# EDGAR Filing Document

**Accession Number:** 0001851484
**File Stem:** 0001213900-26-065310
**Filing Date:** 2026-6
**Character Count:** 7544
**Document Hash:** 620ba3118ea941a390e881244c62c399
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001213900-26-065310.hdr.sgml**: 20260604

**ACCESSION NUMBER**: 0001213900-26-065310

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20260604

**DATE AS OF CHANGE**: 20260604

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CITIUS ONCOLOGY, INC.
- **CENTRAL INDEX KEY:** 0001851484
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 994362660
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-93794
- **FILM NUMBER:** 261065394

**BUSINESS ADDRESS:**
- **STREET 1:** 11 COMMERCE DRIVE
- **STREET 2:** 1ST FLOOR
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016
- **BUSINESS PHONE:** (908) 967-6677

**MAIL ADDRESS:**
- **STREET 1:** 11 COMMERCE DRIVE
- **STREET 2:** FIRST FLOOR
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** TenX Keane Acquisition
- **DATE OF NAME CHANGE:** 20210315
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Citius Pharmaceuticals, Inc.
- **CENTRAL INDEX KEY:** 0001506251
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 273425913
- **STATE OF INCORPORATION:** NV
- **FISCAL YEAR END:** 0930

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** 11 COMMERCE DRIVE
- **STREET 2:** 1ST FLOOR
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016
- **BUSINESS PHONE:** (908) 967-6676

**MAIL ADDRESS:**
- **STREET 1:** 11 COMMERCE DRIVE
- **STREET 2:** 1ST FLOOR
- **CITY:** CRANFORD
- **STATE:** NJ
- **ZIP:** 07016

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Trail One, Inc.
- **DATE OF NAME CHANGE:** 20110314

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** TrailOne, Inc.
- **DATE OF NAME CHANGE:** 20101119

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 4)**

**Citius Oncology, Inc.**

*(Name of Issuer)*

**Common Shares, $0.0001 par value per share**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Leonard L. Mazur**<br>Chief Executive Officer<br>11 Commerce Drive, 1st Floor<br>Cranford NJ 07016<br>(908) 967-6677

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**05/15/2026**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Citius Pharmaceuticals, Inc.** | Name of reporting person<br>**Citius Pharmaceuticals, Inc.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**OO** | Source of funds (See Instructions)<br>**OO** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**X1** | Citizenship or place of organization<br>**X1** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**66049615.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**66049615.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**66049615.00** | Aggregate amount beneficially owned by each reporting person<br>**66049615.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**71.0%** | Percent of class represented by amount in Row (11)<br>**71.0%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** CO

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Shares, $0.0001 par value per share

**(b) Name of Issuer:**
Citius Oncology, Inc.

**(c) Address of Issuer's Principal Executive Offices:**
11 Commerce Drive, 1st Floor, Cranford, NJ, 07016

EXPLANATORY NOTE

This Amendment No. 4 to the Schedule 13D of the Reporting Person filed on August 16, 2024, as amended on July 25, 2025, September 12, 2025, and December 17, 2025 (this "Amendment"), amends and supplements the Schedule 13D as specifically set forth herein, to report a material decrease in the Reporting Person's percentage beneficial ownership of the Issuer's common stock resulting solely from increases in the Issuer's outstanding shares.

The information provided herein is intended to encompass the information that would have been included in amendments previously required upon the occurrence of the events summarized below.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The Reporting Person is the beneficial owner of 66,049,615 shares of the Issuer's common stock, which represents approximately 71.0% of the Issuer's outstanding common stock, based upon 92,981,204 shares of common stock outstanding as of May 14, 2026 (per the Issuer's Form 10-Q for the quarter ended March 31, 2026, filed May 15, 2026). The decrease in the Reporting Person's percentage beneficial ownership since Amendment No. 3 resulted solely from increases in the Issuer's outstanding shares of common stock and not from any acquisition or disposition of shares by the Reporting Person.

Additional Event Requiring Amendment

On February 10, 2026, the Issuer reported that 88,275,204 shares of common stock were outstanding (as of such date), as disclosed in its Quarterly Report on Form 10-Q for the quarter ended December 31, 2025. Based on 66,049,615 shares beneficially owned by the Reporting Person, this reflected a decrease in the Reporting Person's percentage beneficial ownership to approximately 74.9%.

**(b)**
The Reporting Person has sole voting and dispositive power of 66,049,615 shares of the Issuer's common stock beneficially owned.

Note: In its Current Report on Form 8-K filed on May 6, 2026 (the "Form 8-K"), the Issuer disclosed the immediate exercise of warrants for 12,777,778 shares and the issuance of replacement warrants. According to the Form 8-K, such shares are being held in abeyance by the transfer agent due to a 9.99% beneficial ownership limitation and therefore are not included in the outstanding share count used above.

**(c)**
—

### 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.

**Reporting Person:** Citius Pharmaceuticals, Inc.

**Signature:** /s/ Leonard Mazur

**Name/Title:** Leonard Mazur, Chief Executive Officer

**Date:** 06/04/2026