Rene Russo - Nov 21, 2025 Form 4 Insider Report for Xilio Therapeutics, Inc. (XLO)

Signature
/s/ Kevin Brennan, Attorney-in-Fact
Stock symbol
XLO
Transactions as of
Nov 21, 2025
Transactions value $
$0
Form type
4
Date filed
11/25/2025, 04:10 PM
Previous filing
Jun 18, 2025

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Russo Rene PRESIDENT AND CEO, Director 828 WINTER STREET, SUITE 300, WALTHAM /s/ Kevin Brennan, Attorney-in-Fact 2025-11-25 0001722066

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction XLO Stock Option (right to buy) Award $0 +2.08M $0.00 2.08M Nov 21, 2025 Common Stock 2.08M $0.84 Direct F1, F2
transaction XLO Stock Option (right to buy) Disposed to Issuer -240K -100% 0 Nov 21, 2025 Common Stock 240K $5.51 Direct F3, F4
transaction XLO Stock Option (right to buy) Award +240K 240K Nov 21, 2025 Common Stock 240K $1.50 Direct F3, F4
transaction XLO Stock Option (right to buy) Disposed to Issuer -473K -100% 0 Nov 21, 2025 Common Stock 473K $5.89 Direct F3, F4
transaction XLO Stock Option (right to buy) Award +473K 473K Nov 21, 2025 Common Stock 473K $1.50 Direct F3, F4
transaction XLO Stock Option (right to buy) Disposed to Issuer -135K -100% 0 Nov 21, 2025 Common Stock 135K $11.69 Direct F3, F4
transaction XLO Stock Option (right to buy) Award +135K 135K Nov 21, 2025 Common Stock 135K $1.50 Direct F3, F4
transaction XLO Stock Option (right to buy) Disposed to Issuer -50K -100% 0 Nov 21, 2025 Common Stock 50K $16.00 Direct F3, F4
transaction XLO Stock Option (right to buy) Award +50K 50K Nov 21, 2025 Common Stock 50K $1.50 Direct F3, F4
transaction XLO Stock Option (right to buy) Disposed to Issuer -100K -100% 0 Nov 21, 2025 Common Stock 100K $13.83 Direct F4, F5
transaction XLO Stock Option (right to buy) Award +100K 100K Nov 21, 2025 Common Stock 100K $1.50 Direct F4, F5
transaction XLO Stock Option (right to buy) Disposed to Issuer -150K -100% 0 Nov 21, 2025 Common Stock 150K $12.66 Direct F4, F6
transaction XLO Stock Option (right to buy) Award +150K 150K Nov 21, 2025 Common Stock 150K $1.50 Direct F4, F6
transaction XLO Stock Option (right to buy) Disposed to Issuer -350K -100% 0 Nov 21, 2025 Common Stock 350K $2.69 Direct F4, F7
transaction XLO Stock Option (right to buy) Award +350K 350K Nov 21, 2025 Common Stock 350K $1.50 Direct F4, F7
transaction XLO Stock Option (right to buy) Disposed to Issuer -700K -100% 0 Nov 21, 2025 Common Stock 700K $2.79 Direct F3, F4
transaction XLO Stock Option (right to buy) Award +700K 700K Nov 21, 2025 Common Stock 700K $1.50 Direct F3, F4
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id Content
F1 On October 8, 2025, the Board of Directors (the "Board") approved the adoption of the Xilio Therapeutics, Inc. 2025 Stock Incentive Plan (the "2025 Plan"), subject to stockholder approval of the adoption of the 2025 Plan. On October 8, 2025, the Compensation Committee of the Board granted these options (referred to as "Tranche 1 Options" in the 2025 Plan) to the Reporting Person, subject to stockholder approval of the adoption of the 2025 Plan. The stockholders approved the adoption of the 2025 Plan on November 21, 2025.
F2 The options vest in 36 equal monthly installments over the three-year period beginning on December 21, 2025, subject to the Reporting Person's continued service to the registrant through each applicable vesting date.
F3 Immediately exercisable.
F4 The transactions reported herein reflect a one-time option repricing, effective on November 21, 2025, which reduced the exercise price of each repriced option to $1.50 per share unless such repriced stock option is exercised prior to November 21, 2026, in which case, the original exercise price must be paid (the "Option Repricing"). Except as modified by the Option Repricing, all other terms and conditions of the repriced options, including, without limitation, any provisions with respect to vesting and expiration, remain in full force and effect.
F5 This option was granted on December 22, 2021. The shares underlying the option began vesting on January 1, 2022 and continue to vest in equal monthly installments thereafter through December 1, 2025.
F6 This option was granted on February 22, 2022. The shares underlying the option began vesting on March 1, 2022 and continue to vest in equal monthly installments thereafter through February 1, 2026.
F7 This option was granted on January 1, 2023. The shares underlying the option began vesting on February 1, 2023 and continue to vest in equal monthly installments thereafter through January 1, 2027.