# EDGAR Filing Document

**Accession Number:** 0000894158
**File Stem:** 0001104659-25-055181
**Filing Date:** 2025-6
**Character Count:** 18192
**Document Hash:** 962ba742a4c3d92a0c985993ce896e4a
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-055181.hdr.sgml**: 20250602

**ACCESSION NUMBER**: 0001104659-25-055181

**CONFORMED SUBMISSION TYPE**: 8-K

**PUBLIC DOCUMENT COUNT**: 14

**CONFORMED PERIOD OF REPORT**: 20250527

**ITEM INFORMATION**: Regulation FD Disclosure

**ITEM INFORMATION**: Other Events

**ITEM INFORMATION**: Financial Statements and Exhibits

**FILED AS OF DATE**: 20250602

**DATE AS OF CHANGE**: 20250602

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Theriva Biologics, Inc.
- **CENTRAL INDEX KEY:** 0000894158
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 133808303
- **STATE OF INCORPORATION:** NV
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 8-K
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-12584
- **FILM NUMBER:** 251013106

**BUSINESS ADDRESS:**
- **STREET 1:** 9605 MEDICAL CENTER DRIVE
- **STREET 2:** SUITE 270
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850
- **BUSINESS PHONE:** (734) 332-7800

**MAIL ADDRESS:**
- **STREET 1:** 9605 MEDICAL CENTER DRIVE
- **STREET 2:** SUITE 270
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Synthetic Biologics, Inc.
- **DATE OF NAME CHANGE:** 20120305

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ADEONA PHARMACEUTICALS, INC.
- **DATE OF NAME CHANGE:** 20081027

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** PIPEX PHARMACEUTICALS, INC.
- **DATE OF NAME CHANGE:** 20061214

?xml version='1.0' encoding='ASCII'?

**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**

**Date of Report (Date of earliest event reported): May 27, 2025**

**THERIVA BIOLOGICS, INC.**

(Exact name of registrant as specified in its charter)

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| | | |
|:---|:---|:---|
| **Nevada** | **001-12584** | **13-3808303** |
| (State or other jurisdiction of<br> incorporation) | (Commission File No.) | (IRS Employer Identification<br> No.) |

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**9605 Medical Center Drive, Suite 270**

**Rockville, Maryland 20850**

(Address of principal executive offices and zip code)

**(301) 417-4364**

Registrant's telephone number, including area code

**N/A**

(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 (see General Instruction A.2. below):

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| |
|:---|
| Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| Soliciting material pursuant to Rule 14a-12(b) under the Exchange Act (17 CFR 240.14a-12) |
| Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |

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

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| | | |
|:---|:---|:---|
| &nbsp;&nbsp;**Title of each class** | &nbsp;&nbsp;**Trading Symbol(s)** | &nbsp;&nbsp;**Name of each exchange on<br> which registered** |
| &nbsp;&nbsp;Common stock, par value $0.001 per share | &nbsp;&nbsp;TOVX | &nbsp;&nbsp;NYSE American |

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Indicate by check mark whether the registrant is an emerging growth company as defined in in Rule 405 of the Securities Act of 1933 (17 CFR §230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (17 CFR §240.12b-2 of this chapter).

Emerging growth company ◻

If an emerging growth company, indicate by checkmark 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 7.01. Regulation FD Disclosure.**

On May 27, 2025, Theriva Biologics, Inc. (the "Company") issued a press release announcing a poster presentation by Dr. Jaume Català-Mora, Pediatric Ophthalmologist, Sant Joan de Déu-Barcelona Children's Hospital, of results from the investigator-sponsored Phase 1 study of VCN-01 in refractory retinoblastoma patients at the 2025 American Society of Clinical Oncology (ASCO) annual meeting, taking place May 30, 2025 - June 3, 2025 in Chicago, Illinois.

A copy of the poster titled "A Phase I dose-escalation study to assess the oncolytic virus VCN-01 safety and efficacy in refractory retinoblastoma patients" is filed as an exhibit to this Current Report on Form 8-K. Based on the study results it was concluded that VCN-01 was well tolerated, after intravitreal administration at the 2 doses, the most frequently reported treatment-related adverse events were Grade 1 or 2 uveitis. VCN-01 did not cause retinal toxicity. There were no dose limiting toxicities and no ocular or systemic toxicities equal to or greater than Grade 3 during the evaluation period.

&nbsp;&nbsp;&nbsp;&nbsp;· Some degree of ocular inflammation and associated
turbidity was observed after VCN-01 injection. Inflammation was managed, and vitreous haze improved in some cases, by local and systemic
administration of anti-inflammatory drugs.

&nbsp;&nbsp;&nbsp;&nbsp;· VCN-01 does not appear to change the retinal
function, and selective VCN-01 replication in retinoblastoma cells has been observed by immunohistochemical analysis.

&nbsp;&nbsp;&nbsp;&nbsp;· Replication of VCN-01 was detected over time
within retinoblastoma tumors but was not observed in healthy tissue.

&nbsp;&nbsp;&nbsp;&nbsp;· Intravitreal VCN-01 demonstrated promising antitumor
activity:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Four patients presented a response characterized by unequivocal improvement in vitreous seed density.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Eye enucleation was avoided in 3 patients to date, one of whom has retained their eye after 4 years of
follow-up.

The information in this Item 7.01 furnished as Exhibit 99.1 to this Current Report on Form 8-K shall not be deemed to be "filed" for purposes of Section 18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section or Sections 11 and 12(a)(2) of the Securities Act of 1933, as amended and shall not be incorporated by reference into any filing with the U.S. Securities and Exchange Commission made by the Company, whether made before or after the date hereof, regardless of any general incorporation language in such filing.

**Item 8.01. Other Events.**

On May 27, 2025, the Company issued a press release announcing a poster presentation by Dr. Jaume Català-Mora, Pediatric Ophthalmologist, Sant Joan de Déu-Barcelona Children's Hospital of results from investigator-sponsored Phase 1 study of VCN-01 in refractory retinoblastoma patients at the 2025 American Society of Clinical Oncology (ASCO) annual meeting, taking place May 30, 2025 -June 3, 2025 in Chicago, Illinois.

Based on the study results it was concluded that VCN-01 was well tolerated, after intravitreal administration at the 2 doses, the most frequently reported treatment-related adverse events were Grade 1 or 2- uveitis being the most common adverse effect. VCN-01 did not cause retinal toxicity. There were no dose limiting toxicities and no ocular or systemic toxicities equal to or greater than Grade 3 during the evaluation period.

&nbsp;&nbsp;&nbsp;&nbsp;· Some degree of ocular inflammation and associated
turbidity was observed after VCN-01 injection. Inflammation was managed, and vitreous haze improved in some cases, by local and systemic
administration of anti-inflammatory drugs.

&nbsp;&nbsp;&nbsp;&nbsp;· VCN-01 does not appear to change the retinal
function, and selective VCN-01 replication in retinoblastoma cells has been observed by immunohistochemical analysis.

&nbsp;&nbsp;&nbsp;&nbsp;· Replication of VCN-01 was detected over time
within retinoblastoma tumors but was not observed in healthy tissue

&nbsp;&nbsp;&nbsp;&nbsp;· Intravitreal VCN-01 demonstrated promising antitumor
activity:

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Four patients presented a response characterized by unequivocal improvement in vitreous seed density.

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;o Eye enucleation was avoided in 3 patients to date, one of whom has retained their eye after 4 years of
follow-up.

**Item 9.01. Financial Statements and Exhibits.**

(d) Exhibits.

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| | |
|:---|:---|
| **Exhibit<br> Number** | **Description** |
| [99.1](tm2516499d1_ex99-1.htm) | [Poster Presentation titled "A Phase I dose-escalation study to assess the oncolytic virus VCN-01 safety and efficacy in refractory retinoblastoma patients"](tm2516499d1_ex99-1.htm) |
| 104 | Cover Page Interactive Data File (embedded within the XBRL document) |

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**SIGNATURES**

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

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| | | | |
|:---|:---|:---|:---|
| Dated: June 2, 2025 | **THERIVA BIOLOGICS, INC.** | **THERIVA BIOLOGICS, INC.** | **THERIVA BIOLOGICS, INC.** |
|  | By: | /s/ Steven A. Shallcross | /s/ Steven A. Shallcross |
|  |  | Name: | Steven A. Shallcross |
|  |  | Title: | Chief Executive Officer and Chief Financial Officer |

---

## Exhibit 99.1

**Exhibit 99.1**

![](tm2516499d1_ex99-1img01.jpg)

P - 161: A PHASE I DOSE - ESCALATION STUDY TO ASSESS THE ONCOLYTIC VIRUS VCN - 01 SAFETY AND EFFICACY IN REFRACTORY RETINOBLASTOMA PATIENTS Jaume Catalá - Mora1,\*, Jaume Mora 1,2 , Margarida Simao 1 , Francis Munier 3 , Livia Romero 4 , Ligia Fu 5 , Jesus Ardila 6 , Ida Russo 7 , Karina Senyase Zamarripa 8 , Jesús Díaz - Cascajosa 1 , Eduard Pedemonte - Sarrias 1 , Marina Barraso - Rodrigo 1 , Itziar Alonso Colmenero 1 , Dolors Molies - Navarrete 1 , Ana Mato - Berciano 9 , Carmen Blasco 9 , Manel Cascallo 9 , Guillermo L. Chantada 10 , Ángel Montero - Carcaboso 10 1 Hospital Sant Joan de Déu, Barcelona, Esplugues de Llobregat, Barcelona, Spain; 2 Pediatric Cancer Center Barcelona, Hospital Sant Joan de Déu, Barcelona, Spain; 3 Hopital Ophtalmique Jules Gonin, Lausanne, Switzerland; 4 Unidad Oncología Ocular Instituto Oncológico Dr. Luis Razetti, Caracas, Venezuela; 5 Hospital Escuela Universitario, Tegucigalpa, Honduras; 6 Centro Médico Imbanaco, Cali, Colombia; 7 Ospedale Pediatrico Bambino Gesù, Roma, Italy; 8 HONU Childcare, Leon, Guanjuato, Mexico; 9 Theriva Biologics, Parets del Vallès, Barcelona, Spain; 10 Fundació Sant Joan de Déu, Espplugues de Llobregat, Barcelona, Spain. Patients (from 1 year to under 12 years of age) with intraocular retinoblastoma who failed conservative therapy facing imminent enucleation were eligible for this phase I, dose - escalation study (NCT 03284268) with two dose levels of VCN - 01 intravitreal injection (2 E+ 9 vp/eye per dose for the first patient) and 2 E+ 10 vp/eye dose in two doses on day 1 and 15 for the remaining 8 patients . The primary objective was to determine the safety and tolerability of intravitreal injections of VCN - 01 through assessment of adverse events and laboratory tests to establish the maximum tolerated dose (MTD) of VCN - 01 virus . Dose limiting toxicity (DLT) was defined as ≥ grade IV ocular toxicity or ≥ grade III systemic toxicity according to CTCAEv 04 . Response assessed by RB - RECIST criteria and toxicity were evaluated at day 42 of the first injection . Additionally, different biological samples were obtained to evaluate the excretion profile of VCN - 01 and to assess immune response by the presence of neutralizing antibodies in patients . Trial Design & Methods Retinoblastoma is the most frequent intraocular malignancy in children . Novel treatments must address three main needs : tumor selectivity to maximize anticancer action, reduced toxicity in healthy eye tissues, and reduced exposure to chemotherapy to minimize the risk of subsequent malignant neoplasms . Zabilugene almadenorepvec (VCN - 01) 1 is an oncolytic adenovirus targeting the E 2 F pathway and expressing hyaluronidase that is currently being tested in several indications : Preclinical work demonstrated antitumor activity for retinoblastoma in patient derived retinoblastoma models 2 . Additionally, evidences for VCN - 01 tumor selectivity were collected, with absence of replication in normal retinas in rabbit . We report here a first - in - children study aiming to assess its safety profile and initial efficacy . Background Results/Graphs/Data \*Address correspondence to : Jaume Català Mora (jaume . catala@sjd . es) References 1. Rodríguez - García A et al. (2015) Safety and efficacy of VCN - 01, an oncolytic adenovirus combining fiber HSG - binding domain replacement with RGD and hyaluronidase expression. Clin Cancer Res 21:1406 - 18 2. Pascual Pasto G et al. (2019) Therapeutic targeting of the RB1 pathway in retinoblastoma with the oncolytic adenovirus VCN - 01. Sci Transl Med 11:eaat9321 D1 D15 D28 D45 D180 MRI - MDD Oft - ERG Safety visit 6 months Follow - up VCN - 01 Oft - Lab ERG VCN - 01 MRI - MDD Oft - ERG Demographics High dose Low dose 2E+10 vp/eye (n=8) 2E +9 vp/eye (n=1) 3.2 2 Median Age, years (2 - 7) NA Range 5/3 0/1 Sex (Male / Female) 16.35 12 Median Weight, Kg (9,4 - 31.0) NA Range 103.5 98 Median Height, cm (87 - 126) NA Range 3 1 Somatic Type of mutation RB1 gene 5 NA Germinal 5 NA With active tumor in ONLY one eye, and the contralateral eye already enucleated If germinal 0 0 A Group IIRC Classification for Intraocular retinoblastoma (International Intraocular Retinoblastoma Classification) 1 0 B Group 2 0 C Group 5 1 D Group 0 0 E Group Previous treatments Vitreous seeds Subretinal Seeds Retinal tumor IIRC Laterality Patient (dose) Intravitreal chemotherapy Intraarterial chemotherapy - Mel / Topo + + + D Unilateral #1 (2.0x10 9 vp) - - + - + D Bilateral #2 (2.0x10 10 vp) Mel Carbo /Mel / Topo + - + C Bilateral #4 (2.0x10 10 vp) Mel / Topo - + - + D Unilateral #5 (2.0x10 10 vp) Carbo /Mel - + - + D Bilateral #8 (2.0x10 10 vp) Topo - + + + D Bilateral #9 (2.0x10 10 vp) Topo Carbo /Mel / Topo + - - C Unilateral #11 (2.0x10 10 vp) Topo Carbo /Mel / Topo + - + B Bilateral #12 (2.0x10 10 vp) Topo Carbo /Mel / Topo + - + D Unilateral #13 (2.0x10 10 vp) Conclusions Acknowledgements VCN - 01 was well tolerated, uveitis being the most common adverse effect. VCN - 01 did not cause retinal toxicity. The response in these heavily pre - treated eyes was encouraging. Safety Profile Grade 3 All Grades Description/Nature of the event (MedDRA PT) MedDRA System Organ Class (SOC) % n % n 44% 4 78% 7 Uveitis Eye disorders 0% 0 11% 1 Eye oedema Eye disorders 0% 0 11% 1 Conjunctival hyperemia Eye disorders 0% 0 11% 1 Eye inflammation Eye disorders Adverse reactions (events associated with VCN - 01, monotherapy) Number events VCN - 01 Relatedness Description/Nature of the event (MedDRA PT) MedDRA System Organ Class (SOC) 3 Related Uveitis Eye disorders 1 Non - related Retinal detachment Eye disorders 1 Non - related Vitreous and anterior chamber haemorrhage Eye disorders 1 Non - related Enucleation Eye disorders Serious Adverse Events Staining of VCN - 01 viral proteins in healthy retina Patient #2 (germline mutation) Conserved retina Calcified tumor area Conserved retina Tumor area Conserved retina Tumor area Conserved retina Necrotic tumor Patient #9 (germline mutation) Patient #8 (germline mutation) Patient #1 Other safety evidences: • No evidence of extraocular relapse • No systemic toxicities occurred. • VCN - 01 caused changes in electroretinograms due to turbidity, but they were reversible • 2 doses of VCN - 01 at 2E+10 vp/eye was defined as the RP2D • From the second patient onwards, all patients received pre - emptive oral and/or topical steroids to prevent uveitis. Uveitis was improved or resolved at day 42 in most patients. • One patient with G3 uveitis did not receive the second dose because of medical decision and also experienced glaucoma requiring treatment. VCN - 01 does not replicate in healthy retinal tissue of patients with either somatic or germline Rb mutation No DLT observed Preliminary E fficacy Evaluation Status at Enucleation Enucleation Date Final RB_RECIST Response at D42 Vitreous seed response after Dose 2 Tumor response after Dose 2 Vitreous seed response after Dose 1 Tumor response after Dose 1 Number of doses Patient (dose) Tumor progression D44 SD SD SD SD SD 2 #1 (2.0x10 9 vp) Tumor progression D62 PR PR PR PR PR 2 #2 (2.0x10 10 vp) n.a No PR PR SD PR PR 3 #4 (2.0x10 10 vp) Lack of response D56 SD SD SD SD SD 2 #5 (2.0x10 10 vp) Tumor progression D170 PR PR SD PR SD 2 #8 (2.0x10 10 vp) Tumor progression D37 PD SD SD SD SD 2 #9 (2.0x10 10 vp) n.a No PR PR - PR - 2 #11 (2.0x10 10 vp) n.a No PR - - PR PR 1 #12 (2.0x10 10 vp) Tumor progression D93 SD SD SD SD SD 2 #13 (2.0x10 10 vp) Expected enucleation w/o response: D37 - 43; Subsequent eye - conservative treatment was administered to patients #4, #8, #11, #12 and #13 Analysis of VCN - 01 presence on biological samples Active Tumor (vitreous seeds) • 3 - years old • Bilateral retinoblastoma (with germline Rb 1 mutation), with 1 st eye already enucleated . • Previous treatments : • Systemic chemotherapy CBP/VP - 16 /VCR (followed by intraarterial dosing of topotecan/melphalan) . • Tumor relapse 9 months later Intravitreous melphalan : NO RESPONSE . Calcified Tumor (from previous treatments) D0 (pre - injection) D28 D64 D189 D240 Case - study Patient #3 • Absence of VCN - 01 genomes in blood . Persistence of VCN - 01 genomes in aqueous humor correlates with vitreous seed presence . Our more since appreciation to the patients and their families that participated in this trial. This work has been partially funded by Cure4RB Project – RETOS 2015 (MiNECO, Spain) 5 patients with partial response, 3 with stable disease and 1 with progressive disease. The eyes of 3 out of 5 patients with PR are preserved with vision after receiving eye - conservative therapy (follow - up 12 - 49 mont hs)