On May 18, 2026 Provectus Biopharmaceuticals, Inc. ("Provectus" or the "Company") (OTCQB: PVCT) reported data from a preclinical safety and efficacy evaluation of PV-10 — a formulation of the Company’s proprietary, pharmaceutical-grade rose bengal sodium (RBS) active pharmaceutical ingredient — administered by oral and intravesical routes as a single agent and in combination with anti-human PD-1 against an orthotopic bladder carcinoma tumor xenograft model in immunologically humanized mice. Translational Drug Development, LLC (TD2 Oncology) of Scottsdale, Arizona, an oncology contract research organization, conducted the study. TD2 Oncology was created from the Translational Genomics Research Institute (TGEN) in 2003. TGEN, a precision medicine research organization, is a part of City of Hope, one of the largest cancer research and treatment organizations in the U.S.
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Across the seven-arm study, oral PV-10 monotherapy was the top-ranked treatment arm under a scoring framework that assessed anti-tumor response, survival benefit, safety and tolerability, data quality, and translational potential. Notably, two animals treated with oral PV-10 — one from the monotherapy group and one from the group of PV-10 in combination with anti-PD-1 — survived to study end and showed an absence of gross bladder tumor at necropsy, a finding not observed in any untreated, vehicle-control, or anti-PD-1 monotherapy animal.
Study Design and Context
This preclinical study utilized the UMUC3-Luc luciferase-expressing bladder carcinoma cell line implanted orthotopically into the bladder of human peripheral blood mononuclear cell (PBMC)-engrafted NOD.Cg-Prkdcscid Il2rgtm1Sug/JicTac (NOG) mice, an immunologically humanized model that allows evaluation of treatment effects in the presence of a functional human immune compartment. Tumor progression was monitored longitudinally by bioluminescence imaging (BLI). The study used 54 female mice across seven groups and ran for 45 days. As is inherent to human PBMC-engrafted NOG models, graft-versus-host disease (GvHD) independently contributed to morbidity across all engrafted groups; the scoring framework weighted survival accordingly and all arm-level comparisons are interpreted in this context.
The seven study arms were:
Group 1: No treatment (negative control, n=8),
Group 2: Human PBMC engraftment + vehicle instillation (active vehicle control, n=7),
Group 3: Human PBMC + PV-10 3 mg/dose intravesical (OB-IVS), once weekly ×4 weeks (n=7),
Group 4: Human PBMC + PV-10 2 mg/dose oral (PO), 5 days on/2 days off to study end (n=8),
Group 5: Human PBMC + anti-human PD-1 10 mg/kg intraperitoneal, twice weekly ×4 weeks (n=8),
Group 6: Human PBMC + PV-10 3 mg/dose OB-IVS + anti-PD-1 10 mg/kg (n=8), and
Group 7: Human PBMC + PV-10 2 mg/dose PO + anti-PD-1 10 mg/kg (n=8).
To evaluate the study’s treatment arm (Groups 3-7) results, Provectus applied a scoring framework of five weighted domains: anti-tumor response (30%), survival benefit (25%), safety and tolerability (25%), data quality and interpretability (12%), and translational and development potential (8%). Each domain was scored on a zero-to-ten scale using a pre-specified rubric grounded exclusively in observed study data, including Day 23 BLI tumor burden, time-to-morbidity, body weight trajectory, evaluable animal counts at key timepoints, and long-term survivor necropsy findings. The scoring framework was then validated through a sensitivity analysis across five weighting scenarios: base case, safety-first, efficacy-heavy, survival-dominant, and equal weight configurations. Notably, the rank order of all five active treatment arms was invariant across every scenario tested.
Key Study Findings
Oral PV-10 monotherapy (Group 4): The top-ranked arm:
Day 23 BLI tumor burden approximately 40% lower than the vehicle control on a geometric mean basis (log₁₀ mean 10.39 vs. 10.61),
Body weight nadir of −1.9% across all eight animals, the best tolerability profile among all PBMC-engrafted groups,
One long-term survivor (Day 45) whose gross necropsy did not record bladder tumor, compared to the near-universal "tumor throughout bladder" finding in untreated, vehicle-control, and anti-PD-1 monotherapy animals,
Top scores in survival, safety, and data quality domains of the scoring framework, each at 10.0 out of 10.0, and
Weighted total score of 9.24 out of 10.
Oral PV-10 + anti-PD-1 combination (Group 7): The second-ranked arm:
Highest translational potential score, reflecting the established clinical rationale for combining checkpoint blockade with novel immunomodulatory agents in bladder cancer,
Body weight nadir of −14.4%; anti-PD-1-associated GvHD burden limited safety score relative to Group 4,
One long-term survivor (Day 45) whose gross necropsy similarly did not record bladder tumor, and
Weighted score of 7.84 out of 10.
Intravesical PV-10 (Groups 3 and 6): The intravesical arms at 3 mg/dose (30–60 mg/mL concentration) were not tolerated at the instillation parameters tested:
Six of seven Group 3 mice and three of eight Group 6 mice were lost by Day 12, following the first intravesical dosing event, consistent with acute mucosal toxicity at the concentrations employed.
These findings represent a maximum tolerated concentration failure at the doses tested, not a negative efficacy signal. The intravesical route remains scientifically open at lower concentrations; clinical intravesical agents such as BCG and mitomycin-C are administered at substantially lower concentrations than those employed in this study.
Drug Development Evaluation Framework
Domain scores and sensitivity analysis results are presented in Tables 1 and 2 below.
Table 1. Domain Scores by Arm
Group Treatment Response (30%) Survival (25%) Safety (25%) Data Quality (12%) Translation (8%) Weighted Total
1 No Treatment 4.5 10.0 10.0 10.0 5.0 7.95/10
2 PBMC + Vehicle 6.0 10.0 9.0 9.0 5.0 8.03/10
3 PV-10 OB-IVS 0.0 0.0 5.0 1.0 1.0 1.45/10
4 PV-10 PO 8.0 10.0 10.0 10.0 8.0 9.24/10
5 anti-PD-1 5.0 10.0 6.0 10.0 7.0 7.26/10
6 PV-10 OB-IVS + anti-PD-1 5.0 0.0 1.0 3.0 2.0 2.27/10
7 PV-10 PO + anti-PD-1 7.4 8.8 6.0 10.0 9.0 7.84/10
Groups 1 and 2 are control arms of the study and are included in the above table for scoring framework calibration. They are not ranked against the treatment arms of Groups 3 to 7.
Table 2. Sensitivity Analysis
Weighting scenario Group 3
PV-10 OB-IVS Group 4
PV-10 PO Group 5
anti-PD-1 Group 6
PV-10 OB-IVS + anti-PD-1 Group 7
PV-10 PO + anti-PD-1 G4 lead over G7
Base case (30/25/25/12/8) 1.45 (#5) 9.24 (#1) 7.26 (#3) 2.27 (#4) 7.84 (#2) +1.40
Safety-first (20/20/40/12/8) 2.20 (#4) 9.44 (#1) 7.16 (#3) 1.92 (#5) 7.56 (#2) +1.88
Efficacy-heavy (40/30/15/10/5) 0.90 (#5) 9.10 (#1) 7.25 (#3) 2.55 (#4) 7.95 (#2) +1.15
Survival-dominant (20/40/25/10/5) 1.40 (#5) 9.50 (#1) 7.85 (#3) 1.65 (#4) 7.95 (#2) +1.55
Equal weight (20/20/20/20/20) 1.40 (#5) 9.20 (#1) 7.60 (#3) 2.20 (#4) 8.24 (#2) +0.96
In Table 2, the narrowest Group 4–Group 7 margin occurs under equal weight (+0.96), driven by Group 7’s high translation domain score (9.0 vs Group 4’s 8.0). Group 4’s lead widens under safety-first weighting (+1.88), reflecting Group 4’s perfect safety score versus Group 7’s GvHD-penalized score of 6.0.
Dominic Rodrigues, Provectus’s President and Vice Chairman of the Board of Directors, said "This preclinical study marks three firsts for Provectus: the first evaluation of PV-10 in bladder cancer, the first evaluation of any PV-10 route in an orthotopic tumor model, and the first evaluation of oral PV-10 against a solid tumor cancer. Historical Company and research collaborator preclinical work employed solid tumor cancer flank mouse models to evaluate PV-10 administered by intratumoral injection."
He added, "These oral PV-10 findings are encouraging. The long-term survivor necropsy findings — two animals treated with oral PV-10 that showed an absence of gross bladder tumor at Day 45 — are an important signal. PV-10’s mechanism’s capacity to perturb the tumor microenvironment and drive antitumor immune activity is not bladder cancer-specific. That is precisely what makes this result scientifically interesting and developmentally promising beyond the indication in which it was observed."
Ed Pershing, Provectus’s Chairman and Chief Executive Officer, said, "The path from this preclinical signal to the clinic requires FDA acceptance of an expanded Investigational New Drug application, which we currently have for intratumoral administration of PV-10, to permit oral PV-10 human testing. That is our next goal and regulatory milestone. As we consider which indication to pursue first in a Phase 1 study, we are drawn to cancers where the gap between what standard of care offers and what patients need remains widest. Bladder cancer is one such disease. Pancreatic cancer and glioblastoma are others we are watching closely. Oral PV-10’s tolerability profile — demonstrated here in a tumor model with no dose-limiting events and a body weight nadir below two percent — is directly relevant to patients in those settings. This preclinical study tells us oral PV-10 belongs in that conversation."
(Press release, Provectus Biopharmaceuticals, MAY 18, 2026, View Source [SID1234665849])