Abstract P1-10-08: Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer

Mutations in estrogen receptor alpha (ERα) are detected in up to 30% of breast cancer patients who have relapsed during endocrine therapy. ERα mutations functionally confer resistance to existing classes of endocrine therapies, likely through gaining constitutive activity. The fact that current ER-directed therapies are only partially effective in the ERα mutant setting, and that a significant proportion of resistant breast cancer metastases continue to remain dependent on ERα signaling for growth/survival, highlights the critical need to develop the next generation of ERα antagonists that can overcome aberrant ERα activity. Using structure-based drug design approaches we have identified a novel class of ERα antagonist referred to as Selective ERα Covalent Antagonist (SERCA) that inactivate both wild-type and mutant ERα by targeting a unique cysteine residue that is not conserved among other steroid hormone receptors. Biophysical, biochemical and cellular analyses confirm the covalent mechanism of action, specific binding to ER and selective inhibition of ERα-dependent transcription of SERCAs. H3B-6545 is a highly selective SERCA that potently antagonizes wild-type and mutant ERα in biochemical and cell based assays demonstrating increased potency over standard of care and other experimental agents. In vivo, H3B-6545 shows superior efficacy to fulvestrant in the MCF-7 xenograft model with once daily oral dosing, achieving maximal antitumor activity at doses >10x below the maximum tolerated dose in mice. In addition, H3B-6545 shows superior antitumor activity to both tamoxifen and fulvestrant in patient derived xenograft models of breast cancer carrying estrogen receptor mutations. In summary, H3B-6545 is a first-in-class, orally available and selective ER covalent antagonist with a compelling pre-clinical profile that is being developed for the treatment of ERα positive breast cancer.

Citation Format: Korpal M, Puyang X, Furman C, Zheng GZ, Banka D, Wu J, Zhang Z, Thomas M, Mackenzie C, Yao H, Rimkunas V, Kumar P, Caleb B, Karr C, Subramanian V, Irwin S, Larsen N, Vaillancourt F, Nguyen T-V, Davis A, Chan B, Hao MH, O'Shea M, Prajapati S, Agoulnik S, Kuznetsov G, Kumar N, Yu Y, Lai G, Hart A, Eckley S, Fekkes P, Bowser T, Joshi JJ, Selvaraj A, Wardell S, Norris J, Smith S, Reynolds D, Mitchell L, Wang J, Yu L, Kim A, Rioux N, Sahmoud T, Warmuth M, Smith PG, Zhu P. Development of a first-in-class oral selective ERα covalent antagonist (SERCA) for the treatment of ERαWT and ERαMUT breast cancer [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-10-08.

Meta-analysis comparing denosumab and zoledronic acid for treatment of bone metastases in patients with advanced solid tumours

The purpose of this meta-analysis was to evaluate the efficacy of denosumab, compared with zoledronic acid (ZA), in delaying skeletal-related events (SREs) and enhancing overall survival in patients with advanced solid tumours and bone metastases. A systematic literature search of several electronic databases, including PubMed, Medline, Embase, the Cochrane Library, CKNI and Web of Science with Conference Proceedings, was performed. Only randomised controlled trials assessing denosumab in comparison with ZA, in patients with advanced solid tumours and metastatic-stage disease, were included. The primary outcome was the time to first SRE. The risk of developing subsequent on-study SREs and overall survival were also evaluated. Three randomised controlled trials with a total of 5,544 patients with advanced solid tumours and bone metastases were included in the meta-analysis. There were 2,776 patients treated with denosumab and 2,768 treated with ZA. The pooled analysis showed that denosumab was superior to ZA in delaying time to first on-study SRE (odds ratio [OR]: 0.82; 95% CI: 0.75-0.89, p < 0.0001) and multiple SREs (risk ratio: 0.81; 95% CI: 0.74-0.88, p < 0.0001). However, no significant difference was found in overall survival improvement between denosumab and ZA (OR: 1.02; 95% CI: 0.91-1.15, p = 0.71). This meta-analysis indicates that denosumab is superior to ZA in delaying SREs for patients with bone metastases. No significant difference was observed between denosumab and ZA, regarding overall survival. We support denosumab as a potential novel treatment option for the management of bone metastases in advanced solid tumours.

Blockade of mGluR1 receptor results in analgesia and disruption of motor and cognitive performances: effects of A-841720, a novel non-competitive mGluR1 receptor antagonist

BACKGROUND AND PURPOSE

To further assess the clinical potential of the blockade of metabotropic glutamate receptors (mGluR1) for the treatment of pain.

EXPERIMENTAL APPROACH

We characterized the effects of A-841720, a novel, potent and non-competitive mGluR1 antagonist in models of pain and of motor and cognitive function.

KEY RESULTS

At recombinant human and native rat mGluR1 receptors, A-841720 inhibited agonist-induced calcium mobilization, with IC50 values of 10.7+/-3.9 and 1.0 +/- 0.2 nM, respectively, while showing selectivity over other mGluR receptors, in addition to other neurotransmitter receptors, ion channels, and transporters. Intraperitoneal injection of A-841720 potently reduced complete Freund's adjuvant-induced inflammatory pain (ED50 = 23 micromol kg(-1)) and monoiodoacetate-induced joint pain (ED50 = 43 micromol kg(-1)). A-841720 also decreased mechanical allodynia observed in both the sciatic nerve chronic constriction injury and L5-L6 spinal nerve ligation (SNL) models of neuropathic pain (ED50 = 28 and 27 micromol kg(-1), respectively). Electrophysiological studies demonstrated that systemic administration of A-841720 in SNL animals significantly reduced evoked firing in spinal wide dynamic range neurons. Significant motor side effects were observed at analgesic doses and A-841720 also impaired cognitive function in the Y-maze and the Water Maze tests.

CONCLUSIONS AND IMPLICATIONS

The analgesic effects of a selective mGluR1 receptor antagonist are associated with motor and cognitive side effects. The lack of separation between efficacy and side effects in pre-clinical models indicates that mGluR1 antagonism may not provide an adequate therapeutic window for the development of such antagonists as novel analgesic agents in humans.

Pyridopyrimidine analogues as novel adenosine kinase inhibitors

A novel series of pyridopyrimidine analogues 9 was identified as potent adenosine kinase inhibitors based on the SAR and computational studies. Substitution of the C7 position of the pyridopyrimidino core with C2' substituted pyridino moiety increased the in vivo potency and enhanced oral bioavailability of these adenosine kinase inhibitors.

[Evaluation of synovectomy in hemophilic arthropathy follow-up of 26 cases]

Thirty-five joint synovectomies performed between 1973 and 1986 in 26 patients with hemophilic arthropathy at the Department of orthopaedics, University of Colorado Health Sciences Center (UCHSC), USA, were reviewed. There were 15 knees, 15 elbows, 3 ankles and 2 shoulders. Arthroscopic synovectomy was performed on 8 knees. The remaining 27 synovectomies were performed by open surgical synovectomy. Twenty-one (60%) of the 35 joints have had no recurrent hemarthrosis reported, in 14 (40%) there were occasional episodes of bleeding. Among 9 (60%) of the 15 knees and 9 (60%) of the 15 elbows, no further hemarthrosis was observed; 6 (40%) of the knees and 6 (40%) of the elbows reported occasional bleeding episodes. After synovectomy the range of motion improved in 6 (17.2%), 11 (31.4%) remained unchanged and 18 (51.4%) demonstrated decrease. Five joints lost 5 to 10 degrees, 4 joints lost 10 to 20 degrees and 9 joints lost more than 20 degrees. In the group of arthroscopic knee synovectomy the average of motion loss was 20 degrees while in the open surgical knee synovectomy the average motion loss was 38 degrees. After synovectomy the possibility of recurrent hemarthrosis would be 50% and three years later it would be decreased to 31.6%. This review demonstrated that synovectomy was an effective treatment and the decreased degree of the motion after arthroscopy was less than that of open surgery.

Microscopic and submicroscopic studies on the peripheral nerve and the skeletal muscle of the female. cadaver found in the Han Tomb No.1

The present paper deals with the microscopic and submicroscopic structures of the peripheral nerve of the lumbar plexus and the skeletal muscle of the m. psoas major of the ancient female cadaver buried about 2100 years ago, which was excavated from the Han Tomb No. 1 at Mawangdui (Mawangtui) near Changsha, Hunan Province. The connective tissues in the peripheral nerve and the skeletal muscle of the ancient cadaver were found well preserved. Under the electron microscope were observed the characteristic periodic bands of the collagenous fibrils as well as some axons and degenerated myelin sheath in the lumbar plexus. And in some of the better preserved nerve fibers, their axons and myelin sheaths are readily discernible. In the m. psoas major, cross striations are clearly visible in some muscle fibers. The remains of a blood vessel with only their connective tissues left were observed in the nerve of the lumbar plexus. Bacterial spores appeared in the two tissues.