[SCHEDULE 13G/A] CytomX Therapeutics, Inc. SEC Filing

Rhea-AI Filing Summary

Biotechnology Value Fund (BVF) and related entities have filed Amendment No. 5 to Schedule 13G for CytomX Therapeutics, Inc. (CTMX). As of the close of business on 9 July 2025, the group collectively holds 5,769,231 common-share equivalents in the form of Tranche 2 warrants that are exercisable at $3.77 per share and expire on 3 July 2026. The warrants include a 9.99 % beneficial-ownership blocker that limits exercise to keep the holder’s ownership below that threshold.

Beneficial ownership is reported on a disaggregated basis: BVF (3.07 M shares; 1.9 %), BVF II (2.35 M; 1.5 %), and Biotechnology Value Trading Fund OS (0.27 M; <1 %). Through control relationships, BVF GP Holdings and BVF Partners L.P. may be deemed to beneficially own 3.3 % and 3.5 % of outstanding shares, respectively. All entities disclaim ultimate beneficial ownership beyond their respective capacities.

The percentages are calculated against a base of 157.54 M common shares outstanding following the issuer’s May 2025 equity offering, plus the warrants counted as if exercised. No holder exceeds the 5 % reporting threshold individually, and the filing is made on Schedule 13G to reflect passive investment intent; the certification confirms the securities were not acquired to influence control of CTMX.

Key takeaways for investors

• BVF remains a notable but non-controlling holder with a ~3.5 % aggregate economic interest.
• Exposure is entirely via $3.77 warrants, providing potential upside without current voting power.
• The 9.99 % blocker limits near-term ownership expansion but allows full exercise should total shares outstanding rise.
• The amendment updates ownership levels following the issuer’s recent public offering and does not signal activism.

Insights

Securities Analyst

TL;DR: BVF discloses 3.5 % passive stake in CTMX via $3.77 warrants; no control intent signaled.

This 13G/A shows BVF’s continued interest in CytomX but at a level well below activist thresholds. The entire position is option-like, giving economic upside without immediate dilution to other holders. The 9.99 % blocker further limits potential voting influence. Because the warrants expire in mid-2026, BVF has roughly one year to decide on exercise, which could inject up to $22 M in cash into CTMX if fully exercised (5.77 M × $3.77). From a governance standpoint, the filing is neutral: there is no intent to influence control, and ownership remains modest relative to the float. Market impact should therefore be limited unless future amendments show sizeable increases or a switch to a Schedule 13D.

Portfolio Manager

TL;DR: Modest, warrant-based exposure suggests BVF is positioning for upside, not control—overall neutral event.

BVF’s structure avoids cash outlay today while preserving levered upside if CytomX executes. The $3.77 strike is only attractive if the company’s pipeline warrants a higher valuation before July 2026. Because current beneficial ownership is below 5 %, the position won’t materially constrain liquidity for other investors. The absence of common shares means no immediate voting bloc, keeping corporate actions unaffected. For portfolio positioning, the disclosure neither strengthens nor weakens the investment case; it merely highlights that a sophisticated biotech fund sees optionality worth holding.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 5)

CytomX Therapeutics, Inc.

(Name of Issuer)

Common Stock, $0.00001 par value per share

(Title of Class of Securities)

23284F105

(CUSIP Number)

07/03/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BIOTECHNOLOGY VALUE FUND L P

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,074,013.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,074,013.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,074,013.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.9 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF I GP LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,074,013.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,074,013.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,074,013.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.9 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BIOTECHNOLOGY VALUE FUND II LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,351,446.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,351,446.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,351,446.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.5 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF II GP LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 2,351,446.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,351,446.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,351,446.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

1.5 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

Biotechnology Value Trading Fund OS LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 270,616.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 270,616.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

270,616.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.2 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF Partners OS Ltd.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 270,616.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 270,616.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

270,616.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.2 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF GP HOLDINGS LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,425,459.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,425,459.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,425,459.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.3 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF PARTNERS L P/IL

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,769,231.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,769,231.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,769,231.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.5 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

BVF INC/IL

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,769,231.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,769,231.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,769,231.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.5 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

CUSIP No. 23284F105

1

Names of Reporting Persons

LAMPERT MARK N

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 5,769,231.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 5,769,231.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

5,769,231.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.5 %

12

Type of Reporting Person (See Instructions)

IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: CytomX Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 151 Oyster Point Blvd., Suite 400, South San Francisco, CA 94080
Item 2.
(a)	Name of person filing: Biotechnology Value Fund, L.P. ("BVF") BVF I GP LLC ("BVF GP") Biotechnology Value Fund II, L.P. ("BVF2") BVF II GP LLC ("BVF2 GP") Biotechnology Value Trading Fund OS LP ("Trading Fund OS") BVF Partners OS Ltd. ("Partners OS") BVF GP Holdings LLC ("BVF GPH") BVF Partners L.P. ("Partners") BVF Inc. Mark N. Lampert ("Mr. Lampert") Each of the foregoing is referred to as a "Reporting Person" and collectively as the "Reporting Persons."
(b)	Address or principal business office or, if none, residence: Biotechnology Value Fund, L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF I GP LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 Biotechnology Value Fund II, L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF II GP LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 Biotechnology Value Trading Fund OS LP PO Box 309 Ugland House Grand Cayman, KY1-1104 Cayman Islands BVF Partners OS Ltd. PO Box 309 Ugland House Grand Cayman, KY1-1104 Cayman Islands BVF GP Holdings LLC 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF Partners L.P. 44 Montgomery St., 40th Floor San Francisco, California 94104 BVF Inc. 44 Montgomery St., 40th Floor San Francisco, California 94104 Mark N. Lampert 44 Montgomery St., 40th Floor San Francisco, California 94104
(c)	Citizenship: Biotechnology Value Fund, L.P. Delaware BVF I GP LLC Delaware Biotechnology Value Fund II, L.P. Delaware BVF II GP LLC Delaware Biotechnology Value Trading Fund OS LP Cayman Islands BVF Partners OS Ltd. Cayman Islands BVF GP Holdings LLC Delaware BVF Partners L.P. Delaware BVF Inc. Delaware Mark N. Lampert United States
(d)	Title of class of securities: Common Stock, $0.00001 par value per share
(e)	CUSIP No.: 23284F105
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: As of the close of business on July 9, 2025, the Reporting Persons and a certain Partners managed account (the "Partners Managed Account") held certain Tranche 2 Warrants (the "Warrants") exercisable for an aggregate of 5,769,231 Shares. The Warrants are exercisable at any time at an exercise price of $3.77 per Share and expire on July 3, 2026. The exercise of the Warrants is subject to the limitations of the Warrants Blocker (as defined below). As of the close of business on July 9, 2025, the Warrants Blocker did not prohibit the exercise of any of the Warrants held by the Reporting Persons and the Partners Managed Account. A holder of Warrants will not have the right to exercise any portion of its Warrants to the extent that the holder (together with its affiliates) would beneficially own more than 9.99% of the Shares outstanding immediately after such exercise (the "Warrants Blocker"). As of the close of business on July 9, 2025, (i) BVF beneficially owned 3,074,013 Shares, consisting of 3,074,013 Shares underlying the Warrants held by it; (ii) BVF2 beneficially owned 2,351,446 Shares, consisting of 2,351,446 Shares underlying the Warrants held by it; and (iii) Trading Fund OS beneficially owned 270,616 Shares, consisting of 270,616 Shares underlying the Warrants held by it. BVF GP, as the general partner of BVF, may be deemed to beneficially own the 3,074,013 Shares beneficially owned by BVF. BVF2 GP, as the general partner of BVF2, may be deemed to beneficially own the 2,351,446 Shares beneficially owned by BVF2. Partners OS, as the general partner of Trading Fund OS, may be deemed to beneficially own the 270,616 Shares beneficially owned by Trading Fund OS. BVF GPH, as the sole member of each of BVF GP and BVF2 GP, may be deemed to beneficially own the 5,425,459 Shares beneficially owned in the aggregate by BVF and BVF2. Partners, as the investment manager of BVF, BVF2 and Trading Fund OS, and the sole member of Partners OS, may be deemed to beneficially own the 5,769,231 Shares beneficially owned in the aggregate by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, including 73,156 Shares held in the Partners Managed Account, consisting of 73,156 Shares underlying the Warrants held by the Partners Managed Account. BVF Inc., as the general partner of Partners, may be deemed to beneficially own the 5,769,231 Shares beneficially owned by Partners. Mr. Lampert, as a director and officer of BVF Inc., may be deemed to beneficially own the 5,769,231 Shares beneficially owned by BVF Inc. The foregoing should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of any Shares owned by another Reporting Person. BVF GP disclaims beneficial ownership of the Shares beneficially owned by BVF. BVF2 GP disclaims beneficial ownership of the Shares beneficially owned by BVF2. Partners OS disclaims beneficial ownership of the Shares beneficially owned by Trading Fund OS. BVF GPH disclaims beneficial ownership of the Shares beneficially owned by BVF and BVF2. Each of Partners, BVF Inc. and Mr. Lampert disclaims beneficial ownership of the Shares beneficially owned by BVF, BVF2 and Trading Fund OS and held in the Partners Managed Account, and the filing of this statement shall not be construed as an admission that any such person or entity is the beneficial owner of any such securities.
(b)	Percent of class: The following percentages are based upon a denominator that is the sum of: (i) 157,544,369 Shares outstanding as of May 13, 2025, which is the total number of Shares outstanding following the Issuer's public offering as reported in the Issuer's Prospectus filed with the Securities and Exchange Commission on May 12, 2025 and (ii) certain or all of the 5,769,231 Shares underlying the Warrants held by the Reporting Persons and the Partners Managed Account, as applicable. As of the close of business on July 9, 2025, (i) BVF beneficially owned approximately 1.9% of the outstanding Shares, (ii) BVF2 beneficially owned approximately 1.5% of the outstanding Shares, (iii) Trading Fund OS beneficially owned less than 1% of the outstanding Shares, (iv) BVF GP may be deemed to beneficially own approximately 1.9% of the outstanding Shares, (v) BVF2 GP may be deemed to beneficially own approximately 1.5% of the outstanding Shares, (vi) Partners OS may be deemed to beneficially own less than 1% of the outstanding Shares, (vii) BVF GPH may be deemed to beneficially own approximately 3.3% of the outstanding Shares, and (viii) each of Partners, BVF Inc. and Mr. Lampert may be deemed to beneficially own approximately 3.5% of the outstanding Shares (less than 1% of the outstanding Shares are held in the Partners Managed Account).
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Cover Pages Items 5-9.
	(ii) Shared power to vote or to direct the vote: See Cover Pages Items 5-9.
	(iii) Sole power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
	(iv) Shared power to dispose or to direct the disposition of: See Cover Pages Items 5-9.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. See Exhibit 99.1 to the Schedule 13G filed with the Securities and Exchange Commission on January 3, 2022.
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

BIOTECHNOLOGY VALUE FUND L P

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF I GP LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BIOTECHNOLOGY VALUE FUND II LP

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF II GP LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

Biotechnology Value Trading Fund OS LP

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF Partners OS Ltd.

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF GP HOLDINGS LLC

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF PARTNERS L P/IL

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

BVF INC/IL

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert, Authorized Signatory
Date:	07/09/2025

LAMPERT MARK N

Signature:	/s/ Mark N. Lampert
Name/Title:	Mark N. Lampert
Date:	07/09/2025

FAQ

How many CytomX (CTMX) shares does Biotechnology Value Fund currently beneficially own?

The BVF group holds warrants for 5,769,231 shares, representing an aggregate ~3.5 % stake in CTMX.

What is the exercise price and expiry date of BVF’s CytomX warrants?

The Tranche 2 warrants are exercisable at $3.77 per share and expire on 3 July 2026.

Why is BVF filing a Schedule 13G/A instead of a Schedule 13D?

The certification states the securities were acquired without intent to influence control, qualifying for the passive Schedule 13G filing.

What is the 9.99 % warrant blocker mentioned in the filing?

The blocker prevents any holder from exercising warrants if doing so would cause them to own more than 9.99 % of outstanding shares immediately after exercise.

Which BVF entities hold the largest portions of the CytomX warrants?

Biotechnology Value Fund L.P. holds 3.07 M warrants (1.9 %), and Biotechnology Value Fund II L.P. holds 2.35 M warrants (1.5 %).

When did the events triggering this Schedule 13G/A occur?

The reportable event date is 3 July 2025, with the filing signed on 9 July 2025.