Cancer Clinical Trials: The Rear-View Mirror and the Crystal Ball.

Clinical trials are key to translating scientific advances into progress in cancer research and care. Confronted by developments in basic science, the landscape of clinical cancer research is rapidly evolving. Here, we review recent changes in clinical trials' design and conduct, and we forecast future directions toward personalized and global impact.

All is not lost: learning from 9p21 loss in cancer.

The cancer research community continues to search for additional biomarkers of response and resistance to immune checkpoint treatment (ICT). The ultimate goal is to direct the use of ICT in patients whose tumors are most likely to benefit to achieve a refinement that is equivalent to that of a genotype-matched targeted treatment. Dissecting the mechanisms of ICT resistance can help us characterize ICT nonresponders more efficiently. In this opinion, we argue that there may be additional knowledge gained about immune evasion in cancer by analyzing the loss of the human 9p21.3 locus; as an example, we highlight findings of 9p21.3 loss from the investigator-initiated, pan-cancer INSPIRE study, in which patients were treated with pembrolizumab (anti-PD-1 antibody) ICT.

Pembrolizumab plus concurrent chemoradiotherapy versus placebo plus concurrent chemoradiotherapy in patients with locally advanced squamous cell carcinoma of the head and neck (KEYNOTE-412): a randomised, double-blind, phase 3 trial.

BACKGROUND: Despite multimodal therapy, 5-year overall survival for locally advanced head and neck squamous cell carcinoma (HNSCC) is about 50%. We assessed the addition of pembrolizumab to concurrent chemoradiotherapy for locally advanced HNSCC. METHODS: In the randomised, double-blind, phase 3 KEYNOTE-412 trial, participants with newly diagnosed, high-risk, unresected locally advanced HNSCC from 130 medical centres globally were randomly assigned (1:1) to pembrolizumab (200 mg) plus chemoradiotherapy or placebo plus chemoradiotherapy. Randomisation was done using an interactive response technology system and was stratified by investigator's choice of radiotherapy regimen, tumour site and p16 status, and disease stage, with participants randomly assigned in blocks of four per stratum. Participants, investigators, and sponsor personnel were masked to treatment assignments. Local pharmacists were aware of assignments to support treatment preparation. Pembrolizumab and placebo were administered intravenously once every 3 weeks for up to 17 doses (one before chemoradiotherapy, two during chemoradiotherapy, 14 as maintenance therapy). Chemoradiotherapy included cisplatin (100 mg/m2) administered intravenously once every 3 weeks for two or three doses and accelerated or standard fractionation radiotherapy (70 Gy delivered in 35 fractions). The primary endpoint was event-free survival analysed in all randomly assigned participants. Safety was analysed in all participants who received at least one dose of study treatment. This study is registered with ClinicalTrials.gov, NCT03040999, and is active but not recruiting. FINDINGS: Between April 19, 2017, and May 2, 2019, 804 participants were randomly assigned to the pembrolizumab group (n=402) or the placebo group (n=402). 660 (82%) of 804 participants were male, 144 (18%) were female, and 622 (77%) were White. Median study follow-up was 47·7 months (IQR 42·1-52·3). Median event-free survival was not reached (95% CI 44·7 months-not reached) in the pembrolizumab group and 46·6 months (27·5-not reached) in the placebo group (hazard ratio 0·83 [95% CI 0·68-1·03]; log-rank p=0·043 [significance threshold, p≤0·024]). 367 (92%) of 398 participants treated in the pembrolizumab group and 352 (88%) of 398 participants treated in the placebo group had grade 3 or worse adverse events. The most common grade 3 or worse adverse events were decreased neutrophil count (108 [27%] of 398 participants in the pembrolizumab group vs 100 [25%] of 398 participants in the placebo group), stomatitis (80 [20%] vs 69 [17%]), anaemia (80 [20%] vs 61 [15%]), dysphagia (76 [19%] vs 62 [16%]), and decreased lymphocyte count (76 [19%] vs 81 [20%]). Serious adverse events occurred in 245 (62%) participants in the pembrolizumab group versus 197 (49%) participants in the placebo group, most commonly pneumonia (43 [11%] vs 25 [6%]), acute kidney injury (33 [8%] vs 30 [8%]), and febrile neutropenia (24 [6%] vs seven [2%]). Treatment-related adverse events led to death in four (1%) participants in the pembrolizumab group (one participant each from aspiration pneumonia, end-stage renal disease, pneumonia, and sclerosing cholangitis) and six (2%) participants in the placebo group (three participants from pharyngeal haemorrhage and one participant each from mouth haemorrhage, post-procedural haemorrhage, and sepsis). INTERPRETATION: Pembrolizumab plus chemoradiotherapy did not significantly improve event-free survival compared with chemoradiotherapy alone in a molecularly unselected, locally advanced HNSCC population. No new safety signals were seen. Locally advanced HNSCC remains a challenging disease that requires better treatment approaches. FUNDING: Merck Sharp & Dohme, a subsidiary of Merck & Co, Rahway, NJ, USA.

Prospective manipulation of the gut microbiome with microbial ecosystem therapeutic 4 (MET4) in HPV-related locoregionally-advanced oropharyngeal cancer squamous cell carcinoma (LA-OPSCC) undergoing primary chemoradiation: ROMA2 study.

BACKGROUND: Gut microbiome modulation to boost antitumor immune responses is under investigation. METHODS: ROMA-2 evaluated the microbial ecosystem therapeutic (MET)-4 oral consortia, a mixture of cultured human stool-derived immune-responsiveness associated bacteria, given with chemoradiation (CRT) in HPV-related oropharyngeal cancer patients. Co-primary endpoints were safety and changes in stool cumulative MET-4 taxa relative abundance (RA) by 16SRNA sequencing. Stools and plasma were collected pre/post-MET-4 intervention for microbiome and metabolome analysis. RESULTS: Twenty-nine patients received ≥1 dose of MET-4 and were evaluable for safety: drug-related adverse events (AEs) occurred in 13/29 patients: all grade 1-2 except one grade 3 (diarrhea). MET-4 was discontinued early in 7/29 patients due to CRT-induced toxicity, and in 1/29 due to MET-4 AEs. Twenty patients were evaluable for ecological endpoints: there was no increase in stool MET-4 RA post-intervention but trended to increase in stage III patients (p = 0.06). MET-4 RA was higher in stage III vs I-II patients at week 4 (p = 0.03) and 2-month follow-up (p = 0.01), which correlated with changes in plasma and stool targeted metabolomics. CONCLUSIONS: ROMA-2 did not meet its primary ecologic endpoint, as no engraftment was observed in the overall cohort. Exploratory findings of engraftment in stage III patients warrants further investigation of microbiome interventions in this subgroup.

Ezabenlimab (BI 754091), an anti-PD-1 antibody, in patients with advanced solid tumours.

BACKGROUND: Ezabenlimab (BI 754091) is a humanised monoclonal antibody targeting programmed cell death protein-1. We report results from open-label, dose-escalation/expansion, Phase I trials that evaluated the safety, maximum tolerated dose (MTD), pharmacokinetics and antitumour activity of ezabenlimab at the recommended Phase II dose in patients with selected advanced solid tumours. STUDY DESIGN: Study 1381.1 (NCT02952248) was conducted in Canada, the United Kingdom and the United States. Study 1381.4 (NCT03433898) was conducted in Japan. Study 1381.3 (NCT03780725) was conducted in the Netherlands. The primary endpoints were: number of patients experiencing dose-limiting toxicities (DLTs) in the first cycle (dose escalation parts), number of patients with DLTs during the entire treatment period and objective response (dose expansion part of Study 1381.1). RESULTS: Overall, 117 patients received ezabenlimab intravenously every 3 weeks (80 mg, n = 3; 240 mg, n = 111; 400 mg, n = 3). No DLTs were observed and the MTD was not reached. Fifty-eight patients (52.3%) had grade ≥ 3 adverse events, most commonly anaemia (10.8%) and fatigue (2.7%). In 111 assessed patients treated with ezabenlimab 240 mg, disease control rate was 56.8% and objective response rate was 16.2%. Three patients had complete response; at data cut-off (November 2021) one remained in response and was still receiving ongoing treatment (duration of response [DoR]: 906 days). Partial responses occurred across several tumour types; DoR ranged from 67 to 757 days. CONCLUSIONS: Ezabenlimab was well tolerated and associated with durable antitumour activity in multiple solid tumours, comparable to other immune checkpoint inhibitors in similar patient populations and treatment settings.

A phase 1b study of the ERK inhibitor MK-8353 plus pembrolizumab in patients with advanced solid tumors.

Combining a checkpoint inhibitor with an inhibitor of extracellular signal-regulated kinase (ERK) may result in synergistic antitumor activity. We evaluated MK-8353, an ERK1 and ERK2 inhibitor, plus pembrolizumab in a phase 1b study in patients with advanced solid tumors. This open-label, nonrandomized, dose-escalation study (NCT02972034) enrolled adults with advanced solid tumors previously treated with 1‒5 prior lines of therapy. MK-8353 was administered orally in combination with pembrolizumab 200 mg every 3 weeks as follows: twice daily (arm A; MK-8353 50‒350 mg), once daily (arm B; MK-8353 50‒600 mg), or once daily every other week (arm C; MK-8353 50‒300 mg). The primary objective was evaluation of safety via occurrence of dose-limiting toxicities (DLTs). A secondary objective was objective response by RECIST v1.1 per investigator assessment. Among 110 evaluable patients (arm A, n = 22; arm B, n = 50; arm C, n = 38), median age was 58.0 (range, 35‒79) years and 50% had received 1 or 2 prior lines of therapy. DLTs occurred in 19 patients (n = 6 [27%], n = 8 [16%], and n = 5 [13%], respectively); the most frequent was grade 3 maculopapular rash (n = 15). Grade 3/4 treatment-related AEs occurred in 35% of patients; the most common were maculopapular rash (13%) and increased lipase (5%); none were grade 5. Eight patients (7%) attained an objective response (arm B, n = 7 [complete response, n = 1; partial response, n = 6]; arm C, n = 1 [complete response]). In conclusion, MK-8353 once daily plus pembrolizumab could be administered with a manageable toxicity profile but had modest antitumor activity in patients with advanced solid tumors.

A tailored phase I-specific patient-reported outcome (PRO) survey to capture the patient experience of symptomatic adverse events.

BACKGROUND: Patient perspectives are fundamental to defining tolerability of investigational anti-neoplastic therapies in clinical trials. Phase I trials present a unique challenge in designing tools for efficiently collecting patient-reported outcomes (PROs) given the difficulty of anticipating adverse events of relevance. However, phase I trials also offer an opportunity for investigators to optimize drug dosing based on tolerability for future larger-scale trials and in eventual clinical practice. Existing tools for comprehensively capturing PROs are generally cumbersome and are not routinely used in phase I trials. METHODS: Here, we describe the creation of a tailored survey based on the National Cancer Institute's PRO-CTCAE for collecting patients' perspectives on symptomatic adverse events in phase I trials in oncology. RESULTS: We describe our stepwise approach to condensing the original 78-symptom library into a modified 30 term core list of symptoms which can be efficiently applied. We further show that our tailored survey aligns with phase I trialists' perspectives on symptoms of relevance. CONCLUSIONS: This tailored survey represents the first PRO tool developed specifically for assessing tolerability in the phase I oncology population. We provide recommendations for future work aimed at integrating this survey into clinical practice.

Phase Ib/II Study of the Efficacy and Safety of Binimetinib (MEK162) Plus Panitumumab for Mutant or Wild-Type RAS Metastatic Colorectal Cancer.

INTRODUCTION: Activating RAS gene mutations occur in approximately 55% of patients with metastatic colorectal cancer (mCRC) and are associated with poorer clinical outcomes due to epidermal growth factor receptor (EGFR) blockade resistance. Combined EGFR and mitogen-activated protein kinase (MEK) inhibition may extend response to EGFR inhibition and overcome acquired resistance. This phase Ib/II dose escalation trial evaluated the safety and activity of dual inhibition with binimetinib (MEK1/2 inhibitor) and panitumumab (EGFR inhibitor [EGFRi]) in patients with RAS mutant or BRAF wild type (WT)/RAS WT mCRC. METHODS: Phase Ib dose escalation started with binimetinib 45 mg twice daily plus panitumumab 6 mg/kg administered every 2 weeks. In the phase II study, patients with measurable mCRC were enrolled into 4 groups based on previous anti-EGFR monoclonal antibody therapy and RAS mutational status. RESULTS: No patients in the phase Ib portion (n = 10) had a response; 70% of patients had stable disease. In the phase II portion (n = 43), overall response rate (ORR, confirmed) was 2.3% with one partial response in the RAS WT group, DCR was 30.2%, and median progression-free survival was 1.8 months (95%CI, 1.6-3.3). All patients experienced ≥1 adverse event, with the most common being diarrhea (71.7%), vomiting (52.8%), nausea (50.9%), fatigue (49.1%), dermatitis acneiform (43.4%), and rash (41.5%). Most patients required treatment interruption or dose reduction due to difficulties tolerating treatment. CONCLUSIONS: The combination of binimetinib and panitumumab had substantial toxicity and limited clinical activity for patients with mutant or WT RAS mCRC, independent of EGFRi treatment history (Trial registration: NCT01927341).

Precision cancer medicine: Concepts, current practice, and future developments.

Precision cancer medicine is a multidisciplinary team effort that requires involvement and commitment of many stakeholders including the society at large. Building on the success of significant advances in precision therapy for oncological patients over the last two decades, future developments will be significantly shaped by improvements in scalable molecular diagnostics in which increasingly complex multilayered datasets require transformation into clinically useful information guiding patient management at fast turnaround times. Adaptive profiling strategies involving tissue- and liquid-based testing that account for the immense plasticity of cancer during the patient's journey and also include early detection approaches are already finding their way into clinical routine and will become paramount. A second major driver is the development of smart clinical trials and trial concepts which, complemented by real-world evidence, rapidly broaden the spectrum of therapeutic options. Tight coordination with regulatory agencies and health technology assessment bodies is crucial in this context. Multicentric networks operating nationally and internationally are key in implementing precision oncology in clinical practice and support developing and improving the ecosystem and framework needed to turn invocation into benefits for patients. The review provides an overview of the diagnostic tools, innovative clinical studies, and collaborative efforts needed to realize precision cancer medicine.

Results of an open-label phase 1b study of the ERK inhibitor MK-8353 plus the MEK inhibitor selumetinib in patients with advanced or metastatic solid tumors.

AIM: We evaluated MK-8353 (small molecule inhibitor of extracellular signal-regulated kinase 1/2) plus selumetinib (mitogen-activated extracellular signal-regulated kinase 1/2 inhibitor) in patients with advanced solid tumors. METHODS: This phase 1b, open-label, dose-escalation study (NCT03745989) enrolled adults with histologically/cytologically documented, locally advanced/metastatic solid tumors. MK-8353/selumetinib dose combinations were intended to be investigated in sequence: 50/25, 100/50, 150/75, 200/75, 200/100, and 250/100. Each agent was administered orally BID 4 days on/3 days off in repeating cycles every 21 days. Primary objectives were safety and tolerability and to establish preliminary recommended phase 2 doses for combination therapy. RESULTS: Thirty patients were enrolled. Median (range) age was 61.5 (26-78) years and 93% had received previous cancer therapy. Among 28 patients in the dose-limiting toxicities [DLT]-evaluable population, 8 experienced DLTs: 1/11 (9%) in the MK-8353/selumetinib 100/50-mg dose level experienced a grade 3 DLT (urticaria), and 7/14 (50%) in the 150/75-mg dose level experienced grade 2/3 DLTs (n = 2 each of blurred vision, retinal detachment, vomiting; n = 1 each of diarrhea, macular edema, nausea, retinopathy). The DLT rate in the latter dose level exceeded the prespecified target DLT rate (~30%). Twenty-six patients (87%) experienced treatment-related adverse events (grade 3, 30%; no grade 4/5), most commonly diarrhea (67%), nausea (37%), and acneiform dermatitis (33%). Three patients (10%) experienced treatment-related adverse events leading to treatment discontinuation. Best response was stable disease in 14 patients (n = 10 with MK-8353/selumetinib 150/75 mg). CONCLUSION: MK-8353/selumetinib 50/25 mg and 100/50 mg had acceptable safety and tolerability, whereas 150/75 mg was not tolerable. No responses were observed.

Population pharmacokinetic modelling of tremelimumab in patients with advanced solid tumours and the impact of disease status on time-varying clearance.

AIMS: Tremelimumab, a cytotoxic T-lymphocyte-associated protein 4 human monoclonal antibody of the immunoglobulin G2 κ isotype, has been studied in oncology clinical trials as both monotherapy and in combination with durvalumab. This study characterized the pharmacokinetics of tremelimumab as monotherapy and in combination with durvalumab and evaluated the impact of patient covariates on pharmacokinetics. METHODS: A pooled-analysis population pharmacokinetics model was built using NONMEM methodology. Pharmacokinetic data from 5 studies spanning different tumour types and therapy regimens were pooled for model development (956 patients). A dataset pooled from 4 additional studies was used for external validation (554 patients). Demographic and relevant clinical covariates were explored during model development. RESULTS: Tremelimumab exhibited linear pharmacokinetics, well described by a 2-compartment model, with time-varying clearance (0.276 L/day at baseline) associated primarily with therapy regimen and linked with changes in disease status. As monotherapy and combination therapy, tremelimumab clearance over 1 year increased by ~16% and decreased by ~17%, respectively. Pharmacokinetic behaviour was consistent across patient demographics and cancer subtypes. Patients with higher bodyweight and lower albumin levels at baseline had significantly higher clearance; however, no dosage adjustments are warranted. A flat dose (75 mg) was projected to provide comparable exposure to weight-based dosing (1 mg/kg) in adults. CONCLUSION: Tremelimumab exhibited linear pharmacokinetics but consistently opposite trends of time-varying clearance as monotherapy and in combination with durvalumab. Baseline bodyweight and albumin were significant covariates, but conversion from weight-based dosing at 1 mg/kg to flat dosing at 75 mg had no clinically relevant impact.

Evaluation of the patient experience of symptomatic adverse events on Phase I clinical trials using PRO-CTCAE.

BACKGROUND: Adverse event (AE) reporting in early-phase clinical trials is essential in determining the tolerability of experimental anticancer therapies. The patient-reported outcome version of the CTCAE (PRO-CTCAE) evaluates AE components such as severity and interference in daily life. The aim of this study was to correlate the grade of clinician-reported AEs with patients' reported experience of these toxicities using PRO-CTCAE. METHODS: Patients with advanced solid tumours enrolled on Phase I clinical trials were surveyed using the PRO-CTCAE. Symptomatic AEs were recorded by physicians using the CTCAE. A logistic regression model was used to assess associations between CTCAE grade and PRO responses. RESULTS: Of 219 evaluable patients, 81 experienced a high-grade (3/4) clinician-reported symptom, and of these, only 32 (40%) and 26 (32%) patients concordantly reported these as either severe or very severe, and interfering with daily life either 'quite a bit' or 'very much', respectively. Of the 137 patients who experienced a low-grade (1/2) clinician-reported AE as their worst symptom, 98 (72%) and 118 (86%) patients concordantly reported these as either mild-moderate severity and minimally interfering with daily life, respectively. There was a statistically significant association between clinician-reported AE grade and interference. Interference scores were also associated with dose reductions. CONCLUSION: This is the first study to explore patient-reported severity and interference from symptomatic toxicities and compare clinician grading of the same toxicities. The study provided further evidence to support the added value of the PRO-CTCAE in Phase I oncology trials, which would make AE reporting patient-centred. Further work is needed to determine how this would affect the assessment of tolerability.

Circulating Biomarkers for Therapeutic Monitoring of Anti-cancer Agents.

Circulating biomarkers have emerged as valuable surrogates for evaluating disease states in solid malignancies. Their relative ease of access and rapid turnover has bolstered clinical applications in monitoring treatment efficacy and cancer progression. In this review, the roles of various circulating biomarkers in monitoring treatment response are described. Non-specific markers of disease burden, tumor markers (eg CA 125, CEA, PSA, etc.), circulating tumor cells, nucleic acids, exosomes, and metabolomic arrays are highlighted. Specifically, the discovery of each of these markers is reviewed, with examples illustrating their use in influencing treatment decisions, and barriers to their application noted where these exist. Finally, opportunities for future work using these circulating biomarkers are discussed.

Complementary Medicine Use Amongst Patients with Metastatic Cancer Enrolled in Phase III Clinical Trials.

BACKGROUND: Complementary medicines (CM) are frequently used by patients with cancer. Controversy exists over the effectiveness and risk that CM may add to conventional cancer therapy. The incidence of CM use among patients enrolled in phase III clinical trials is unknown. METHODS: Medication lists from 6 international phase III clinical trials were retrospectively reviewed to identify patients using CM. Patients had metastatic breast, colorectal, or lung cancers. Quality of life, adverse events, overall survival, and progression-free survival were compared between CM users and non-users. Baseline differences between groups were adjusted with propensity score matching groups. RESULTS: Seven hundred and six of 3446 patients (20.5%) used at least one CM. CM use was highest among patients with breast cancer (35.6%). CM users had more favorable baseline prognostic factors (ECOG 0-1, non-smoking status, younger age, and fewer metastases). CM use was associated with lower rates of adverse events (50% vs. 62%, P = .002) and quality of life was similar between both groups. After adjustment with propensity score matching, CM use was also associated with longer overall survival in patients with lung cancer (adjusted hazard ratio 0.80, 95%CI, 0.68-0.94, P =.0054). However, several key control variables like EGFR status were not available. CONCLUSION: One in 5 patients in phase III clinical trials report using CM. CM was not associated with worse cancer-specific outcomes. However, CM users had more favorable baseline prognostic factors, and likely other confounders that may have contributed to improved outcomes observed in the lung cohort. Physicians should monitor for CM use and potential interactions with clinical trial drugs.

Treatment with pembrolizumab in programmed death ligand 1-positive recurrent glioblastoma: Results from the multicohort phase 1 KEYNOTE-028 trial.

BACKGROUND: Current treatments for recurrent glioblastoma offer limited benefit. The authors report the antitumor activity and safety of the anti-programmed death 1 (anti-PD-1) immunotherapy, pembrolizumab, in programmed death ligand 1 (PD-L1)-positive, recurrent glioblastoma. METHODS: Adult patients with PD-L1-positive tumors were enrolled in the recurrent glioblastoma cohort of the multicohort, phase 1b KEYNOTE-028 study (ClinicalTrials.gov identifier, NCT02054806) and received pembrolizumab 10 mg/kg every 2 weeks for up to 2 years. The primary endpoint was investigator-assessed overall response rate according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Archival tumor samples were assessed for PD-L1 expression levels (prospectively) and T-cell-inflamed gene expression profile score (retrospectively). RESULTS: After a median follow-up of 14 months (range, 2-55 months) among the 26 enrolled patients, the overall response rate was 8% (95% CI, 1%-26%). Two partial responses, lasting 8.3 and 22.8 months, occurred. Progression-free survival (median, 2.8 months; 95% CI, 1.9-8.1 months) rate at 6 months was 37.7%, and the overall survival (median, 13.1 months; 95% CI, 8.0-26.6 months) rate at 12 months was 58%. Correlation of therapeutic benefit to level of PD-L1 expression, gene expression profile score, or baseline steroid use could not be established. Treatment-related adverse events occurred in 19 patients (73%), and 5 patients experienced grade 3 or 4 events (there were no grade 5 events). Immune-mediated adverse events and infusion reactions occurred in 7 patients (27%). CONCLUSIONS: Pembrolizumab monotherapy demonstrated durable antitumor activity in a subset of patients with manageable toxicity in this small, signal-finding, recurrent glioblastoma cohort. Future studies evaluating rationally designed pembrolizumab combination regimens may improve outcomes in patients with recurrent glioblastoma.

Transitions in oral and gut microbiome of HPV+ oropharyngeal squamous cell carcinoma following definitive chemoradiotherapy (ROMA LA-OPSCC study).

BACKGROUND: Oral and gut microbiomes have emerged as potential biomarkers in cancer. We characterised the oral and gut microbiomes in a prospective observational cohort of HPV+ oropharyngeal squamous cell carcinoma (OPSCC) patients and evaluated the impact of chemoradiotherapy (CRT). METHODS: Saliva, oropharyngeal swabs over the tumour site and stool were collected at baseline and post-CRT. 16S RNA and shotgun metagenomic sequencing were used to generate taxonomic profiles, including relative abundance (RA), bacterial density, α-diversity and ß-diversity. RESULTS: A total of 132 samples from 22 patients were analysed. Baseline saliva and swabs had similar taxonomic composition (R2 = 0.006; p = 0.827). Oropharyngeal swabs and stool taxonomic composition varied significantly by stage, with increased oral RA of Fusobacterium nucleatum observed in stage III disease (p < 0.05). CRT significantly reduced the species richness and increased the RA of gut-associated taxa in oropharyngeal swabs (p < 0.05), while it had no effect in stool samples. These findings remained significant when adjusted by stage, smoking status and antibiotic use. CONCLUSIONS: Baseline oral and gut microbiomes differ by stage in this HPV+ cohort. CRT caused a shift towards a gut-like microbiome composition in oropharyngeal swabs. Stage-specific features and the transitions in oral microbiome might have prognostic and therapeutic implications.

Small molecules, big impact: 20 years of targeted therapy in oncology.

The identification of molecular targets and the growing knowledge of their cellular functions have led to the development of small molecule inhibitors as a major therapeutic class for cancer treatment. Both multitargeted and highly selective kinase inhibitors are used for the treatment of advanced treatment-resistant cancers, and many have also achieved regulatory approval for early clinical settings as adjuvant therapies or as first-line options for recurrent or metastatic disease. Lessons learned from the development of these agents can accelerate the development of next-generation inhibitors to optimise the therapeutic index, overcome drug resistance, and establish combination therapies. The future of small molecule inhibitors is promising as there is the potential to investigate novel difficult-to-drug targets, to apply predictive non-clinical models to select promising drug candidates for human evaluation, and to use dynamic clinical trial interventions with liquid biopsies to deliver precision medicine.

Phase I study of daily and weekly regimens of the orally administered MDM2 antagonist idasanutlin in patients with advanced tumors.

Aim The oral MDM2 antagonist idasanutlin inhibits the p53-MDM2 interaction, enabling p53 activation, tumor growth inhibition, and increased survival in xenograft models. Methods We conducted a Phase I study of idasanutlin (microprecipitate bulk powder formulation) to determine the maximum tolerated dose (MTD), safety, pharmacokinetics, pharmacodynamics, food effect, and clinical activity in patients with advanced malignancies. Schedules investigated were once weekly for 3 weeks (QW × 3), once daily for 3 days (QD × 3), or QD × 5 every 28 days. We also analyzed p53 activation and the anti-proliferative effects of idasanutlin. Results The dose-escalation phase included 85 patients (QW × 3, n = 36; QD × 3, n = 15; QD × 5, n = 34). Daily MTD was 3200 mg (QW × 3), 1000 mg (QD × 3), and 500 mg (QD × 5). Most common adverse events were diarrhea, nausea/vomiting, decreased appetite, and thrombocytopenia. Dose-limiting toxicities were nausea/vomiting and myelosuppression; myelosuppression was more frequent with QD dosing and associated with pharmacokinetic exposure. Idasanutlin exposure was approximately dose proportional at low doses, but less than dose proportional at > 600 mg. Although inter-patient variability in exposure was high with all regimens, cumulative idasanutlin exposure over the whole 28-day cycle was greatest with a QD × 5 regimen. No major food effect on pharmacokinetic exposure occurred. MIC-1 levels were higher with QD dosing, increasing in an exposure-dependent manner. Best response was stable disease in 30.6% of patients, prolonged (> 600 days) in 2 patients with sarcoma. Conclusions Idasanutlin demonstrated dose- and schedule-dependent p53 activation with durable disease stabilization in some patients. Based on these findings, the QD × 5 schedule was selected for further development. TRIAL REGISTRATION: NCT01462175 (ClinicalTrials.gov), October 31, 2011.

Phase 1 study of the immunotoxin LMB-100 in patients with mesothelioma and other solid tumors expressing mesothelin.

BACKGROUND: LMB-100 is an antibody-toxin conjugate with an antimesothelin Fab linked to a 24-kilodalton portion of Pseudomonas exotoxin A with mutations that decrease immunogenicity. The objective of the current first-in-human phase 1 study was to determine the maximum tolerated dose (MTD) and safety in patients with advanced solid tumors expressing mesothelin. METHODS: Cohorts of 1 to 7 patients received intravenous LMB-100 at 7 dose levels from 40 µg/kg to 250 µg/kg intravenously on days 1, 3, and 5 of a 21-day cycle. RESULTS: Of the 25 patients accrued, 17 had mesothelioma, 3 each had ovarian or pancreatic cancer, and 2 patients had gastric cancer. Dose-limiting toxicities occurred in 2 of 4 patients treated at a dose of 250 µg/kg (capillary leak syndrome) and in 3 of 7 patients treated at a dose of 170 µg/kg (creatinine increase). The MTD of LMB-100 was 140 µg/kg. Of the 10 patients with mesothelioma who were treated at doses of 170 µg/kg or 140 µg/kg, 8 had stable disease and 2 developed progressive disease. Peak LMB-100 plasma concentrations were dose-dependent during cycle 1. The development of antidrug antibodies decreased LMB-100 blood levels in 8 of 21 patients (38%) who received cycle 2 and 9 of 11 patients (81.8%) who received cycle 3. CONCLUSIONS: The MTD for single-agent LMB-100 was found to be 140 µg/kg given on a schedule of every other day for 3 doses every 3 weeks. Although less immunogenic than the first-generation antimesothelin immunotoxin SS1P, the majority of patients developed antidrug antibodies after 2 cycles, indicating that LMB-100 has limited antitumor efficacy as a single agent. Phase 2 studies of LMB-100 plus pembrolizumab currently are ongoing for patients with mesothelioma and lung cancer. LAY SUMMARY: Mesothelin, a cell surface antigen, is an attractive target for cancer therapy given its limited expression in normal human tissues and high expression in many human cancers. LMB-100 is a recombinant antimesothelin immunotoxin consisting of a humanized antimesothelin antibody fragment fused to a truncated Pseudomonas exotoxin A. In the current study, the authors determined the safety, maximum tolerated dose, and pharmacokinetics of LMB-100, as well as the generation of antidrug antibodies. Ongoing phase 2 clinical trials are evaluating the combination of LMB-100 plus pembrolizumab in patients with treatment-refractory mesothelioma and non-small cell lung cancer.

Hypofractionated radiotherapy alone with 2.4 Gy per fraction for head and neck cancer during the COVID-19 pandemic: The Princess Margaret experience and proposal.

BACKGROUND: The objective of this study was to identify a subgroup of patients with head and neck squamous cell carcinoma (HNSCC) who might be suitable for hypofractionated radiotherapy (RT-hypo) during the COVID-19 pandemic. METHODS: HNSCC cases (oropharynx/larynx/hypopharynx) treated with definitive RT-hypo (60 Gy in 25 fractions over 5 weeks), moderately accelerated radiotherapy (RT-acc) alone (70 Gy in 35 fractions over 6 weeks), or concurrent chemoradiotherapy (CCRT) during 2005-2017 were included. Locoregional control (LRC) and distant control (DC) after RT-hypo, RT-acc, and CCRT were compared for various subgroups. RESULTS: The study identified 994 human papillomavirus-positive (HPV+) oropharyngeal squamous cell carcinoma cases (with 61, 254, and 679 receiving RT-hypo, RT-acc, and CCRT, respectively) and 1045 HPV- HNSCC cases (with 263, 451, and 331 receiving RT-hypo, RT-acc, and CCRT, respectively). The CCRT cohort had higher T/N categories, whereas the radiotherapy-alone patients were older. The median follow-up was 4.6 years. RT-hypo, RT-acc, and CCRT produced comparable 3-year LRC and DC for HPV+ T1-2N0-N2a disease (seventh edition of the TNM system [TNM-7]; LRC, 94%, 100%, and 94%; P = .769; DC, 94%, 100%, and 94%; P = .272), T1-T2N2b disease (LRC, 90%, 94%, and 97%; P = .445; DC, 100%, 96%, and 95%; P = .697), and T1-2N2c/T3N0-N2c disease (LRC, 89%, 93%, and 95%; P = .494; DC, 89%, 90%, and 87%; P = .838). Although LRC was also similar for T4/N3 disease (78%, 84%, and 88%; P = .677), DC was significantly lower with RT-hypo or RT-acc versus CCRT (67%, 65%, and 87%; P = .005). For HPV- HNSCC, 3-year LRC and DC were similar with RT-hypo, RT-acc, and CCRT in stages I and II (LRC, 85%, 89%, and 100%; P = .320; DC, 99%, 98%, and 100%; P = .446); however, RT-hypo and RT-acc had significantly lower LRC in stage III (76%, 69%, and 91%; P = .006), whereas DC rates were similar (92%, 85%, and 90%; P = .410). Lower LRC in stage III predominated in patients with laryngeal squamous cell carcinoma receiving RT-acc (62%) but not RT-hypo (80%) or CCRT (92%; RT-hypo vs CCRT: P = .270; RT-acc vs CCRT: P = .004). CCRT had numerically higher LRC in comparison with RT-hypo or RT-acc in stage IV (73%, 65%, and 66%; P = .336). CONCLUSIONS: It is proposed that RT-hypo be considered in place of CCRT for HPV+ T1-T3N0-N2c (TNM-7) HNSCCs, HPV- T1-T2N0 HNSCCs, and select stage III HNSCCs during the COVID-19 outbreak.