Premises”). The Premises are currently leased by the Company from Wateridge Property Owner, LP, a Delaware limited partnership (the “Master Landlord”), pursuant to the Lease dated May 4, 2020, as amended by the First Amendment to Lease Agreement dated April 5, 2021 (collectively, the “Master Lease”).

The term of the Sublease commenced on June 15, 2026, and continues for a period of twelve (12) months from commencement (the “Sublease Term”). First Tracks has the option to extend the Sublease Term for a renewal period commencing on the first day following the expiration of the initial Sublease Term and continuing until the earlier of (a) April 4, 2028, or (b) twelve months from the commencement of the renewal term, subject to delivery of written notice to the Company at least three months prior to the expiration of the initial Sublease Term. First Tracks also has the right to terminate the Sublease at any time during the Sublease Term upon at least three months’ prior written notice to the Company.

Under the Sublease, First Tracks is obligated to pay as monthly rent an amount equal to the monthly Basic Rent (as designated in the Master Lease) owed by the Company under the Master Lease, plus Additional Rent (as defined in the Master Lease) due under the Master Lease, payable in advance on the first day of each month during the Sublease Term. First Tracks is also responsible for any charges actually incurred for services requested by First Tracks that the Company is liable to the Master Landlord for under the Master Lease. The Company remains responsible for the timely payment of Basic Rent and Additional Rent under the Master Lease and for otherwise complying with its obligations under the Master Lease except to the extent assumed by First Tracks.

The Sublease is subordinate to the Master Lease, and First Tracks has agreed to comply with the applicable terms and provisions of the Master Lease as incorporated into the Sublease.

The Company has covenanted that it will not surrender or terminate the Master Lease prior to its scheduled expiration date without the consent of First Tracks (other than in connection with the exercise of its Termination Option (as defined in the Master Lease)), and will not amend or modify the Master Lease in any manner that would materially and adversely affect First Tracks’ rights or obligations under the Sublease. If the Company’s tenancy or right to possession under the Master Lease terminates for any reason, the Sublease will immediately cease and terminate.

The foregoing description of the Sublease does not purport to be complete and is subject to, and qualified in its entirety by, the full text of the Sublease, a copy of which will be filed with the Company’s transition report on Form 10-K/T for the transition period from January 1, 2026 to June 30, 2026.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, as amended, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.