Osilodrostat Continues to Show Promise for Cushing’s Disease

NEW ORLEANS — The investigational drug osilodrostat (Novartis) continues to show promise for treating Cushing’s disease, now with new phase 3 trial data.

The data from the phase 3, multicenter, double-blind randomized withdrawal study (LINC-3) of osilodrostat in 137 patients with Cushing’s disease were presented here at ENDO 2019: The Endocrine Society Annual Meeting by Beverly M.K. Biller, MD, of the Neuroendocrine & Pituitary Tumor Center at Massachusetts General Hospital, Boston.

“Osilodrostat was effective and shows promise for the treatment of patients with Cushing’s disease,” Biller said.

Osilodrostat is an oral 11β-hydroxylase inhibitor, the enzyme that catalyzes the last step of cortisol biosynthesis in the adrenal cortex. Its mechanism of action is similar to that of the older Cushing’s drug metyrapone, but osilodrostat has a longer plasma half-life and is more potent against 11β-hydroxylase.

Significantly more patients randomized to osilodrostat maintained a mean urinary free cortisol (mUFC) response versus placebo at 34 weeks following a 24-week open-label period plus 8-week randomized phase, with rapid and sustained mUFC reduction in most patients.

Patients also experienced improvements in clinical signs of hypercortisolism and quality of life. The drug was generally well-tolerated and had no unexpected side effects.

Asked to comment, session comoderator Julia Kharlip, MD, associate medical director of the Pituitary Center at the University of Pennsylvania, Philadelphia, told Medscape Medical News, “This drug is incredibly exciting because over 80% of people were controlled fairly rapidly. People could get symptom relief but also a reliable response. You don’t have to wonder when you’re treating a severely affected patient if it’s going to work. It’s likely going to work.”

However, Kharlip cautioned that it remains to be seen whether osilodrostat continues to work long-term, given that the older drug metyrapone — which must be given four times a day versus twice daily for osilodrostat — is known to become ineffective over time because the pituitary tumor eventually overrides the enzyme blockade.

“Based on how osilodrostat is so much more effective at smaller doses, there’s more hope that it will be effective long term…If the effectiveness and safety profile that we’re observing now continues to show the same performance years in a row, then we’ve got our drug.”

Osilodrostat Potentially Addresses an Unmet Medical Need

Cushing’s disease is a rare disorder of chronic hypercortisolism with significant burden, increased mortality, and decreased quality of life. Pituitary surgery is the recommended first-line treatment for most patients, but not all patients remit with surgery and some require additional treatment.

Pasireotide (Signifor, Novartis), an orphan drug approved in the United States and Europe for the treatment of Cushing’s disease in patients who fail or are ineligible for surgical therapy, is also only effective in a minority of patients.

“There hasn’t been a medicine effective for long-term treatment, so a lot of patients end up getting bilateral adrenalectomy, thereby exchanging one chronic medical disease for another,” Kharlip explained.

Biller commented during the question-and-answer period, “I think because not all patients are placed in remission with surgery initially and because other patients subsequently recur — a problem that is more common than we used to believe — we do need medical therapies.”

She continued, “I think it’s important to have a large choice of medical therapies that work in different places in the hypothalamic-pituitary-adrenal axis.

“Even though surgery is the right initial therapy for everyone, I think in terms of subsequent medical therapy we have to tailor that to the individual circumstances of the patient in terms of the goals of treatment, and perhaps what other medicines they’re on, the degree of cortisol excess [and other factors].”

Highly Significant Normalization in Mean UFC Versus Placebo

In a prior 22-week phase 2 study (LINC-2), osilodrostat normalized mUFC in most patients. Results of the extension phase were reported by Medscape Medical News 2 years ago.

The current phase 3 study, LINC-3, was conducted on the basis of that proof-of-concept study, Biller said.

The trial was conducted in 19 countries across four continents in patients with persistent or recurrent Cushing’s disease screened for mUFC > 1.5 times the upper limit of normal and other entry criteria. In total, 137 patients were enrolled and randomized.

Participants were a median age of 40 years, 77% were female, and 88% had undergone prior pituitary surgery. Nearly all (96%) had received at least one previous treatment for Cushing’s.

At baseline, patients’ mean mUFC (364 µg/24 hours) was 7.3 times the upper limit of normal, which is “quite significant hypercortisolemia,” Biller noted.

All patients initially received osilodrostat, with a rapid dose uptitration every 2 weeks from 2 to 30 mg orally twice daily until they achieved a normal UFC.

They continued on open-label medication until week 24, when urine samples were collected. Patients who had an mUFC less than the upper limit of normal and had not had a dose increase in the prior 12 weeks were eligible for the double-blind phase. Those who were ineligible continued taking open-label drug.

The 70 eligible patients were randomized to continue taking osilodrostat (n = 36) or were switched to placebo (n = 34) for another 8 weeks. After that, the patients taking placebo were switched back to osilodrostat until week 48. A total of 113 patients completed the 48 weeks.

The primary efficacy endpoint was mUFC at 34 weeks (the end of the 8-week randomized phase).

For those randomized to continue on the drug, mUFC remained in the normal range in 86.1% of patients versus just 29.4% of those who had been switched to placebo for the 8 weeks. The difference was highly significant (odds ratio, 13.7; P < .001), Biller reported.

A key secondary endpoint, proportion of patients with an mUFC at or below the ULN at 24 weeks without up-titration after week 12, was achieved in 53%.

The mean dose at 48 weeks was 11.0 mg/day, “a fairly low dose,” she noted.

Clinical features were also improved at week 48, including systolic and diastolic blood pressure (percentage change –6.8 and –6.6, respectively), weight (–4.6), waist circumference (–4.2), fasting plasma glucose (–7.1), and HbA1c (–5.4).

Scores on the Cushing Quality of Life scale improved by 52.4 points, and Beck Depression Inventory scores dropped by 31.8 points.

Most Adverse Events Temporary, Manageable

The most commonly reported adverse events were nausea (41.6%), headache (33.6%), fatigue (28.5%), and adrenal insufficiency (27.7%), and 10.9% of patients overall discontinued because of an adverse event.

Adverse events related to hypocortisolism occurred in 51.1% of patients overall, with 10.2% being grade 3 or 4.  However, most of these were single episodes of mild-to-moderate intensity and mainly occurred during the initial 12-week titration period. Most patients responded to dose reduction or glucocorticoid supplementation.

Adverse events related to accumulation of adrenal hormone precursors occurred in 42.3% of patients overall, with the most common being hypokalemia (13.1%) and hypertension (12.4%).

No male patients had signs or symptoms related to increased androgens or estrogens. However, 12 female patients experienced hirsutism, most of those patients also had acne, and one had hypertrichosis. None discontinued because of those symptoms.

Kharlip commented, “What’s really inspiring was that even though half of the patients had symptoms related to adrenal insufficiency, it sounded as if they were quickly resolved with treatment and none discontinued because of it.”

“And it may have been related to study design where the medication was titrated very rapidly. There is probably a way to do this more gently and get the good results without the side effects.”

Kharlip also praised the international consortium that devised the protocol and collaborated in the research effort.

“It’s incredibly exciting and gratifying to see the world come together to get these data. It’s such a rare disease. To be able to have something like that in the field is a dream, to have a working consortium. The protocol was effective in demonstrating efficacy. It’s just a win on so many levels for a disease that currently doesn’t have a good therapy…I struggle with these patients all the time so I’m thrilled that there is hope.”

An ongoing confirmatory phase 3 study, LINC-4, is evaluating patients up to 48 weeks.

Biller is a consultant for and has received grants from Novartis and Strongbridge. Kharlip has  reported no relevant financial relationships.

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From https://www.medscape.com/viewarticle/910864#vp_1

A Phase III Study of Osilodrostat to Treat Cushing’s Disease

CLCI699C2302: A Phase III, Multi-center, Randomized, Double-blind, 48 Week Study with an Initial 12 Week Placebo-controlled Period to Evaluate the Safety and Efficacy of Osilodrostat in Patients with Cushing’s Disease

Purpose

In people with a disorder known as Cushing’s disease, levels of the hormone cortisol are very high in the urine and blood. Lowering cortisol levels relieves the symptoms of Cushing’s disease. Osilodrostat is an investigational drug that inhibits an enzyme needed for cortisol to be made.

In this study, researchers are assessing the safety and effectiveness of osilodrostat in patients with Cushing¿s disease and observing its ability to reduce cortisol levels. In the first 12 weeks of the study, patients will receive osilodrostat or a placebo (inactive drug). After week 12 and continuing through week 48, all patients will receive osilodrostat. Patients will then have the option to continue taking osilodrostat for up to 100 weeks into the study, if they wish.

Osilodrostat is taken orally (by mouth).

Eligibility

To be eligible for this study, patients must meet several criteria, including but not limited to the following:

  • Patients must have Cushing¿s disease with elevated levels of cortisol in the urine.
  • An acceptable amount of time must have passed between the completion of prior therapies and entry into the study, to allow for a sufficient “washout” period.
  • This study is for patients ages 18 to 75.

For more information about this study and to inquire about eligibility, please contact Dr. Eliza Geer at 646-888-2627.

Protocol

17-351

Phase

III

Investigator

Co-Investigators

Diseases

Sloan Kettering (New York City) Clinical Trials & Research

 

Clinical trials are research studies that test new treatments to see how well they work. Our Pituitary and Skull Base Tumor Center is leading clinical trials investigating new medical therapies for patients with Cushing’s disease and acromegaly. They are also involved in quality-of-life studies aimed at improving long-term follow-up care for patients who need it.

Our experts can help determine which clinical trials are right for you. The following clinical trials for pituitary tumors are currently enrolling new patients.

To learn more about a particular study, choose from the list below. For more information about our research and clinical trials, call us at 212-639-3935, or talk with your doctor.

Osilodrostat maintained cortisol control in Cushing’s syndrome

Osilodrostat, a drug that normalized cortisol in 89% of patients with Cushing’s syndrome who took it during a phase II study, continued to exert a sustained benefit during a 31-month extension phase.

In an intent-to-treat analysis, all of the 16 patients who entered the LINC-2 extension study responded well to the medication, with no lapse in cortisol control, Rosario Pivonello, MD, said at the annual meeting of the Endocrine Society.

“We also saw significant improvements in systolic and diastolic blood pressure and decreases in fasting plasma glucose,” said Dr. Pivonello of the University of Naples Federico II, Italy. “Surprisingly, after 31 months, we also observed declines in body mass index and weight.”

Osilodrostat, made by Novartis, is an oral inhibitor of 11 beta–hydroxylase. The enzyme catalyzes the last step of cortisol synthesis in the adrenal cortex. The drug was granted orphan status in 2014 by the European Medicines Agency.

In the LINC-2 study, 19 patients took osilodrostat at an initial dose of either 4 mg/day or 10 mg/day, if baseline urinary-free cortisol exceeded three times the upper normal limit. The dose was escalated every 2 weeks to up to 60 mg/day, until cortisol levels were at or below the upper limit of normal. In this study, the main efficacy endpoint was normalization of cortisol, or at least a 50% decrease from baseline at weeks 10 and 22.

Overall response was 89%. Osilodrostat treatment reduced urinary-free cortisol in all patients, and 79% had normal cortisol levels at week 22. The most common adverse events were asthenia, adrenal insufficiency, diarrhea, fatigue, headache, nausea, and acne. New or worsening hirsutism and/or acne were reported among four female patients, all of whom had increased testosterone levels.

The LINC-2 extension study enrolled 16 patients from the phase II cohort, all of whom had responded to the medication. They were allowed to continue on their existing effective dose through the 31-month period.

Dr. Pivonello presented response curves that tracked cortisol levels from treatment initiation in the LINC-2 study. The median baseline cortisol level was about 1,500 nmol per 24 hours. By the fourth week of treatment, this had normalized in all of the patients who entered the extension phase. The response curve showed continued, stable cortisol suppression throughout the entire 31-month period.

Four patients dropped out during the course of the study. Dr. Pivonello didn’t discuss the reasons for these dropouts. He did break down the results by response, imputing the missing data from these four patients. In this analysis, the majority (87.5%) were fully controlled, with urinary-free cortisol in the normal range. The remainder were partially controlled, experiencing at least a 50% decrease in cortisol from their baseline levels. These responses were stable, with no patient experiencing loss of control over the follow-up period.

The 12 remaining patients are still taking the medication, and they experienced other clinical improvements as well. Systolic blood pressure decreased by a mean of 2.2% (from 130 mm Hg to 127 mm Hg). Diastolic blood pressure also improved, by 6% (from 85 mm Hg to 80 mm Hg).

Fasting plasma glucose dropped from a mean of 89 mg/dL to 82 mg/dL. Weight decreased from a mean of 84 kg to 74 kg, with a corresponding decrease in body mass index, from 29.6 kg/m2 to 26.2 kg/m2.

Serum aldosterone decreased along with cortisol, dropping from a mean of 168 pmol/L to just 19 pmol/L. Adrenocorticotropic hormone increased, as did 11-deoxycortisol, 11-deoxycorticosterone, and testosterone.

Pituitary tumor size was measured in six patients. It increased in three and decreased in three. Dr. Pivonello didn’t discuss why this might have occurred.

The most common adverse events were asthenia, adrenal insufficiency, diarrhea, fatigue, headache, nausea, and acne. These moderated over time in both number and severity.

However, there were eight serious adverse events among three patients, including prolonged Q-T interval on electrocardiogram, food poisoning, gastroenteritis, headache, noncardiac chest pain, symptoms related to pituitary tumor (two patients), and uncontrolled Cushing’s syndrome.

Two patients experienced hypokalemia. Six experienced mild events related to hypocortisolism.

Novartis is pursuing the drug with two placebo-controlled phase III studies (LINC-3 and LINC-4), Dr. Pivonello said. An additional phase II study is being conducted in Japan.

Dr. Pivonello has received consulting fees and honoraria from Novartis, which sponsored the study.

Medical Therapies in Cushing’s Syndrome

Chapter

The Hypothalamic-Pituitary-Adrenal Axis in Health and Disease

pp 165-179

Date: 03 December 2016

Medical Therapies in Cushing’s Syndrome

Abstract

Medical therapy has an important, albeit secondary, role in patients with Cushing’s syndrome. While medications are not currently used as definitive therapy of this condition, they can be very effective in controlling hypercortisolism in patients who fail surgery, those who are not surgical candidates, or those whose tumor location is unknown. Medical therapies can be particularly helpful to control hypercortisolism in patients with Cushing’s disease who underwent radiation therapy and are awaiting its salutary effects.

Currently available treatment options include several steroidogenesis inhibitors (ketoconazole, metyrapone, mitotane, etomidate), which block one or several steps in cortisol synthesis in the adrenal glands, centrally acting agents (cabergoline, pasireotide), which decrease ACTH secretion, and glucocorticoid receptor antagonists, which are represented by a single agent (mifepristone). With the exception of pasireotide and mifepristone, available agents are used “off-label” to manage hypercortisolism. Several other medications are at various stages of development and may offer additional options for the management of this serious condition.

As more potential molecular targets become known and our understanding of the pathogenesis of Cushing’s syndrome improves, it is anticipated that novel, rationally designed medical therapies may emerge. Clinical trials are needed to further investigate the relative risks and benefits of currently available and novel medical therapies and examine the potential role of combination therapy in the management of Cushing’s syndrome.

Keywords

Cabergoline, Etomidate, Ketoconazole, Levoketoconazole, Metyrapone, Mifepristone, Mitotane, Osilodrostat, Pasireotide, Pituitary adenoma

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