Post-Operative Cushing Syndrome Care

Justine Herndon, PA-C, and Irina Bancos, MD, on Post-Operative Cushing Syndrome Care

– Curative procedures led to widespread resolution or improvement of hyperglycemia

by Scott Harris , Contributing Writer, MedPage Today January 18, 2022

In a recent study, two-thirds of people with Cushing syndrome (CS) saw resolved or improved hyperglycemia after a curative procedure, with close post-operative monitoring an important component of the process.

Among 174 patients with CS included in the longitudinal cohort study (pituitary in 106, ectopic in 25, adrenal in 43), median baseline HbA1c was 6.9%. Of these, 41 patients were not on any therapy for hyperglycemia, 93 (52%) took oral medications, and 64 (37%) were on insulin.

At the end of the period following CS remission (median 10.5 months), 37 (21%) patients had resolution of hyperglycemia, 82 (47%) demonstrated improvement, and 55 (32%) had no change or worsened hyperglycemia. Also at the end of follow-up, HbA1c had fallen 0.84% (P<0.0001), with daily insulin dose decreasing by a mean of 30 units (P<0.0001).

Justine Herndon, PA-C, and Irina Bancos, MD, both endocrinology researchers with Mayo Clinic in Minnesota, served as co-authors of the report, which was published in the Journal of the Endocrine Society. Here they discuss the study and its findings with MedPage Today. The exchange has been edited for length and clarity.

What was the study’s main objective?

Herndon: As both a hospital diabetes provider and clinic pituitary/gonadal/adrenal provider, I often hear questions from colleagues about how to manage a patient’s diabetes post-operatively after cure from CS. While clinical experience has been helpful in guiding these discussions, the literature offered a paucity of data on diabetes/hyperglycemia specifically after surgery. There was also a lack of data on specific subgroups of CS, whether by sub-type or severity.

Therefore, we felt it was important to see what our past patient experiences showed in terms of changes in laboratory data, medications, and which patients were more likely to see improvement in their diabetes/hyperglycemia. The overall goal was to help clinicians provide appropriate patient education and care following a curative procedure.

In addition to its primary findings, the study also identified several factors associated with resolution or improvement of hyperglycemia. What were these factors?

Bancos: Both clinical and biochemical severity of CS, as well as Cushing subtype, were associated with improvement. We calculated severity based on symptoms and presence of comorbidities, and we calculated biochemical severity based on hormonal measurements. As clinical and biochemical scores were strongly correlated, we chose only one (biochemical) for multivariable analysis.

In the multivariable analysis of biochemical severity of Cushing, subtype of Cushing, and subtype of hyperglycemia, we found that patients with a severe biochemical severity score were 2.4 fold more likely to see improved hyperglycemia than people with a moderate or mild severity score (OR 2.4 (95% CI 1.1-4.9). We also found that patients with the nonadrenal CS subtype were 2.9 fold more likely to see improved hyperglycemia when compared to people with adrenal CS (OR of 2.9 (95% CI 1.3-6.4).

The type of hyperglycemia (diabetes versus prediabetes) was not found to be significant.

Did anything surprise you about the study results?

Herndon: I was surprised to see improvement in hyperglycemia in patients who were still on steroids, as you would expect the steroids to still have an impact. This shows how much a CS curative procedure truly leads to changes in the comorbidities that were a result of the underlying disease.

Also, I was surprised that the type of hyperglycemia was not a predictor of improvement after cure, although it was quite close. We also had a few patients whose hyperglycemia worsened, and we could not find a specific factor that predicted which patients did not improve.

What are the study’s implications for clinicians who treat people with CS?

Bancos: We think our study shows the clear need for closer follow-up — more frequently than the typical three-to-six months for diabetes. This can be accomplished through review of more than just HbA1c, such as reviewing blood glucose logbooks, asking about hypoglycemia symptoms, and so forth.

Patients with severe CS who are being treated with insulin or hypoglycemic medications are especially likely to decrease their medications to avoid hypoglycemia during postoperative period.

Read the study here.

Bancos reported advisory board participation and/or consulting with Strongbridge, Sparrow Pharmaceutics, Adrenas Therapeutics, and HRA Pharma outside the submitted work. Herndon did not disclose any relevant financial relationships with industry.

Korlym: Failure to Show a Reasonable Expectation of Success Dooms Obviousness Allegations

In Teva Pharmaceuticals USA, Inc. v. Corcept Therapeutics, Inc.,1 the Federal Circuit affirmed the obviousness analysis performed by the Patent Trial and Appeal Board (“PTAB”), which found that Corcept’s patent for methods of treating Cushing’s disease by co-administering two different types of drugs with a specific range of dosing amounts was not obvious—even where the prior art directed one to combine the two—because there was no reasonable expectation of success for the specific dose claimed in the patent.

Background

The patent relates to methods for treating Cushing’s syndrome by co-administering mifepristone and a strong CYP3A inhibitor. Cushing’s syndrome is a metabolic disorder caused by excess cortisol.,2 Mifepristone was recognized in the prior art as a potential treatment for Cushing’s syndrome in the 1980’s.,3 Decades later, Corcept sponsored the first major clinical trial of mifepristone in patients with Cushing’s syndrome, in which participants were dosed with 300 to 1200 mg per day of mifepristone. Thereafter, Corcept filed a New Drug Application (“NDA”) with the U.S. Food and Drug Administration (“FDA”) to seek marketing approval for Korlym®, a 300 mg mifepristone tablet to control “hypercalcemia secondary to hypercortisolism” in patients with Cushing’s syndrome.,4

The FDA approved the NDA, including the prescribing information contained in the label.5 The label “recommended [a] starting dose [of] 300 mg once daily” and allowed for a dosage increase “in 300 mg increments to a maximum of 1200 mg once daily.”6 The label specifically warned against using mifepristone “with strong CYP3A inhibitors” and limited the dose to “300 mg per day when used with strong CYP3A inhibitors.”7

However, when it approved the NDA, the FDA issued several post market requirements, one of which was that Corcept must conduct a drug-drug interaction study with mifepristone and a strong CYP3A inhibitor.8 A memo from the Office of Clinical Pharmacology was provided to Corcept by the FDA (“the Lee memo”), which explained that “[t]he degree of change in exposure of mifepristone when co-administered with strong CYP3A inhibitors is unknown” and “may present a safety risk.”9 The concern was that without the required study the patients with Cushing’s syndrome that take strong inhibitors may be unable to use mifepristone.10

Corcept conducted the study requested in the Lee memo.11 Based on the resulting data, Corcept sought a patent claiming a method of treating Cushing’s syndrome by co-administering mifepristone and a strong CYP3A4 inhibitor, which is the patent at issue here.12 Claim 1, which is representative of the claims, reads:

A method of treating Cushing’s syndrome in a patient who is taking an original once-daily dose of 1200 mg or 900 mg per day of mifepristone, comprising the steps of:

reducing the original once-daily dose to an adjusted once-daily dose of 600 mg mifepristone,

administering the adjusted once-daily dose of 600 mg mifepristone and a strong CYP3A inhibitor to the patient,

wherein said strong CYP3A inhibitor is selected from the group consisting of ketoconazole, itraconazole, nefazodone, ritonavir, nelfmavir, indinavir, boceprevir, clarithromycin, conivaptan, lopinavir, posaconazole, saquinavir, telaprevir, cobicistat, troleandomycin, tipranivir, paritaprevir, and voriconazole.13

Procedural Posture

In 2018 Corcept brought suit against Teva in the District of New Jersey alleging that Teva’s proposed generic infringed the patent, among others.14 Teva then sought post-grant review of the patent’s claims at the PTAB, arguing that the claims would have been obvious over the Korlym® label and the Lee memo, optionally in combination with FDA guidance on drug-drug interaction studies.15

The PTAB instituted review, “construed the claims to require safe administration of mifepristone,” and found that Teva failed to meet its burden of showing that a “skilled artisan would have had a reasonable expectation of success for safe co-administration of more than 300 mg of mifepristone with a strong CYP3A inhibitor.”16 Thus, the PTAB concluded that Teva failed to prove obviousness.17

Teva’s Arguments on Appeal

Teva argued to the Federal Circuit that the PTAB committed two legal errors in finding that Teva did not prove obviousness: (1) it “required precise predictability, rather than a reasonable expectation of success in achieving the claimed invention,” and (2) it found that Teva “failed to prove the general working conditions disclosed in the prior art encompassed the claimed invention” instead of applying the Federal Circuit’s “prior-art-range precedents.”18

The Federal Circuit Panel, consisting of Chief Judge Moore and Judges Newman and Reyna, rejected both of Teva’s arguments.19

The Panel determined that the PTAB “did not err by requiring Teva to show a reasonable expectation of success for a specific mifepristone dosage.”

In discussing the proper standard for evaluating a reasonable expectation of success, the Panel cited prior Federal Circuit decisions explaining that the analysis “must be tied to the scope of the claimed invention.”20 It noted that because the claims of the patent require administration of a specific dosage of mifepristone, the PTAB was required to frame its analysis around that specific dosage.21 The Panel emphasized that Teva was not “required to prove a skilled artisan would have precisely predicted safe co-administration of 600 mg of mifepristone” because “[a]bsolute predictability is not required.”22 Teva was, however, required “to prove a reasonable expectation of success in achieving the specific invention claimed, a 600 mg dosage.”23

The Panel explained that the PTAB found that Teva failed to prove a reasonable expectation of success.24 Based on the prior art, a skilled artisan would not have reasonably “expected co-administration of more than 300 mg of mifepristone with strong CYP3A inhibitor to be a safe treatment of Cushing’s syndrome or related symptoms in patients.”25 Moreover, the PTAB found that a skilled artisan “would have had no expectation as to whether co-administering dosages of mifepristone above the 300 mg/day threshold” would be successful.26 Thus, because there was no expectation of success for any dosage over 300 mg, the PTAB concluded that there could not have been an expectation of success for the specific dosage of 600 mg per day.27 The Panel found that this analysis by the PTAB was correct under Federal Circuit precedent, and that “[n]othing about this analysis required precise predictability, only a reasonable expectation of success tied to the claimed invention.”28

The Panel decided that the PTAB did not err in finding that “the prior art ranges do not overlap with the claimed range”

The Panel next considered the applicability of the Federal Circuit’s precedent concerning claimed ranges that overlap with those disclosed in the prior art.29 The PTAB refused to apply that line of cases, finding that “Teva had failed to prove the general working conditions disclosed in the prior art encompass the claimed invention.”30

The Panel noted a Federal Circuit decision that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”31 In other words, “a prima facie case of obviousness typically exists when the ranges of a claimed composition overlap the ranges disclosed in the prior art.”32 “But overlap is not strictly necessary for a conclusion of obviousness” and can exist even where the ranges are “close enough” that a skilled artisan would expect them to exhibit similar properties.33

Here, the Panel explained that “[s]ubstantial evidence supports the [PTAB’s] finding that the general working conditions disclosed in the prior art did not encompass the claimed invention, i.e., there was no overlap in ranges.”34 The Korlym® label warned against taking mifepristone with a strong CYP3A inhibitor altogether, and stated that anyone nonetheless combining the two should take a maximum of 300 mg/day of mifepristone.35 This 300 mg/day cap was also repeated in other industry publications.36 The PTAB found that “the prior art capped the range of co-administration dosages at 300 mg per day.”37 The Panel agreed with this finding, concluding that the claimed range was not disclosed in the prior art.38

Teva attempted to argue that the claimed range overlaps with monotherapy dosages—which were dosages of mifepristone alone—in the prior art.39 However, because “monotherapy dosages alone cannot create an overlap with the claimed range, which is limited to co-administering mifepristone with a strong CYP3A inhibitor,” the PTAB had to determine “whether a skilled artisan would have expected “monotherapy and co-administration dosages to behave similarly.”40 As the Panel had already concluded in its reasonable expectation of success analysis, a “skilled artisan would have no such expectation.”41

Conclusion

Although Teva argued that this was an “uncommonly clear-cut obviousness case” where the prior art discloses “the problem, . . . the solution, . . . and the way to find the solution,” the Panel disagreed, explaining that: “At best, the prior art directed a skilled artisan to try combing the Korlym Label, Lee, and the FDA guidance. But without showing a reasonable expectation of success, Teva did not prove obviousness.”42 Thus, the Panel’s decision helps to clarify that evaluating obviousness based on ranges disclosed in the prior art is a fact-specific analysis, in which bright lines should not be drawn.

1 Teva Pharm. USA, Inc. v. Corcept Therapeutics, Inc., No. 21-1360, slip op. (Fed. Cir. Dec. 7, 2021).
2 Id. at 2.
3 Id.
4 Id. at 2-3.
5 Id. at 3.
6 Id.
7 Id. at 3-4.
8 Id. at 3.
9 Id.
10 Id.
11 Id. at 4.
12 Id.
13 Id. at 3.
14 Corcept Therapeutics, Inc. v. Teva Pharmaceuticals USA, Inc., No. 18-3632 (D.N.J.).
15 Teva Pharmaceuticals USA, Inc. v. Corcept Therapeutics, Inc., PGR2019-00048, 2020 WL 6809812 (P.T.A.B. Nov. 18, 2020) (Final Decision).
16 Id. (emphasis added).
17 Id.
18 Teva Pharm. USA, Inc. v. Corcept Therapeutics, Inc., No. 21-1360, slip op. at 5 (Fed. Cir. Dec. 7, 2021)
19 See generally id.
20 Id. at 6 (citing Allergan, Inc. v. Apotex Inc., 753 F.3d 952, 966 (Fed. Cir. 2014); Intelligent Bio-Sys., Inc. v. Illumina Cambridge Ltd., 821 F.3d 1359, 1366 (Fed. Cir. 2016)).
21 Id.
22 Id.
23 Id.
24 Id.
25 Id. at 6-7 (citing Final Decision at *22).
26 Id. at 7.
27 Id.
28 Id.
29 Id. at 8.
30 Id.
31 Id. (citing E.I. DuPont de Nemours & Co. v. Synvina C. V., 904 F.3d 996, 1006 (Fed. Cir. 2018)).
32 Id. at 8-9.
33 Id. at 9.
34 Id.
35 Id.
36 Id.
37 Id.
38 Id.
39 Id.
40 Id. at 9-10.
41 Id. at 10.
42 Id.

FDA Approval for Endogenous Cushing’s Syndrome Drug Recorlev

Ahead of its New Year’s Day decision deadline at the FDA, Xeris Biopharma has snagged an approval for Recorlev, a drug formerly known as levoketoconazole.

Based on results from phase 3 studies called SONICS and LOGICS, the FDA approved the drug for adults with Cushing’s syndrome. Xeris picked up Recorlev earlier this year in its acquisition of rare disease biotech Strongbridge Biopharma. It’s planning to launch in the first quarter of 2022.

Recorlev’s approval covers the treatment of endogenous hypercortisolemia in adults with Cushing’s syndrome who aren’t eligible for surgery or haven’t responded to surgery.

Endogenous Cushing’s disease is caused by a benign tumor in the pituitary gland that prompts the body to produce elevated levels of cortisol, which over time triggers a range of devastating physical and emotional symptoms for patients.

 

In the SONICS study, the drug significantly cut and normalized mean urinary free cortisol concentrations without a dose increase, according to the company. The LOGICS trial confirmed the drug’s efficacy and safety, Xeris says.

Cushion’s is a potentially fatal endocrine disease, and patients often experience years of symptoms before an accurate diagnosis, the company says. After a diagnosis, they’re presented with limited effective treatment options.

Following the approval, the company’s “experienced endocrinology-focused commercial organization can begin rapidly working to help address the needs of Cushing’s syndrome patients in the U.S. who are treated with prescription therapy,” Xeris CEO Paul R. Edick said in a statement.

Aside from its forthcoming Recorlev launch, Xeris markets Gvoke for severe hypoglycemia and Keveyis for primary periodic paralysis.

Back in October, the company partnered up with Merck to help reformulate some of the New Jersey pharma giant’s monoclonal antibody drugs.

From https://www.fiercepharma.com/pharma/xeris-biopharma-scores-fda-approval-for-endogenous-cushing-s-syndrome-drug-recorlev

No Synthetic Steroid Version of Korlym at This Time

Teva Pharmaceuticals suffered a fresh legal setback on Tuesday in its effort to market a generic version of the synthetic steroid Korlym to treat Cushing’s syndrome.

The Israeli drugmaker failed to convince the U.S. Court of Appeals for the Federal Circuit that the Patent Trial and Appeal Board improperly denied its bid to cancel a patent held by Corcept Therapeutics covering a method for using Korlym to treat the hormone disorder.

Menlo Park, California-based Corcept last year made over $353 million from sales of Korlym, the company’s only drug, according to a filing with the U.S. Securities and Exchange Commission.

Corcept’s patent relates to using a specific dose of Korlym’s active ingredient mifepristone and another drug to treat Cushing’s syndrome, which creates an excess of the hormone cortisol and causes high blood sugar, among other things.

Corcept sued Teva in New Jersey in 2018, alleging its proposed generic version of Korlym infringed the patent and others, in a case that is still ongoing. Teva asked the Patent Trial and Appeal Board to cancel the patent because earlier publications made it obvious that Corcept’s method would work to treat the disorder.

The board ruled for Corcept last year, and Teva appealed. Teva told the Federal Circuit that the PTAB held it to an improperly high standard for proving that the patent was invalid based on prior art.

Chief U.S. Circuit Judge Kimberly Moore, joined by Circuit Judges Pauline Newman and Jimmie Reyna, rejected Teva’s argument on Tuesday. Moore said the board found that a person of ordinary skill wouldn’t have reasonably expected Corcept’s treatment to be safe and effective before Corcept created it.

Moore also rejected Teva’s argument that the prior art disclosed a range of potential dosages that covered Corcept’s treatment.

Teva, Corcept and lawyers for the two companies didn’t immediately respond to requests for comment.

The case is Teva Pharmaceuticals USA Inc v. Corcept Therapeutics Inc, U.S. Court of Appeals for the Federal Circuit, No. 21-1360.

For Teva: John Rozendaal of Sterne Kessler Goldstein & Fox

For Corcept: Eric Stops of Quinn Emanuel Urquhart & Sullivan

From https://www.reuters.com/legal/transactional/teva-loses-bid-cancel-corcept-drug-patent-federal-circuit-2021-12-07/

Updated Cushing’s disease guideline highlights new diagnosis, treatment ‘roadmap’

An updated guideline for the treatment of Cushing’s disease focuses on new therapeutic options and an algorithm for screening and diagnosis, along with best practices for managing disease recurrence.

Despite the recent approval of novel therapies, management of Cushing’s disease remains challenging. The disorder is associated with significant comorbidities and has high mortality if left uncontrolled.

Adrenal transparent _Adobe
Source: Adobe Stock

“As the disease is inexorable and chronic, patients often experience recurrence after surgery or are not responsive to medications,” Shlomo Melmed, MB, ChB, MACP, dean, executive vice president and professor of medicine at Cedars-Sinai Medical Center in Los Angeles, and an Endocrine Today Editorial Board Member, told Healio. “These guidelines enable navigation of optimal therapeutic options now available for physicians and patients. Especially helpful are the evidence-based patient flow charts [that] guide the physician along a complex management path, which usually entails years or decades of follow-up.”

Shlomo Melmed

The Pituitary Society convened a consensus workshop with more than 50 academic researchers and clinical experts across five continents to discuss the application of recent evidence to clinical practice. In advance of the virtual meeting, participants reviewed data from January 2015 to April 2021 on screening and diagnosis; surgery, medical and radiation therapy; and disease-related and treatment-related complications of Cushing’s disease, all summarized in recorded lectures. The guideline includes recommendations regarding use of laboratory tests, imaging and treatment options, along with algorithms for diagnosis of Cushing’s syndrome and management of Cushing’s disease.

Updates in laboratory, testing guidance

If Cushing’s syndrome is suspected, any of the available diagnostic tests could be useful, according to the guideline. The authors recommend starting with urinary free cortisol, late-night salivary cortisol, overnight 1 mg dexamethasone suppression, or a combination, depending on local availability.

If an adrenal tumor is suspected, the guideline recommends overnight dexamethasone suppression and using late-night salivary cortisol only if cortisone concentrations can also be reported.

The guideline includes several new recommendations in the diagnosis arena, particularly on the role of salivary cortisol assays, according to Maria Fleseriu, MD, FACE, a Healio | Endocrine Today Co-editor, professor of medicine and neurological surgery and director of the Pituitary Center at Oregon Health & Science University in Portland.

Maria Fleseriu

“Salivary cortisol assays are not available in all countries, thus other screening tests can also be used,” Fleseriu told Healio. “We also highlighted the sequence of testing for recurrence, as many patients’ urinary free cortisol becomes abnormal later in the course, sometimes up to 1 year later.”

The guideline states combined biochemical and imaging for select patients could potentially replace petrosal sinus sampling, a very specialized procedure that cannot be performed in all hospitals, but more data are needed.

“With the corticotropin-releasing hormone stimulation test becoming unavailable in the U.S. and other countries, the focus is now on desmopressin to replace corticotropin-releasing hormone in some of the dynamic testing, both for diagnosis of pseudo-Cushing’s as well as localization of adrenocorticotropic hormone excess,” Fleseriu said.

The guideline also has a new recommendation for anticoagulation for high-risk patients; however, the exact duration and which patients are at higher risk remains unknown.

“We always have to balance risk for clotting with risk for bleeding postop,” Fleseriu said. “Similarly, recommended workups for bone disease and growth hormone deficiency have been further structured based on pitfalls specifically related to hypercortisolemia influencing these complications, as well as improvement after Cushing’s remission in some patients, but not all.”

New treatment options

The guideline authors recommended individualizing medical therapy for all patients with Cushing’s disease based on the clinical scenario, including severity of hypercortisolism. “Regulatory approvals, treatment availability and drug costs vary between countries and often influence treatment selection,” the authors wrote. “However, where possible, it is important to consider balancing cost of treatment with the cost and the adverse consequences of ineffective or insufficient treatment. In patients with severe disease, the primary goal is to treat aggressively to normalize cortisol concentrations.”

Fleseriu said the authors reviewed outcomes data as well as pros and cons of surgery, repeat surgery, medical treatments, radiation and bilateral adrenalectomy, highlighting the importance of individualized treatment in Cushing’s disease.

“As shown over the last few years, recurrence rates are much higher than previously thought and patients need to be followed lifelong,” Fleseriu said. “The role of adjuvant therapy after either failed pituitary surgery or recurrence is becoming more important, but preoperative or even primary medical treatment has been also used more, too, especially in the COVID-19 era.”

The guideline summarized data on all medical treatments available, either approved by regulatory agencies or used off-label, as well as drugs studied in phase 3 clinical trials.

“Based on great discussions at the meeting and subsequent emails to reach consensus, we highlighted and graded recommendations on several practical points,” Fleseriu said. “These include which factors are helpful in selection of a medical therapy, which factors are used in selecting an adrenal steroidogenesis inhibitor, how is tumor growth monitored when using an adrenal steroidogenesis inhibitor or glucocorticoid receptor blocker, and how treatment response is monitored for each therapy. We also outline which factors are considered in deciding whether to use combination therapy or to switch to another therapy and which agents are used for optimal combination therapy.”

Future research needed

The guideline authors noted more research is needed regarding screening and diagnosis of Cushing’s syndrome; researchers must optimize pituitary MRI and PET imaging using improved data acquisition and processing to improve microadenoma detection. New diagnostic algorithms are also needed for the differential diagnosis using invasive vs. noninvasive strategies. Additionally, the researchers said the use of anticoagulant prophylaxis and therapy in different populations and settings must be further studied, as well as determining the clinical benefit of restoring the circadian rhythm, potentially with a higher nighttime medication dose, as well as identifying better markers of disease activity and control.

“Hopefully, our patients will now experience a higher quality of life and fewer comorbidities if their endocrinologist and care teams are equipped with this informative roadmap for integrated management, employing a consolidation of surgery, radiation and medical treatments,” Melmed told Healio.

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