Intratumoral Drug Concentration Research Articles

DNAR-10. PHASE I CLINICAL TRIAL OF PEPOSERTIB PLUS RADIOTHERAPY IN ADULTS WITH NEWLY-DIAGNOSED MGMT-UNMETHYLATED GLIOBLASTOMA

Abstract BACKGROUND DNA-dependent protein kinase (DNA-PK) is an attractive target in GBM because it promotes unwanted DNA repair and renders cancer cells less vulnerable to DNA damaging agents, such as radiotherapy (RT). Peposertib, a small molecule inhibitor of DNA-PK, has demonstrated pre-clinical efficacy in sensitizing GBM to RT, resulting in tumor regression. METHODS 21 patients with newly-diagnosed MGMT-unmethylated GBM received peposertib plus 6-weeks of RT to determine the maximum-tolerated dose (MTD) based on the Bayesian Optimal Interval design. The dose-limiting toxicity (DLT) period was 10-weeks. Patients received at least 6-cycles of adjuvant temozolomide (NCT04555577). Single-nuclei RNA-sequencing (snRNA-Seq) and spatial transcriptomics (Visium, 10x Genomics) were performed on matched pair primary-recurrent tumors and controls, incorporating tumor cell state and cell type definitions by automated cluster classification and differential expression of marker genes. RESULTS The MTD of peposertib in combination with RT was 300mg per RT fraction day. One DLT (G3 radiation necrosis @300mg) was observed. After a median follow-up of 15.4 months (interquartile-range 8.9-18.5), mPFS was 10.8 months (95%CI 8.33-NR) and mOS was 22.9 months (95%CI 16-NR). 6/21 (29%) patients have undergone re-resection to date. snRNA-Seq on 102,709 cells from 12 primary and 3 recurrent tumors revealed that pre-treatment tumor cell states were progenitor-like, while treatment with peposertib plus RT was associated with differentiated and inflammatory malignant cell states, along with macrophage infiltration. Spatial transcriptomics of 8 matched primary-recurrent tumors (20,793 transcriptomes) confirmed malignant cell differentiation and enrichment of pro-inflammatory macrophages after inhibition of DNA-PK. 5 patients will be enrolled into a window-of-opportunity expansion cohort to evaluate intratumoral drug concentration. CONCLUSION The combination of peposertib and intracranial RT was safe. Survival data for this MGMT-unmethylated GBM population was promising. Single nuclei and spatial transcriptomic analyses revealed enrichment of pro-inflammatory macrophages in the tumor microenvironmentafter DNA-PK inhibition. The study was supported by EMD-Serono (CrossRef Funder ID: 10.13039/100004755).

Ganoderic acid T, a Ganoderma triterpenoid, modulates the tumor microenvironment and enhances the chemotherapy and immunotherapy efficacy through downregulating galectin-1 levels

Ganoderic acid T (GAT), a triterpenoid molecule of Ganoderma lucidum, exhibits anti-cancer activity; however, the underlying mechanisms remain unclear. Therefore, in this study, we aimed to investigate the anti-cancer molecular mechanisms of GAT and explore its therapeutic applications for cancer treatment. GAT exhibited potent anti-cancer activity in an ES-2 orthotopic ovarian cancer model in a humanized mouse model, leading to significant alterations in the tumor microenvironment (TME). Specifically, GAT reduced the proportion of α-SMA+ cells and enhanced the infiltration of tumor-infiltrating lymphocytes (TILs) in tumor tissues. After conducting proteomic analysis, it was revealed that GAT downregulates galectin-1 (Gal-1), a key molecule in the TME. This downregulation has been confirmed in multiple cancer cell lines and xenograft tumors. Molecular docking suggested a theoretical direct interaction between GAT and Gal-1. Further research revealed that GAT induces ubiquitination of Gal-1. Moreover, GAT significantly augmented the anti-cancer effects of paclitaxel, thereby increasing intratumoral drug concentrations and reducing tumor size. Combined with immunotherapy, GAT enhanced the tumor-suppressive effects of the anti-programmed death-ligand 1 antibody and increased the proportion of CD8+ cells in the EMT6 syngeneic mammary cancer model. In conclusion, GAT inhibited tumor growth, downregulated Gal-1, modulated the TME, and promoted chemotherapy and immunotherapy efficacy. Our findings highlight the potential of GAT as an effective therapeutic agent for cancer.

Photodynamic therapy promotes hypoxia‐activated nitrogen mustard drug release

AbstractPhotodynamic therapy (PDT) has become a promising method for tumor treatment due to its non‐invasive and high spatiotemporal selectivity. However, PDT is still hindered by reactive oxygen species deficiency, because solid tumors feature a hypoxic microenvironment. PDT combined with hypoxia‐activated chemotherapy drugs can effectively induce tumor death, overcoming the limitations of the sole PDT for the fight against hypoxia. Herein, we designed a nanosystem (PCe6AZOM) that enhances the release of hypoxia‐activated drugs (AZOM) by PDT. Under hypoxic conditions, the azo bond of AZOM is cleaved by azo reductase, releasing highly cytotoxic AZOM and resulting in a significant increase in intratumor drug concentration. Meanwhile, the commercial photosensitizer Ce6 can aggravate the oxygen‐poor state during the PDT process and further cause more AZOM release. Moreover, the cascade reactions in the nanosystem could activate singlet oxygen and enhance drug release through 660 nm light laser irradiation, contributing to more effective induction of tumor apoptosis and tumor growth retardation in vitro and in vivo.

Antitumor activity of nab-sirolimus versus mTOR inhibitors temsirolimus, sirolimus, and everolimus in A549 NSCLC xenografts.

e15096 Background: The mTORC1 pathway, often activated by mutations in genes like TSC1, TSC2, PIK3CA, PTEN, STK11, and KEAP1, plays a pivotal role in cancer progression; in some settings, alterations in STK11 and KEAP1 may be associated with treatment resistance and poor prognosis. Despite the broad importance of the mTORC1 pathway in cancer cell growth and survival, mTOR inhibitors (mTORis) temsirolimus (TEM), sirolimus (SIRO), and everolimus (EVE) have limited clinical application in the cancer setting. nab-Sirolimus, an injectable form of albumin-bound SIRO that leverages unique transport properties of albumin known to increase tumor drug accumulation, is approved for treatment of malignant PEComa. Here, we report the antitumor activity of nab-sirolimus in comparison to other mTORis in A549 NSCLC ( KRAS G12S, STK11 Q37*, and KEAP1 G333C) xenografts, and the correlation of antitumor activity, tumor PK profile, and mTOR pathway suppression. Methods: Athymic mice bearing subcutaneous A549 NSCLC xenografts were treated with either saline or equal weekly doses of nab-sirolimus (administered intravenously [IV]; 5 or 15 mg/kg/week), TEM (IV; 5 mg/kg/week), or SIRO or EVE (both oral; 15 mg/kg/week). Tumors were harvested at different time points after mTORi treatment and analyzed for tumor drug levels (LC-MS/MS) and mTOR pathway biomarkers (pS6 and p4EBP1) via western blot (WB). Results: In A549 xenografts, nab-sirolimus (IV) treatment resulted in significantly greater suppression of tumor growth compared with TEM (IV), SIRO (oral), and EVE (oral) (Table). Average intratumoral drug concentrations 24 hours after IV mTORi treatment were significantly higher with nab-sirolimus (420-539 ng/g) compared with TEM (TEM [parent] 34.9 ng/g; SIRO [active metabolite measured from TEM] 13.2 ng/g) and compared with 7-day steady-state concentrations for oral SIRO (17 ng/g) and EVE (10 ng/g). WB confirmed that nab-sirolimus consistently inhibited mTOR targets pS6 and p4EBP1, whereas TEM, SIRO, and EVE were less effective. Conclusions: nab-Sirolimus resulted in significantly higher intratumoral drug concentration, stronger inhibition of mTOR targets, and greater antitumor activity compared to other IV and oral mTORis in a KRAS/STK11/KEAP1 mutated NSCLC xenograft model. These results support further clinical evaluation of nab-sirolimus as a single agent or in combination with other therapeutic agents in oncology. [Table: see text]

Phase I clinical trial of peposertib plus radiation in adults with newly diagnosed MGMT-unmethylated glioblastoma.

2076 Background: DNA-dependent protein kinase (DNA-PK) is a pivotal component of DNA damage repair (DDR) pathways and is an attractive target in glioblastoma because its expression renders tumors less vulnerable to radiotherapy. Peposertib is a small molecule DNA-PK inhibitor that has been pre-clinically shown to potentiate radiotherapy and regress glioblastoma tumors. We conducted a two-stage phase I trial of peposertib plus radiation in patients with newly-diagnosed MGMT-unmethylated glioblastoma (NCT04555577). Methods: In stage 1, patients received concurrent peposertib plus standard-of-care radiotherapy to determine the maximum-tolerated dose (MTD) based on the Bayesian Optimal Interval design (maximum n=24). Stage 2 is a window-of-opportunity expansion cohort and will include 5 surgical patients to evaluate intratumoral drug concentration. Both groups receive 6 cycles of adjuvant temozolomide. Results: Eighteen patients completed the 10-week dose-limiting toxicity (DLT) period; 3@50mg, 3@100mg, 3@200mg, 9@300mg. One DLT (G3 radiation necrosis [RN] at 300mg) was observed. Enrollment of the last three patients into the 300mg dose level began in December 2023 and will complete stage 1. To date, most notable toxicity was transient G3 dermatitis of the scalp (2@200mg, 1@300mg; not a DLT per protocol). Therefore, radiation dose constraints to the skin were incorporated and subsequent patients did not experience this toxicity. After a median follow up of 14.3 months (9.3-18.4), the median OS was 22.9 months [95% CI (16-NR)] and median PFS was 12.7 months [95% CI (9-NR)]. Next-generation sequencing (NGS) was available for 16 archival tumor tissue specimens from patients treated on this trial. Two patients had pathology-proven RN (one within and one outside of the DLT period). Both tumors had baseline mutations in DDR genes (i.e. ATRX, DICER1). Recurrent tissue was available for 4 patients after treatment with peposertib, 2 of which demonstrated gain of DDR gene mutations (2 ATM mutations in one patient and gain of MAD2L2 mutation in another patient). Conclusions: The initial safety data of peposertib plus radiation in patients with newly-diagnosed MGMT unmethylated glioblastoma is favorable. The cases with RN in tumors with DDR mutations, the gain of DDR mutations in recurrent tumors, and the cases of scalp dermatitis suggest peposertib activity may correlate with DDR function, and possibly potentiates the effect of radiation. Stage I is an independent stage of the protocol that will enable MTD determination. Complete safety and survival data and correlations with genomics and spatial transcriptomics for Stage I patients will be presented at the meeting. The study was supported by EMD Serono (CrossRef Funder ID: 10.13039/100004755). Clinical trial information: NCT04555577 .

Continuous iontronic chemotherapy reduces brain tumor growth in embryonic avian in vivo models

Local and long-lasting administration of potent chemotherapeutics is a promising therapeutic intervention to increase the efficiency of chemotherapy of hard-to-treat tumors such as the most lethal brain tumors, glioblastomas (GBM). However, despite high toxicity for GBM cells, potent chemotherapeutics such as gemcitabine (Gem) cannot be widely implemented as they do not efficiently cross the blood brain barrier (BBB). As an alternative method for continuous administration of Gem, we here operate freestanding iontronic pumps – “GemIPs” – equipped with a custom-synthesized ion exchange membrane (IEM) to treat a GBM tumor in an avian embryonic in vivo system. We compare GemIP treatment effects with a topical metronomic treatment and observe that a remarkable growth inhibition was only achieved with steady dosing via GemIPs. Daily topical drug administration (at the maximum dosage that was not lethal for the embryonic host organism) did not decrease tumor sizes, while both treatment regimes caused S-phase cell cycle arrest and apoptosis. We hypothesize that the pharmacodynamic effects generate different intratumoral drug concentration profiles for each technique, which causes this difference in outcome. We created a digital model of the experiment, which proposes a fast decay in the local drug concentration for the topical daily treatment, but a long-lasting high local concentration of Gem close to the tumor area with GemIPs. Continuous chemotherapy with iontronic devices opens new possibilities in cancer treatment: the long-lasting and highly local dosing of clinically available, potent chemotherapeutics to greatly enhance treatment efficiency without systemic side-effects. Significance statementIontronic pumps (GemIPs) provide continuous and localized administration of the chemotherapeutic gemcitabine (Gem) for treating glioblastoma in vivo. By generating high and constant drug concentrations near the vascularized growing tumor, GemIPs offer an efficient and less harmful alternative to systemic administration. Continuous GemIP dosing resulted in remarkable growth inhibition, superior to daily topical Gem application at higher doses. Our digital modelling shows the advantages of iontronic chemotherapy in overcoming limitations of burst release and transient concentration profiles, and providing precise control over dosing profiles and local distribution. This technology holds promise for future implants, could revolutionize treatment strategies, and offers a new platform for studying the influence of timing and dosing dependencies of already-established drugs in the fight against hard-to-treat tumors.

Laser-assisted topical delivery of vismodegib reduces hedgehog gene expression in human basal cell carcinomas in vivo.

Systemically delivered hedgehog inhibitors including vismodegib and sonidegib are widely used to treat basal cell carcinomas (BCCs). Ablative fractional laser (AFL)-assisted topical delivery of vismodegib has been demonstrated in preclinical studies. The aim of this explorative clinical study was to evaluate intratumoral vismodegib concentrations and effect on hedgehog pathway gene expression following AFL-assisted topical vismodegib delivery to BCCs. In an open-label clinical trial, 16 nodular BCCs (in n = 9 patients) received one application of CO2 -AFL (40 mJ/microbeam, 10% density) followed by topical vismodegib emulsion. After 3-4 days, vismodegib concentrations in tumor biopsies (n = 15) and plasma were analyzed and compared with samples from patients receiving oral treatment (n = 3). GLI1, GLI2, PTCH1, and PTCH2 expression was determined by quantitative polymerase chain reaction (n = 7) and GLI1 additionally by in situ hybridization (n = 3). Following AFL-assisted topical administration, vismodegib was detected in 14/15 BCCs and reached a median concentration of 6.2 µmol/L, which compared to concentrations in BCC tissue from patients receiving oral vismodegib (9.5 µmol/L, n = 3, p = 0.8588). Topical vismodegib reduced intratumoral GLI1 expression by 51%, GLI2 by 55%, PTCH1 and PTCH2 each by 73% (p ≤ 0.0304) regardless of vismodegib concentrations (p ≥ 0.3164). In situ hybridization demonstrated that GLI1 expression was restricted to tumor tissue and downregulated in response to vismodegib exposure. A single AFL-assisted topical application of vismodegib resulted in clinically relevant intratumoral drug concentrations and significant reductions in hedgehog pathway gene expressions.

Reprogramming the pancreatic cancer stroma and immune landscape by a silicasome nanocarrier delivering nintedanib, a protein tyrosine kinase inhibitor

The prevailing desmoplastic stroma and immunosuppressive microenvironment within pancreatic ductal adenocarcinoma (PDAC) pose substantial challenges to therapeutic intervention. Despite the potential of protein tyrosine kinase (PTK) inhibitors in mitigating the desmoplastic stromal response and enhancing the immune milieu, their efficacy is curtailed by suboptimal pharmacokinetics (PK) and insufficient tumor penetration. To surmount these hurdles, we have pioneered a novel strategy, employing lipid bilayer-coated mesoporous silica nanoparticles (termed "silicasomes") as a carrier for the delivery of Nintedanib. Nintedanib, a triple PTK inhibitor that targets vascular endothelial growth factor, platelet-derived growth factor and fibroblast growth factor receptors, was encapsulated in the pores of silicasomes via a remote loading mechanism for weak bases. This innovative approach not only enhanced pharmacokinetics and intratumor drug concentrations but also orchestrated a transformative shift in the desmoplastic and immune landscape in a robust orthotopic KRAS-mediated pancreatic carcinoma (KPC) model. Our results demonstrate attenuation of vascular density and collagen content through encapsulated Nintedanib treatment, concomitant with significant augmentation of the CD8+/FoxP3+ T-cell ratio. This remodeling was notably correlated with tumor regression in the KPC model. Strikingly, the synergy between encapsulated Nintedanib and anti-PD-1 immunotherapy further potentiated the antitumor effect. Both free and encapsulated Nintedanib induced a transcriptional upregulation of PD-L1 via the extracellular signal-regulated kinase (ERK) pathway. In summary, our pioneering approach involving the silicasome carrier not only improved antitumor angiogenesis but also profoundly reshaped the desmoplastic stromal and immune landscape within PDAC. These insights hold excellent promise for the development of innovative combinatorial strategies in PDAC therapy.

Drug-Eluting Porous Embolic Microspheres for Trans-Arterial Delivery of Dual Synergistic Anticancer Therapy for the Treatment of Liver Cancer.

Blockage of blood supply while administering chemotherapy to tumors, using trans-arterial chemoembolization (TACE), is the most common treatment for intermediate and advanced-stage unresectable Hepatocellular carcinoma (HCC). However, HCC is characterized by a poor prognosis and high recurrence rates (≈30%), partly due to a hypoxic pro-angiogenic and pro-cancerous microenvironment. This study investigates how modifying tissue stress while improving drug exposure in target organs may maximize the therapeutic outcomes. Porous degradable polymeric microspheres (MS) are designed to obtain a gradual occlusion of the hepatic artery that nourishes the liver, while enabling efficient drug perfusion to the tumor site. The fabricated porous MS are introduced intrahepatically and designed to release a combination therapy of Doxorubicin (DOX) and Tirapazamine (TPZ), which is a hypoxia-activated prodrug. Liver cancer cell lines that are treated with the combination therapy under hypoxia reveal a synergic anti-proliferation effect. An orthotopic liver cancer model, based on N1-S1 hepatoma in rats, is used for the efficacy, biodistribution, and safety studies. Porous DOX-TPZ MS are very effective in suppressing tumor growth in rats, and induction tissue necrosis is associated with high intratumor drug concentrations. Porous particles without drugs show some advantages over nonporous particles, suggesting that morphology may affect the treatment outcomes.

A novel convex acoustic lens-attached ultrasound drug delivery system and its testing in a murine melanoma subcutaneous model

Target-specific drug release is indispensable to improve chemotherapeutic efficacy as it enhances drug uptake and penetration into tumors. Sono-responsive drug-loaded nano-/micro-particles are a promising solution for achieving target specificity by exposing them to ultrasound near tumors. However, the complicated synthetic processes and limited ultrasound (US) exposure conditions, such as limited control of ultrasound focal depth and acoustic power, prevent the practical application of this approach in clinical practice. Here, we propose a convex acoustic lens-attached US (CALUS) as a simple, economic, and efficient alternative of focused US for drug delivery system (DDS) application. The CALUS was characterized both numerically and experimentally using a hydrophone. In vitro, microbubbles (MBs) inside microfluidic channels were destroyed using the CALUS with various acoustic parameters (acoustic pressure [P], pulse repetition frequency [PRF], and duty cycle) and flow velocity. In vivo, tumor inhibition was evaluated using melanoma-bearing mice by characterizing tumor growth rate, animal weight, and intratumoral drug concentration with/without CALUS DDS. US beams were measured to be efficiently converged by CALUS, which was consistent with our simulation results. The acoustic parameters were optimized through the CALUS-induced MB destruction test (P = 2.34 MPa, PRF = 100 kHz, and duty cycle = 9%); this optimal parameter combination successfully induced MB destruction inside the microfluidic channel with an average flow velocity of up to 9.6 cm/s. The CALUS also enhanced the therapeutic effects of an antitumor drug (doxorubicin) in vivo in a murine melanoma model. The combination of the doxorubicin and the CALUS inhibited tumor growth by ∼ 55% more than doxorubicin alone, clearly indicating synergistic antitumor efficacy. Our tumor growth inhibition performance was better than other methods based on drug carriers, even without a time-consuming and complicated chemical synthesis process. This result suggests that our novel, simple, economic, and efficient target-specific DDS may offer a transition from preclinical research to clinical trials and a potential treatment approach for patient-centered healthcare.

The effect of blood velocity in solid tumor on intratumorally accumulation and penetration of nanocarriers and drugs

Due to the tumor heterogeneity, the velocity of blood flow is significantly different in either various malignancy types or in diversified positioning within a certain tumor. However, despite the nanodrugs administered in a systemic manner are transported into tumors through complicated vessel network, the effects of intratumoral blood velocity on the intratumoral accumulation of nanocarriers and its underlying mechanisms still remain largely unexplored so far. Consequently, we herein constructed several animal models with diverse intratumoral blood velocity via regulating the intratumoral coagulation environment (ICE), and subsequently evaluated the instrumental roles they played on intratumoral accumulation and penetration of nanocarriers and drugs. Interestingly, we discovered when the ICE featured an anti-coagulable state, the blood velocity in tumor vessels was consequently increased, leading to the high frequency of nanocarriers flowing through tumor vessels, improved intratumoral penetration of nanocarriers as well as the promoted intratumoral drug concentrations. On the other hand, when the ICE became a hypercoagulable state, the blood velocity in tumor vessels was prominently decreased correspondingly, generating the low frequency of nanocarriers flowing through tumor vessels and massed retention of nanodrugs in tumor vessels, which increased the number of drugs within tumor as well. Therefore, the evidence indicated that the variation in blood flow velocity caused by modifying ICE have different advantages in improving the efficiency of tumor-targeted nano drugs, which might propose a new perspective to consider how tumor-targeting nanodrugs enter solid tumors and further exert efficacious tumor-killing effectiveness under disparate tumor vascular microenvironment.

Mechanistically Weighted Metric to Predict In Vivo Antibody-Receptor Occupancy: An Analytical Approach.

In situ clinical measurement of receptor occupancy (RO) is challenging, particularly for solid tumors, necessitating the use of mathematical models that predict tumor receptor occupancy to guide dose decisions. A potency metric, average free tissue target to initial target ratio (AFTIR), was previously described based on a mechanistic compartmental model and is informative for near-saturating dose regimens. However, the metric fails at clinically relevant subsaturating antibody doses, as compartmental models cannot capture the spatial heterogeneity of distribution faced by some antibodies in solid tumors. Here we employ a partial differential equation (PDE) Krogh cylinder model to simulate spatiotemporal receptor occupancy and derive an analytical solution, a mechanistically weighted global AFTIR, that can better predict receptor occupancy regardless of dosing regimen. In addition to the four key parameters previously identified, a fifth key parameter, the absolute receptor density (targets/cell), is incorporated into the mechanistic AFTIR metric. Receptor density can influence equilibrium intratumoral drug concentration relative to whether the dose is saturating or not, thereby influencing the tumor penetration depth of the antibody. We derive mechanistic RO predictions based on distinct patterns of antibody tumor penetration, presented as a global AFTIR metric guided by a Thiele Modulus and a local saturation potential (drug equivalent of binding potential for positron emissions tomography imaging) and validate the results using rigorous global and local sensitivity analysis. This generalized AFTIR serves as a more accurate analytical metric to aid clinical dose decisions and rational design of antibody-based therapeutics without the need for extensive PDE simulations. SIGNIFICANCE STATEMENT: Determining antibody-receptor occupancy (RO) is critical for dosing decisions in pharmaceutical development, but direct clinical measurement of RO is often challenging and invasive, particularly for solid tumors. Significant efforts have been made to develop mathematical models and simplified analytical metrics of RO, but these often require complex computer simulations. Here we present a mathematically rigorous but simplified analytical model to accurately predict RO across a range of affinities, doses, drug, and tumor properties.

CINOVA: a phase II study of CPC634 (nanoparticulate docetaxel) in patients with platinum resistant recurrent ovarian cancer

ObjectiveRecurrent platinum-resistant ovarian cancer has a poor prognosis with limited therapeutic options. Sub‐therapeutic intra-tumoral drug concentrations may add to therapy resistance. CPC634 (docetaxel entrapped in CriPec nanoparticles) was designed to...

Tirapazamine-loaded CalliSpheres microspheres: Preparation and characterization as a chemoembolization agent for liver cancer

Tirapazamine (TPZ), a hypoxia-selective cytotoxic agent, has proved to exert synergistic tumor-killing activity with transcatheter arterial embolization (TAE) against liver cancer. This advances TPZ to transcatheter therapies for liver cancer, particularly in combination with drug-eluting microspheres. We describe methods for preparing and characterizing TPZ-loaded CalliSpheres microspheres (CSMTPZs) with regard to their properties as a chemoembolization agent, which includes 1) preparation of CSMTPZs and determination of drug loading level, 2) in vitro determination of TPZ release, 3) assessment of CSMTPZ size and appearance, and 4) determination of TPZ pharmacokinetics and intratumoral drug concentration in vivo. These methods can be adapted for further clinical I trial.•This is to our knowledge the first methods for preparing and characterizing tirapazamine-loaded microspheres with regard to their properties as a chemoembolization agent•Detailed protocols for preparation of CSMTPZs, determination of drug loading level, in vitro determination of TPZ release, assessment of CSMTPZ size and appearance, and in vivo determination of TPZ pharmacokinetics and intratumoral drug concentration•Adaptable to experiments on other animal models and clinical trials

CTNI-26. SURGICAL WINDOW OF OPPORTUNITY TRIAL OF NAVTEMADLIN (KRT 232; AMG232) IN PATIENTS WITH RECURRENT GLIOBLASTOMA

Abstract BACKGROUND KRT232 is an orally bioavailable, selective small molecule inhibitor of MDM2 that blocks the protein-protein interaction between MDM2 and p53. We performed a surgical window of opportunity trial of KRT232 in patients with recurrent GBM. METHODS The primary endpoint was to determine the tumor tissue concentration of KRT232. Prior to surgery, patients received KRT232 at either 120mg (n = 10, minimal dose that is consistently associated with alterations in serum MIC-1) or 240mg (n = 10; recommended phase 2 dose as monotherapy) for two days prior to surgical resection. Surgery was performed 3-6 hours following the last administration of KRT232. Tissue was analyzed for KRT232 concentration by LC/MS and for correlative studies. Participants with TP53 wild-type tumors were eligible to continue KRT232 following recovery from surgery at the RP2D of 240mg QD x 7 days q3weeks. RESULTS Twenty-one patients were enrolled from July 2018 to April 2020. One patient was deemed ineligible after surgery due to non-GBM tumor. Study met the prespecified criteria of target intra-tumor drug concentration of ≥ 25nM in contrast enhancing tissue in more than 50% of the patients in the 120mg cohort (67.1 ± 42.7nM in 8/10 patients) and 240mg (328.7 ± 468.1nM in 10/10 patients) cohort. Serum MIC-1 fold-changes from baseline (FCB) approximately 24 hours after a single dose of KRT232 were higher in the 240mg cohort (9.1 ± 4.1-FCB) than the 120mg cohort (3.6 ± 2.0-FCB). CDKN1A (p21), a downstream marker of p53, was significantly upregulated in analyzed participants whose GBM was TP53 wildtype, but not in TP53 mutant GBM or control samples (GBM treated with standard of care). CONCLUSION KRT232 at both 120mg and 240mg achieves adequate tumor tissue penetration and affects downstream pathways in TP53 wildtype GBM. The study has moved to Alliance to complete a phase 1 study of radiation + KRT232 in patients with newly diagnosed MGMT unmethylated GBM.

CTNI-09. DIFFUSE MIDLINE GLIOMA-ADAPTIVE COMBINATORY TRIAL (DMG-ACT): A COMBINATION PLATFORM TRIAL IN PEDIATRIC AND YOUNG ADULT PATIENTS WITH DIFFUSE MIDLINE GLIOMA

Abstract Despite advances in understanding the biology of diffuse midline gliomas (DMGs), clinical outcomes have not significantly improved. Therapy development is limited by: lack of preclinical data across multiple models and laboratories, limited knowledge about blood-brain barrier penetrance, and lack of multi-agent therapeutic approaches. We aimed to address these limitations by designing and implementing an innovative platform clinical trial (DMG-ACT). DMG-ACT is an open-label, multi-institutional, international trial of combination therapy for patients with DMG between 2 and 39 years of age. This study utilizes a novel Bayesian drug combination platform design with adaptive shrinkage (ComPAS). ComPAS allows for ongoing assessment of therapy efficacy with data borrowing across arms and the ability to eliminate ineffective drug combinations and add new promising combinations throughout the trial. The current treatment arms include ONC201 in combination with paxalisib. Patients enter one of three cohorts: newly-diagnosed (Cohort 1), post-radiation (Cohort 2), and relapsed/progressive (Cohort 3). Each cohort offers a target validation phase for patients who have not yet undergone biopsy to assess intratumoral pharmacokinetics/pharmacodynamics of pre-biopsy, single-agent dosing. Cohorts 1 and 3 offer radiation (Cohort 1) or re-irradiation (Cohort 3) with concomitant single-agent therapy followed by maintenance with combination therapy. The primary efficacy endpoints are median progression-free survival at 6 months (Cohorts 1 and 2) and overall survival at 7 months (Cohort 3). Exploratory endpoints include intratumoral drug concentrations; toxicity profile of combination therapy during radiation; toxicity profile and efficacy of combination therapy; CSF, ctDNA, stool, and flow cytometry biomarker analyses; and health related quality of life, cognitive, and patient/proxy-reported outcome measures. Additional therapy combinations that have shown additive or synergistic benefit in preclinical testing will be incorporated in future trial iterations and several are currently in development. The trial was launched in October 2021, with a total of 21 patients enrolled as of May 2022.

DIPG-09. Diffuse Midline Glioma-Adaptive Combinatory Trial (DMG-ACT): A biology-driven platform trial in pediatric and young adult patients with diffuse midline glioma

BACKGROUND: Despite advances in our understanding of the biology of diffuse midline gliomas (DMGs), little progress has been made in improving outcomes. Therapy development is limited by lack of preclinical data across multiple model systems and laboratories; limited knowledge about blood-brain barrier penetrance; and lack of multi-agent therapies. We aim to address these issues through DMG-ACT, where we translate robust preclinical data using ONC201 as the therapy backbone in a multi-arm, combination strategy within an innovative trial design. DESIGN: DMG-ACT is an open-label, multi-institutional trial of combination therapy for patients with DMG between 2 and 39 years of age. The trial utilizes a novel Bayesian drug combination platform design with adaptive shrinkage (ComPAS). ComPAS allows ongoing assessment of therapy efficacy with borrowing of data across different arms and the ability to eliminate ineffective drug combinations and add new promising combinations throughout the trial. ONC201 is the backbone therapy in each arm and given in combination with other agents that show additive or synergistic benefit in preclinical testing. Patients enter into one of three cohorts: newly diagnosed (Cohort 1), post-radiation (Cohort 2), and relapsed/progressive (Cohort 3). The cohorts offer a target validation option to assess intratumoral pharmacokinetics and pharmacodynamics of drug given prior to tumor biopsy. Cohort 1 and 3 offer radiation or re-irradiation with concomitant single agent therapy followed by maintenance combination therapy. The primary efficacy endpoints are median progression-free survival at 6 months (Cohort 1 and 2) and overall survival at 7 months (Cohort 3). Exploratory endpoints include intratumoral drug concentration, toxicity profile of combination therapy during radiation therapy, toxicity profile and efficacy of combination therapy, CSF and ctDNA analysis, and health related quality of life, cognitive, and patient/proxy-reported outcome measures. This trial was successfully launched in November 2021 with updates to be presented at the meeting.

OS06.2A Local immunotherapy of glioblastoma via AAV-mediated gene transfer of checkpoint inhibitors in combination with CAR-NK cells

Abstract BACKGROUND Glioblastoma (GB) is the most common primary brain tumor which is characterized by low immunogenicity of tumor cells and prevalent immunosuppression in the tumor microenvironment (TME). Since expression of PD-L1 on GB cells has been described, immunotherapy with checkpoint inhibitors (CIs) may be a promising approach for GB treatment. However, systemic administration of CIs bears the risk of autoimmune-like side effects, while the intratumoral drug concentration reached may not be sufficient. METHODS We studied delivery of CIs through targeted Adeno-associated viral vectors (AAVs) encoding an anti PD-1 immunoadhesin (aPD-1) as a novel approach towards local immunotherapy in the syngeneic GL261-HER2 glioma model. Tumor cell-specific delivery was achieved by targeting HER2 via a specific designed ankyrin repeat protein (DARPin). We investigated the effects of this strategy alone and in combination with local injection of HER2-specific CAR-NK cells (NK-92/5.28.z), which have already shown efficacy in preclinical GB models and are currently under investigation in the CAR2BRAIN phase I clinical trial. Furthermore, aPD-1 functionality and cellular response to viral transduction as well as compatibility of both therapy approaches has been evaluated in various in vitro models. RESULTS HER2-AAV transduction efficacy of GB cells correlated with HER2 expression level, while target cells did not show anti-viral responses upon transduction. After transduction with aPD-1 HER2-AAVs, aPD-1 immunoadhesin was secreted in a time-dependent manner, bound its target on PD-1-expressing cells and was able to re-activate T-cells due to PD-1 blockade. AAV-transduction did not interfere with CAR-NK cell mediated tumor cell lysis. Biodistribution studies in mice revealed the presence of aPD-1 up to 10 days after a single HER2-AAV injection. In subcutaneous GL261-HER2 tumors, local treatment with HER2-AAVaPD-1 or HER2-AAVIgG-Fc+ NK-92/5.28.z therapy had no significant effect, whereas combination therapy profoundly delayed tumor growth. CONCLUSIONS Local therapy with aPD-1 encoding HER2-AAVs in combination with NK-92/5.28.z cells is a promising novel strategy for GB immunotherapy with the potential to enhance efficacy and reduce side effects.

Phase I study of transarterial chemoembolization of lung metastases.

3602 Background: Lung chemoembolization (via the bronchial or pulmonary artery) is a new treatment option for unresectable and unablatable lung metastases. Methods: 10 patients with unresectable and unablatable lung, endobronchial, or mediastinal metastases, who failed systemic chemotherapy, were enrolled in this single center, single arm, phase I trial. Pulmonary and bronchial angiography was performed in all patients, to determine the blood supply to the lung metastases. Based on the angiographic findings, bronchial or pulmonary artery chemoembolization was performed, using a lipiodol / mitomycin emulsion, followed by spherical particles. Technical success, safety, efficacy, and pharmacokinetics were evaluated. Wilcoxon signed-rank test was used to compare change in size of treated versus untreated tumors. Results: On angiography, all patients had lung metastases that were hypervascular compared to normal lung. 90% of patients had lung metastases supplied by the bronchial artery, and 10% were supplied by the pulmonary artery. Technical success rate of intra-tumoral drug delivery was 100% (95% CI: 76-100%). There were no severe adverse events, and all patients met criteria for discharge 4 hours post procedure. Response rate of treated lesions was 10% by RECIST and 40% by PERCIST. Treated tumors were mostly stable to decreased in size after chemoembolization (median change in size: 0%; IQR: -11% to 2%; mean: -4%), and untreated tumors were mostly increased in size (median change in size: 10%; IQR: 0% to 17%; mean 9%; p= 0.02). Intra-tumoral lipiodol retention at 4-6 weeks was correlated with decreased tumor size and metabolic activity. Pharmacokinetics showed that 45% of the mitomycin dose underwent burst release in 2 minutes, and 55% of the dose was retained intratumorally with a half-life > 5 hours. Initial tumor-to-plasma ratio of mitomycin concentration was 380. Half-life of intratumoral lipiodol retention was 16 days. In vitro experiments showed 50% emulsion separation in 6.2 days, and 50% drug release in 7.1 hours. Conclusions: Lung chemoembolization can safely treat lung, mediastinal, and endobronchial metastases, with minimal systemic toxicity. High intratumoral drug concentrations after chemoembolization can overcome chemoresistance. Clinical trial information: NCT04200417.

Interventional Radiology for Local Immunotherapy in Oncology.

Human intratumoral immunotherapy (HIT-IT) is under rapid development, with promising preliminary results and high expectations for current phase III trials. While outcomes remain paramount for patients and the referring oncologists, the technical aspects of drug injection are critical to the interventional radiologist to ensure optimal and reproducible outcomes. The technical considerations for HIT-IT affect the safety, efficacy, and further development of this treatment option. Image-guided access to the tumor allows the therapeutic index of a treatment to be enhanced by increasing the intratumoral drug concentration while minimizing its systemic exposure and associated on-target off-tumor adverse events. Direct access to the tumor also enables the acquisition of cancer tissue for sequential sampling to better understand the pharmacodynamics of the injected immunotherapy and its efficacy through correlation of immune responses, pathologic responses, and imaging tumor response. The aim of this article is to share the technical insights of HIT-IT, with particular consideration for patient selection, lesion assessment, image guidance, and technical injection options. In addition, the organization of a standard patient workflow is discussed, so as to optimize HIT-IT outcome and the patient experience.