ph-991053
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Keveyis Prior Authorization with Quantity Limit Program Summary

Policy Number: PH-991053

This program applies to Blue Partner, Commercial, GenPlus, NetResults A series, SourceRx and Health Insurance Marketplace formularies.

Keveyis Prior Authorization with Quantity Limit

TARGET AGENT(S)

Keveyis® (dichlorphenamide)

Brand (generic)

GPI

Multisource Code

Quantity Limit (per day or as listed)

Keveyis (dichlorphenamide)

50 mg tablet

37100020000305

M, N, O, Y

4 tablets

PRIOR AUTHORIZATION AND QUANTITY LIMIT CRITERIA FOR APPROVAL

Initial Evaluation

Target Agent(s) will be approved when ALL of the following are met:

  1. ONE of the following:
    1. The patient has a diagnosis of primary hypokalemic periodic paralysis, primary hyperkalemic periodic paralysis, or a related variant of familial periodic paralysis (e.g., congenital myasthenic syndrome, Andersen-Tawil syndrome, paramyotonia congenita, potassium-associated myotonia) AND BOTH of the following:
      1. The patient has implemented and maintained dietary and lifestyle changes to help prevent episodes

AND

      1. ONE of the following:
        1. The patient has tried and had an inadequate response to acetazolamide

OR

        1. The patient has an intolerance or hypersensitivity to acetazolamide

OR

        1. The patient has an FDA labeled contraindication to acetazolamide

OR

    1. The patient has another FDA approved indication for the requested agent

AND

  1. The patient does NOT have any FDA labeled contraindications to the requested agent

AND

  1. ONE of the following:
    1. The requested quantity (dose) does NOT exceed the program quantity limit

OR

    1. ALL of the following:
      1. The requested quantity (dose) is greater than the program quantity limit

AND

      1. The requested quantity (dose) does NOT exceed the maximum FDA labeled dose for the requested indication

AND

      1. The requested quantity (dose) cannot be achieved with a lower quantity of a higher strength that does not exceed the program quantity limit

OR

    1. ALL of the following:
      1. The requested quantity (dose) is greater than the program quantity limit

AND

      1. The requested quantity (dose) is greater than the maximum FDA labeled dose for the requested indication

AND

      1. The prescriber has provided information in support of therapy with a higher dose for the requested indication

Length of Approval:  3 months
 

Renewal Evaluation

Target Agent(s) will be approved when ALL of the following are met:

  1. The patient has been previously approved for the requested agent through the plan’s Prior Authorization process

AND

  1. If the patient has a diagnosis of primary hypokalemic periodic paralysis, primary hyperkalemic periodic paralysis, or a related variant of familial periodic paralysis, the patient has continued to maintain dietary and lifestyle changes to help prevent episodes

AND

  1. The patient has had clinical benefit with the requested agent

AND

  1. The patient does NOT have any FDA labeled contraindications to the requested agent

AND

  1. ONE of the following:
  1. The requested quantity (dose) does NOT exceed the program quantity limit

OR

  1. ALL of the following:
  1. The requested quantity (dose) is greater than the program quantity limit

AND

  1. The requested quantity (dose) does NOT exceed the maximum FDA labeled dose for the requested indication

AND

  1. The requested quantity (dose) cannot be achieved with a lower quantity of a higher strength that does not exceed the program quantity limit

OR

  1. ALL of the following
  1. The requested quantity (dose) is greater than the program quantity limit

AND

  1. The requested quantity (dose) is greater than the maximum FDA labeled dose for the requested indication

AND

  1. The prescriber has provided information in support of therapy with a higher dose for the requested indication

Length of Approval:  12 months

FDA APPROVED INDICATIONS AND DOSAGE1

Agent(s)

Indication(s)

Dosage

Keveyis®

(dichlorphenamide)

Tablets

Treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants

Initial dose: 50 mg orally once or twice daily. Max of 200 mg daily.

Titrate to individual response at weekly intervals.

CLINICAL RATIONALE

Primary periodic paralyses are rare autosomal dominant conditions characterized by episodes of flaccid paralysis secondary to abnormal sarcolemmal excitability. All forms are associated with mutations in the skeletal muscle sodium, calcium, and potassium channels. These conditions are rarely life threatening, but a number of patients develop permanent weakness and muscle degeneration with age.3 The two most common forms are hypokalemic periodic paralysis and hyperkalemic periodic paralysis.2 There are related variants that have overlapping features with hyper- and hypokalemic periodic paralysis, including paramyotonia congenita, potassium aggravated myotonia, and congenital myasthenic syndrome.  Treatment options include trigger avoidance, potassium supplementation, and carbonic anhydrase inhibitors.2,3 Treatment and prevention varies by the form of periodic paralysis diagnosed:

  • Hypokalemic2,3
    • Recommendations for trigger avoidance:
      • Follow a low-carbohydrate, low-Na diet
      • Avoid alcohol
      • Reduce stressors and physiological stress
      • Avoid hyperosmolar states (dehydration, hyperglycemia)
  • Pharmacological prevention:
      • Acetazolamide: 125-1000 mg daily for adults, and 5-10 mg/kg/d for children
      • Potassium supplementation: 30-60 mEq daily
      • Dichlorphenamide: 50-200 mg daily
      • Potassium sparing diuretics: triamterene 50-150 mg daily, spironolactone 25-100 mg daily, eplerenone 50-100 mg daily
    • Acute Attack:
      • Non-pharmacologic: mild exercise at attack onset
      • Potassium supplement: oral potassium supplementation of 1 mEq/kg to a max of 200 mEq in 24 hours (avoid slow release formulations)

  • Hyperkalemic2,3
    • Recommendations for trigger avoidance:
      • Regularly ingest carbohydrate rich foods low in potassium
      • Avoid fasting
      • Avoid strenuous exercises after meals
      • Avoid cold exposure
      • Avoid potassium sparing agents
    • Pharmacological prevention:
      • Acetazolamide: 125-1000 mg daily for adults, and 5-10 mg/kg/d for children
      • Dichlorphenamide: 50-200 mg daily
      • Hydrochlorothiazide: 25-75 mg daily
    • Acute attacks:
      • Non-pharmacologic:  light exercise and a carbohydrate snack
      • Beta agonist: albuterol 1-2 puffs

Efficacy1

Dichlorphenamide for hypokalemic and hyperkalemic periodic paralysis was studied in two clinical studies.  Study 1 was a 9-week, double blind, placebo-controlled multicenter study examining the average number of self-reported muscle weakness per week with 44 hypokalemic periodic paralysis patients and 21 hyperkalemic periodic paralysis patients. Hypokalemic patients experienced 2.2 fewer episodes per week vs. placebo (p=0.02). Hyperkalemic patients experienced 3.9 fewer episodes per week vs. placebo (p=0.08). Study 2 was a 35-week, double blind, placebo-controlled, multi-center, two-period crossover study with 42 hypokalemic periodic paralysis patients and 31 hyperkalemic periodic paralysis patients.  In hypokalemic periodic paralysis patients, the primary endpoint was the incidence of acute intolerable worsening necessitating withdrawal. Two hypokalemic periodic paralysis patients on dichlorphenamide and 11 patients on placebo observed intolerable worsening (p=0.02).  In hyperkalemic periodic paralysis patients, the primary endpoint was average number of self-reported episodes per week.  Patients on dichlorphenamide had 2.3 fewer attacks per week compared to patients on placebo (0.006).  For both studies, patients naïve to therapy were started at 50 mg twice daily, patients previously on dichlorphenamide were continued on the same dose, and patients previously on acetazolamide were given a dichlorphenamide dose at 20% of the acetazolamide dose.

Primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants are a heterogeneous group of conditions, for which the response to dichlorphenamide may vary. Therefore, prescribers should evaluate the patient's response to dichlorphenamide after 2 months of treatment to decide whether dichlorphenamide should be continued.

Safety1

Dichlorphenamide has the following contraindications:

  • Hepatic insufficiency
  • Severe pulmonary obstruction
  • Hypersensitivity to dichlorphenamide or other sulfonamides
  • Concomitant use with high dose aspirin

REFERENCES

  1. Keveyis prescribing information. Taro Pharmaceuticals USA, Inc. November 2019.
  2. Venance SL, Cannon SC, Fialho D, Fontaine B, Hanna MG, Ptacek LJ, et al. CINCH Investigators. The primary periodic paralyses: Diagnosis, pathogenesis and treatment. Brain. 2006;129:8–17.
  3. Statland JM, Fontaine B, Hanna MG, et al. Review of the Diagnosis and Treatment of Periodic Paralysis. Muscle Nerve. 2017;57(4):522-530.

 

This pharmacy policy is not an authorization, certification, explanation of benefits or a contract. Eligibility and benefits are determined on a case-by-case basis according to the terms of the member’s plan in effect as of the date services are rendered. All pharmacy policies are based on (i) information in FDA approved package inserts (and black box warning, alerts, or other information disseminated by the FDA as applicable); (ii) research of current medical and pharmacy literature; and/or (iii) review of common medical practices in the treatment and diagnosis of disease as of the date hereof. Physicians and other providers are solely responsible for all aspects of medical care and treatment, including the type, quality, and levels of care and treatment.
 
The purpose of pharmacy policies are to provide a guide to coverage. Pharmacy policies are not intended to dictate to physicians how to practice medicine. Physicians should exercise their medical judgment in providing the care they feel is most appropriate for their patients.
 
Neither this policy, nor the successful adjudication of a pharmacy claim, is guarantee of payment.

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