A Phase 2 Randomized, Double-Blind, Multicenter Trial of Imexon Plus Gemcitabine Versus Gemcitabine Plus Placebo in Patients With Metastatic Chemotherapy-naïve Pancreatic Adenocarcinoma

Chemotherapy and radiotherapy for advanced pancreatic cancer

BACKGROUND

Pancreatic cancer (PC) is a lethal disease with few effective treatment options. Many anti-cancer therapies have been tested in the locally advanced and metastatic setting, with mixed results. This review synthesises all the randomised data available to help better inform patient and clinician decision-making. It updates the previous version of the review, published in 2018.

OBJECTIVES

To assess the effects of chemotherapy, radiotherapy, or both on overall survival, severe or life-threatening adverse events, and quality of life in people undergoing first-line treatment of advanced pancreatic cancer.

SEARCH METHODS

We searched for published and unpublished studies in CENTRAL, MEDLINE, Embase, and CANCERLIT, and handsearched various sources for additional studies. The latest search dates were in March and July 2023.

SELECTION CRITERIA

We included randomised controlled trials comparing chemotherapy, radiotherapy, or both with another intervention or best supportive care. Participants were required to have locally advanced, unresectable pancreatic cancer or metastatic pancreatic cancer not amenable to curative intent treatment. Histological confirmation was required. Trials were required to report overall survival.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We included 75 studies in the review and 51 in the meta-analysis (11,333 participants). We divided the studies into seven categories: any anti-cancer treatment versus best supportive care; various chemotherapy types versus gemcitabine; gemcitabine-based combinations versus gemcitabine alone; various chemotherapy combinations versus gemcitabine plus nab-paclitaxel; fluoropyrimidine-based studies; miscellaneous studies; and radiotherapy studies. In general, the included studies were at low risk for random sequence generation, detection bias, attrition bias, and reporting bias, at unclear risk for allocation concealment, and high risk for performance bias. Compared to best supportive care, chemotherapy likely results in little to no difference in overall survival (OS) (hazard ratio (HR) 1.08, 95% confidence interval (CI) 0.88 to 1.33; absolute risk of death at 12 months of 971 per 1000 versus 962 per 1000; 4 studies, 298 participants; moderate-certainty evidence). The adverse effects of chemotherapy and impacts on quality of life (QoL) were uncertain. Many of the chemotherapy regimens were outdated. Eight studies compared non-gemcitabine-based chemotherapy regimens to gemcitabine. These showed that 5-fluorouracil (5FU) likely reduces OS (HR 1.69, 95% CI 1.26 to 2.27; risk of death at 12 months of 914 per 1000 versus 767 per 1000; 1 study, 126 participants; moderate certainty), and grade 3/4 adverse events (QoL not reported). Fixed dose rate gemcitabine likely improves OS (HR 0.79, 95% CI 0.66 to 0.94; risk of death at 12 months of 683 per 1000 versus 767 per 1000; 2 studies, 644 participants; moderate certainty), and likely increase grade 3/4 adverse events (QoL not reported). FOLFIRINOX improves OS (HR 0.51, 95% CI 0.43 to 0.60; risk of death at 12 months of 524 per 1000 versus 767 per 1000; P < 0.001; 2 studies, 652 participants; high certainty), and delays deterioration in QoL, but increases grade 3/4 adverse events. Twenty-eight studies compared gemcitabine-based combinations to gemcitabine. Gemcitabine plus platinum may result in little to no difference in OS (HR 0.94, 95% CI 0.81 to 1.08; risk of death at 12 months of 745 per 1000 versus 767 per 1000; 6 studies, 1140 participants; low certainty), may increase grade 3/4 adverse events, and likely worsens QoL. Gemcitabine plus fluoropyrimidine improves OS (HR 0.88, 95% CI 0.81 to 0.95; risk of death at 12 months of 722 per 1000 versus 767 per 1000; 10 studies, 2718 participants; high certainty), likely increases grade 3/4 adverse events, and likely improves QoL. Gemcitabine plus topoisomerase inhibitors result in little to no difference in OS (HR 1.01, 95% CI 0.87 to 1.16; risk of death at 12 months of 770 per 1000 versus 767 per 1000; 3 studies, 839 participants; high certainty), likely increases grade 3/4 adverse events, and likely does not alter QoL. Gemcitabine plus taxane result in a large improvement in OS (HR 0.71, 95% CI 0.62 to 0.81; risk of death at 12 months of 644 per 1000 versus 767 per 1000; 2 studies, 986 participants; high certainty), and likely increases grade 3/4 adverse events and improves QoL. Nine studies compared chemotherapy combinations to gemcitabine plus nab-paclitaxel. Fluoropyrimidine-based combination regimens improve OS (HR 0.79, 95% CI 0.70 to 0.89; risk of death at 12 months of 542 per 1000 versus 628 per 1000; 6 studies, 1285 participants; high certainty). The treatment arms had distinct toxicity profiles, and there was little to no difference in QoL. Alternative schedules of gemcitabine plus nab-paclitaxel likely result in little to no difference in OS (HR 1.10, 95% CI 0.82 to 1.47; risk of death at 12 months of 663 per 1000 versus 628 per 1000; 2 studies, 367 participants; moderate certainty) or QoL, but may increase grade 3/4 adverse events. Four studies compared fluoropyrimidine-based combinations to fluoropyrimidines alone, with poor quality evidence. Fluoropyrimidine-based combinations are likely to result in little to no impact on OS (HR 0.84, 95% CI 0.61 to 1.15; risk of death at 12 months of 765 per 1000 versus 704 per 1000; P = 0.27; 4 studies, 491 participants; moderate certainty) versus fluoropyrimidines alone. The evidence suggests that there was little to no difference in grade 3/4 adverse events or QoL between the two groups. We included only one radiotherapy (iodine-125 brachytherapy) study with 165 participants. The evidence is very uncertain about the effect of radiotherapy on outcomes.

AUTHORS' CONCLUSIONS

Combination chemotherapy remains standard of care for metastatic pancreatic cancer. Both FOLFIRINOX and gemcitabine plus a taxane improve OS compared to gemcitabine alone. Furthermore, the evidence suggests that fluoropyrimidine-based combination chemotherapy regimens improve OS compared to gemcitabine plus nab-paclitaxel. The effects of radiotherapy were uncertain as only one low-quality trial was included. Selection of the most appropriate chemotherapy for individuals still remains unpersonalised, with clinicopathological stratification remaining elusive. Biomarker development is essential to assist in rationalising treatment selection for patients.

Cascade synthetic strategies opening access to medicinal-relevant aliphatic 3- and 4-membered N-heterocyclic scaffolds

Cascade reactions are often 'employed' by nature to construct structurally diverse nitrogen-containing heterocycles in a highly stereoselective fashion, i.e., secondary metabolites important for pharmacy. Nitrogen-containing heterocycles of three- and four-membered rings, as standalone and bicyclic compounds, inhibit different enzymes and are pharmacophores of approved drugs or drug candidates considered in many therapies, e.g. anticancer, antibacterial or antiviral. Domino transformations are in most cases in line with modern green chemistry concepts due to atom economy, one-pot procedures often without use the protective groups, time-saving and at markedly lower costs than multistep transformations. The tandem approaches can help to obtain novel N-heterocyclic scaffolds, functionalized according to structural requirements of the target in cells, taking into account the nature of functional group and stereochemistry. On the other hand cascade strategies allow to modify small N-heterocyclic rings in a systematic way, which is beneficial for structure-activity relationship (SAR) analyses. This review is focused on the biological relevance of the N-heterocyclic scaffolds with smaller 3- and 4-membered rings among approved drugs and leading structures of drug candidates. The cascade synthetic strategies offering N-heterocyclic scaffolds, at relatively good yields and high stereoselectivity, are discussed here. The review covers mainly years from 2015 to 2021.

Impact of Value Frameworks on the Magnitude of Clinical Benefit: Evaluating a Decade of Randomized Trials for Systemic Therapy in Solid Malignancies

In the era of rapid development of new, expensive cancer therapies, value frameworks have been developed to quantify clinical benefit (CB). We assessed the evolution of CB since the 2015 introduction of The American Society of Clinical Oncology and The European Society of Medical Oncology value frameworks. Randomized clinical trials (RCTs) assessing systemic therapies for solid malignancies from 2010 to 2020 were evaluated and CB (Δ) in 2010–2014 (pre-value frameworks (PRE)) were compared to 2015–2020 (POST) for overall survival (OS), progression-free survival (PFS), response rate (RR), and quality of life (QoL). In the 485 studies analyzed (12% PRE and 88% POST), the most common primary endpoint was PFS (49%), followed by OS (20%), RR (12%), and QoL (6%), with a significant increase in OS and decrease in RR as primary endpoints in the POST era (p = 0.011). Multivariable analyses revealed significant improvement in ΔOS POST (OR 2.86, 95% CI 0.46 to 5.26, p = 0.02) while controlling for other variables. After the development of value frameworks, median ΔOS improved minimally. The impact of value frameworks has yet to be fully realized in RCTs. Efforts to include endpoints shown to impact value, such as QoL, into clinical trials are warranted.

Synthesis and Antiproliferative Activity of Phosphorus Substituted 4-Cyanooxazolines, 2-Aminocyanooxazolines, 2-Iminocyanooxazolidines and 2-Aminocyanothiazolines by Rearrangement of Cyanoaziridines

Several phosphorus-substituted N-acylated cyanoaziridines 2 and N-carbamoylated cyanoziridines 5 were prepared in good to high yields. N-Acylated cyanoaziridines 2 were used, after ring expansion, in an efficient synthesis of oxazoline derivative 3a and in a completely regio-controlled reaction in the presence of NaI. Conversely, N-carbamoyl cyanoaziridines 5 reacted with NaI to obtain a regioisomeric mixture of 2-aminocyanooxazolines 7. Mild acidic conditions can be used for the isomerization of N-thiocarbamoyl cyanoaziridine 6a into a 2-aminocyanothiazoline derivative 8a by using BF₃·OEt₂ as a Lewis acid. Likewise, a one pot reaction of NH-cyanoaziridines 1 with isocyanates obtained 2-iminocyanooxazolidines 9 regioselectively. This synthetic methodology involves the addition of isocyanates to starting cyanoaziridines to obtain N-carbamoyl cyanoaziridines 5, which after the ring opening, reacts with a second equivalent of isocyanate to give the final 2-imino cyanooxazolidines 9. In addition, the cytotoxic effect on the cell lines derived from human lung adenocarcinoma (A549) was also screened. 2-Iminooxazolidines 9 exhibited moderate activity against the A549 cell line in vitro. Furthermore, a selectivity towards cancer cells (A549) over non-malignant cells (MCR-5) was detected.

Two decades of research toward the treatment of locally advanced and metastatic pancreatic cancer: Remarkable effort and limited gain

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy that is diagnosed at the locally advanced or metastatic stage in approximately 80% of cases. Relative to other tumor types, progress in the treatment of this disease has been painfully slow. While agents targeting DNA repair have proven successful in a subset of patients, the majority of PDACs do not exhibit validated molecular targets. Hence, conventional chemotherapy remains at the forefront of therapy for this disease. In this review, we study two decades of efforts to improve upon the gemcitabine backbone - 67 phase II and III trials enrolling 16,446 patients - that culminated in the approvals of gemcitabine/nab-paclitaxel (Gem/NabP) and FOLFIRINOX. Today, these remain gold standards for the first-line treatment of locally advanced unresectable and metastatic PDAC, while ongoing efforts focus on improving upon the Gem/NabP backbone. Because real world data often do not reflect the data of randomized controlled trials (RCTs), we also summarize the retrospective evidence comparing the efficacy of Gem/NabP and FOLFIRINOX in the first-line setting - 29 studies reporting a median overall survival of 10.7 and 9.1 months for FOLFIRINOX and Gem/NabP, respectively. These values are surprisingly comparable to those reported by the pivotal RCTs at 11.1 and 8.5 months. Finally, there is a paucity of RCT data regarding the efficacy of second-line therapy. Hence, we conclude this review by summarizing the data that ultimately demonstrate a small but significant survival benefit of second-line therapy with Gem/NabP or FOLFIRINOX. Collectively, these studies describe the long journey, the steady effort, and the myriad lessons to be learned from 20 years of PDAC trials to inform strategies for success in clinical trials moving forward.

A computational study of the main degradation product of antitumor drug imexon

We theoretically study, from the thermodynamic point of view, the possibility of the two degradation pathways of antitumor drug of imexon. According to the theoretical results obtained at DFT level in both gas and aqueous phases, the two degradation pathways of imexon are characterized by negative reaction Gibbs free energies. It has been found that 4-imino-5-methylene-imidazolidin-2-one is the favored degradation product of imexon.

Herein, the focus of this work has been on calculating the geometries, relative energies and electronic properties of all possible prototropic tautomers of 4-imino-5-methylene-imidazolidin-2-one using the DFT and MP2 levels. The bulk water environment has been simulated by continuum model using Solvation Model based on Density (SMD). The UV spectra of two dominant tautomers of 4-imino-5-methylene-imidazolidin-2-one are also predicted using time-dependent density functional theory and the results are compared with the available experimental data. The comparison of the simulated and the experimental absorption spectra has allowed us to accurately characterize the predominant tautomer of the degradation product in aqueous medium.