Metabolism of new drug modalities research advances - 2023 year in review.

With contributions from colleagues across academia and industry, we have put together the annual reviews of research advances on drug biotransformation and bioactivation since 2016 led by Cyrus Khojasteh. While traditional small molecules and biologics are still predominant in drug discovery, we start to notice a paradigm shift toward new drug modalities (NDMs) including but not limited to peptide and oligonucleotide therapeutics, protein degraders (heterobifunctional degraders and molecule glues), conjugated drugs and covalent inhibitors. The readers can learn more on each new drug modality from several recent comprehensive reviews (Blanco et al. 2022; Hillebrand et al. 2024; Phuna et al. 2024). Based on this trend, we put together this stand-alone review branched from our previous efforts (Baillie et al. 2016; Khojasteh et al. 2023) with a focus on the metabolism of NDMs. We collected 11 articles which exemplify recent discoveries and perspectives in this field.

Biotransformation research advances - 2023 year in review.

This annual review marks the eighth in the series starting with Baillie et al. (2016) Our objective is to explore and share articles which we deem influential and significant in the field of biotransformation. Its format is to highlight important aspects captured in synopsis followed by a commentary with relevant figure and references.

Bioactivation and reactivity research advances - 2023 year in review.

Advances in the field of bioactivation have significantly contributed to our understanding and prediction of drug-induced liver injury (DILI). It has been established that many adverse drug reactions, including DILI, are associated with the formation and reactivity of metabolites. Modern methods allow us to detect and characterize these reactive metabolites in earlier stages of drug development, which helps anticipate and circumvent the potential for DILI. Improved in silico models and experimental techniques that better reflect in vivo environments are enhancing predictive capabilities for DILI risk. Further, studies on the mechanisms of bioactivation, including enzyme interactions and the role of individual genetic differences, have provided valuable insights for drug optimizations. Cumulatively, this progress is continually refining our approaches to drug safety evaluation and personalized medicine.

An Integrated Hepatocyte Stability Assay for Simultaneous Metabolic Stability Assessment and Metabolite Profiling.

The determination of metabolic stability is critical for drug discovery programs, allowing for the optimization of chemical entities and compound prioritization. As such, it is common to perform high-volume in vitro metabolic stability experiments early in the lead optimization process to understand metabolic liabilities. Additional metabolite identification experiments are subsequently performed for a more comprehensive understanding of the metabolic clearance routes to aid medicinal chemists in the structural design of compounds. Collectively, these experiments require extensive sample preparation and a substantial amount of time and resources. To overcome the challenges, a high-throughput integrated assay for simultaneous hepatocyte metabolic stability assessment and metabolite profiling was developed. This assay platform consists of four parts: 1) an automated liquid-handling system for sample preparation and incubation, 2) a liquid chromatography and high-resolution mass spectrometry-based system to simultaneously monitor the parent compound depletion and metabolite formation, 3) an automated data analysis and report system for hepatic clearance assessment; and 4) streamlined autobatch processing for software-based metabolite profiling. The assay platform was evaluated using eight control compounds with various metabolic rates and biotransformation routes in hepatocytes across three species. Multiple sample preparation and data analysis steps were evaluated and validated for accuracy, repeatability, and metabolite coverage. The combined utility of an automated liquid-handling instrument, a high-resolution mass spectrometer, and multiple streamlined data processing software improves the process of these highly demanding screening assays and allows for simultaneous determination of metabolic stability and metabolite profiles for more efficient lead optimization during early drug discovery. SIGNIFICANCE STATEMENT: Metabolic stability assessment and metabolite profiling are pivotal in drug discovery to fully comprehend metabolic liabilities for chemical entity optimization and lead selection. Process of these assays can be repetitive and resource demanding. Here, we developed an integrated hepatocyte stability assay that combines automation, high-resolution mass spectrometers, and batch-processing software to improve and combine the workflow of these assays. The integrated approach allows simultaneous metabolic stability assessment and metabolite profiling, significantly accelerating screening and lead optimization in a resource-effective manner.

Improving the palliative-procedure decision-making process for patients with peritoneal carcinomatosis: A secondary analysis.

BACKGROUND: Peritoneal carcinomatosis (PC) is common in patients with advanced gynecologic and gastrointestinal cancers. Frequently, patients with PC undergo palliative surgery or procedures to manage disease-related complications and side effects. However, there are limited data regarding patients' and family caregivers' decision-making processes about these procedures. Thus, we sought to describe the decision-making experiences of patients with PC who elect to pursue palliative surgical procedures and their family caregivers. METHODS: We conducted a secondary analysis of qualitative data collected during a pilot randomized controlled trial of BOLSTER, a nurse-led telehealth intervention for patients with PC and their caregivers after an acute hospitalization and palliative procedure. Participants in both study arms described their experiences in semi-structured interviews. We re-analyzed coded qualitative data with a focus on understanding decision-making experiences surrounding palliative surgery and procedures using conventional content analysis. RESULTS: Interviews from 32 participants, 23 patients and 9 caregivers, were analyzed. Participants reported their decision-making was complicated by illness uncertainty and a desire for clear, effective communication with surgical and medical oncology teams. Participants requested more information about the impact of palliative procedures on their daily life. Several also noted that, without improved understanding, a misalignment between patient and family caregiver goals and palliative procedures may inadvertently increase suffering. CONCLUSION: Discussions related to patients' goals and preferences can improve the quality of treatment decision-making in patients with PC and their caregivers. Future research should test interventions to improve advanced cancer patients' illness understanding and decision-making surrounding palliative surgery and procedures.

Feasibility and acceptability of a nurse-led telehealth intervention (BOLSTER) to support patients with peritoneal carcinomatosis and their caregivers: A pilot randomized clinical trial.

OBJECTIVE: Patients with advanced gynecologic (GYN) and gastrointestinal (GI) cancers frequently develop peritoneal carcinomatosis (PC), which limits prognosis and diminishes health-related quality of life (HRQoL). Palliative procedures may improve PC symptoms, yet patients and caregivers report feeling unprepared to manage ostomies, catheters, and other complex needs. Our objectives were to (1) assess the feasibility of an efficacy trial of a nurse-led telehealth intervention (BOLSTER) for patients with PC and their caregivers; and (2) assess BOLSTER's acceptability, potential to improve patients' HRQoL and self-efficacy, and potential impact on advance care planning (ACP). METHODS: Pilot feasibility RCT. Recently hospitalized adults with advanced GYN and GI cancers, PC, and a new complex care need and their caregivers were randomized 1:1 to BOLSTER or enhanced discharge planning (EDP). We defined feasibility as a ≥ 50% approach-to-consent ratio and acceptability as ≥70% satisfaction with BOLSTER. We assessed patients' HRQoL and self-efficacy at baseline and six weeks, then compared the proportion experiencing meaningful improvements by arm. ACP documentation was identified using natural language processing. RESULTS: We consented 77% of approached patients. In the BOLSTER arm, 91.0% of patients and 100.0% of caregivers were satisfied. Compared to EDP, more patients receiving BOLSTER experienced improvements in HRQoL (68.4% vs. 40.0%) and self-efficacy for managing symptoms (78.9% vs. 35.0%) and treatment (52.9% vs. 42.9%). The BOLSTER arm had more ACP documentation. CONCLUSIONS: BOLSTER is a feasible and acceptable intervention with the potential to improve patients' HRQoL and promote ACP. An efficacy trial comparing BOLSTER to usual care is underway. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03367247; PI: Wright.

A phase 2 trial exploring the significance of homologous recombination status in patients with platinum sensitive or platinum resistant relapsed ovarian cancer receiving combination cediranib and olaparib.

OBJECTIVE: Combination cediranib/olaparib has reported activity in relapsed ovarian cancer. This phase 2 trial investigated the activity of cediranib/olaparib in relapsed ovarian cancer and its association with homologous recombination deficiency (HRD). METHODS: Seventy patients were enrolled to cohorts of either platinum-sensitive or platinum-resistant ovarian cancer and received olaparib tablets 200 mg twice daily and cediranib tablets 30 mg once daily under a continuous dosing schedule. HRD testing was performed on pre-treatment, on-treatment and archival biopsies by sequencing key homologous recombination repair (HRR) genes and by genomic LOH analysis. The primary objective for the platinum-sensitive cohort was the association of HRD, defined as presence of HRR gene mutation, with progression-free survival (PFS). The primary objective for the platinum-resistant cohort was objective response rate (ORR), with a key secondary endpoint evaluating the association of HRD status with activity. RESULTS: In platinum-sensitive ovarian cancer (N = 35), ORR was 77.1% (95% CI 59.9-89.6%) and median PFS was 16.4 months (95% CI 13.2-18.6). Median PFS in platinum-sensitive HRR-HRD cancers (N = 22) was 16.8 months (95% CI 11.3-18.6), and 16.4 months (95% CI 9.4-NA) in HRR-HR proficient cancers (N = 13; p = 0.57). In platinum-resistant ovarian cancer (N = 35), ORR was 22.9% (95% CI 10.4-40.1%) with median PFS 6.8 months (95% CI 4.2-9.1). Median PFS in platinum-resistant HRR-HRD cancers (N = 7) was 10.5 months (95% CI 3.6-NA) and 5.6 months (95% CI 3.6-7.6) in HRR-HR proficient cancers (N = 18; p = 0.23). CONCLUSIONS: Cediranib/olaparib had clinical activity in both platinum-sensitive and -resistant ovarian cancer. Presence of HRR gene mutations was not associated with cediranib/olaparib activity in either setting.

Uterine serous carcinoma and uterine carcinosarcoma: molecular features, clinical advances, and emerging therapies.

Endometrial cancer, including high-grade subtypes, has a rising incidence and mortality. Uterine serous carcinoma (USC) and uterine carcinosarcoma (UCS) make up a small but increasing proportion of endometrial cancer cases and account for a significant portion of endometrial cancer mortality. Despite being molecularly and clinically distinct, both USC and UCS have a poor prognosis. Thus far, there have been few therapeutic strategies directed at these endometrial cancer subtypes. This review summarizes the genomic and molecular features of USC and UCS, clinical advances in the treatment of primary advanced and recurrent endometrial cancer, and novel molecularly-driven treatment strategies.

Efficacy of ChatGPT in Cantonese Sentiment Analysis: Comparative Study.

BACKGROUND: Sentiment analysis is a significant yet difficult task in natural language processing. The linguistic peculiarities of Cantonese, including its high similarity with Standard Chinese, its grammatical and lexical uniqueness, and its colloquialism and multilingualism, make it different from other languages and pose additional challenges to sentiment analysis. Recent advances in models such as ChatGPT offer potential viable solutions. OBJECTIVE: This study investigated the efficacy of GPT-3.5 and GPT-4 in Cantonese sentiment analysis in the context of web-based counseling and compared their performance with other mainstream methods, including lexicon-based methods and machine learning approaches. METHODS: We analyzed transcripts from a web-based, text-based counseling service in Hong Kong, including a total of 131 individual counseling sessions and 6169 messages between counselors and help-seekers. First, a codebook was developed for human annotation. A simple prompt ("Is the sentiment of this Cantonese text positive, neutral, or negative? Respond with the sentiment label only.") was then given to GPT-3.5 and GPT-4 to label each message's sentiment. GPT-3.5 and GPT-4's performance was compared with a lexicon-based method and 3 state-of-the-art models, including linear regression, support vector machines, and long short-term memory neural networks. RESULTS: Our findings revealed ChatGPT's remarkable accuracy in sentiment classification, with GPT-3.5 and GPT-4, respectively, achieving 92.1% (5682/6169) and 95.3% (5880/6169) accuracy in identifying positive, neutral, and negative sentiment, thereby outperforming the traditional lexicon-based method, which had an accuracy of 37.2% (2295/6169), and the 3 machine learning models, which had accuracies ranging from 66% (4072/6169) to 70.9% (4374/6169). CONCLUSIONS: Among many text analysis techniques, ChatGPT demonstrates superior accuracy and emerges as a promising tool for Cantonese sentiment analysis. This study also highlights ChatGPT's applicability in real-world scenarios, such as monitoring the quality of text-based counseling services and detecting message-level sentiments in vivo. The insights derived from this study pave the way for further exploration into the capabilities of ChatGPT in the context of underresourced languages and specialized domains like psychotherapy and natural language processing.

Tracking and Profiling Repeated Users Over Time in Text-Based Counseling: Longitudinal Observational Study With Hierarchical Clustering.

BACKGROUND: Due to their accessibility and anonymity, web-based counseling services are expanding at an unprecedented rate. One of the most prominent challenges such services face is repeated users, who represent a small fraction of total users but consume significant resources by continually returning to the system and reiterating the same narrative and issues. A deeper understanding of repeated users and tailoring interventions may help improve service efficiency and effectiveness. Previous studies on repeated users were mainly on telephone counseling, and the classification of repeated users tended to be arbitrary and failed to capture the heterogeneity in this group of users. OBJECTIVE: In this study, we aimed to develop a systematic method to profile repeated users and to understand what drives their use of the service. By doing so, we aimed to provide insight and practical implications that can inform the provision of service catering to different types of users and improve service effectiveness. METHODS: We extracted session data from 29,400 users from a free 24/7 web-based counseling service from 2018 to 2021. To systematically investigate the heterogeneity of repeated users, hierarchical clustering was used to classify the users based on 3 indicators of service use behaviors, including the duration of their user journey, use frequency, and intensity. We then compared the psychological profile of the identified subgroups including their suicide risks and primary concerns to gain insights into the factors driving their patterns of service use. RESULTS: Three clusters of repeated users with clear psychological profiles were detected: episodic, intermittent, and persistent-intensive users. Generally, compared with one-time users, repeated users showed higher suicide risks and more complicated backgrounds, including more severe presenting issues such as suicide or self-harm, bullying, and addictive behaviors. Higher frequency and intensity of service use were also associated with elevated suicide risk levels and a higher proportion of users citing mental disorders as their primary concerns. CONCLUSIONS: This study presents a systematic method of identifying and classifying repeated users in web-based counseling services. The proposed bottom-up clustering method identified 3 subgroups of repeated users with distinct service behaviors and psychological profiles. The findings can facilitate frontline personnel in delivering more efficient interventions and the proposed method can also be meaningful to a wider range of services in improving service provision, resource allocation, and service effectiveness.

Successful treatment of stage IVB ovarian carcinosarcoma with PARP Inhibitor: A case report.

•Ovarian carcinosarcoma is a rare ovarian cancer histology that has limited treatment options.•In this study, we present an unusual association between carcinosarcoma and a STIC lesion.•In select patients with carcinosarcoma, PARP inhibition may provide clinical benefit.

Genetic disruption of dopamine ß-hydroxylase dysregulates innate responses to predator odor in mice.

In rodents, exposure to predator odors such as cat urine acts as a severe stressor that engages innate defensive behaviors critical for survival in the wild. The neurotransmitters norepinephrine (NE) and dopamine (DA) modulate anxiety and predator odor responses, and we have shown previously that dopamine ß-hydroxylase knockout (Dbh -/-), which reduces NE and increases DA in mouse noradrenergic neurons, disrupts innate behaviors in response to mild stressors such as novelty. We examined the consequences of Dbh knockout on responses to predator odor (bobcat urine) and compared them to Dbh-competent littermate controls. Over the first 10 min of predator odor exposure, controls exhibited robust defensive burying behavior, whereas Dbh -/- mice showed high levels of grooming. Defensive burying was potently suppressed in controls by drugs that reduce NE transmission, while excessive grooming in Dbh -/- mice was blocked by DA receptor antagonism. In response to a cotton square scented with a novel "neutral" odor (lavender), most control mice shredded the material, built a nest, and fell asleep within 90 min. Dbh -/- mice failed to shred the lavender-scented nestlet, but still fell asleep. In contrast, controls sustained high levels of arousal throughout the predator odor test and did not build nests, while Dbh -/- mice were asleep by the 90-min time point, often in shredded bobcat urine-soaked nesting material. Compared with controls exposed to predator odor, Dbh -/- mice demonstrated decreased c-fos induction in the anterior cingulate cortex, lateral septum, periaqueductal gray, and bed nucleus of the stria terminalis, but increased c-fos in the locus coeruleus and medial amygdala. These data indicate that relative ratios of central NE and DA signaling coordinate the type and valence of responses to predator odor.

Genetic disruption of dopamine ß-hydroxylase dysregulates innate responses to predator odor in mice.

In rodents, exposure to predator odors such as cat urine acts as a severe stressor that engages innate defensive behaviors critical for survival in the wild. The neurotransmitters norepinephrine (NE) and dopamine (DA) modulate anxiety and predator odor responses, and we have shown previously that dopamine ß-hydroxylase knockout (Dbh -/-), which reduces NE and increases DA in mouse noradrenergic neurons, disrupts innate behaviors in response to mild stressors such as novelty. We examined the consequences of Dbh knockout (Dbh -/-) on responses to predator odor (bobcat urine) and compared them to Dbh-competent littermate controls. Over the first 10 min of predator odor exposure, controls exhibited robust defensive burying behavior, whereas Dbh -/- mice showed high levels of grooming. Defensive burying was potently suppressed in controls by drugs that reduce NE transmission, while excessive grooming in Dbh -/- mice was blocked by DA receptor antagonism. In response to a cotton square scented with a novel "neutral" odor (lavender), most control mice shredded the material, built a nest, and fell asleep within 90 min. Dbh -/- mice failed to shred the lavender-scented nestlet, but still fell asleep. In contrast, controls sustained high levels of arousal throughout the predator odor test and did not build nests, while Dbh -/- mice were asleep by the 90-min time point, often in shredded bobcat urine-soaked nesting material. Compared with controls exposed to predator odor, Dbh -/- mice demonstrated decreased c-fos induction in the anterior cingulate cortex, lateral septum, periaqueductal gray, and bed nucleus of the stria terminalis, but increased c-fos in the locus coeruleus and medial amygdala. These data indicate that relative ratios of central NE and DA signaling coordinate the type and valence of responses to predator odor.

Combined aromatase, CDK4/6 and PI3K blockade using letrozole/abemaciclib/LY3023414 in endometrial cancer.

Several lines of preclinical evidence indicate that combining PI3K and CDK4/6 inhibitors may further enhance the efficacy of hormonal therapy by overcoming de novo and acquired resistance to PI3K and CDK4/6 blockade. We evaluated the combination of abemaciclib, letrozole and LY3023414 (an orally available, selective inhibitor of the class I PI3K isoforms and mTORC1/2) in recurrent endometrial cancer (EC). This study was terminated prematurely after 5 patients initiated protocol therapy due to discontinuation of further development of LY3023414. We report our findings from these patients, including one with recurrent endometrioid EC with AKT1, CTNNB1 and ESR1 hotspot mutations who had previously progressed through letrozole/everolimus and achieved a partial response to letrozole/abemaciclib/LY3023414.

Single-stranded DNA Gap Accumulation is a Functional Biomarker for USP1 Inhibitor Sensitivity.

Recent studies suggest that PARP inhibitors and POLQ inhibitors confer synthetic lethality in BRCA1-deficient tumors by accumulation of single-stranded DNA (ssDNA) gaps at replication forks. Loss of USP1, a deubiquitinating enzyme, is also synthetic lethal with BRCA1 deficiency, and USP1 inhibitors are now undergoing clinical development for these cancers. Here, we show that USP1 inhibitors also promote the accumulation of ssDNA gaps during replication in BRCA1-deficient cells, and this phenotype correlates with the drug sensitivity. USP1 inhibition increased monoubiquitinated PCNA at replication forks, mediated by the ubiquitin ligase RAD18, and knockdown of RAD18 caused USP1 inhibitor resistance and suppression of ssDNA gaps. USP1 inhibition overcame PARP inhibitor resistance in a BRCA1-mutated xenograft model and induced ssDNA gaps. Furthermore, USP1 inhibition was synergistic with PARP and POLQ inhibition in BRCA1-mutant cells, with enhanced ssDNA gap accumulation. Finally, in patient-derived ovarian tumor organoids, sensitivity to USP1 inhibition alone or in combination correlated with the accumulation of ssDNA gaps. Assessment of ssDNA gaps in ovarian tumor organoids therefore represents a rapid approach for predicting response to USP1 inhibition in ongoing clinical trials.

Niraparib, Dostarlimab, and Bevacizumab as Combination Therapy in Pretreated, Advanced Platinum-Resistant Ovarian Cancer: Findings From Cohort A of the OPAL Phase II Trial.

PURPOSE: To report the results of OPAL (ClinicalTrials.gov identifier: NCT03574779) cohort A, a single-arm substudy of niraparib plus dostarlimab and bevacizumab for the treatment of advanced, platinum-resistant ovarian cancer (PROC). METHODS: Participants with PROC who received 1-2 previous lines of therapy were treated with niraparib (200 or 300 mg once daily), dostarlimab (500 mg once every 3 weeks for four 21-day cycles, followed by 1,000 mg once every 6 weeks), and bevacizumab (15 mg/kg once every 3 weeks). The primary end point was investigator-assessed objective response rate (ORR) per RECIST v1.1. Safety was also assessed. Exploratory biomarker end points included evaluation of changes in the tumor molecular profile and microenvironment using baseline and on-treatment tumor samples. RESULTS: Of 41 enrolled participants (median age, 66.0 years [range, 37-83 years]), 9.8% had tumors that were BRCA-mutated, 19.5% were homologous recombination (HR)-deficient, and 17.1% were HR repair (HRR)-mutated. As of the cutoff date, all participants discontinued treatment. The ORR was 17.1% (80% CI, 9.8 to 27.0), including one complete response (2.4%); the disease control rate was 73.2% (80% CI, 62.3 to 82.2). Two participants withdrew before first postbaseline scan because of adverse events (AEs). Grade ≥3 treatment-emergent AEs were reported in 92.7% of participants, with the most common being hypertension (26.8%). Response was not correlated with BRCA, HRR, HR deficiency (HRD), or PD-L1 status. Changes suggesting immune activation were observed in on-treatment samples after triplet therapy. CONCLUSION: Results demonstrated modest activity of niraparib, dostarlimab, and bevacizumab in participants with PROC, many of whom had prognostic factors for poor treatment response. Most participants with response were bevacizumab-naïve. No association was found with HRD, BRCA, or PD-L1 status. AEs were consistent with previous monotherapy reports, except that hypertension was reported more frequently.

Phase 1 dose expansion and biomarker study assessing first-in-class tumor microenvironment modulator VT1021 in patients with advanced solid tumors.

BACKGROUND: Preclinical studies have demonstrated that VT1021, a first-in-class therapeutic agent, inhibits tumor growth via stimulation of thrombospondin-1 (TSP-1) and reprograms the tumor microenvironment. We recently reported data from the dose escalation part of a phase I study of VT1021 in solid tumors. Here, we report findings from the dose expansion phase of the same study. METHODS: We analyzed the safety and tolerability, clinical response, and biomarker profile of VT1021 in the expansion portion of the phase I study (NCT03364400). Safety/tolerability is determined by adverse events related to the treatment. Clinical response is determined by RECIST v1.1 and iRECIST. Biomarkers are measured by multiplexed ion beam imaging and enzyme-linked immunoassay (ELISA). RESULTS: First, we report the safety and tolerability data as the primary outcome of this study. Adverse events (AE) suspected to be related to the study treatment (RTEAEs) are mostly grade 1-2. There are no grade 4 or 5 adverse events. VT1021 is safe and well tolerated in patients with solid tumors in this study. We report clinical responses as a secondary efficacy outcome. VT1021 demonstrates promising single-agent clinical activity in recurrent GBM (rGBM) in this study. Among 22 patients with rGBM, the overall disease control rate (DCR) is 45% (95% confidence interval, 0.24-0.67). Finally, we report the exploratory outcomes of this study. We show the clinical confirmation of TSP-1 induction and TME remodeling by VT1021. Our biomarker analysis identifies several plasmatic cytokines as potential biomarkers for future clinical studies. CONCLUSIONS: VT1021 is safe and well-tolerated in patients with solid tumors in a phase I expansion study. VT1021 has advanced to a phase II/III clinical study in glioblastoma (NCT03970447).

The network of cells that surround a tumor, the tumor microenvironment, can help cancers to grow. Therapies targeting the tumor microenvironment may help to stop tumor growth. One such therapy is VT1021. In animal models, VT1021 treatment stops tumor cells from growing by changing the tumor microenvironment. Here, we have tested VT1021 in a clinical trial and found that VT1021 treatment is safe and well tolerated in patients with cancer. We also see signs of efficacy in some patients and observe evidence that VT1021 modifies the tumor microenvironment, which may help to block tumor growth. Finally, we identified several markers from the blood that may help to predict which patients will best benefit from VT1021 treatment. With further testing in clinical trials, VT1021 may be a useful therapy for patients with cancer.

Tissue distribution and retention drives efficacy of rapidly clearing VHL-based PROTACs.

BACKGROUND: Proteolysis-targeting chimeras (PROTACs) are being developed for therapeutic use. However, they have poor pharmacokinetic profiles and their tissue distribution kinetics are not known. METHODS: A typical von Hippel-Lindau tumor suppressor (VHL)-PROTAC 14C-A947 (BRM degrader)-was synthesized and its tissue distribution kinetics was studied by quantitative whole-body autoradiography (QWBA) and tissue excision in rats following IV dosing. Bile duct-cannulated (BDC) rats allowed the elucidation of in vivo clearance pathways. Distribution kinetics was evaluated in the tissues and tumors of mice to support PK-PD correlation. In vitro studies enabled the evaluation of cell uptake mechanisms and cell retention properties. RESULTS: Here, we show that A947 quickly distributes into rat tissues after IV dosing, where it accumulates and is retained in tissues such as the lung and liver although it undergoes fast clearance from circulation. Similar uptake/retention kinetics enable tumor growth inhibition over 2-3 weeks in a lung cancer model. A947 quickly excretes in the bile of rats. Solute carrier (SLC) transporters are involved in hepatocyte uptake of PROTACs. Sustained BRM protein degradation is seen after extensive washout that supports prolonged cell retention of A947 in NCI-H1944 cells. A947 tissue exposure and pharmacodynamics are inversely correlated in tumors. CONCLUSIONS: Plasma sampling for VHL-PROTAC does not represent the tissue concentrations necessary for efficacy. Understanding of tissue uptake and retention could enable less frequent IV administration to be used for therapeutic dosing.

Proteolysis-targeting chimeras (PROTACs) are a type of potential cancer medicine designed to target proteins primarily present in tumours. There is limited data on how it is absorbed, distributed, metabolised and excreted from tissues. Here, we studied the tissue distribution of synthetic PROTAC molecules labelled with radioactivity following intravenous injection in rodent models. We find that PROTAC can rapidly distribute to target tumour tissues and its prolonged retention within the tumour cells can contribute to prevention of further tumour growth, as demonstrated in the lung cancer model. These findings suggest the evaluation of PROTAC therapeutic effectiveness directly from tumour tissues provides more relevant assessment than sampling from blood circulation, which may have implications for a reduction in intravenous dosing.

Phase I and Randomized Phase II Study of Ruxolitinib With Frontline Neoadjuvant Therapy in Advanced Ovarian Cancer: An NRG Oncology Group Study.

PURPOSE: The interleukin-6/Janus kinase (JAK)/signal transducers and activators of transcription 3 axis is a reported driver of chemotherapy resistance. We hypothesized that adding the JAK1/2 inhibitor ruxolitinib to standard chemotherapy would be tolerable and improve progression-free survival (PFS) in patients with ovarian cancer in the upfront setting. MATERIALS AND METHODS: Patients with ovarian/fallopian tube/primary peritoneal carcinoma recommended for neoadjuvant chemotherapy were eligible. In phase I, treatment was initiated with dose-dense paclitaxel (P) 70 mg/m2 once daily on days 1, 8, and 15; carboplatin AUC 5 intravenously day 1; and ruxolitinib 15 mg orally (PO) twice a day, every 21 days (dose level 1). Interval debulking surgery (IDS) was required after cycle 3. Patients then received three additional cycles of chemotherapy/ruxolitinib, followed by maintenance ruxolitinib. In the randomized phase II, patients were randomly assigned to paclitaxel/carboplatin with or without ruxolitinib at 15 mg PO twice a day for three cycles, IDS, followed by another three cycles of chemotherapy/ruxolitinib, without further maintenance ruxolitinib. The primary phase II end point was PFS. RESULTS: Seventeen patients were enrolled in phase I. The maximum tolerated dose and recommended phase II dose were established to be dose level 1. One hundred thirty patients were enrolled in phase II with a median follow-up of 24 months. The regimen was well tolerated, with a trend toward higher grade 3 to 4 anemia (64% v 27%), grade 3 to 4 neutropenia (53% v 37%), and thromboembolic events (12.6% v 2.4%) in the experimental arm. In the randomized phase II, the median PFS in the reference arm was 11.6 versus 14.6 in the experimental, hazard ratio (HR) for PFS was 0.702 (log-rank P = .059). The overall survival HR was 0.785 (P = .24). CONCLUSION: Ruxolitinib 15 mg PO twice a day was well tolerated with acceptable toxicity in combination with paclitaxel/carboplatin chemotherapy. The primary end point of prolongation of PFS was achieved in the experimental arm, warranting further investigation.

Randomized Phase II Study of Gemcitabine With or Without ATR Inhibitor Berzosertib in Platinum-Resistant Ovarian Cancer: Final Overall Survival and Biomarker Analyses.

PURPOSE: The multicenter, open-label, randomized phase 2 NCI-9944 study (NCT02595892) demonstrated that addition of ATR inhibitor (ATRi) berzosertib to gemcitabine increased progression-free survival (PFS) compared to gemcitabine alone (hazard ratio [HR]=0.57, one-sided log-rank P = .044, which met the one-sided significance level of 0.1 used for sample size calculation). METHODS: We report here the final overall survival (OS) analysis and biomarker correlations (ATM expression by immunohistochemistry, mutational signature 3 and a genomic biomarker of replication stress) along with post-hoc exploratory analyses to adjust for crossover from gemcitabine to gemcitabine/berzosertib. RESULTS: At the data cutoff of January 27, 2023 (>30 months of additional follow-up from the primary analysis), median OS was 59.4 weeks with gemcitabine/berzosertib versus 43.0 weeks with gemcitabine alone (HR 0.79, 90% CI 0.52 to 1.2, one-sided log-rank P = .18). An OS benefit with addition of berzosertib to gemcitabine was suggested in patients stratified into the platinum-free interval ≤3 months (N = 26) subgroup (HR, 0.48, 90% CI 0.22 to 1.01, one-sided log-rank P =.04) and in patients with ATM-negative/low (N = 24) tumors (HR, 0.50, 90% CI 0.23 to 1.08, one-sided log-rank P = .06). CONCLUSION: The results of this follow-up analysis continue to support the promise of combined gemcitabine/ATRi therapy in platinum resistant ovarian cancer, an active area of investigation with several ongoing clinical trials.