Abstract 4033: Pan-exon mutant KIT inhibitor DCC-3009 demonstrates tumor regressions in preclinical gastrointestinal stromal tumor models

Introduction: Gastrointestinal stromal tumors (GISTs) are typically driven by primary mutations in KIT exons 9 or 11. Heterogeneous drug-resistant secondary mutations arise in patients treated with FDA approved KIT inhibitors, including imatinib and sunitinib. Drug resistant secondary mutations are found at multiple regions in the ATP pocket (encoded by exons 13 and 14) or activation switch (encoded by exons 17 and 18) of KIT kinase. In addition, multiple drug-resistant clones can arise within a tumor or in metastatic tumor sites. An inhibitor that can broadly and potently inhibit the spectrum of KIT mutations is highly sought. Ripretinib has been FDA approved as a 4th line treatment for GIST and has broad activity against KIT mutations, including clinical potency in patients with mutations in KIT exons 11, 17, or 18. DCC-3009 was designed as a next generation KIT inhibitor that broadly and potently inhibits primary KIT mutations in exons 9 and 11 and secondary drug-resistant mutations across exons 13, 14, 17, and 18. DCC-3009 is a potent and selective inhibitor in enzyme and cell-based assays, and has demonstrated efficacy in xenograft models driven by drug resistant KIT mutations.

Methods: DCC-3009 was tested for inhibition of KIT mutants using standard enzyme and cell-based assays. Levels of phosphorylated KIT were determined by Western blot or ELISA. Proliferation was measured using the fluorescent dye resazurin. KIT mutant xenograft or patient-derived xenograft models were performed at Crown Biosciences or Labcorp, AAALAC accredited facilities, with the approval of Animal Care and Use Committees.

Results: In BaF3 cells transfected with KIT mutants, DCC-3009 was shown to potently inhibit the spectrum of known primary and secondary drug-resistant mutations in GIST. The pan-mutant KIT profile of DCC-3009 was shown in vitro to be superior to 2nd and 3rd line standard of care therapies sunitinib and regorafenib. DCC-3009 was selective for KIT when screened against a large panel of kinases. DCC-3009 has optimized pharmaceutical properties for oral administration. In pharmacokinetic/pharmacodynamic studies DCC-3009 achieved sufficient free drug levels to significantly inhibit drug-resistant KIT mutants for 12 hr post dose. In xenograft studies, treatment with DCC-3009 twice daily led to tumor regression in drug-resistant models with KIT exon 9/13, 11/13 or 11/17 mutations.

Conclusions: DCC-3009 is a pan-exon mutant KIT inhibitor exhibiting high potency in KIT mutants in pre-clinical models spanning exons 9, 11, 13, 14, 17 and 18. In vivo, DCC-3009 exhibited efficacy in drug-resistant models with KIT exon 9/13, 11/13 or 11/17 mutations. Based on this profile, DCC-3009 has entered formal preclinical development.

Citation Format: Bryan D. Smith, Subha Vogeti, Timothy M. Caldwell, Hanumaiah Telikepalli, Yu Mi Ahn, Gada Al-Ani, Stacie L. Bulfer, Andrew Greenwood, Cale L. Heiniger, Joshua W. Large, Cynthia B. Leary, Wei-Ping Lu, Kylie Luther, William C. Patt, Max D. Petty, Yeni K. Romero, Forrest A. Stanley, Kristen L. Stoltz, Daniel C. Tanner, Sihyung Yang, Yu Zhan, Bertrand Le Bourdonnec, Daniel L. Flynn. Pan-exon mutant KIT inhibitor DCC-3009 demonstrates tumor regressions in preclinical gastrointestinal stromal tumor models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4033.

Abstract 4045: DCC-3084, a RAF dimer inhibitor, broadly inhibits BRAF class I, II, III, BRAF fusions, and RAS-driven solid tumors leading to tumor regression in preclinical models

Background: Mutations in the RAS/MAPK pathway are a frequent driver of cancer, with oncogenic RAS or RAF mutations occurring in >30% of all cancers. First generation BRAF inhibitors are approved for use for tumors with Class I BRAF mutations (V600X). However, these drugs are not efficacious in RAF dimer mutant and RAS mutant cancers due to paradoxical activation of RAF dimers. Herein, we describe DCC-3084, a potent and selective investigational Switch Control inhibitor of BRAF and CRAF kinase dimers that targets Class I, II and III BRAF mutations, BRAF fusions, and BRAF/CRAF heterodimers. DCC-3084 combines with inhibitors of additional nodes in the MAPK pathway to potentially target a large unmet medical need in RAS and RAF mutant cancers.

Methods: Inhibition of RAF kinases, including off-rate analysis, was measured using recombinant enzymes. X-ray crystallography was used for structure-based drug design. Cellular proliferation was measured using resazurin to monitor cell viability. Synergy in cells was measured using BLISS scores and curve shift analysis. Inhibition of ERK or RSK phosphorylation was measured by AlphaLISA or ELISA. Pharmacokinetics (PK) in the plasma, brain and CSF compartments were measured following oral dosing in Wistar rats. RAF and RAS mutant mouse xenograft models were used to assess PK, pharmacodynamics (PD), and efficacy.

Results: DCC-3084 is a potent and selective Switch Control inhibitor of RAF dimers that was designed to target Class I, II, III BRAF mutants, BRAF fusions, and BRAF/CRAF heterodimers. DCC-3084 inhibits BRAF and CRAF, exhibiting slow off-rates (t1/2 >20 hr). Potent single-agent inhibition of MAPK pathway signaling and cellular proliferation was observed in a wide range of Class I, II, III BRAF and BRAF fusion altered cell lines. Synergy was observed in combination with inhibitors of other nodes in the RAS/MAPK pathway in RAS mutant cell lines. DCC-3084 was demonstrated to be CNS penetrable and exhibited dose dependent oral exposure with robust inhibition of the RAS/MAPK pathway in PK/PD models. DCC-3084 accumulated in tumor tissue relative to plasma, further demonstrating a favorable pharmaceutical profile. Oral treatment of DCC-3084 as a single agent resulted in tumor regression in BRAF mutant and KRAS Q61K mutant mouse xenograft models and tumor growth inhibition in KRAS G12C/D mutant models. Additionally, DCC-3084 in combination with a MEKi resulted in tumor regression in KRAS mutant models.

Conclusions: The Switch Control inhibitor DCC-3084 broadly inhibits Class I, II and III BRAF mutations, BRAF fusions, and BRAF/CRAF heterodimers leading to tumor regression in preclinical models. The overall preclinical profile of DCC-3084 supports IND-enabling activities towards clinical development in a key area of unmet medical need in RAS and RAF mutant cancers.

Citation Format: Stacie L. Bulfer, Bertrand Le Bourdonnec, Jeffery D. Zwicker, Yu Mi Ahn, Gada Al-Ani, Hikmat Al-Hashimi, Chase Crawley, Kristin M. Elliott, Saqib Faisal, Andrew M. Harned, Cale L. Heiniger, Molly M. Hood, Salim Javed, Michael Kennedy, Joshua W. Large, Cynthia B. Leary, Wei-Ping Lu, Kylie Luther, Max D. Petty, Hunter R. Picard, Justin T. Proto, Yeni K. Romero, Forrest A. Stanley, Kristen L. Stoltz, Daniel C. Tanner, Hanumaiah Telikepalli, Mary J. Timson, Lakshminarayana Vogeti, Subha Vogeti, Sihyung Yang, Lexy H. Zhong, Bryan D. Smith, Daniel L. Flynn. DCC-3084, a RAF dimer inhibitor, broadly inhibits BRAF class I, II, III, BRAF fusions, and RAS-driven solid tumors leading to tumor regression in preclinical models. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4045.

Biodiversity information platforms: From standards to interoperability

One of the most serious bottlenecks in the scientific workflows of biodiversity sciences is the need to integrate data from different sources, software applications, and services for analysis, visualisation and publication. For more than a quarter of a century the TDWG Biodiversity Information Standards organisation has a central role in defining and promoting data standards and protocols supporting interoperability between disparate and locally distributed systems.Although often not sufficiently recognized, TDWG standards are the foundation of many popular Biodiversity Informatics applications and infrastructures ranging from small desktop software solutions to large scale international data networks. However, individual scientists and groups of collaborating scientist have difficulties in fully exploiting the potential of standards that are often notoriously complex, lack non-technical documentations, and use different representations and underlying technologies. In the last few years, a series of initiatives such as Scratchpads, the EDIT Platform for Cybertaxonomy, and biowikifarm have started to implement and set up virtual work platforms for biodiversity sciences which shield their users from the complexity of the underlying standards. Apart from being practical work-horses for numerous working processes related to biodiversity sciences, they can be seen as information brokers mediating information between multiple data standards and protocols.The ViBRANT project will further strengthen the flexibility and power of virtual biodiversity working platforms by building software interfaces between them, thus facilitating essential information flows needed for comprehensive data exchange, data indexing, web-publication, and versioning. This work will make an important contribution to the shaping of an international, interoperable, and user-oriented biodiversity information infrastructure.

Experimental and Modelling Study of the Unimolecular Thermal Decompostion of CHF3

The unimolecular thermal decomposition reaction CHF3 (+M)→CF2 + HF (+M) was studied in shock waves by monitoring the UV absorption of the forming CF2 radicals. The results of the present and previous experiments on the temperature and pressure dependence of the rate constants are analyzed in terms of unimolecular rate theory. Falloff curves (for 1500–1900 K) are represented in terms of fitted limiting low pressure rate constants k 0 = [Ar] 1.1 × 1016exp(−53.0 kcal mol−1/RT) cm3mol−1s−1, limiting high pressure rate constants k ∞ = 1.25 × 1015 exp(−75.8 kcal mol−1/RT) s−1 from quantum-chemical calculations, and center broadening factors F cent = 0.170(± 0.04) including strong and weak collision contributions from unimolecular rate theory. With these results, approximate analytical expressions of the falloff curves well represent the measured and calculated rate constants over wide ranges of pressure and temperature.

Systematic root cause analysis of adverse drug events in a tertiary referral hospital

BACKGROUND

Adverse drug events (ADEs) occur frequently, and serious ADEs are associated with mortality or prolonged morbidity. As many ADEs are preventable, identification and modification of systems and processes that permit ADEs has the potential to reduce the rate of ADEs.

METHODS

Root cause analysis was systematically employed in a blame-free fashion to investigate the patterns of serious ADEs that occurred during a 29-month period at Hermann Hospital (Houston), and process improvements were implemented on the basis of these findings. The consistently nonpunitive responses to the results of the initial and subsequent root cause analyses was gradually seen, accepted, and ultimately embraced by the hospital staff.

RESULTS

The most commonly identified root causes were environmental factors (for example, increased census, increased acuity, change of shift) and staffing issues (for example, personnel new to a unit). Policy changes that led to increased use of forcing or constraining functions (for example, removal of concentrated intravenous potassium solutions from floor stocks) and better personnel support (for example, early awareness and response to localized increases in census and acuity) were particularly effective. Although limited by our lack of active surveillance and not necessarily directly due to the process changes that we implemented, the rate of voluntarily reported serious ADEs/100,000 patient days decreased during this time from 7.2 to 4.0, a decline of 45% (p < 0.001).

CONCLUSION

Systematic application of root cause analysis followed by implementation of process changes that target the underlying cause(s) of each event can be successfully implemented in a large hospital.

Temperature Dependence of Collisional Deactivation of Highly Vibrationally Excited Biphenylene

Collisional energy transfer between highly vibrationally excited biphenylene and a variety of mono- and polyatomic bath gases has been measured at temperatures between 333 and 523 K. Biphenylene molecules were initially prepared with an additional vibrational energy of 28490 cm

Temperature Dependence of Collisional Energy Transfer in Highly Excited Aromatics Studied by Classical Trajectory Calculations

The temperature dependence of the gas-phase collisional relaxation of highly vibrationally excited aromatic molecules has been studied using large scale classical trajectory calculations. The investigations have focused on azulene collisions with different colliders (He, Ar and N

Promoting positive outcomes from patient complaints

Complaints from patients often indicate their difficulty in coping with the health care system. Nurses need to acknowledge these complaints and help the patient resolve the problem. They need to see complaints as part of a continuous dialogue with their patients and their families. In addition, nurses need to use these complaints to assess the needs of the patient and to evaluate the care and delivery of services. This article presents nine steps the nurse can take when a patient or family member has a complaint.

Cortical and striatal neurone number in Huntington's disease

The total cortical and striatal neurone and glial numbers were estimated in five cases of Huntington's disease (three males, two females) and five age- and sex-matched control cases. Serial 500-microns-thick gallocyanin-stained frontal sections through the left hemisphere were analysed using Cavalieri's principle for volume and the optical disector for cell density estimations. The average cortical neurone number of five controls (mean age 53 +/- 13 years, range 36-72 years) was 5.97 x 10(9) +/- 320 x 10(6), the average number of small striatal neurones was 82 x 10(6) +/- 15.8 x 10(6). The left striatum (caudatum, putamen, and accumbens) contained a mean of 273 x 10(6) +/- 53 x 10(6) glial cells (oligodendrocytes, astrocytes and unclassifiable glial profiles). The mean cortical neurone number in Huntington's disease patients (mean age 49 +/- 14 years, range 36-75 years) was diminished by about 33% to 3.99 x 10(9) +/- 218 x 10(6) nerve cells (P < or = 0.012, Mann-Whitney U-test). The mean number of small striatal neurones decreased tremendously to 9.72 x 10(6) +/- 3.64 x 10(6) (-88%). The decrease in total glial cells was less pronounced (193 x 10(6) +/- 26 x 10(6)) but the mean glial index, the numerical ratio of glial cells per neurone, increased from 3.35 to 22.59 in Huntington's disease. Qualitatively, neuronal loss was most pronounced in supragranular layers of primary sensory areas (Brodmann's areae 3,1,2; area 17, area 41). Layer IIIc pyramidal cells were preferentially lost in association areas of the temporal, frontal, and parietal lobes, whereas spared layer IV granule cells formed a conspicuous band between layer III and V in these fields. Methodological issues are discussed in context with previous investigations and similarities and differences of laminar and lobar nerve cell loss in Huntington's disease are compared with nerve cell degeneration in other neuropsychiatric diseases.

Stimulation of renal sodium excretion in mature rats

In adult rats a saline load is followed by an increase in renal excretion of sodium and by a low rate of ion exchange (hydrogen ions and potassium for sodium), caused by inhibited aldosterone secretion. Under analogous conditions a saline load provoked sodium retention and a distinct increase in renal excretion of hydrogen ions and potassium in young rats, which can be explained by a non-regulated, very intensive ion exchange. The repeated administration of NaCl solution alone and in combination with cyclopenthiazide produced an accelerated maturation of kidney function in 10- and 33-day-old rats measurable by an increase in sodium excretion and reduced ion exchange. In adult rats as well as immediately after birth (5-day-old rats) this effect cannot be provoked by the various pretreatments acting in mature rats.