Included as part of the PRECAUTIONS section.
ISTURISA lowers cortisol levels and can lead to hypocortisolism and sometimes life-threatening adrenal insufficiency. Lowering of cortisol can cause nausea, vomiting, fatigue, abdominal pain, loss of appetite, dizziness. Significant lowering of serum cortisol may result in hypotension, abnormal electrolyte levels, and hypoglycemia [see ADVERSE REACTIONS].
Hypocortisolism can occur at any time during ISTURISA treatment. Evaluate patients for precipitating causes of hypocortisolism (infection, physical stress, etc.). Monitor 24-hour urine free cortisol, serum or plasma cortisol, and patientâ€™s signs and symptoms periodically during ISTURISA treatment.
Decrease or temporarily discontinue ISTURISA if urine free cortisol levels fall below the target range, there is a rapid decrease in cortisol levels, and/or patients report symptoms of hypocortisolism. Stop ISTURISA and administer exogenous glucocorticoid replacement therapy if serum or plasma cortisol levels are below target range and patients have symptoms of adrenal insufficiency. Re-initiate ISTURISA at a lower dose when urine free cortisol, serum or plasma cortisol levels are within target range, and/or patient symptoms have resolved. After ISTURISA discontinuation, cortisol suppression may persist beyond the 4 hour half-life of ISTURISA.
Educate patients on the symptoms associated with hypocortisolism and advise them to contact a healthcare provider if they occur.
ISTURISA is associated with a dose-dependent QT interval prolongation (maximum mean estimated QTcF increase of up to 5.3 ms at 30 mg), which may cause cardiac arrhythmias [see ADVERSE REACTIONS, CLINICAL PHARMACOLOGY].
Perform an ECG to obtain a baseline QTc interval measurement prior to initiating therapy with ISTURISA and monitor for an effect on the QTc interval thereafter. Correct hypokalemia and/or hypomagnesemia prior to ISTURISA initiation and monitor periodically during treatment with ISTURISA. Correct electrolyte abnormalities if indicated. Consider temporary discontinuation of ISTURISA in the case of an increase in QTc interval > 480 ms.
Use caution in patients with risk factors for QT prolongation, (such as congenital long QT syndrome, congestive heart failure, bradyarrythmias, uncorrected electrolyte abnormalities, and concomitant medications known to prolong the QT interval) and consider more frequent ECG monitoring.
Elevations In Adrenal Hormone Precursors And Androgens
ISTURISA blocks cortisol synthesis and may increase circulating levels of cortisol and aldosterone precursors (11-deoxy cortisol and 11-deoxycorticosterone) and androgens.
Elevated 11-deoxycorticosterone levels may activate mineralocorticoid receptors and cause hypokalemia, edema and hypertension [see ADVERSE REACTIONS]. Hypokalemia should be corrected prior to initiating ISTURISA. Monitor patients treated with ISTURISA for hypokalemia, worsening of hypertension and edema. ISTURISA-induced hypokalemia should be treated with intravenous or oral potassium supplementation based on event severity. If hypokalemia persists despite potassium supplementation, consider adding mineralocorticoid antagonists. ISTURISA dose reduction or discontinuation may be necessary.
Accumulation of androgens may lead to hirsutism, hypertrichosis and acne (in females). Inform patients of the symptoms associated with hyperandrogenism and advise them to contact a healthcare provider if they occur.
Patient Counseling Information
Advise patients to read the FDA-approved patient labeling (PATIENT INFORMATION).
Instruct patients on the importance of laboratory monitoring and adhering to their return visit schedule [see DOSAGE AND ADMINISTRATION].
Advise patients that ISTURISA is associated with hypocortisolism-related events. Advise patients to report symptoms of hypercortisolism to their healthcare provider [see WARNINGS AND PRECAUTIONS].
Advise patients of the signs and symptoms of QT prolongation. Advise patients to contact their healthcare provider immediately for signs or symptoms of QT prolongation.
Advise patients that an ECG will be taken before treatment and periodically thereafter. Advise patients with cardiac disease and risk factors for QT prolongation that adjustments in cardiac medications may be made and electrolyte disturbances may require correction [see WARNINGS AND PRECAUTIONS].
Adrenal Hormone Precursors/Androgens
Advise patients that elevation of adrenal hormone precursors may occur and lead to low potassium levels, worsening of hypertension, and edema. Advise patients to report the occurrence of these symptoms to their healthcare provider.
Advise patients that elevations of androgens may occur and may lead to hirsutism, hypertrichosis, and acne (in females). Advise patients to report the occurrence of these symptoms to their healthcare provider [see WARNINGS AND PRECAUTIONS].
Advise females not to breastfeed during treatment with ISTURISA and for at least one week after treatment [see Use In Specific Populations].
Carcinogenesis, Mutagenesis, And Impairment Of Fertility
Carcinogenicity studies were conducted in Wistar Han rats and CD1 mice. Hepatocellular adenomas and carcinomas occurred in male rats at ≥ 10 mg/kg and in females at 30 mg/kg (18-and 65-times the 30 mg twice daily maximum clinical dose, by AUC, respectively). Thyroid follicular adenoma/carcinoma was also observed in male rats at 30 mg/kg. Hepatocellular adenomas and carcinomas occurred in male mice at > 10 mg kg (6 times the maximum clinical dose, by AUC) but not in female mice at any dose ≤ 30 mg/kg (31 times the maximum clinical dose, by AUC). These findings are likely rodent specific and considered not relevant to humans. Genetic profiling studies support activation of hepatic constitutive androstane receptors as the likely tumorigenic mechanism in rodents and is not a significant concern for human risk at clinical exposure to osilodrostat.
Genotoxicity assays conducted in vitro in bacterial systems and in vitro and in vivo in mammalian systems with and without metabolic activation indicate that there is no genotoxic risk in humans with osilodrostat.
Impairment Of Fertility
In a fertility and early embryonic-development study in Wistar Han rats, doses of 50 mg/kg (118 times the 30 mg twice daily maximum clinical dose, by AUC) resulted in changes to estrous cyclicity and impaired female fertility and embryo viability. No effect on reproductive performance in females was observed at 5 mg/kg (8 times the maximum clinical dose). Fertility and reproductive performance were not affected in male rats up to 50 mg/kg (77 times the maximum clinical dose, by AUC).
Use In Specific Populations
There are no available data on osilodrostat use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. There are risks to the mother and fetus associated with active Cushingâ€™s Syndrome during pregnancy (see Clinical Considerations).
No adverse developmental outcomes were observed in reproduction studies in pregnant rats and rabbits when exposed to osilodrostat during organogenesis at doses that produced maternal exposures of 7 and 0.5-times the 30 mg twice daily maximum clinical dose, by AUC. In rabbits, exposures associated with maternal toxicity at 7-times the maximum clinical dose resulted in decreased fetal viability. No adverse developmental outcomes were observed in a pre-and postnatal development study with administration of osilodrostat to pregnant rats from organogenesis through lactation at 8-times the 30 mg twice daily maximum clinical dose (see Data).
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2%-4% and 15%-20%, respectively.
Disease-Associated Maternal And/Or Embryo/Fetal Risk
Active Cushing Syndrome during pregnancy has been associated with an increased risk of maternal and fetal morbidity and mortality (including gestational diabetes, gestational hypertension, pre-eclampsia, maternal death, miscarriage, fetal loss, and preterm birth).
Osilodrostat administered to pregnant Wistar Han rats from gestation day 6-17 at doses of 0.5, 5, 50 mg/kg did not adversely affect embryo-fetal development up to 5 mg/kg (8-times the 30mg twice daily maximum clinical dose, by AUC). Maternal toxicity, increased embryonic and fetal deaths, decreased fetal weights, and malformations occurred at 50 mg/kg (118-times the maximum clinical dose, by AUC).
Osilodrostat administered to pregnant New Zealand rabbits from gestation day 7-20 at doses of 3, 10, and 30 mg/kg did not adversely affect embryo-fetal development at 3mg/kg (0.5-times the 30 mg twice daily maximum clinical dose, by AUC). Maternal toxicity, increased embryo resorption and decreased fetal viability was observed at ≥ 10mg/kg (7-times the maximum clinical dose, by AUC).
Osilodrostat administered to Wistar Han rats from gestation day 6 through lactation day 20 at doses of 1, 5, and 20 mg/kg did not adversely impact behavioral, developmental, or reproductive parameters up to 5 mg/kg (~ 8 times the 30 mg twice daily maximum clinical dose, by AUC). Delayed parturition and dystocia in maternal rats and decreased pup survival were observed at 20 mg/kg (43-times the maximum clinical dose, by AUC).
There are no available data on the presence of osilodrostat in human or animal milk, the effects on the breastfed infant, or the effects on milk production. Because of the potential for serious adverse reactions (such as adrenal insufficiency) in the breastfed infant, advise patients that breastfeeding is not recommended during treatment with ISTURISA and for one week after the final dose.
The safety and effectiveness of ISTURISA in pediatric patients have not been established.
Of the 167 patients in clinical trials with ISTURISA, 10 (6%) were 65 years and older. There were no patients above 75 years of age. Based on the available data on the use of ISTURISA in patients older than 65 years, no dosage adjustment is required [see CLINICAL PHARMACOLOGY].
No dosage adjustment of ISTURISA in patients with impaired renal function is required [see DOSAGE AND ADMINISTRATION, CLINICAL PHARMACOLOGY]. In patients with moderate to severe renal impairment, UFC levels should be interpreted with caution due to reduced UFC excretion.
Dosage adjustment is not required in patients with mild hepatic impairment (Child-Pugh A) but is required for patients with moderately impaired hepatic function (Child-Pugh B) and for patients with severe hepatic impairment (Child-Pugh C) [see DOSAGE AND ADMINISTRATION, CLINICAL PHARMACOLOGY]. More frequent monitoring of adrenal function may be required during dose titration in all patients with hepatic impairment.