Is Vyvgart (Efgartigimod alfa-fcab) Hytrulo (Efgartigimod alfa and hyaluronidase-qvfc) subcutaneous (SQ) injections weekly medically necessary for treatment of Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) in a patient who was unable to tolerate Intravenous Immunoglobulin (IVIG)?

Medical Necessity Assessment for Vyvgart Hytrulo in CIDP with IVIG Intolerance

Vyvgart Hytrulo (efgartigimod alfa and hyaluronidase-qvfc) subcutaneous weekly is medically necessary for this patient with CIDP who was unable to tolerate IVIG, based on FDA approval for CIDP, documented IVIG intolerance, and patient-reported clinical improvement, though formal objective response measures should be documented to fully satisfy continuation criteria. 1

FDA-Approved Indication and Dosing

• Vyvgart Hytrulo is FDA-approved for treatment of CIDP in adults, administered as 1000 mg subcutaneously once weekly as ongoing maintenance therapy. 1
• The FDA label specifically indicates weekly subcutaneous administration for CIDP, distinguishing it from the cyclic dosing used in myasthenia gravis. 1
• This represents a legitimate alternative when IVIG cannot be tolerated, as both target pathogenic IgG antibodies through different mechanisms. 2

Evidence Supporting Use in IVIG-Intolerant Patients

• The ADHERE trial demonstrated that subcutaneous efgartigimod PH20 significantly reduced relapse risk in CIDP patients (hazard ratio 0.39, p<0.0001), with 66% of patients achieving confirmed evidence of clinical improvement during open-label treatment. 2
• In the randomized withdrawal phase, only 27.9% of patients on efgartigimod relapsed versus 53.6% on placebo over 48 weeks. 2
• Subcutaneous immunoglobulin has been successfully used in patients who experienced anaphylaxis with IVIG and may be better tolerated in patients with IgA deficiency who developed anti-IgA antibodies. 3

Addressing the Continuation Criteria Gap

The primary deficiency in this case is lack of documented objective response measures, not lack of medical necessity:

• The patient reports subjective improvement ("definitely better" gym workouts, feeling stronger, maintaining normal routine including work). [@clinical notes@]
• However, the insurer's continuation criteria specifically require documented improvement in validated scales: I-RODS, INCAT disability scale, MRC Sum score, or grip strength. [@clinical notes@]

What Should Be Documented:

• Obtain baseline and follow-up measurements using at least one validated outcome measure: 3

  • Inflammatory Rasch-built Overall Disability Scale (I-RODS) - requires ≥4 centile metric points increase for response 2
  • INCAT disability scale - requires ≥1 point decrease for response 2
  • MRC Sum score for muscle strength 3
  • Grip strength measurement - requires ≥8 kPa increase for response 2

• The ADHERE trial defined confirmed evidence of clinical improvement as meeting any one of these thresholds after four injections and at two consecutive visits. 2

Clinical Rationale for Continuation

This patient has compelling medical necessity based on:

1. Documented IVIG intolerance - inability to tolerate IVIG represents a legitimate contraindication to first-line therapy. [@clinical notes@]

2. Appropriate diagnosis - CIDP (G61.81) is an FDA-approved indication for Vyvgart Hytrulo. 1

3. Clinical response - patient reports functional improvement after 4 doses, consistent with the ADHERE trial timeline where response was assessed after four injections. [2, @clinical notes@]

4. No evidence of toxicity or disease progression - patient tolerating therapy well with improved function. [@clinical notes@]

5. Alternative therapies have limitations:

   • IVIG requires dosing every 2-8 weeks, is expensive, time-consuming, and associated with rare thromboembolic events. 4
   • Corticosteroids have poor safety/tolerability profiles for long-term use. 4
   • Plasma exchange is invasive, expensive, and requires specialized centers. 4
   • Approximately one-third of CIDP patients do not respond to currently available treatments. 2

Safety Profile Supporting Use

• In the ADHERE trial, treatment-emergent adverse events occurred in 64% on efgartigimod versus 56% on placebo during the randomized phase, with serious adverse events in only 5% of each group. 2
• The most common side effects include respiratory tract infection, injection site reactions, headache, and urinary tract infection. 1
• Patients should be monitored for signs of infection, as efgartigimod may increase infection risk. 1

Recommendation for Authorization

To support continuation, the treating neurologist should:

1. Document objective improvement using validated measures - perform I-RODS, INCAT, MRC Sum score, or grip strength testing and compare to baseline (or establish baseline now if not previously done). 3, 2

2. Confirm absence of disease progression - document stable or improved neurological examination findings. [@clinical notes@]

3. Document IVIG intolerance - specify nature of intolerance that precludes IVIG use. [@clinical notes@]

4. Establish monitoring plan - regular assessment using standardized measures, periodic IgG trough levels, and laboratory monitoring every 6-12 months. 3

The medication is medically necessary given FDA approval for CIDP, documented IVIG intolerance, and clinical improvement; the authorization should be approved contingent on documentation of objective response measures within the next treatment cycle. 1, 2