ATR inhibition activates cancer cell cGAS/STING-interferon signaling and promotes antitumor immunity in small-cell lung cancer.

Patients with small-cell lung cancer (SCLC) have poor prognosis and typically experience only transient benefits from combined immune checkpoint blockade (ICB) and chemotherapy. Here, we show that inhibition of ataxia telangiectasia and rad3 related (ATR), the primary replication stress response activator, induces DNA damage-mediated micronuclei formation in SCLC models. ATR inhibition in SCLC activates the stimulator of interferon genes (STING)-mediated interferon signaling, recruits T cells, and augments the antitumor immune response of programmed death-ligand 1 (PD-L1) blockade in mouse models. We demonstrate that combined ATR and PD-L1 inhibition causes improved antitumor response than PD-L1 alone as the second-line treatment in SCLC. This study shows that targeting ATR up-regulates major histocompatibility class I expression in preclinical models and SCLC clinical samples collected from a first-in-class clinical trial of ATR inhibitor, berzosertib, with topotecan in patients with relapsed SCLC. Targeting ATR represents a transformative vulnerability of SCLC and is a complementary strategy to induce STING-interferon signaling-mediated immunogenicity in SCLC.

Salvage chemotherapy regimens with arsenic trioxide for relapsed or refractory neuroblastoma: a promising approach.

In patients with relapsed or refractory neuroblastoma (NB), the limited efficacy of conventional chemotherapies necessitates the exploration of new treatment options. Previous studies have highlighted the anti-tumor properties of arsenic trioxide (ATO) in high-risk NB (HR-NB). This study aims to assess the effectiveness and safety of ATO combined with salvage chemotherapy regimens, featuring cyclophosphamide and topotecan, as a foundational treatment for children with relapsed or refractory NB. Eleven patients (four relapsed, seven refractory NB) were retrospectively analyzed for efficacy and treatment relevance. Salvage treatments, incorporating ATO (0.18 mg/kg daily for 8 h intravenously on days 1 to 10), were administered upon disease progression or relapse, with assessments conducted every two cycles. Treatments had 63.6% efficacy, with six cases of partial response, one case of stable disease, and four cases of disease progression. The overall response rate was 54.5%, and the disease control rate was 63.6%. Importantly, the systemic toxicity experienced by patients following salvage chemotherapy with ATO was mild. Salvage chemotherapy regimens featuring ATO demonstrated potential for prolonging disease stabilization for relapsed or refractory HR-NB patients, exhibiting both favorable efficacy and safety profiles. This suggests further clinical exploration and promotion of this therapeutic approach in the treatment of NB.

Point 1. The inadequate effectiveness of traditional chemotherapy in individuals with recurrent or resistant neuroblastoma (NB) necessitates the investigation of novel therapeutic approaches. Point 2. Arsenic trioxide (ATO)-based salvage treatments are both effective and less toxic in relapsed or refractory NB. Point 3. Salvage chemotherapy regimens incorporating ATO have shown promise in extending disease stabilization in relapsed or refractory high-risk NB patients, with favorable efficacy and safety profiles, which suggests further clinical exploration and promotion of this therapeutic approach in the treatment of NB.

Enhancement of the Clastogenic Effects of Topotecan In Vivo by Tyrosyl-DNA Phosphodiesterase 1 Inhibitors.

Topotecan administered intraperitoneally at single doses of 0.25, 0.5, and 1 mg/kg induced chromosomal aberrations in bone marrow cells of F1(CBA×C57BL/6) hybrid mice in a dose-dependent manner. A tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibitor, an usnic acid derivative OL9-116 was inactive in a dose range of 20-240 mg/kg, but enhanced the cytogenetic effect of topotecan (0.25 mg/kg) at a dose of 40 mg/kg (per os). The TDP1 inhibitor, a coumarin derivative TX-2552 (at doses of 20, 40, 80, and 160 mg/kg per os), increased the level of aberrant metaphases induced by topotecan (0.25 mg/kg) by 2.1-2.6 times, but was inactive at a dose of 10 mg/kg. The results indicate that TDP1 inhibitors enhance the clastogenic activity of topotecan in mouse bone marrow cells in vivo and are characterized by different dose profiles of the co-mutagenic effects.

A sensitive bioanalytical ultra-high-performance liquid chromatography-tandem mass spectrometry method for the simultaneous quantitation of lactone and carboxylate forms of topotecan in plasma and vitreous.

Topotecan (TPT) is used in the treatment of retinoblastoma, the most common malignant intraocular tumor in children. TPT undergoes pH-dependent hydrolysis of the lactone ring to the ring-opened carboxylate form, with the lactone form showing antitumor activity. A selective, and highly sensitive ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed for the determination of both forms of TPT in one mobile phase composition in plasma and vitreous humor matrices. The method showed an excellent linear range of 0.375-120 ng/mL for the lactone. For the carboxylate, the linear range was from 0.75 to 120 ng/mL. The matrix effect and the recovery for the lactone ranged from 98.5% to 106.0% in both matrices, for the carboxylate form, it ranged from 94.9% to 101.2%. The dynamics of the transition between TPT lactone and TPT carboxylate were evaluated at different pH environments. The stability of TPT forms was assessed in plasma and vitreous humor at 8 and 37°C and a very fast conversion of lactone to carboxylate form occurred at 37°C in both matrices. The method developed facilitates the investigation of TPT pharmacodynamics and the release kinetics in the development of the innovative local drug delivery systems.

Intravitreal Topotecan for Vitreous Seeds in Retinoblastoma: A Long-term Review of 91 Eyes.

PURPOSE: To study the long-term efficacy of intravitreal topotecan (IVT) for vitreous seeds in eyes with retinoblastoma and risk factors for their recurrence. DESIGN: Retrospective, non-comparative, interventional study. PARTICIPANTS: Ninety-one eyes of 90 patients with retinoblastoma treated between January 2013 and April 2019. METHODS: Patients with recurrent or refractory vitreous seeds after completion of intravenous or intra-arterial chemotherapy were treated with IVT (30 µg/0.15 ml) by the safety-enhanced technique. The injection was repeated every 4 weeks until the regression of seeds. Patients with a minimum follow-up of 12 months were included in the analysis. MAIN OUTCOME MEASURES: Primary outcome measures were vitreous seed regression and eye salvage. Secondary outcomes were risk factors for vitreous seed recurrence after treatment with IVT, vision salvage, and complications of IVT. RESULTS: The median age of the patients was 18 months, with most having group D (n = 58 [64%]) and group E (n = 26 [29%]) retinoblastoma. Vitreous seeds were refractory in 46 eyes (51%) and recurrent in 45 eyes (49%). A total of 317 IVT injections were administered, with the median being 3 injections. The median number of IVT injections required was 2.5 injections for dust, 3 injections for sphere, and 5 injections for cloud morphologic features. Recurrence of vitreous seeds after IVT was seen in 17 eyes (19%) at a mean follow-up of 7.9 months. At a mean follow-up 34 months, vitreous seed regression was achieved in 88 eyes (97%) and eye salvage was achieved in 77 eyes (85%). Older age (P = 0.018) and recurrence of retinal tumor (15/17 eyes; P < 0.01) significantly increased the risk of vitreous seed recurrence. Cataract was the most common complication seen in 17 eyes (9%). CONCLUSIONS: Intravitreal topotecan at an every 3- to 4-week regimen is effective against both refractory and recurrent vitreous seeds. The vitreous seed morphologic features correspond to the number of injections required for regression. Increasing age and recurrence of retinal tumor increase the risk of vitreous seed recurrence after treatment with IVT. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Electrochemical Nanosensor for the Simultaneous Determination of Anticancer Drugs Epirubicin and Topotecan Using UiO-66-NH2/GO Nanocomposite Modified Electrode.

In this work, UiO-66-NH2/GO nanocomposite was prepared using a simple solvothermal technique, and its structure and morphology were characterized using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD). An enhanced electrochemical sensor for the detection of epirubicin (EP) was proposed, which utilized a UiO-66-NH2/GO nanocomposite-modified screen-printed graphite electrode (UiO-66-NH2/GO/SPGE). The prepared UiO-66-NH2/GO nanocomposite improved the electrochemical performance of the SPGE towards the redox reaction of EP. Under optimized experimental conditions, this sensor demonstrates a remarkable limit of detection (LOD) of 0.003 µM and a linear dynamic range from 0.008 to 200.0 µM, providing a highly capable platform for sensing EP. Furthermore, the simultaneous electro-catalytic oxidation of EP and topotecan (TP) was investigated at the UiO-66-NH2/GO/SPGE surface utilizing differential pulse voltammetry (DPV). DPV measurements revealed the presence of two distinct oxidation peaks of EP and TP, with a peak potential separation of 200 mV. Finally, the UiO-66-NH2/GO/SPGE sensor was successfully utilized for the quantitative analysis of EP and TP in pharmaceutical injection, yielding highly satisfactory results.

Self-assembled ordered AuNRs-modified electrodes for simultaneous determination of dopamine and topotecan with improved data reproducibility.

Gold nanomaterials have been widely explored in electrochemical sensors due to their high catalytic property and good stability in multi-medium. In this paper, the reproducibility of the signal among batches of gold nanorods (AuNRs)-modified electrodes was investigated to improve the data stabilization and repeatability. Ordered and random self-assembled AuNRs-modified electrodes were used as electrochemical sensors for the simultaneous determination of dopamine (DA) and topotecan (TPC), with the aim of obtaining an improved signal stability in batches of electrodes and realizing the simultaneous determination of both substances. The morphology and structure of the assemblies were analyzed and characterized by UV-Vis spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray powder diffraction (XRD). Electrochemical studies showed that the ordered AuNRs/ITO electrodes have excellent signal reproducibility among several individuals due to the homogeneous mass transfer in the ordered arrangement of the AuNRs. Under the optimized conditions, the simultaneous detection results of DA and TPC showed good linearity in the ranges 1.75-45 µM and 1.5-40 µM, and the detection limits of DA and TPC were 0.06 µM and 0.17 µM, respectively. The results showed that the prepared ordered AuNR/ITO electrode had high sensitivity, long-term stability, and reproducibility for the simultaneous determination of DA and TPC, and it was expected to be applicable for real sample testing.

Dual modulation of blue-fluorescent carbon dots for simultaneous detection of topotecan and pantoprazole.

This study introduces a novel approach for the simultaneous determination of topotecan (TOP) and pantoprazole (PNT), two drugs whose interaction is critical in clinical applications. The significance of this study originates from the need to understand the pharmacokinetic changes of TOP after PNT administration, which can inform necessary dose adjustments of TOP. To achieve this, nitrogen blue emissive carbon dots (B@NCDs) were produced and employed due to their unique fluorescent properties. When TOP is added to B@NCDs, it exhibits strong native fluorescence at 545 nm without influencing the B@NCDs' fluorescence at 447 nm. Conversely, PNT causes quenching of B@NCDs fluorescence, a property that enables the distinct detection of both drugs. The B@NCDs were fully characterized using different techniques, including ultraviolet-visible spectrophotometry, fluorescence analysis, X-ray diffraction (XRD), transmission electron microscopy (TEM), and FTIR spectroscopy. The proposed method demonstrated excellent linearity, selectivity, and sensitivity, with low detection limits (LOD, S/N = 3); 0.0016 µg mL-1 for TOP and 0.36 µg mL-1 for PNT. Applied to spiked rabbit plasma samples, this method offers a new approach for evaluating the pharmacokinetic interaction between TOP and PNT. It enables the determination of all pharmacokinetic parameters of TOP before and after coadministration with PNT, providing essential insights into whether dose adjustments are necessary. This research not only contributes to the field of drug monitoring and interaction studies but also exemplifies the potential of B@NCDs in complex biological matrices, paving the way for further pharmacological and therapeutic applications.

Suvemcitug plus chemotherapy for platinum-resistant epithelial ovarian, fallopian tube and primary peritoneal cancer: A phase 1b dose-escalation trial.

OBJECTIVE: The use of bevacizumab has been hampered by safety concerns despite demonstrable progression-free survival (PFS) benefit in subjects with platinum-resistant ovarian cancer, highlighting the need for novel effective and safe antiangiogenic agents. This study aimed to characterize the tolerability, safety, and antitumor activities of escalating doses of anti-VEGF antibody suvemcitug plus chemotherapy in platinum-resistant ovarian cancer patients. METHODS: This open-label, dose-escalation trial enrolled adult patients (≥18 years) with platinum-resistant histologically or cytologically-confirmed epithelial ovarian, fallopian tube and primary peritoneal cancer. Eligible patients received paclitaxel or topotecan plus escalating doses of suvemcitug 0.5, 1, 1.5, or 2 mg/kg once every two weeks. The primary endpoints were safety and tolerability, and antitumor activities of suvemcitug. RESULTS: Twenty-nine subjects received paclitaxel (n = 11) or topotecan (n = 18). No dose-limiting toxicities occurred. The most common adverse events of special interest were proteinuria (41.4%), hypertension (20.7%) and epistaxis (10.3%). No gastrointestinal perforations occurred. Nine subjects (31.0%, 95% CI 15.3-50.8) demonstrated investigators-confirmed objective response, including complete response in 1 and partial response in 8. The median PFS was 5.4 months (95% CI 2.2-7.4). CONCLUSIONS: Suvemcitug demonstrated an acceptable safety profile and promising antitumor activities in platinum-resistant ovarian cancer patients, supporting its further clinical development.

RESILIENT Part 2: A Randomized, Open-Label Phase III Study of Liposomal Irinotecan Versus Topotecan in Adults With Relapsed Small Cell Lung Cancer.

PURPOSE: The phase III RESILIENT trial compared second-line liposomal irinotecan with topotecan in patients with small cell lung cancer (SCLC). PATIENTS AND METHODS: Patients with SCLC and progression on or after first-line platinum-based chemotherapy were randomly assigned (1:1) to intravenous (IV) liposomal irinotecan (70 mg/m2 every 2 weeks in a 6-week cycle) or IV topotecan (1.5 mg/m2 daily for 5 consecutive days, every 3 weeks in a 6-week cycle). The primary end point was overall survival (OS). Key secondary end points included progression-free survival (PFS) and objective response rate (ORR). RESULTS: Among 461 randomly assigned patients, 229 received liposomal irinotecan and 232 received topotecan. The median follow-up was 18.4 months. The median OS was 7.9 months with liposomal irinotecan versus 8.3 months with topotecan (hazard ratio [HR], 1.11 [95% CI, 0.90 to 1.37]; P = .31). The median PFS per blinded independent central review (BICR) was 4.0 months with liposomal irinotecan and 3.3 months with topotecan (HR, 0.96 [95% CI, 0.77 to 1.20]; nominal P = .71); ORR per BICR was 44.1% (95% CI, 37.6 to 50.8) and 21.6% (16.4 to 27.4), respectively. Overall, 42.0% and 83.4% of patients receiving liposomal irinotecan and topotecan, respectively, experienced grade ≥3 related treatment-emergent adverse events (TEAEs). The most common grade ≥3 related TEAEs were diarrhea (13.7%), neutropenia (8.0%), and decreased neutrophil count (4.4%) with liposomal irinotecan and neutropenia (51.6%), anemia (30.9%), and leukopenia (29.1%) with topotecan. CONCLUSION: Liposomal irinotecan and topotecan demonstrated similar median OS and PFS in patients with relapsed SCLC. Although the primary end point of OS was not met, liposomal irinotecan demonstrated a higher ORR than topotecan. The safety profile of liposomal irinotecan was consistent with its known safety profile; no new safety concerns emerged.

Primary results of the AGO-Zervix-1 Study: A prospective, randomized phase III study to compare the effects of paclitaxel and topotecan with those of cisplatin and topotecan in the treatment of patients with recurrent and persistent cervical cancer.

BACKGROUND: Before the era of immunotherapies and antibody-drug conjugates, there were limited chemotherapeutic options for patients with recurrent and metastatic cervical cancer. Combination therapies with cisplatin have shown some superiority over monotherapy. This study examined platinum-free treatment regimens, comparing a combination of topotecan and paclitaxel (TP) with topotecan and cisplatin (TC) in patients with recurrent or metastatic cervical cancer, with or without prior platinum-based treatment. METHODS: The AGO-Zervix-1 Study (NCT01405235) is a prospective, randomized phase III study in which patients were randomly assigned at a 1:1 ratio to treatment within the control arm with topotecan (0.75 mg/m2) on days 1-3 and cisplatin (50 mg/m2) on day 1 every 3 weeks and in the study arm topotecan (1.75 mg/m2) and paclitaxel (70 mg/m2) on days 1, 8, and 15 every 4 weeks or treatment. The primary study aim was overall survival; progression-free survival, toxicity, and quality of life were secondary aims. The interim and final analysis is here reported after recruitment of 173 of 312 planned patients. RESULTS: Median overall survival in the TP arm was 9.6 months, compared with 12.0 months in the TC arm (log-rank test, P = 0.33). Median progression-free survival rates were 4.4 months with TP and 4.2 months with TC (log-rank test, P = 0.47). Leukopenia and nausea/vomiting were more frequent in the cisplatin-containing arm. Otherwise, toxicity profiles were comparable. There were no differences in FACT-G-assessed quality of life. CONCLUSION: Platinum-based combination chemotherapy remains the standard of care chemotherapy regimen for patients with recurrent or metastatic cervical cancer.

Quantification of Unencapsulated Drug in Target Tissues Demonstrates Pharmacological Properties and Therapeutic Effects of Liposomal Topotecan (FF-10850).

PURPOSE: Quantifying unencapsulated drug concentrations in tissues is crucial for understanding the mechanisms underlying the efficacy and safety of liposomal drugs; however, the methodology for this has not been fully established. Herein, we aimed to investigate the enhanced therapeutic potential of a pegylated liposomal formulation of topotecan (FF-10850) by analyzing the concentrations of the unencapsulated drug in target tissues, to guide the improvement of its dosing regimen. METHODS: We developed a method for measuring unencapsulated topotecan concentrations in tumor and bone marrow interstitial fluid (BM-ISF) and applied this method to pharmacokinetic assessments. The ratios of the area under the concentration-time curves (AUCs) between tumor and BM-ISF were calculated for total and unencapsulated topotecan. DNA damage and antitumor effects of FF-10850 or non-liposomal topotecan (TPT) were evaluated in an ES-2 mice xenograft model. RESULTS: FF-10850 exhibited a much larger AUC ratio between tumor and BM-ISF for unencapsulated topotecan (2.96), but not for total topotecan (0.752), than TPT (0.833). FF-10850 promoted milder DNA damage in the bone marrow than TPT; however, FF-10850 and TPT elicited comparable DNA damage in the tumor. These findings highlight the greater tumor exposure to unencapsulated topotecan and lower bone marrow exposure to FF-10850 than TPT. The dosing regimen was successfully improved based on the kinetics of unencapsulated topotecan and DNA damage. CONCLUSIONS: Tissue pharmacokinetics of unencapsulated topotecan elucidated the favorable pharmacological properties of FF-10850. Evaluation of tissue exposure to an unencapsulated drug with appropriate pharmacodynamic markers can be valuable in optimizing liposomal drugs and dosing regimens.

Chemo-immunotherapy with dinutuximab beta in patients with relapsed/progressive high-risk neuroblastoma: does chemotherapy backbone matter?

BACKGROUND: Addition of anti-GD2 antibodies to temozolomide-based chemotherapy has demonstrated increased antitumor activity and progression-free survival in patients with relapsed/progressive high-risk neuroblastoma. However, chemo-immunotherapy is not yet approved for this indication. This study presents the chemo-immunotherapy experience in patients with relapsed/progressive high-risk neuroblastoma treated within the off-label use program of the Neuroblastoma Committee of the French Society of Pediatric Oncology (SFCE). METHODS: Dinutuximab beta (dB) was administered alongside temozolomide-topotecan (TOTEM) or temozolomide-irinotecan (TEMIRI) at first disease relapse/progression or topotecan-cyclophosphamide (TopoCyclo) at further relapse/progression. Real-world data on demographics, treatment, antitumor activity and safety was collected from all patients after inclusion in SACHA-France (NCT04477681), a prospective national registry, which documents safety and efficacy data on innovative anticancer therapies prescribed to patients ≤ 25 years old as compassionate or off-label use. RESULTS: Between February 2021 and July 2023, 39 patients with confirmed relapsed/progressive high-risk neuroblastoma (median age 6 years, range 1-24) were treated with dB+TopoCyclo (n = 24) or dB+TOTEM/TEMIRI (n = 15) across 17 centers. In total, 163 chemo-immunotherapy cycles were administered, main toxicities were mild or moderate, with higher incidence of hematological adverse drug reactions with dB+TopoCyclo than dB+TOTEM/TEMIRI. Objective response rate was 42% for dB+TopoCyclo (CI95% 22-63%) and 40% for dB+TOTEM/TEMIRI (CI95% 16-68%). CONCLUSION: Similar objective response rates for dB+TopoCyclo and dB+TOTEM/TEMIRI in patients with relapsed/progressive high-risk neuroblastoma emphasize the importance of chemo-immunotherapy, irrespective of the chemotherapy backbone.

Effect of the combined binding of topotecan and catechin/protocatechuic acid to a pH-sensitive DNA tetrahedron on release and cytotoxicity: Spectroscopic and calorimetric studies.

The therapeutic efficacy of chemotherapy drugs can be effectively improved through the dual effects of their combination with natural polyphenols and the delivery of targeted DNA nanostructures. In this work, the interactions of topotecan (TPT), (+)-catechin (CAT), or protocatechuic acid (PCA) with a pH-sensitive DNA tetrahedron (MUC1-TD) in the binary and ternary systems at pHs 5.0 and 7.4 were investigated by fluorescence spectroscopy and calorimetry. The intercalative binding mode of TPT/CAT/PC to MUC1-TD was confirmed, and their affinity was ranked in the order of PCA > CAT > TPT. The effects of the pH-sensitivity of MUC1-TD and different molecular structures of CAT and PCA on the loading, release, and cytotoxicity of TPT were discussed. The weakened interaction under acidic conditions and the co-loading of CAT/PCA, especially PCA, improved the release of TPT loaded by MUC1-TD. The targeting of MUC1-TD and the synergistic effect with CAT/PCA, especially CAT, enhanced the cytotoxicity of TPT on A549 cells. For L02 cells, the protective effect of CAT/PCA reduced the damage caused by TPT. The single or combined TPT loaded by MUC1-TD was mainly concentrated in the nucleus of A549 cells. This work will provide key information for the combined application of TPT and CAT/PCA loaded by DNA nanostructures to improve chemotherapy efficacy and reduce side effects.

BRD4-targeting PROTACs Synergize With Chemotherapeutics Against Osteosarcoma Cell Lines.

BACKGROUND/AIM: Osteosarcoma at an advanced stage has a poor outcome, and novel targeted therapies are needed, especially for metastatic disease. Bromodomain inhibitors (BETi) are epigenetic modulators that broadly impair the expression of oncogenic proteins and exert antitumor effects. BETi can be combined with chemotherapeutics to increase therapeutic responses with superior effects in the form of proteolysis targeting chimeras (PROTACs) that degrade proteins of interest (POI) in multiple cycles. This work aimed to investigate the efficacy of BETi, such as JQ1, dBET57, and MZ1 PROTACs in combination with cytotoxic drugs against osteosarcoma cell lines. MATERIALS AND METHODS: Chemosensitivity of the osteosarcoma cell lines HOS, Saos-2, MG-63, and G292 were tested with BET-directed agents alone or in combination with cytotoxic drugs comprising cisplatin, doxorubicin, topotecan, and gemcitabine using cell viability assays. RESULTS: The BET degraders exhibited highest toxicity to HOS cells and showed synergistic activity in combination with the chemotherapeutics, except for the degrader - topotecan/gemcitabine combinations. Highest synergy between BET agents and chemotherapeutics were found for the more chemoresistant Saos-2 cells and potentiation of toxicity in MG-63 cells for the BET agents - doxorubicin combinations and the MZ1-topotecan pair. HOS and Saos-2 cell lines had reduced protein expression of AXL, BCL-X, e-cadherin, CAIX, EpCAM, ErbB2, and vimentin in response to JQ1, MZ1, and BET57. CONCLUSION: The study suggests that the application of novel BET PROTACs in combination with chemotherapeutics could represent a new therapeutic option to improve the therapy of osteosarcomas. First orally available PROTACs have reached clinical trials.

Enhancement of the Antitumor and Antimetastatic Effect of Topotecan and Normalization of Blood Counts in Mice with Lewis Carcinoma by Tdp1 Inhibitors-New Usnic Acid Derivatives.

Tyrosyl-DNA phosphodiesterase 1 (Tdp1) is an important DNA repair enzyme and one of the causes of tumor resistance to topoisomerase 1 inhibitors such as topotecan. Inhibitors of this Tdp1 in combination with topotecan may improve the effectiveness of therapy. In this work, we synthesized usnic acid derivatives, which are hybrids of its known derivatives: tumor sensitizers to topotecan. New compounds inhibit Tdp1 in the micromolar and submicromolar concentration range; some of them enhance the effect of topotecan on the metabolic activity of cells of various lines according to the MTT test. One of the new compounds (compound 7) not only sensitizes Krebs-2 and Lewis carcinomas of mice to the action of topotecan, but also normalizes the state of the peripheral blood of mice, which is disturbed in the presence of a tumor. Thus, the synthesized substances may be the prototype of a new class of additional therapy for cancer.

Bevacizumab, Irinotecan, or Topotecan Added to Temozolomide for Children With Relapsed and Refractory Neuroblastoma: Results of the ITCC-SIOPEN BEACON-Neuroblastoma Trial.

PURPOSE: Outcomes for children with relapsed and refractory high-risk neuroblastoma (RR-HRNB) remain dismal. The BEACON Neuroblastoma trial (EudraCT 2012-000072-42) evaluated three backbone chemotherapy regimens and the addition of the antiangiogenic agent bevacizumab (B). MATERIALS AND METHODS: Patients age 1-21 years with RR-HRNB with adequate organ function and performance status were randomly assigned in a 3 × 2 factorial design to temozolomide (T), irinotecan-temozolomide (IT), or topotecan-temozolomide (TTo) with or without B. The primary end point was best overall response (complete or partial) rate (ORR) during the first six courses, by RECIST or International Neuroblastoma Response Criteria for patients with measurable or evaluable disease, respectively. Safety, progression-free survival (PFS), and overall survival (OS) time were secondary end points. RESULTS: One hundred sixty patients with RR-HRNB were included. For B random assignment (n = 160), the ORR was 26% (95% CI, 17 to 37) with B and 18% (95% CI, 10 to 28) without B (risk ratio [RR], 1.52 [95% CI, 0.83 to 2.77]; P = .17). Adjusted hazard ratio for PFS and OS were 0.89 (95% CI, 0.63 to 1.27) and 1.01 (95% CI, 0.70 to 1.45), respectively. For irinotecan ([I]; n = 121) and topotecan (n = 60) random assignments, RRs for ORR were 0.94 and 1.22, respectively. A potential interaction between I and B was identified. For patients in the bevacizumab-irinotecan-temozolomide (BIT) arm, the ORR was 23% (95% CI, 10 to 42), and the 1-year PFS estimate was 0.67 (95% CI, 0.47 to 0.80). CONCLUSION: The addition of B met protocol-defined success criteria for ORR and appeared to improve PFS. Within this phase II trial, BIT showed signals of antitumor activity with acceptable tolerability. Future trials will confirm these results in the chemoimmunotherapy era.

Synergistic effect of a nonsteroidal anti-inflammatory drug in combination with topotecan on small cell lung cancer cells.

BACKGROUND: The topoisomerase I inhibitor topotecan (TPT) is used in the treatment of recurrent small cell lung cancer (SCLC). However, the drug has a limited success rate and causes distress to patients due to its side effects, such as hematologic toxicities, including anemia and thrombocytopenia. Due to these pharmacokinetic limitations and undesirable side effects of chemotherapeutic drugs, the development of combination therapies has gained popularity in SCLC. Meclofenamic acid (MA), a nonsteroidal anti-inflammatory drug, has demonstrated anticancer effects on various types of cancers through different mechanisms. This study aims to investigate the potential synergistic effects of MA and TPT on the small cell lung cancer cell line DMS114. METHODS AND RESULTS: To assess the cytotoxic and apoptotic effects of the combined treatment of MA and TPT, trypan blue exclusion assay, Annexin V, acridine orange/propidium iodide staining, western blot, and cell cycle analysis were conducted. The results demonstrated that the combination of MA and TPT elicited synergistic effects by enhancing toxicity in DMS114 cells (P < 0.01) without causing toxicity in healthy epithelial lung cells MRC5. The strongest synergistic effect was observed when the cells were treated with 60 µM MA and 10 nM TPT for 48 h (CI = 0,751; DRI = 10,871). CONCLUSION: This study, for the first time, furnishes compelling evidence that MA and TPT synergistically reduce cellular proliferation and induce apoptosis in SCLC cells. Combinations of these drugs holds promise as a potential therapeutic strategy to improve efficacy and reduce the side effects associated with TPT.

Phase 1 study of high-dose DFMO, celecoxib, cyclophosphamide and topotecan for patients with relapsed neuroblastoma: a New Approaches to Neuroblastoma Therapy trial.

BACKGROUND: MYC genes regulate ornithine decarboxylase (Odc) to increase intratumoral polyamines. We conducted a Phase I trial [NCT02030964] to determine the maximum tolerated dose (MTD) of DFMO, an Odc inhibitor, with celecoxib, cyclophosphamide and topotecan. METHODS: Patients 2-30 years of age with relapsed/refractory high-risk neuroblastoma received oral DFMO at doses up to 9000 mg/m2/day, with celecoxib (500 mg/m2 daily), cyclophosphamide (250 mg/m2/day) and topotecan (0.75 mg/m2/day) IV for 5 days, for up to one year with G-CSF support. RESULTS: Twenty-four patients (median age, 6.8 years) received 136 courses. Slow platelet recovery with 21-day courses (dose-levels 1 and 2) led to subsequent dose-levels using 28-day courses (dose-levels 2a-4a). There were three course-1 dose-limiting toxicities (DLTs; hematologic; anorexia; transaminases), and 23 serious adverse events (78% fever-related). Five patients (21%) completed 1-year of therapy. Nine stopped for PD, 2 for DLT, 8 by choice. Best overall response included two PR and four MR. Median time-to-progression was 19.8 months, and 3 patients remained progression-free at >4 years without receiving additional therapy. The MTD of DFMO with this regimen was 6750 mg/m2/day. CONCLUSION: High-dose DFMO is tolerable when added to chemotherapy in heavily pre-treated patients. A randomized Phase 2 trial of DFMO added to chemoimmunotherapy is ongoing [NCT03794349].

Lurbinectedin in patients with small cell lung cancer with chemotherapy-free interval ≥30 days and without central nervous metastases.

OBJECTIVES: This report focuses on lurbinectedin activity and safety in a subgroup of small cell lung cancer (SCLC) patients from a Basket phase 2 study (Trigo et al. Lancet Oncology 2020;21:645-654) with chemotherapy-free interval (CTFI) ≥ 30 days. This pre-planned analysis was requested for obtaining regulatory approval of lurbinectedin in Switzerland. MATERIALS AND METHODS: Patients with extensive-stage SCLC, no central nervous system (CNS) metastases, and disease progression after platinum-containing therapy were included. Topotecan data from a contemporary, randomized, controlled phase 3 study (ATLANTIS) were used as indirect external control in a matched patient population (n = 98 patients). RESULTS: Lurbinectedin showed a statistically significant higher overall response rate (ORR) by investigator assessment (IA) compared to topotecan subgroup (41.0 % vs. 25.5 %; p = 0.0382); higher ORR by Independent Review Committee (IRC) (33.7 % vs. 25.5 %); longer median duration of response (IA: 5.3 vs. 3.9 months; IRC: 5.1 vs. 4.3 months), and longer median overall survival (10.2 vs. 7.6 months). Grade ≥ 3 hematological abnormalities were remarkably lower with lurbinectedin: anemia 12.0 % vs. 54.1 %; leukopenia 30.1 % vs. 68.4 %; neutropenia 47.0 % vs. 75.5 %, and thrombocytopenia 6.0 % vs. 52.0 %. Febrile neutropenia was observed at a higher incidence with topotecan (6.1 % vs. 2.4 % with lurbinectedin) despite that the use of growth-colony stimulating factors was mandatory with topotecan. CONCLUSION: With the limitations of an indirect comparison, however using recent and comparable SCLC datasets, this post hoc analysis shows that SCLC patients with CTFI ≥ 30 days and no CNS metastases have a positive benefit/risk ratio with lurbinectedin, superior to that observed with topotecan.