An ALK2 inhibitor, BLU-782, prevents heterotopic ossification in a mouse model of fibrodysplasia ossificans progressiva.

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disease driven by gain-of-function variants in activin receptor-like kinase 2 (ALK2), the most common variant being ALK2R206H. In FOP, ALK2 variants display increased and dysregulated signaling through the bone morphogenetic protein (BMP) pathway resulting in progressive and permanent replacement of skeletal muscle and connective tissues with heterotopic bone, ultimately leading to severe debilitation and premature death. Here, we describe the discovery of BLU-782 (IPN60130), a small-molecule ALK2R206H inhibitor developed for the treatment of FOP. A small-molecule library was screened in a biochemical ALK2 binding assay to identify potent ALK2 binding compounds. Iterative rounds of structure-guided drug design were used to optimize compounds for ALK2R206H binding, ALK2 selectivity, and other desirable pharmacokinetic properties. BLU-782 preferentially bound to ALK2R206H with high affinity, inhibiting signaling from ALK2R206H and other rare FOP variants in cells in vitro without affecting signaling of closely related homologs ALK1, ALK3, and ALK6. In vivo efficacy of BLU-782 was demonstrated using a conditional knock-in ALK2R206H mouse model, where prophylactic oral dosing reduced edema and prevented cartilage and heterotopic ossification (HO) in both muscle and bone injury models. BLU-782 treatment preserved the normal muscle-healing response in ALK2R206H mice. Delayed dosing revealed a short 2-day window after injury when BLU-782 treatment prevented HO in ALK2R206H mice, but dosing delays of 4 days or longer abrogated HO prevention. Together, these data suggest that BLU-782 may be a candidate for prevention of HO in FOP.

Assessing Completeness of Cancer Treatment Data from an Academic Medical Center's Tumor Registry Through Comparison to the Central Registry.

Background: Researchers often rely on hospital tumor registry data to provide comprehensive cancer therapy information. The purpose of this study was to determine the completeness of treatment information found in the abstracted records of patients seen at an academic medical center located in a rural Midwestern state. Approach: The cohort included 846 Iowa residents diagnosed with a single malignant tumor of the female breast, colon/rectum, lung, pancreas, or prostate in 2017-2018 with an abstract recorded by the academic medical center and at least 1 other hospital. Treatment/no treatment agreement between the academic medical center's abstract and the central registry's consolidated abstract was examined for the following summary variables of the North American Association of Central Cancer Registries (NAACCR): surgery of the primary site, chemotherapy, radiation therapy, immunotherapy, and hormone therapy. Treatment summary variables from the academic medical center abstract that agreed with the corresponding variables from the central registry abstract were classified as concordant. The proportion of concordance for each treatment modality was the outcome measure, and 95% confidence intervals were calculated with the Agresti-Coull method. Concordance was also examined at the specific treatment level. Results: There was high concordance between the treatment information recorded in the academic medical center and the central registry records. The average proportion of treatment/no treatment agreement across all treatment modalities and cancer sites was 0.97 (SD, 0.02). Concordance remained high even when examining specific treatments (average concordance, 0.95; SD, 0.04). The lowest treatment/no treatment concordance proportion was 0.92 (95% CI, 0.86-0.96) for chemotherapeutic treatment of pancreatic cancer. We also found that the academic medical center's summary variables captured most treatments given at other facilities, ranging from 74.4% capture of immunotherapy to 88.2% capture of surgery of the primary site. Conclusions: These results indicate that NAACCR-formatted, summary variables from the academic medical center's tumor registry are likely to provide comprehensive treatment information for those individuals diagnosed or treated in this setting. Analyses of either the academic medical record registry records or consolidated records from the central registry should yield similar results. Future research should establish whether similar findings are obtained at other medical centers.

Discovery of BLU-945, a Reversible, Potent, and Wild-Type-Sparing Next-Generation EGFR Mutant Inhibitor for Treatment-Resistant Non-Small-Cell Lung Cancer.

While epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have changed the treatment landscape for EGFR mutant (L858R and ex19del)-driven non-small-cell lung cancer (NSCLC), most patients will eventually develop resistance to TKIs. In the case of first- and second-generation TKIs, up to 60% of patients will develop an EGFR T790M mutation, while third-generation irreversible TKIs, like osimertinib, lead to C797S as the primary on-target resistance mutation. The development of reversible inhibitors of these resistance mutants is often hampered by poor selectivity against wild-type EGFR, resulting in potentially dose-limiting toxicities and a sub-optimal profile for use in combinations. BLU-945 (compound 30) is a potent, reversible, wild-type-sparing inhibitor of EGFR+/T790M and EGFR+/T790M/C797S resistance mutants that maintains activity against the sensitizing mutations, especially L858R. Pre-clinical efficacy and safety studies supported progression of BLU-945 into clinical studies, and it is currently in phase 1/2 clinical trials for treatment-resistant EGFR-driven NSCLC.

Cancer in the HIV/AIDS Population in Iowa, 1991-2015.

PURPOSE: As survival rates for individuals with HIV/AIDS diagnoses increase, cancer is becoming a more prevalent disease in this population. Data regarding the concurrent diagnoses of HIV/AIDS and cancer has not previously been examined and analyzed in the state of Iowa. METHODS: The Iowa Cancer Registry and Iowa Department of Public Health's HIV/AIDS surveillance databases were linked, and matches were identified. Characteristics of Iowans with HIV/AIDS later diagnosed with cancer between 1991 and 2015 were compared to Iowans without HIV/AIDS using proportional incidence ratios (PIRs). RESULTS: 490 patients met inclusion criteria; 91% had AIDS and 9% had HIV only. Compared to individuals without HIV/AIDS, significantly higher PIRs for cancer were found in younger persons, males, African Americans, metropolitan (metro) residents, and Iowans with Medicaid or the uninsured. Specifically, PIRs associated with the following cancers were higher in the population with HIV/AIDS: Kaposi sarcoma, non-Hodgkin lymphomas (NHLs), and squamous cell neoplasms of the anus. When stratified by AIDS-defining cancers and non-AIDS-defining cancers, the main differences were individuals with AIDS-defining cancers had elevated PIRs among those diagnosed between 1991-1998 and had Kaposi sarcoma or Burkitt lymphoma, while those with non-AIDS-defining cancers were diagnosed between 2007-2015 and were diagnosed with anal, male or female genital, lymphoma other than NHL, liver, lung, or other squamous cell neoplasm cancers. When comparing nonmetropolitan (nonmetro) vs metro Iowans with HIV/AIDS, PIRs for nonmetro patients were elevated in those diagnosed with cancer between 50-59 years old, whites, and individuals diagnosed with squamous cell neoplasms. CONCLUSION: Our results indicate Iowans with HIV/AIDS have higher proportions of certain types of cancers compared to the general population and provide baseline information for future initiatives aimed at preventing or detecting cancer among those living with HIV/AIDS.

Discovery of MK-8318, a Potent and Selective CRTh2 Receptor Antagonist for the Treatment of Asthma.

A novel series of tricyclic tetrahydroquinolines were identified as potent and selective CRTh2 receptor antagonists. The agonism and antagonism switch was achieved through structure-based drug design (SBDD) using a CRTh2 receptor homologue model. The challenge of very low exposures in pharmacokinetic studies was overcome by exhaustive medicinal chemistry lead optimization through focused SAR studies on the tricyclic core. Further optimization resulted in the identification of the preclinical candidate 4-(cyclopropyl((3aS,9R,9aR)-7-fluoro-4-(4-(trifluoromethoxy)benzoyl)-2,3,3a,4,9,9a-hexahydro-1H-cyclopenta[b]quinolin-9-yl)amino)-4-oxobutanoic acid (15c, MK-8318) with potent and selective CRTh2 antagonist activity and a favorable PK profile suitable for once daily oral dosing for potential treatment of asthma.

Precision Targeted Therapy with BLU-667 for RET-Driven Cancers.

The receptor tyrosine kinase rearranged during transfection (RET) is an oncogenic driver activated in multiple cancers, including non-small cell lung cancer (NSCLC), medullary thyroid cancer (MTC), and papillary thyroid cancer. No approved therapies have been designed to target RET; treatment has been limited to multikinase inhibitors (MKI), which can have significant off-target toxicities and limited efficacy. BLU-667 is a highly potent and selective RET inhibitor designed to overcome these limitations. In vitro, BLU-667 demonstrated ≥10-fold increased potency over approved MKIs against oncogenic RET variants and resistance mutants. In vivo, BLU-667 potently inhibited growth of NSCLC and thyroid cancer xenografts driven by various RET mutations and fusions without inhibiting VEGFR2. In first-in-human testing, BLU-667 significantly inhibited RET signaling and induced durable clinical responses in patients with RET-altered NSCLC and MTC without notable off-target toxicity, providing clinical validation for selective RET targeting.Significance: Patients with RET-driven cancers derive limited benefit from available MKIs. BLU-667 is a potent and selective RET inhibitor that induces tumor regression in cancer models with RET mutations and fusions. BLU-667 attenuated RET signaling and produced durable clinical responses in patients with RET-altered tumors, clinically validating selective RET targeting. Cancer Discov; 8(7); 836-49. ©2018 AACR.See related commentary by Iams and Lovly, p. 797This article is highlighted in the In This Issue feature, p. 781.

The Discovery of 3-((4-Chloro-3-methoxyphenyl)amino)-1-((3R,4S)-4-cyanotetrahydro-2H-pyran-3-yl)-1H-pyrazole-4-carboxamide, a Highly Ligand Efficient and Efficacious Janus Kinase 1 Selective Inhibitor with Favorable Pharmacokinetic Properties.

The discovery of a potent selective low dose Janus kinase 1 (JAK1) inhibitor suitable for clinical evaluation is described. As part of an overall goal to minimize dose, we pursued a medicinal chemistry strategy focused on optimization of key parameters that influence dose size, including lowering human Clint and increasing intrinsic potency, bioavailability, and solubility. To impact these multiple parameters simultaneously, we used lipophilic ligand efficiency as a key metric to track changes in the physicochemical properties of our analogs, which led to improvements in overall compound quality. In parallel, structural information guided advancements in JAK1 selectivity by informing on new vector space, which enabled the discovery of a unique key amino acid difference between JAK1 (Glu966) and JAK2 (Asp939). This difference was exploited to consistently produce analogs with the best balance of JAK1 selectivity, efficacy, and projected human dose, ultimately culminating in the discovery of compound 28.

Identification of quinazoline based inhibitors of IRAK4 for the treatment of inflammation.

Interleukin-1 receptor associated kinase 4 (IRAK4) has been implicated in IL-1R and TLR based signaling. Therefore selective inhibition of the kinase activity of this protein represents an attractive target for the treatment of inflammatory diseases. Medicinal chemistry optimization of high throughput screening (HTS) hits with the help of structure based drug design led to the identification of orally-bioavailable quinazoline based IRAK4 inhibitors with excellent pharmacokinetic profile and kinase selectivity. These highly selective IRAK4 compounds show activity in vivo via oral dosing in a TLR7 driven model of inflammation.

Identification of N-(1H-pyrazol-4-yl)carboxamide inhibitors of interleukin-1 receptor associated kinase 4: Bicyclic core modifications.

IRAK4 plays a critical role in the IL-1R and TLR signalling, and selective inhibition of the kinase activity of the protein represents an attractive target for the treatment of inflammatory diseases. A series of permeable N-(1H-pyrazol-4-yl)carboxamides was developed by introducing lipophilic bicyclic cores in place of the polar pyrazolopyrimidine core of 5-amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamides. Replacement of the pyrazolo[1,5-a]pyrimidine core with the pyrrolo[2,1-f][1,2,4]triazine, the pyrrolo[1,2-b]pyridazine, and thieno[2,3-b]pyrazine cores guided by cLogD led to the identification of highly permeable IRAK4 inhibitors with excellent potency and kinase selectivity.

Discovery of 5-Amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamide Inhibitors of IRAK4.

Interleukin-1 receptor associated kinase 4 (IRAK4) is an essential signal transducer downstream of the IL-1R and TLR superfamily, and selective inhibition of the kinase activity of the protein represents an attractive target for the treatment of inflammatory diseases. A series of 5-amino-N-(1H-pyrazol-4-yl)pyrazolo[1,5-a]pyrimidine-3-carboxamides was developed via sequential modifications to the 5-position of the pyrazolopyrimidine ring and the 3-position of the pyrazole ring. Replacement of substituents responsible for poor permeability and improvement of physical properties guided by cLogD led to the identification of IRAK4 inhibitors with excellent potency, kinase selectivity, and pharmacokinetic properties suitable for oral dosing.

Reactions of oxetan-3-tert-butylsulfinimine for the preparation of substituted 3-aminooxetanes.

The oxetane ring is useful in drug discovery as a bioisostere for both the geminal dimethyl group and the carbonyl group. A convenient, straightforward approach to access structurally diverse 3-aminooxetanes through the reactivity of oxetan-3-tert-butylsulfinimine and the corresponding sulfinylaziridine is described.

A robust platform for the synthesis of new tetracycline antibiotics.

Tetracyclines and tetracycline analogues are prepared by a convergent, single-step Michael-Claisen condensation of AB precursor 1 or 2 with D-ring precursors of wide structural variability, followed by removal of protective groups (typically in two steps). A number of procedural variants of the key C-ring-forming reaction are illustrated in multiple examples. These include stepwise deprotonation of a D-ring precursor followed by addition of 1 or 2, in situ deprotonation of a D-ring precursor in mixture with 1 or 2, and in situ lithium-halogen exchange of a benzylic bromide D-ring precursor in the presence of 1 or 2, followed by warming. The AB plus D strategy for tetracycline synthesis by C-ring construction is shown to be robust across a range of different carbocyclic and heterocyclic D-ring precursors, proceeding reliably and with a high degree of stereochemical control. Evidence suggests that Michael addition of the benzylic anion derived from a given D-ring precursor to enones 1 or 2 is quite rapid at -78 degrees C, while Claisen cyclization of the enolate produced is rate-determining, typically occurring upon warming to 0 degrees C. The AB plus D coupling strategy is also shown to be useful for the construction of tetracycline precursors that are diversifiable by latter-stage transformations, subsequent to cyclization to form the C ring. Results of antibacterial assays and preliminary data obtained from a murine septicemia model show that many of the novel tetracyclines synthesized have potent antibiotic activities, both in bacterial cell culture and in vivo. The platform for tetracycline synthesis described gives access to a broad range of molecules that would be inaccessible by semisynthetic methods (presently the only means of tetracycline production) and provides a powerful engine for the discovery and, perhaps, development of new tetracycline antibiotics.

Preparation of the isomeric azaindoline family by intramolecular carbolithiation.

An operationally convenient, one-pot, three-step sequence has been developed that provides access to 3-substituted 4-, 5-, 6-, and 7-azaindolines (2,3-dihydro-1H-pyrollopyridines) via intramolecular carbolithiation of the aryllithium derived from an appropriate (N,N-diallylamino)bromopyridine. Whereas cyclization proceeds as expected to give 1-allyl-3-methyl-4-azaindoline and 1-allyl-3-methyl-6-azaindoline following protonation of the 3-CH2Li group of the azaindoline, the isomeric 3-methyl-5-azaindoline and 3-methyl-7-azaindoline are generated as 3-methyl-N-allyl anions prior to quench with MeOH.

A practical, enantioselective synthetic route to a key precursor to the tetracycline antibiotics.

A practical, enantioselective synthetic route to a key precursor to the tetracycline antibiotics is reported. The route proceeds in nine steps (21% yield) from the commercial substance methyl 3-hydroxy-5-isoxazolecarboxylate. Key steps in the route involve enantioselective addition of divinylzinc to 3-benzyloxy-5-isoxazolecarboxaldehyde and an endo-selective intramolecular furan Diels-Alder cycloaddition reaction. The route described has provided more than 40 g of chromatographically pure 1 with 93% ee.

A convergent enantioselective route to structurally diverse 6-deoxytetracycline antibiotics.

Complex antibiotics based on natural products are almost invariably prepared by semisynthesis, or chemical transformation of the isolated natural products. This approach greatly limits the range of accessible structures that might be studied as new antibiotic candidates. Here we report a short and enantioselective synthetic route to a diverse range of 6-deoxytetracycline antibiotics. The common feature of this class is a scaffold of four linearly fused rings, labeled A through D. We targeted not a single compound but a group of structures with the D ring as a site of structural variability. A late-stage, diastereoselective C-ring construction was used to couple structurally varied D-ring precursors with an AB precursor containing much of the essential functionality for binding to the bacterial ribosome. Five derivatives were synthesized from benzoic acid in yields ranging from 5 to 7% over 14 to 15 steps, and a sixth, (-)-doxycycline, was synthesized in 8.3% yield over 18 steps.

A general route to the synthesis of 1,5-methano- and 1,5-ethano- 2,3,4,5-tetrahydro-1H-3-benzazepines.

A general approach to preparing 1,5-methano- (1) and 1,5-ethano-2,3,4,5-tetrahydro-1H-3-benzazepine (2) is discussed. This strategy involves converting an indanone or tetralone (4) to a cyanohydrin (3) which is subjected to hydrogenolysis followed by lactamization and reduction to provide bicyclic aryl piperidine (1) and bicyclic aryl homopiperidine (2).