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Umifenovir is one of the most often prescribed antiviral medications for the prevention and treatment of COVID-19 and other viral infections. Herein, a UPLC-MS/MS method is developed through using ibrutinib as an internal standard (IS) for quantifying umifenovir in plasma samples. Both umifenovir and the IS were analytically separated on an Acquity BEH C18 column with a total run time of only 2.5 min. At a flow rate of 0.3 mLmin−1, acetonitrile:15 mM ammonium acetate (80:20) was employed as the mobile phase composition. Electrospray ionization in positive mode was used for ionization of the samples. Detection and quantification were performed in multiple reaction monitoring mode with parent-to-daughter ionization of 477.05 → 279.02 and 441.16 → 84.4 for umifenovir and the IS, respectively. The method was validated through following international guidelines for bioanalytical method validation, and all parameters were within the acceptable limits. Moreover, the eco-scale method using AGREE software was used for the evaluation of greenness, and results showed that the method is very environmentally friendly. The validated assay was successfully employed in the bioavailability assessment of a newly developed formulation of kneaded ternary umifenovir/β-cyclodextrin with 1% poloxamer 188 (KDB).

5-Fluorouracil (5-FU) is now used in eye drops for the management of conjunctival malignant melanoma, intraepithelial neoplasia, and corneal and conjunctival squamous cell carcinoma. The previously used methods for 5-FU quantification in AqH were time-consuming and less sensitive. Herein, a highly perceptive bioanalytical UPLC–MS/MS method was developed for the quantitative determination of 5-FU in the aqueous humor (AqH) of rabbits using allopurinol as the internal standard (IS). The 5-FU and IS were well separated in an Acquity™ HILIC column. Acetonitrile and 10 mM of ammonium acetate at 95:5 (v/v) were isocratically pumped at a 0.3 mL/min flow rate with a total runtime of 2.5 min. AqH samples were processed with a liquid–liquid extraction method in ethyl acetate. The 5-FU and IS were identified in the negative mode with electrospray ionization. The parent to daughter ion transitions for the 5-FU and IS occurred at m/z 128.92→41.68 and 134.80→64.10, respectively, as quantified using the multiple reaction monitoring mode. The developed method was validated with the ICH-Harmonized Guideline for Bioanalytical Method Validation, and the parameters were within acceptable limits. The calibration curve was linear at the 10.5–2000 ng/mL concentration range, with a correlation coefficient (R2) of 0.9946, and the lower limit of detection was 3.55 ng/mL. The developed and validated method was rapid, sensitive, accurate and robustly able to quantify 5-FU in rabbit AqH. The method was effectively applied to establish the ocular pharmacokinetics of 5-FU following the topical instillation of 5-FU-containing preparations in rabbits.

Osteosarcoma (OS) metastasizes primarily and almost exclusively to the lungs. The survival rate decreases significantly for patients who develop OS lung metastasis (OSLM). Purpose: To assess the safety and efficacy of colony-stimulating factor-1 receptor inhibitor (CSF-1Ri) (Pexidartinib; PLX) in shifting the OSLM tumor microenvironment (TME) to an anti-tumorigenic state upon local delivery to lungs of a syngeneic mouse model of OSLM. Methods: The safety of PLX upon repeated pulmonary administration (9 doses, every other day at 2 mg/kg) in healthy BALB/c mice was assessed using health scoring, pulmonary mechanics, molecular and cellular composition of bronchoalveolar lavage fluid (BALF), blood count and plasma biochemistry, and H&E of lungs and liver. To establish the OSLM model, murine OS cells, expressing bioluminescent and fluorescent genes (K7M2-Luc-tdT), were used. Mice bearing OSLM were randomized into two groups (vehicle and PLX) and treated over 3 weeks. Tumor burden was evaluated using bioluminescent imaging (BLI) and lung weight. The treatment impact on the abundance and phenotype of tumor-associated macrophages (TAMs) and their CSF-1R expression as well as on the abundance of tumor-infiltrating lymphocytes and their expression to PD-1 were investigated using immunofluorescence, flow cytometry, and western blot. Results: PLX is well tolerated upon local lung administration with all safety markers indicating no alteration compared to naïve and vehicle controls. Treatment did not affect health scores. We did not detect any functional or mechanical alteration on the lungs or systemically (including liver); no marked differences in pulmonary function parameters, proinflammatory cytokines, nor infiltrating differential cell count obtained from BALF were observed. Both total blood count and liver enzymes were within normal range. As a measure of efficacy, treatment with PLX via local lung administration reduced tumor burden, indicated by the in vivo BLI and lung weight. Notably, PLX significantly decreased the abundance of total TAMs, with a more pronounced effect on pro-tumorigenic alternatively-activated (M2-like) TAMs phenotype, thus leading to a 22-fold increase in M1/M2 ratio. PLX further led to a marked decrease in tumor-promoting T regulatory cells (Treg), increase in the CD8/Treg ratio, and decrease in PD-1+ percentage in CD8 T cells in the TME, indicating a shift to a more immunogenic tumor phenotype. Conclusions: We demonstrated that repeated doses of PLX is safe upon local delivery to the lungs of murine model of OSLM, with no alternations in lungs or liver tissue. We further showed that PLX reduces tumor burden, which correlates with a change in the immune phenotype of the OSLM toward a more anti-tumorigenic profile. These results are clinically relevant as PLX has been approved by the FDA, thus opening opportunities for its repurposing to support standard of care therapy in OSLM. Citation Format: Fatemah S. Sunbul, Sulaiman S. Alhudaithi, Rashed M. Almuqbil, Hanming Zhang, Raneem R. Aldaqqa, Shane Albin, Rebecca L. Heise, Valentina Robila, Matthew S. Halquist, Sarah W. Gordon, Paula D. Bos, Sandro R. da Rocha. Remodeling the microenvironment of osteosarcoma lung metastases with inhaled CSF-1Ri immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1991.

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that lacks targeted treatment options. While immune check point blockade leads to significant benefits in the treatment of TNBC when in combination with chemotherapy, recurrence, metastasis, and drug resistance still remain a major challenge. The purpose of this study was to assess the ability of a colony-stimulating factor 1 receptor inhibitor (CSF-1Ri) to shift the phenotype of the tumor microenvironment (TME) in a mouse model of TNBC, and the potential benefit of such tumor priming when the CSF-1Ri is administered in combination with chemotherapy. We focused on targeting tumor-associated macrophages (TAMs) as they are the most abundant immune infiltrate in the TNBC TME and are associated with worse overall survival and an increased chance of metastasis. Targeting TAMs, specifically alternatively activated, anti-inflammatory M2-like TAMs, has been shown to inhibit tumor progression and improve overall survival in several different tumor models. We have selected pexidartnib (PLX) as the CSF-1Ri of choice given its translational potential (FDA approved) and gemcitabine (GMT) as chemotherapy, given its ability to target myeloid derived suppressor cells. We employed a mammary carcinoma 4T1in BALB/c mice as the immunocompetent tumor model. Mice were injected with 100,000 4T1 cells in the 4th mammary fat pad, and tumors grew over the course of fifteen days to a tumor volume of 40 mm3. Mice were then exposed to daily administrations of PLX (8 mg/kg), and weekly administrations of GMT (60 mg/kg). Tumor volumes were recorded every other day. The TME was analyzed with flow cytometry 24h post last treatment to characterize immune infiltrates. Regarding total TAMs (CD45+CD11b+F4/80+), only the combination therapy (11.8% ± 2.1) could significantly decrease this population compared to vehicle control (22% ± 2). PLX (4.7% ± 0.8) is shown to shift the phenotype of the TNBC TME by significantly reducing M2-like TAMs (CD45+CD11b+F4/80+CD206+) compared to vehicle control (15.6% ± 0.4). Interestingly, GMT also promotes a decrease in M2-like TAMs (6.6% ± 0.9), which is further reduced in combination therapy (2.2% ± 0.6), which showed a significant decrease when compared to both vehicle and standalone GMT. Both standalone GMT (82.1 mm3 ± 13.7) and combination therapy (75.7 mm3 ± 10.7) significantly decreased tumor burden compared to vehicle control (153.3 mm3 ± 37.2) after a week of treatment. Furthermore, after five weeks of treatment, combination therapy (304.6 mm3 ± 51.5) had a significant effect on tumor burden compared to GMT (596.9 mm3 ± 122.8), indicating a correlation between tumor phenotype and therapeutic benefit. In conclusion, targeting TAMs in TNBC primes the tumor for combination with chemotherapy in TNBC. Citation Format: Matthew E. Fernandez, Cory B. Fines, Fatemah S. Subul, Sulaiman S. Alhudaithi, Harry D. Bear, Douglas H. Sweet, Sandro R. da Rocha. Macrophage-targeting immunotherapy for triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2328.

The lungs are major sites of metastases for several cancer types, including breast cancer (BC). Prognosis and quality of life of BC patients that develop pulmonary metastases are negatively impacted. The development of strategies to slow the growth and relieve the symptoms of BC lung metastases (BCLM) is thus an important goal in the management of BC. However, systemically administered first line small molecule chemotherapeutics have poor pharmacokinetic profiles and biodistribution to the lungs and significant off-target toxicity, severely compromising their effectiveness. In this work, we propose the local delivery of add-on immunotherapy to the lungs to support first line chemotherapy treatment of advanced BC. In a syngeneic murine model of BCLM, we show that local pulmonary administration (p.a.) of PLX-3397 (PLX), a colony-stimulating factor 1 receptor inhibitor (CSF-1Ri), is capable of overcoming physiological barriers of the lung epithelium, penetrating the tumor microenvironment (TME), and decreasing phosphorylation of CSF-1 receptors, as shown by the Western blot of lung tumor nodules. That inhibition is accompanied by an overall decrease in the abundance of protumorigenic (M2-like) macrophages in the TME, with a concomitant increase in the amount of antitumor (M1-like) macrophages when compared to the vehicle-treated control. These effects with PLX (p.a.) were achieved using a much smaller dose (1 mg/kg, every other day) compared to the systemic doses typically used in preclinical studies (40-800 mg/kg/day). As an additive in combination with intravenous (i.v.) administration of paclitaxel (PTX), PLX (p.a.) leads to a decrease in tumor burden without additional toxicity. These results suggested that the proposed immunochemotherapy, with regional pulmonary delivery of PLX along with the i.v. standard of care chemotherapy, may lead to new opportunities to improve treatment, quality of life, and survival of patients with BCLM.

Olaparib (OLA) is an anticancer agent that acts by inhibiting the poly (ADP-ribose)-polymerase-I (PARP-I). Due to its low solubility and low permeability, it has been placed as a BCS Class-IV drug and hence its clinical use is limited. In this study, we develop the nanocrystals of OLA as a way to improve its solubility and other performances. The OLA-NCs were prepared by antisolvent precipitation method through homogenization and probe sonication technique using a novel amphiphilic polymeric stabilizer (Soluplus®). Particle characterization resulted approximately 103.13 nm, polydispersity-index was 0.104 with positive zeta-potential of +8.67 mV. The crystal morphology by SEM of OLA-NCs (with and without mannitol) exhibited nano-crystalline prism-like structures as compared to the elongated OLA-pure. The DSC, XRD and FTIR were performed to check the interaction of Soluplus, mannitol and OLA did not exhibit any physical interaction among the OLA, Soluplus® and mannitol that is indicated by the presence of parent wave number peak. Two-fold increased solubility of OLA was found in PBS with Soluplus® from the NCs (69.3 ± 6.2 µgmL−1) as compared to pure drug (35.6 ± 7.2 µgmL−1). In vitro release of drug from OLA-NCs was higher (78.2%) at 12 h at pH 6.8 and relatively lower (53.1%) at pH 1.2. In vitro cellular cytotoxicity and anticancer effects were examined on MCF-7 cells. OLA-NCs were found effectively potent to MCF-7 cells compared with OLA-pure with approximately less than half IC50 value during MTT assay. Estimation of p53, Caspase-3 and Caspase-9 in MCF-7 cells indicated that OLA-NCs have significantly (p < 0.05) increased their expressions. After single oral dose in rats, 12 h plasma drug concentration-time profile indicated approximately 2.06-, 2.29-, 2–25- and 2.62-folds increased Cmax, AUC0-12 h, AUC0-∞ and AUMC0-∞, respectively, from the NCs as compared to OLA-pure. Storage stability indicated that the OLA-NCs was physically and chemically stable at 4 °C, 25 °C and 40 °C up to 6-months. Overall, OLA-NCs were deliberated; its potential feasibility to overwhelm the formulation challenges related to poorly soluble drugs and its future clinical applications.

Lung cancers remain the leading cause of cancer-related death in both men and women. Infiltrating immune cells in the tumor microenvironment (TME) play a critical role in the formation, progression, and the response of solid tumors to therapy, including in lung cancers. Clinical studies have established that tumor-associated macrophages (TAMs) and their phenotypical composition are critical immune infiltrates in the lung TME, with the abundance of the M2-like phenotype negatively correlating with patient survival. Colony-Stimulating Factor 1 (CSF-1) receptor (CSF-1R) is a type III protein tyrosine kinase receptor that plays an important role in the recruitment and differentiation of monocytes into tumor-promoting M2-like TAMs and their survival. In this work we evaluated the therapeutic potential of PLX 3397 (PLX), a small molecule CSF-1R inhibitor (CSF-1Ri), upon local lung administration in an immune-competent mouse model of lung cancer. The efficacy of local lung delivered PLX as single therapy was investigated first. As assessed by immunofluorescence of sections of lung tumor nodules, a statistically significant reduction in M2-like TAMs and an increase in M1-like TAMs was observed, thus leading to a shift in the (M1/M2) balance. Those changes in abundance of immune infiltrates correlated with a significant decrease in tumor burden when compared to control. When combined with systemically administered cisplatin (CIS) PLX treatment provided further benefits, leading to a significant decrease in tumor burden when compared to either PLX or CIS treatments alone, as measured by bioluminescence intensity (BLI) in vivo (thoracic area) and ex vivo (lung tissue). This combination therapy led to the most pronounced increase in M1/M2 ratio, followed by a significant decrease in M2-like TAMs with the CIS therapy. This work is clinically relevant as it demonstrates the potential of local lung administration of PLX to support standard of care chemotherapy for lung cancer management. This is important as the pulmonary route of administration is a plausible strategy for reducing the total dose of CSF-1Ris as the tissue of interest (lungs) can be locally targeted. Because the major off-target effect of CSF-1Ris is liver toxicity, reducing systemic concentration will support translation of those therapies, especially in combination with standard of care chemotherapy that has significant off-target toxicity and patient attrition itself. This work is scientifically relevant as we demonstrate for the first time that local administration of a CSF-1Ri to the lungs leads to a shift in the balance of TAMs in the TME of a model of lung tumor, adding to the sparse literature of CSF-1Ris related to lung cancers.