Virtual Screening and Molecular Docking: Discovering Novel c-KIT Inhibitors

: Gastrointestinal stromal tumors (GISTs) are unusual cancers which begin in specialized cells in the gastrointestinal tract wall. Various strategies involving single-agents, combinations, and rapid complementary inhibitor cycling are now being used to control such tumors. Based on promising early clinical trial experience, certain novel KIT, and PDGFRA tyrosine kinase inhibitors have begun advanced clinical development. Resistance to tyrosine kinase inhibitors has brought immense difficulties, with patients now requiring additional therapeutic options. This review describes and discusses the last five years (2016-2020) in developing novel c-KIT kinase inhibitors using virtual screening and docking approaches. Computational techniques can be used to complement experimental studies to identify new candidate molecules for therapeutic use. Molecular modeling strategies allow analysis of the required characteristics that compounds must have to effectively bind c-KIT. Through such analyses, it is possible to both discover and design novel inhibitors against cancer-related proteins that play a critical role in tumor development (including of mutant strains). Docking showed potential in the detection of the key residues responsible for ligand recognition and are very helpful to understand the interactions in the active site that can be used to develop new compounds/classes of anticancer drugs and help millions of cancer patients.

AAV9 is considered the most efficient AAV serotype targeting blood-brain barriers. To enhance effective gene therapy for CNS illnesses, testing novel vectors with more efficient crossing capabilities is vital

Although gene therapy for CNS diseases shows promise in cell and animal investigations, most human trials have failed to satisfy the requisite requirements. Finding novel techniques to boost the efficacy of gene therapy in treating CNS diseases is still crucial. A growing number of clinical trials have proved the efficacy and safety of using AAV vectors, making AAV vector research a gene therapy hotspot. However, due to the presence of the BBB, many siRNA and DNA with potential therapeutic value are difficult to transport from peripheral circulation to the brain using AAV vectors, limiting the clinical impact of gene therapy drugs in the CNS and posing a major challenge to the field of CNS gene therapy. In early studies, AAV9 was considered the most effective AAV serotype for getting through the blood-brain barrier and transduction to central nervous system cells following intravenous injection. Aavrh10 isolated from rhesus monkeys was equal to, if not superior to, AAV9. AAV-PHP.B, a newly built capsid, exhibits 40-fold greater efficacy than AAV9 in astrocyte and neuron transduction. AAV-PHP.eB, a modified AAV-PHP.B variety, was identified to retain PHP.B's AAV-capacity to transduce astrocytes while enhancing neuronal transduction. While the four serotypes AAV9, AAVrh10, AAV-PHP.B, and AAV-PHP.eB have been validated to penetrate mice's BBB following intravenous injection, the number of AAV vectors that can do so is low. Moreover, the manner in which AAV vectors penetrate the BBB remains unclear. To promote efficient gene therapy for CNS diseases, it is still important to test new vectors with more efficient crossing abilities and understand their crossing processes. In addition to technical challenges, AAV vectors in treating CNS diseases may be limited by cautious attitudes to innovative treatments. Continued advances in AAV vector research, together with early clinical trial outcomes, might help researchers achieve the full potential of AAV-based CNS disease therapies.

Safety and efficacy of a novel anti-CD20/CD19 bi-specific CAR T-cell therapy (C-CAR039) in relapsed or refractory (r/r) B-cell non-Hodgkin lymphoma (B-NHL).

2507 Background: C-CAR039 has been developed as a novel 2nd generation 4-1BB bi-specific CAR-T targeting both CD19 and CD20 antigens with an optimized bi-specific antigen binding domain. C-CAR039 can eradicate CD19/CD20 single or double positive tumor cells in vitro and in vivo. The tissue cross reactivity and whole genome membrane proteome array studies further confirmed the specificity of C-CAR039. Methods: GMP manufacturing of C-CAR039 was carried out in a serum free and fully closed semi-automatic system. Dose escalation and expansion studies were conducted to evaluate the safety and efficacy of C-CAR039 in r/r B-NHL patients. C-CAR039 was administered as a single intravenous dose after a 3-day cyclophosphamide plus fludarabine conditioning regimen. Results: As of 1/31/2021, 28 patients were infused and 25 (DLBCL, n = 22; PMBCL, n = 1; tFL, n = 1; FL, n = 1) were evaluable for safety and efficacy at dose ranges of 1.0 x 106 to 5.0x106 CAR-T cells/kg. The median age was 54 (range, 28-71) years, median number of prior lines of therapy was 3 (range, 1–5), 76% (19/25) of patients were in Ann Arbor Stage III/IV, and 80% (20/25) were refractory to their last treatment. 5 patients (20%) received bridging therapy. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded according to ASTCT 2019 criteria. Of the 25 patients, 24 (96%) experienced CRS, 23 (92%) were grade 1 or 2, 1 patient was grade 3. Median time to onset of CRS was 3 days (range, 0-10), with median duration of 4 days (range, 1-25). 2 patients had a grade 1 ICANS. Grade≥3 neutropenia, anemia, thrombocytopenia and infection were reported in 88%, 40%, 16% and 0% of patients, respectively. The best overall response rate was 92%, complete response (CR) rate was 84% and median time to response was 1.0 month (range, 0.9-1.2). With a median follow-up of 5.3 months, 76% remained in CR. Kaplan Meyer estimation of PFS at 6 months was 87.3% (95% CI, 71.2 to 100.0). Median duration of response has not been reached. Furthermore, C-CAR039 showed an encouraging cellular kinetic profile. In 25 evaluable patients, the median Tmax was 11 day, the median Cmax was 139,497 copies/mg gDNA, and the median AUC0̃28DAY of 1,673,844 day*copies/μg gDNA. Conclusions: C-CAR039 demonstrated a favorable safety profile and promising efficacy in this early clinical trial in patients with r/r B-NHL that might allow it to differentiate from existing therapies. The early clinical efficacy signal is encouraging and compares favorably to anti-CD19 CAR-T and peer therapies. These findings will be evaluated in more patients with longer follow-up to confirm safety, efficacy and duration of response. Clinical trial information: NCT04317885 , NCT04655677 , NCT04696432 , NCT04693676 .

Clinical outcomes analysis of TP53-mutated advanced and metastatic biliary tract cancers.

4106 Background: Advanced biliary tract cancers (BTC) are lethal cancers with limited treatment options and short survival. Median progression-free survival (mPFS) in the ABC-02 trial was 8.0 months with gemcitabine-cisplatin (GC) and 5.0 m with gemcitabine alone in the front-line setting. The ABC-06 trial showed mPFS of 4.0 m with second-line FOLFOX. TP53 mutation is known to be associated with poor prognosis in other cancers, but its impact on survival in advanced or metastatic BTC has not been detailed. Methods: Mutational profiles were obtained from a retrospective database collected via an institutional DNA/RNA sequencing panel, FoundationOne, or Guardant360. Out of 149 patients with TP53 mutations in BTC, 90 had advanced or metastatic BTC treated at a single institution between 2015 and 2021. These patients were not candidates for surgery, radiation, or liver-directed therapy. Results: Intrahepatic, hilar, distal, and gallbladder cancer diagnoses were confirmed in 66, 11, 10, and 3 patients. Median age was 63, with a male:female ratio of 1:1. Poorly, moderately, and well-differentiated adenocarcinomas were found in 62, 20, and 1 (not available in 7 patients). The most common TP53 mutations were R175H (n = 5) and R248Q (n = 4). Common co-mutated genes included KRAS (n = 15), ARID1A (n = 15), FGFR2 fusion (n = 14), IDH1 (n = 13), BAP1 (n = 10), CDKN2A (n = 9), and HER2 amplification (n = 8). Microsatellite unstable (MSI-H) tumors were found in 3 patients. The median tumor mutational burden was 2.5/Mb. Patients received front-line GC (n = 54), GC-nab-paclitaxel (GAP, n = 14), FOLFIRINOX (n = 3), and GC with targeted or trial therapy (n = 11, e.g. trastuzumab). mPFS with front-line therapy was 5.0 m (n = 90); it was 4.7 m with GC and 5.1 m with GAP. Patients who had co-mutated IDH1 or FGFR2 fusion had longer mPFS (9.5 and 6.9 m, respectively) than those who did not (n = 63, 3.7 m, p < 0.05) from front-line chemotherapy. mPFS after second-line FOLFOX (n = 17) and FOLFIRI (n = 10) was 2.1 and 1.9 m, respectively, and mPFS after third-line FOLFOX/FOLFIRI was 1.8 m (n = 8). The median overall survival (OS) of patients with co-mutated FGFR2, IDH1, or neither was 34.5, 22.0, and 13.1 m, respectively (p < 0.05). TP53-mutated BTC with mutations other than FGFR2/IDH1 did not show statistically significant difference in PFS or OS. Conclusions: Patients with TP53-mutated advanced BTC have shorter PFS than those without TP53 mutation in front and further-line settings. The presence of co-mutated FGFR2 or IDH1 is associated with improved PFS with chemotherapy (not FGFR/IDH1 inhibitors) and longer OS. Other co-mutations do not appear to have a survival benefit. It is crucial for clinicians to take into account the worse prognosis with TP53 mutation before starting front-line therapy in patients with advanced BTC and consider early clinical trial options.

Immunotherapy Combined With Radiation Therapy for Genitourinary Malignancies

Immunotherapy drugs have recently been approved by the Food and Drug Administration for the treatment of several genitourinary malignancies, including bladder cancer, renal cancer, and prostate cancer. Preclinical data and early clinical trial results suggest that immune checkpoint inhibitors can act synergistically with radiation therapy to enhance tumor cell killing at local irradiated sites and in some cases at distant sites through an abscopal effect. Because radiation therapy is commonly used in the treatment of genitourinary malignancies, there is great interest in testing the combination of immunotherapy with radiation therapy in these cancers to further improve treatment efficacy. In this review, we discuss the current evidence and biological rationale for combining immunotherapy with radiation therapy, as well as emerging data from ongoing and planned clinical trials testing the efficacy and tolerability of this combination in the treatment of genitourinary malignancies. We also outline outstanding questions regarding sequencing, dose fractionation, and biomarkers that remain to be addressed for the optimal delivery of this promising treatment approach.