Marcella Nesi

Discovery of Entrectinib: A New 3-Aminoindazole as a Potent Anaplastic Lymphoma Kinase (Alk), C-Ros Oncogene 1 Kinase (Ros1), and Pan-Tropomyosin Receptor Kinases (Pan-Trks) Inhibitor.

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase responsible for the development of different tumor types. Despite the remarkable clinical activity of crizotinib (Xalkori), the first ALK inhibitor approved in 2011, the emergence of resistance mutations and of brain metastases frequently causes relapse in patients. Within our ALK drug discovery program, we identified compound 1, a novel 3-aminoindazole active on ALK in biochemical and in cellular assays. Its optimization led to compound 2 (entrectinib), a potent orally available ALK inhibitor active on ALK-dependent cell lines, efficiently penetrant the blood-brain barrier (BBB) in different animal species and highly efficacious in in vivo xenograft models. Moreover, entrectinib resulted to be strictly potent on the closely related tyrosine kinases ROS1 and TRKs recently found constitutively activated in several tumor types. Entrectinib is currently undergoing phase I/II clinical trial for the treatment of patients affected by ALK-, ROS1-, and TRK-positive tumors.

Optimization of 6,6-Dimethyl Pyrrolo[3,4-C]Pyrazoles: Identification of Pha-793887, a Potent Cdk Inhibitor Suitable for Intravenous Dosing.

We have recently reported CDK inhibitors based on the 6-substituted pyrrolo[3,4-c]pyrazole core structure. Improvement of inhibitory potency against multiple CDKs, antiproliferative activity against cancer cell lines and optimization of the physico-chemical properties led to the identification of highly potent compounds. Compound 31 (PHA-793887) showed good efficacy in the human ovarian A2780, colon HCT-116 and pancreatic BX-PC3 carcinoma xenograft models and was well tolerated upon daily treatments by iv administration. It was identified as a drug candidate for clinical evaluation in patients with solid tumors.

6-Substituted Pyrrolo[3,4-c]pyrazoles: An Improved Class of CDK2 Inhibitors

We have recently reported a new class of CDK2/cyclin A inhibitors based on a bicyclic tetrahydropyrrolo[3,4‐c]pyrazole scaffold. The introduction of small alkyl or cycloalkyl groups in position 6 of this scaffold allowed variation at the other two diversity points. Conventional and polymer‐assisted solution phase chemistry provided a way of generating compounds with improved biochemical and cellular activity. Optimization of the physical properties and pharmacokinetic profile led to a compound which exhibited good efficacy in vivo on A2780 human ovarian carcinoma.

Pyrrole-3-Carboxamides as Potent and Selective Jak2 Inhibitors.

We report herein the discovery, structure guided design, synthesis and biological evaluation of a novel class of JAK2 inhibitors. Optimization of the series led to the identification of the potent and orally bioavailable JAK2 inhibitor 28 (NMS-P953). Compound 28 displayed significant tumour growth inhibition in SET-2 xenograft tumour model, with a mechanism of action confirmed in vivo by typical modulation of known biomarkers, and with a favourable pharmacokinetic and safety profile.

Syntheses of brostallicin starting from distamycin A

Two syntheses of brostallicin, a DNA minor groove binder now undergoing phase II studies, starting from distamycin A are described. One approach is based upon the selective hydrolysis via imide activation of the C-terminus amide. Besides employing traditional solution-phase synthesis, the convenient use of a polymer-supported reagent is also discussed. The other one is based upon the Curtius rearrangement of the C-terminus side chain of a convenient intermediate, easily prepared in two steps by straightforward functional group manipulation of distamycin A.

Novel Pyrrole Carboxamide Inhibitors of Jak2 as Potential Treatment of Myeloproliferative Disorders.

Compound 1, a hit from the screening of our chemical collection displaying activity against JAK2, was deconstructed for SAR analysis into three regions, which were explored. A series of compounds was synthesized leading to the identification of the potent and orally bioavailable JAK2 inhibitor 16 (NMS-P830), which showed an encouraging tumour growth inhibition in SET-2 xenograft tumour model, with evidence for JAK2 pathway suppression demonstrated by in vivo pharmacodynamic effects.

Generation of doubly trifluoromethylsubstituted carbocations: Synthesis of α,α-bis(trifluoromethyl)benzylamines

Abstract α,α-Bis(trifluoromethylbenzyl)triflates offer a convenient access to the corresponding amines through SN1 type reactions.

Abstract A179: NMS-P113, a novel orally available JAK2 selective inhibitor

The Janus Kinases (JAK1, JAK2, JAK3, TYK2) are non-receptor tyrosine kinases that play important roles in hematopoiesis and immune response. In particular, gene ablation of JAK1 or JAK2 in the mouse is incompatible with life, due to neurological defects/immunodeficency and lack of erythropoiesis, respectively, whereas that of JAK3 or TYK2 is associated with severe immunodeficiency. Activating mutations of JAKs are found in association with malignant transformation. The best characterized gain-of-function mutation, JAK2-V617F in the pseudo-kinase domain of JAK2, is present in hematopoietic cells of patients with myeloproliferative disorders (MPD). In particular, the JAK2-V617F mutation is found in >95% of patients with polycythemia vera (PV), circa 50% of patients with essential thrombocythemia (ET), and circa 50% of myelofibrosis (MF) patients. Recently, a central role of JAK2 has been described in upregulation of the immune checkpoint component PD-L1 mediated by IFN-γ or by chromosome 9p24.1 amplification, suggesting that its inhibition might provide a new strategy to increase immune-mediated tumor inhibition in specific contexts. Although JAK inhibitors have been approved in oncological and autoimmune settings (e.g. the JAK1/JAK2 inhibitor ruxolitinib in MF and the pan-JAK inhibitor tofacitinib in rheumatoid arthritis) and multiple agents are in clinical testing, JAK2 selective compounds might be provide an advantage for long-term MPD therapy or in association with immunotherapy, given that inhibition of other JAK family members leads to immunosuppressive effects. Due to high homology amongst JAK family kinases within the ATP binding pocket, discovery of selective JAK2 inhibitors has represented a significant challenge. Here, we report the characterization of NMS-P113, a potent and selective JAK2 inhibitor. Screening of the NMS compound collection led to the identification of a pyrrole series with promising activity against JAK2. An optimization program led to identification of the potent and orally bioavailable JAK2 inhibitor NMS-P113. In biochemical assay this compound possesses low nanomolar potency against JAK2 (IC50 3 nM), with preferential activity over other JAK family members and high selectivity against a panel of 60 further kinases. In cellular assay, NMS-P113 potently inhibits proliferation of the JAK2 dependent SET-2 human megakaryoblastic leukemia line, derived from an ET patient and which harbors the JAK2-V617F mutation, as well as of Ba/F3 cells engineered to express constitutively activated JAK2 (IC50s circa 200 nM). NMS-P113 is 10-fold less active against the DERL-7 T-cell lymphoma cell line (which is dependent upon JAK1/JAK3) and has poor antiproliferative activity in JAK independent lines. Oral administration of NMS-P113 results in dose-related normalization of spleen weight and erythrocyte precursors count in an erythropoietin-induced model of PV in the mouse. Mechanism of action of NMS-P113, as assessed by inhibition of P-STAT5, was confirmed in vitro and in vivo. A favorable ADME profile with high oral bioavailability, together with permissive therapeutic safety margins in test species, indicate that NMS-P113 is suitable for further development, affording the possibility of reduced undesirable immunosuppressive activities compared to inhibitors that target multiple members of the JAK family. Citation Format: Paola Gnocchi, Maria Gabriella Brasca, Nadia Amboldi, Nilla Avanzi, Simona Bindi, Giulia Canevari, Daniele Casero, Roberta Ceruti, Marina Ciomei, Sabrina Cribioli, Cinzia Cristiani, Marcella Nesi, Wilma Pastori, Veronica Patton, Cinzia Pellizzoni, Gemma Texido, Elena Ardini, Eduard R. Felder, Antonella Isacchi, Daniele Donati, Arturo Galvani. NMS-P113, a novel orally available JAK2 selective inhibitor. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr A179.

Abstract B230: NMS-P948, a potent dual FLT3/KIT inhibitor, also active on secondary resistance mutations.

FMS-like tyrosine kinase 3 (FLT3) and KIT are both members of the class III receptor tyrosine kinase family characterized by an autoinhibitory juxtamembrane (JM) domain that docks with the kinase domain to stabilize a catalytically inactive conformation. Therefore, mutations or deletion in this or in adjacent regions cause constitutive activation of these kinases as observed in 30% of AML patients for FLT3 and in 70% of adult GIST and a subset of melanoma patients for KIT. NMS-P948 is an alkoxy-indazole derivative potent dual inhibitor of FLT3 and KIT (IC 50 26 and 89 nM, respectively), active also against FLT3 and KIT mutations that confer secondary resistance, such as the gatekeeper mutation T670I of KIT. It is a very selective compound, resulting, when tested on a panel of more than 150 human tumor cell lines, strongly active only on cell lines whose proliferation is driven by one of these two kinases (for FLT3: Eol-1, IC 50 = 8 nM; MV-4–11, IC 50 = 8 nM; MOLM-13, IC 50 = 18 nM and for KIT: GIST-430 IC 50 = 7 nM and GIST-882 IC 50 = 99 nM). Mechanism of action is demonstrated on both kinases, with activating and resistance mutations, at low nanomolar concentrations. NMS-P948 has good oral bioavailability in rodents. Antitumor efficacy is observed at as low as 10 mg/kg in xenograft models and no toxicity in terms of body weight loss was observed up to 60 mg/kg. In disseminated human AML MOLM-13 model (FLT3-ITD) NMS-P948 produces a very prolonged survival of treated mice (T/C= 390 at 60 mg/kg OS daily × 10) and this antitumor efficacy results superior to that of quizartinib administered with the same schedule at the MTD (T/C= 207 at 40 mg/kg). In conclusion, NMS-P948 is a promising dual inhibitor of mutated FLT3 and KIT with good in vitro and in vivo pharmacological and pharmacokinetic characteristics and with the potential to act also on patients that developed resistance to first line therapies. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr B230.