Selective NonpeptideSomatostatin Receptor Subtype 5 (sst5 ... · •Suppresses insulin but not...
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-60 -30 0 30 60 90 120 0 100 200 300 Time (min) Blood glucose (mg/dL) -1 0 1 2 3 0 50 100 150 200 250 Time (hours) Blood glucose (mg/dL) -1 0 1 2 3 0 50 100 150 200 250 Time (hours) Blood glucose (mg/dL) 0 100 200 300 400 500 Blood glucose (mg/dL) Selective Nonpeptide Somatostatin Receptor Subtype 5 (sst5) Agonists Suppress Glucose- and Sulfonylurea-induced Insulin Secretion in Rats Emmanuel Sturchler, Melissa A. Fowler, Jon Athanacio, Taylor A. Kredel, Michael Johns, Jian Zhao, Shimiao Wang, Rosa Luo, Ana Karin Kusnetzow, Yun Fei Zhu, Ajay Madan, R. Scott Struthers, Stephen F. Betz, Stacy Markison Crinetics Pharmaceuticals, San Diego, CA. Congenital hyperinsulinism (CHI) results from mutations within the insulin secretion pathway and is characterized by excessive and/or inappropriate insulin secretion by pancreatic islet b -cells. CHI is the most common cause of persistent hypoglycemia in newborns and infants and is estimated to affect 1/30,000 to 1/50,000 live births. Prompt recognition and treatment are vital to prevent coma, long-term neurological complications, and even death. If medical control of CHI is unsuccessful, near-total pancreatectomy may be required. The neuropeptide somatostatin is an important modulator of pancreatic hormonal signaling and activity at different somatostatin receptor (sst) subtypes dictates the suppression of insulin and/or glucagon. Glucagon secretion from a-cells is inhibited through sst2 receptors and insulin secretion from b-cells is inhibited through activation of sst2, sst3, and sst5. The injectable peptide drugs octreotide and lanreotide are potent agonists at sst2 and are often deployed as the last medical intervention to prevent or delay pancreatectomy. These peptides’ sst activity leads to inhibition of glucagon secretion, potentially reducing their effectiveness and compromising a key defense mechanism against hypoglycemia. We hypothesize that agonists targeting sst5 but lacking sst2 activity will possess an optimal efficacy/safety profile for patients with hyperinsulinemic hypoglycemia. Using iterative medicinal chemistry, Crinetics has discovered several classes of highly potent, orally bioavailable, small molecule sst-subtype selective agonists with drug-like pharmaceutical properties. Our discovery efforts aimed at finding a compound to treat CHI have yielded potent and selective nonpeptide sst5 agonists with sub-nanomolar EC 50 s in cell-based assays of receptor activation. These compounds also typically possess similar potency for the rat sst5 receptor. To probe their physiological consequences and to gain mechanistic insights, we compared the acute and chronic effects of these agonists to the peptide pasireotide, a pan-sst agonist that is most potent at sst5, on glycemic control in several rat models, which generally demonstrate a high degree of translation to humans. These preclinical studies evaluated the effects of the sst5 agonists during OGTT, IPGTT, sulfonylurea-induced hypoglycemia, and on blood glucose levels in both the fed and fasted states. In each model, selective nonpeptide sst5 agonists suppressed insulin secretion and raised blood glucose levels while having minimal effects on glucagon secretion, as predicted by their in vitro pharmacology. These results support our efforts to develop potent nonpeptide selective sst5 agonists with pharmaceutical and safety profiles suitable for evaluation in human clinical trials. This work was supported in part by an SBIR grant from the NIH awarded to Dr. Betz (R44DK088501) Conclusions CRN02481 represents a proof of concept molecule in our oral nonpeptide sst5 agonist program: • Potent and selective sst5 agonist • Exhibits good pharmacokinetics in the rat • Increases and extends glucose excursion across different metabolic states • Suppresses insulin but not glucagon secretion • Rescues sulfonylurea-induced hypoglycemia in juvenile rats Small molecule agonists selectively targeting sst5 represent a promising strategy to treat CHI CRN02481 is a selective & orally bioavailable sst5 agonist Hypothesis: targeting sst5 to treat CHI Figure 1. Depiction of blood glucose regulation by pancreatic α- and β-cells. EC 50 (nM) hsst1 hsst2 rsst2 hsst3 hsst5 rsst5 CRN02481 >10000 440 nd 39 0.39 0.36 Octreotide > 10000 0.057 0.081 7.9 2.5 2.5 Pasireotide 5.7 0.59 2.5 0.78 0.076 0.019 CRN02481 raises glucose in both the fed and fasted states in rats Figure 4. Effect of subcutaneous injection of vehicle (grey), CRN02481 (5mg/kg, green), or pasireotide (30 μg/kg, red) on blood glucose over time, insulin, and glucagon levels (at 1h) in fed and fasted male Sprague Dawley rats (n=7-8/group). CRN02481 increases glucose levels and prevents sulfonylurea-induced hypoglycemia in PND10 rats CRN02481 does not inhibit gluconeogenesis during an IP-pyruvate tolerance test Figure 3. Effect of subcutaneous injection of vehicle (grey), CRN02481 (5 mg/kg, green) , or pasireotide (30 μg/kg, red) on blood glucose levels in fasted male Sprague Dawley rats (n=8/group) following IP pyruvate challenge. CRN02481 raises glucose and inhibits insulin release during both IPGTT and OGTT 0 100 200 300 400 500 Glucose (mg/dL) 0 1 2 3 4 Insulin (ng/mL) -60 -30 0 30 60 90 120 0 5 10 15 20 25 Glucagon (pg/mL) 0 100 200 300 400 500 Glucose (mg/dL) 0 1 2 3 4 5 Insulin (ng/mL) -60 -30 0 30 60 90 120 0 10 20 30 Glucagon (pg/mL) IP glucose PO glucose CRN02481 dosed CRN02481 dosed Figure 2. Effect of subcutaneous injection (SC) of vehicle (grey) or 5 mg/kg CRN02481 (green) on plasma glucose, insulin, and glucagon levels in fasted male Sprague Dawley rats (n=8/group) following a glucose challenge. CRN02481 pharmacokinetic characteristics after 10 mg/kg PO dosing in male Sprague Dawley rats C max (ng/mL) AUC 0àt (ng.hr/mL) t max (hr) t 1/2 (hr) Bioavailability, F (%) 78 799 0.5 8.5 32 0 1 2 3 Insulin (ng/mL) 0 5 10 15 20 Glucagon (pg/mL) 0 1 2 3 0 50 100 150 200 Time (h) Blood glucose (mg/dL) 0.0 0.1 0.2 0.3 0.4 0.5 Insulin (ng/mL) 0 10 20 30 Glucagon (pg/mL) Fed Fasted No glyburide With 5 mg/kg glyburide CRN02481 dosed CRN02481 dosed -1 1 3 0.0 0.5 1.0 1.5 Time (h) Insulin (ng/mL) -1 1 3 0 2 4 6 8 Time (h) Insulin (ng/mL) Figure 5. Effect of CRN02481 and the sulfonylurea glyburide on glucose and insulin in juvenile rats. Male Sprague Dawley rats (age PND10) were administrated vehicle or 15 mg/kg (SC) CRN02481. Parallel experiments were done with and without glyburide (5 mg/kg, IP) which mimics the hypoglycemia observed in many CHI patients. (n=8/group). Compound dosed 1.5 g/kg pyruvate, IP Compound dosed Compound dosed Glyburide dosed CRN02481 pasireotide vehicle CRN02481 vehicle
Transcript of Selective NonpeptideSomatostatin Receptor Subtype 5 (sst5 ... · •Suppresses insulin but not...
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Selective Nonpeptide Somatostatin Receptor Subtype 5 (sst5) Agonists Suppress Glucose- and
Sulfonylurea-induced Insulin Secretion in Rats
Emmanuel Sturchler, Melissa A. Fowler, Jon Athanacio, Taylor A. Kredel, Michael Johns, Jian Zhao, Shimiao Wang, Rosa Luo, Ana Karin Kusnetzow, Yun Fei Zhu, Ajay Madan, R. Scott Struthers, Stephen F. Betz, Stacy MarkisonCrinetics Pharmaceuticals, San Diego, CA. Congenital hyperinsulinism (CHI) results from mutations within the insulin secretionpathway and is characterized by excessive and/or inappropriate insulin secretion bypancreatic islet b -cells. CHI is the most common cause of persistent hypoglycemia innewborns and infants and is estimated to affect 1/30,000 to 1/50,000 live births. Promptrecognition and treatment are vital to prevent coma, long-term neurological complications,and even death. If medical control of CHI is unsuccessful, near-total pancreatectomy maybe required. The neuropeptide somatostatin is an important modulator of pancreatichormonal signaling and activity at different somatostatin receptor (sst) subtypes dictatesthe suppression of insulin and/or glucagon. Glucagon secretion from a-cells is inhibitedthrough sst2 receptors and insulin secretion from b-cells is inhibited through activation ofsst2, sst3, and sst5. The injectable peptide drugs octreotide and lanreotide are potentagonists at sst2 and are often deployed as the last medical intervention to prevent or delaypancreatectomy. These peptides’ sst activity leads to inhibition of glucagon secretion,potentially reducing their effectiveness and compromising a key defense mechanismagainst hypoglycemia. We hypothesize that agonists targeting sst5 but lacking sst2 activitywill possess an optimal efficacy/safety profile for patients with hyperinsulinemichypoglycemia.Using iterative medicinal chemistry, Crinetics has discovered several classes of highlypotent, orally bioavailable, small molecule sst-subtype selective agonists with drug-likepharmaceutical properties. Our discovery efforts aimed at finding a compound to treat CHIhave yielded potent and selective nonpeptide sst5 agonists with sub-nanomolar EC50s incell-based assays of receptor activation. These compounds also typically possess similarpotency for the rat sst5 receptor. To probe their physiological consequences and to gainmechanistic insights, we compared the acute and chronic effects of these agonists to thepeptide pasireotide, a pan-sst agonist that is most potent at sst5, on glycemic control inseveral rat models, which generally demonstrate a high degree of translation to humans.These preclinical studies evaluated the effects of the sst5 agonists during OGTT, IPGTT,sulfonylurea-induced hypoglycemia, and on blood glucose levels in both the fed and fastedstates. In each model, selective nonpeptide sst5 agonists suppressed insulin secretion andraised blood glucose levels while having minimal effects on glucagon secretion, aspredicted by their in vitro pharmacology. These results support our efforts to develop potentnonpeptide selective sst5 agonists with pharmaceutical and safety profiles suitable forevaluation in human clinical trials.This work was supported in part by an SBIR grant from the NIH awarded to Dr. Betz(R44DK088501)
Conclusions
CRN02481 represents a proof of concept molecule in
our oral nonpeptide sst5 agonist program:
• Potent and selective sst5 agonist
• Exhibits good pharmacokinetics in the rat
• Increases and extends glucose excursion across different
metabolic states
• Suppresses insulin but not glucagon secretion
• Rescues sulfonylurea-induced hypoglycemia in juvenile rats
Small molecule agonists selectively targeting sst5
represent a promising strategy to treat CHI
CRN02481 is a selective & orally bioavailable sst5
agonist
Hypothesis: targeting sst5 to treat CHI
Figure 1. Depiction of blood glucose regulation by pancreatic α- and β-cells.
EC50
(nM)hsst1 hsst2 rsst2 hsst3 hsst5 rsst5
CRN02481 >10000 440 nd 39 0.39 0.36Octreotide > 10000 0.057 0.081 7.9 2.5 2.5
Pasireotide 5.7 0.59 2.5 0.78 0.076 0.019
CRN02481 raises glucose in both the fed and fasted
states in rats
Figure 4. Effect of subcutaneous injection of vehicle (grey), CRN02481 (5mg/kg, green), orpasireotide (30 μg/kg, red) on blood glucose over time, insulin, and glucagon levels (at 1h) infed and fasted male Sprague Dawley rats (n=7-8/group).
CRN02481 increases glucose levels and prevents
sulfonylurea-induced hypoglycemia in PND10 rats
CRN02481 does not inhibit gluconeogenesis during an
IP-pyruvate tolerance test
Figure 3. Effect of subcutaneous injection of vehicle (grey), CRN02481 (5 mg/kg, green) , orpasireotide (30 μg/kg, red) on blood glucose levels in fasted male Sprague Dawley rats(n=8/group) following IP pyruvate challenge.
CRN02481 raises glucose and inhibits insulin release
during both IPGTT and OGTT
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Figure 2. Effect of subcutaneous injection (SC) of vehicle (grey) or 5 mg/kg CRN02481(green) on plasma glucose, insulin, and glucagon levels in fasted male Sprague Dawleyrats (n=8/group) following a glucose challenge.
CRN02481 pharmacokinetic characteristics after 10 mg/kg PO dosing
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Cmax (ng/mL) AUC0àt (ng.hr/mL) tmax (hr) t1/2 (hr) Bioavailability, F (%)78 799 0.5 8.5 32
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Figure 5. Effect of CRN02481 and the sulfonylurea glyburide on glucose and insulin injuvenile rats. Male Sprague Dawley rats (age PND10) were administrated vehicle or 15mg/kg (SC) CRN02481. Parallel experiments were done with and without glyburide (5mg/kg, IP) which mimics the hypoglycemia observed in many CHI patients. (n=8/group).
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