New discoveries offer possible Cushing’s disease cure

LOS ANGELES — More than a century has passed since the neurosurgeon and pathologist Harvey Cushing first discovered the disease that would eventually bear his name, but only recently have several key discoveries offered patients with the condition real hope for a cure, according to a speaker here.

There are several challenges clinicians confront in the diagnosis and treatment of Cushing’s disease, Shlomo Melmed, MB, ChB, FRCP, MACP, dean, executive vice president and professor of medicine at Cedars-Sinai Medical Center in Los Angeles, said during a plenary presentation. Patients who present with Cushing’s disease typically have depression, impaired mental function and hypertension and are at high risk for stroke, myocardial infarction, thrombosis, dyslipidemia and other metabolic disorders, Melmed said. Available therapies, which range from surgery and radiation to the somatostatin analogue pasireotide (Signifor LAR, Novartis), are often followed by disease recurrence. Cushing’s disease is fatal without treatment; the median survival if uncontrolled is about 4.5 years, Melmed said.

“This truly is a metabolic, malignant disorder,” Melmed said. “The life expectancy today in patients who are not controlled is apparently no different from 1930.”

The outlook for Cushing’s disease is now beginning to change, Melmed said. New targets are emerging for treatment, and newly discovered molecules show promise in reducing the secretion of adrenocorticotropic hormone (ACTH) and pituitary tumor size.

“Now, we are seeing the glimmers of opportunity and optimism, that we can identify specific tumor drivers — SST5, [epidermal growth factor] receptor, cyclin inhibitors — and we can start thinking about personalized, precision treatment for these patients with a higher degree of efficacy and optimism than we could have even a year or 2 ago,” Melmed said. “This will be an opportunity for us to broaden the horizons of our investigations into this debilitating disorder.”

Challenges in diagnosis, treatment

Overall, about 10% of the U.S. population harbors a pituitary adenoma, the most common type of pituitary disorder, although the average size is only about 6 mm and 40% of them are not visible, Melmed said. In patients with Cushing’s disease, surgery is effective in only about 60% to 70% of patients for initial remission, and overall, there is about a 60% chance of recurrence depending on the surgery center, Melmed said. Radiation typically leads to hypopituitarism, whereas surgical or biochemical adrenalectomy is associated with adverse effects and morbidity. Additionally, the clinical features of hypercortisolemia overlap with many common illnesses, such as obesity, hypertension and type 2 diabetes.

“There are thousands of those patients for every patient with Cushing’s disease who we will encounter,” Melmed said.

The challenge for the treating clinician, Melmed said, is to normalize cortisol and ACTH with minimal morbidity, to resect the tumor mass or control tumor growth, preserve pituitary function, improve quality of life and achieve long-term control without recurrence.

“This is a difficult challenge to meet for all of us,” Melmed said.

Available options

Pituitary surgery is typically the first-line option offered to patients with Cushing’s disease, Melmed said, and there are several advantages, including rapid initial remission, a one-time cost and potentially curing the disease. However, there are several disadvantages with surgery; patients undergoing surgery are at risk for postoperative venous thromboembolism, persistent hypersecretion of ACTH, adenoma persistence or recurrence, and surgical complications.

Second-line options are repeat surgery, radiation, adrenalectomy or medical therapy, each with its own sets of pros and cons, Melmed said.

“The reality of Cushing’s disease — these patients undergo first surgery and then recur, second surgery and then recur, then maybe radiation and then recur, and then they develop a chronic illness, and this chronic illness is what leads to their demise,” Melmed said. “Medical therapy is appropriate at every step of the spectrum.”

Zebrafish clues

Searching for new options, Melmed and colleagues introduced a pituitary tumor transforming gene discovered in his lab into zebrafish, which caused the fish to develop the hallmark features of Cushing’s disease: high cortisol levels, diabetes and cardiovascular disease. In the fish models, researchers observed that cyclin E activity, which drives the production of ACTH, was high.

Melmed and colleagues then screened zebrafish larvae in a search for cyclin E inhibitors to derive a therapeutic molecule and discovered R-roscovitine, shown to repress the expression of proopiomelanocortin (POMC), the pituitary precursor of ACTH.

In fish, mouse and in vitro human cell models, treatment with R-roscovitine was associated with suppressed corticotroph tumor signaling and blocked ACTH production, Melmed said.

“Furthermore, we asked whether or not roscovitine would actually block transcription of the POMC gene,” Melmed said. “It does. We had this molecule (that) suppressed cyclin E and also blocks transcription of POMC leading to blocked production of ACTH.”

In a small, open-label, proof-of-principal study, four patients with Cushing’s disease who received roscovitine for 4 weeks developed normalized urinary free cortisol, Melmed said.

Currently, the FDA Office of Orphan Products Development is funding a multicenter, phase 2, open-label clinical trial that will evaluate the safety and efficacy of two of three potential doses of oral roscovitine (seliciclib) in patients with newly diagnosed, persistent or recurrent Cushing disease. Up to 29 participants will be treated with up to 800 mg per day of oral seliciclib for 4 days each week for 4 weeks and enrolled in sequential cohorts based on efficacy outcomes.

“Given the rarity of the disorder, it will probably take us 2 to 3 years to recruit patients to give us a robust answer,” Melmed said. “This zebrafish model was published in 2011, and we are now in 2019. It has taken us 8 years from publication of the data to, today, going into humans with Cushing’s. Hopefully, this will light the pathway for a phase 2 trial.”

 Offering optimism’

Practitioners face a unique paradigm when treating patients with Cushing’s disease, Melmed said. Available first- and second-line therapy options often are not a cure for many patients, who develop multimorbidity and report a low quality of life.

“Then, we are kept in this difficult cycle of what to do next and, eventually, running out of options,” Melmed said. “Now, we can look at novel, targeted molecules and add those to our armamentarium and at least offer our patients the opportunity to participate in trials, or at least offer the optimism that, over the coming years, there will be a light at the end of the tunnel for their disorder.”

Melmed compared the work to Lucas Cranach’s Fons Juventutis (The Fountain of Youth). The painting, completed in 1446, shows sick people brought by horse-drawn ambulance to a pool of water, only to emerge happy and healthy.

“He was imagining this ‘elixir of youth’ (that) we could offer patients who are very ill and, in fact, that is what we as endocrinologists do,” Melmed said. “We offer our patients these elixirs. These Cushing’s patients are extremely ill. We are trying with all of our molecular work and our understanding of pathogenesis and signaling to create this pool of water for them, where they can emerge with at least an improved quality of life and, hopefully, a normalized mortality. That is our challenge.” – by Regina Schaffer

Reference:

Melmed S. From zebrafish to humans: translating discoveries for the treatment of Cushing’s disease. Presented at: AACE Annual Scientific and Clinical Congress; April 24-28, 2019; Los Angeles.

Disclosure: Melmed reports no relevant financial disclosures.

 

From https://www.healio.com/endocrinology/neuroendocrinology/news/online/%7B585002ad-640f-49e5-8d62-d1853154d7e2%7D/new-discoveries-offer-possible-cushings-disease-cure

Novel Therapy Eases Cushing’s Symptoms in Pivotal Trial

by Kristen Monaco, Staff Writer, MedPage Today

LOS ANGELES — An investigational therapy improved quality of life and reduced disease symptoms for patients with endogenous Cushing’s syndrome, according to new findings from the phase III SONICS study.

Patients taking oral levoketoconazole twice daily had significant reductions in mean scores for acne (-1.8), peripheral edema (-0.4), and hirsutism (-2.6), all secondary endpoints of the pivotal trial (P<0.03 for all), reported Maria Fleseriu, MD, of Oregon Health and Science University in Portland.

“We’re looking forward to see the results of further studies and to add this therapy to the landscape of Cushing’s,” Fleseriu said here during a presentation of the findings at AACE 2019, the annual meeting of the American Association of Clinical Endocrinologists. “We have a newer medication and still we cannot make a dent in the outcomes of Cushing’s, especially for patient-reported outcomes.”

Free testosterone levels significantly decreased in women taking levoketoconazole (a ketoconazole stereoisomer and potent steroidogenesis inhibitor), from an average of 0.32 ng/dL down to 0.12 ng/dL (0.011 to 0.004 nmol/L, P<0.0001). Men had a non-significant increase: 5.1 ng/dL up to 5.8 ng/dL (0.177 to 0.202 nmol/L).

There were no significant changes from baseline to the end of maintenance for other secondary endpoints in the analysis: moon facies, facial plethora, striae, bruising, supraclavicular fat, irregular menstruation, and dysmenorrhea. However, significant improvements after 6 months of therapy were seen in patient-reported quality of life compared with baseline (mean 10.6 change on the Cushing QOL questionnaire) as well as a significant reduction in depressive symptoms (mean -4.3 change on the Beck Depression Inventory II).

The open-label, multicenter SONICS (Study of Levoketoconazole in Cushing’s Syndrome) trial included 94 adult men and women with a confirmed diagnosis of Cushing’s syndrome and elevated 24-hour mean urinary free cortisol (mUFC) levels at least 1.5 times the upper limit of normal.

In the dose-titration phase of the study (weeks 2 to 21), patients were titrated up to a max dose of 600 mg levoketoconazole twice daily until mUFC normalization. A 6-month maintenance phase followed with no dose increases, but decreases were allowed if adverse events emerged. An additional 6-month extended evaluation phase followed thereafter.

The study met it’s previously reported primary endpoint, with 30% of patients achieving normalized mUFC levels after 6 months of maintenance therapy without a dose increase (95% CI 21%-40%, P=0.0154).

Levoketoconazole was well tolerated, with only 12.8% of patients discontinuing treatment due to adverse events. The most commonly reported adverse events were nausea (31.9%), headache (27.7%), peripheral edema (19.1%), hypertension (17%), and fatigue (16%), some of which were expected due to steroid withdrawal, Fleseriu said.

Serious adverse events were reported in 14 patients, including prolonged QTc interval in two patients, elevated liver function in one patient, and adrenal insufficiency in another, events similar to those seen with ketoconazole (Nizoral) therapy.

Fleseriu explained that drug-drug interaction is a problem in Cushing’s, as all of the available medications prolong QT interval.

She noted that in SONICS, QT prolongation with levoketoconazole was observed in few patients. It’s still a “concern,” said Fleseriu, especially for patients on other drugs that prolong QT.

Although not yet approved, levoketoconazole has received orphan drug designation from the FDA and the European Medicines Agency for endogenous Cushing’s syndrome. The tentative brand name is Recorlev.

The study was supported by Strongbridge Biopharma.

Fleseriu reported relationships with Strongbridge, Millendo Therapeutics, and Novartis. Co-authors also disclosed relevant relationships with industry.

From https://www.medpagetoday.com/meetingcoverage/aace/79465

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