TRex Bio: Ariella Kelman reports two stock options

One option vested 25% on March 17, 2026, with remaining shares vesting monthly over 36 months; the other vests monthly over 48 months, subject to continued service.

Rhea-AI Filing Summary

TRex Bio, Inc. (TRXB) Chief Medical Officer Ariella Kelman reported two directly held stock options giving her the right to buy 213,534 and 83,659 common shares at exercise prices of $1.24 and $1.28 per share, respectively. The options expire May 20, 2035, and February 18, 2036. Vesting of both options is subject to continued service through the applicable vesting dates.

Insider Trade Summary

2 transactions reported

Mixed 2 txns

Insider Kelman Ariella

Role Chief Medical Officer

Type	Security	Shares	Price	Value
holding	Stock Options(Right to Buy) F1	--	--	--
holding	Stock Option (Right to Buy) F2	--	--	--

Holdings After Transaction: Stock Options(Right to Buy) — 213,534 contracts (Direct); Stock Option (Right to Buy) — 83,659 contracts (Direct)

Footnotes (2)

1. F1. The option had a vesting start date of March 17, 2025. 25% of the option vested on March 17, 2026, and vests as to the remaining shares in equal monthly installments over 36 months thereafter, subject to continued service through the applicable vesting dates.
2. F2. The option had a vesting start date of February 19, 2026 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

Key Figures

Common shares underlying first stock option: 213,534 shares First stock option exercise price: $1.24 per share Common shares underlying second stock option: 83,659 shares +1 more

4 metrics

Common shares underlying first stock option 213,534 shares Direct option; expires May 20, 2035

First stock option exercise price $1.24 per share Option expires May 20, 2035

Common shares underlying second stock option 83,659 shares Direct option; expires February 18, 2036

Second stock option exercise price $1.28 per share Option expires February 18, 2036

Key Terms

vesting start date, equal monthly installments, continued service

3 terms

vesting start date financial

"vesting start date of March 17, 2025"

equal monthly installments financial

"remaining shares in equal monthly installments over 36 months"

continued service financial

"subject to continued service through the applicable vesting dates"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How do Ariella Kelman's TRXB stock options vest?

The option with a March 17, 2025 vesting start date vested 25% on March 17, 2026, then vests as to the remaining shares in equal monthly installments over 36 months thereafter, subject to continued service through applicable vesting dates. The other option, with a February 19, 2026 vesting start date, vests in equal monthly installments over 48 months, subject to continued service through applicable vesting dates.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 10/13/2026 - 08:15 PM EDT Accepted by SEC EDGAR 10/08/2026 - 09:41 PM EDT Learn about SEC filing dates

SEC Form 3

FORM 3

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

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0104
Estimated average burden
hours per response:			0.5

1. Name and Address of Reporting Person^*

Kelman Ariella

(Last) (First) (Middle)

C/O TREX BIO, INC.

269 EAST GRAND AVENUE, SUITE 300

(Street)

SOUTH SAN FRANCISCO CALIFORNIA 94080

(City) (State) (Zip)

UNITED STATES

(Country)

2. Date of Event Requiring Statement (Month/Day/Year)
10/08/2026

3. Issuer Name and Ticker or Trading Symbol
TRex Bio, Inc. [ TRXB ]

3a. Foreign Trading Symbol

5. If Amendment, Date of Original Filed (Month/Day/Year)

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Medical Officer

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options(Right to Buy)	(1)	05/20/2035	Common Stock	213,534	$1.24	D
Stock Option (Right to Buy)	(2)	02/18/2036	Common Stock	83,659	$1.28	D

Explanation of Responses:

1. The option had a vesting start date of March 17, 2025. 25% of the option vested on March 17, 2026, and vests as to the remaining shares in equal monthly installments over 36 months thereafter, subject to continued service through the applicable vesting dates.

2. The option had a vesting start date of February 19, 2026 and vests in equal monthly installments over 48 months, subject to continued service through the applicable vesting dates.

Remarks:

Exhibit List: Exhibit 24 - Power of Attorney

	/s/ Brandon Hants, Attorney-in-Fact	10/08/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 3: SEC 1473 (03-26)