Is continued treatment with Vabysmo (faricimab) medically necessary for a patient with diabetic macular edema?

Medical Necessity of Continued Vabysmo Treatment for Diabetic Macular Edema

Continued treatment with Vabysmo (faricimab) is medically necessary for this patient with bilateral diabetic macular edema, as the right eye demonstrates suboptimal visual acuity (20/30) indicating persistent center-involving DME that warrants ongoing anti-VEGF therapy to prevent vision loss and maintain current visual gains.

Treatment Indication and Standard of Care

Anti-VEGF therapy with faricimab represents the standard of care for center-involving diabetic macular edema with associated vision impairment. 1 The International Council of Ophthalmology guidelines explicitly support intravitreal anti-VEGF agents, including faricimab, as first-line treatment for this condition. 1

Right Eye Justification (20/30 Vision)

• The right eye with 20/30 vision meets treatment criteria, as the DRCR.net protocol established that anti-VEGF therapy should be considered for eyes with vision impairment defined as Snellen equivalent of 20/32 to 20/320. 2
• Vision of 20/30 indicates ongoing disease activity requiring treatment, as "success" criteria (where treatment becomes discretionary) is defined as visual acuity of 20/20 or better. 2
• Continued monthly injections are appropriate until vision and edema are no longer improving or cannot improve further (e.g., vision 20/20 or better, or edema resolved). 2

Left Eye Considerations (20/20 Vision)

• The left eye with 20/20 vision has achieved "success" by DRCR.net criteria, where retreatment becomes discretionary rather than mandatory. 2
• However, treatment should continue if macular edema persists on OCT, even with good visual acuity, as anatomic resolution is equally important to prevent future vision loss. 1
• If edema has resolved in the left eye, treatment intervals can be extended or withheld, with close monitoring for recurrence. 2

Appropriate Treatment Protocol

Initial Treatment Phase

The prescribed regimen of 6 mg every 4 weeks for 6 doses followed by every 8 weeks aligns with evidence-based protocols. 1 The DRCR.net approach recommends:

• A series of several monthly injections followed by continued treatment at monthly intervals until vision and edema stabilize. 2
• At least 4-6 initial injections are necessary, as the DRCR.net protocol demonstrated that 17% of eyes not achieving success after four injections achieved it after five, and 15% after six injections. 1

Continuation Criteria

Treatment should continue based on the following algorithm: 2

1. If edema persists and vision continues to improve → Continue monthly injections
2. If edema persists but vision/OCT no longer improving → Continue injections; consider adding focal laser at 24+ weeks 2
3. If vision ≥20/20 AND OCT central subfield <250 μm → Treatment at investigator discretion; can extend intervals 2
4. If edema resolved or vision cannot improve further → Consider extending intervals or withholding treatment 2

Treatment Interval Extension

After achieving stability, a "treat and extend" approach is appropriate: 3, 4, 1

• Follow-up intervals can be extended to 8 weeks, then 16 weeks if edema remains stable without recurrence. 2, 1
• The American Academy of Ophthalmology supports extending treatment intervals to 10-14 weeks when disease stability is achieved. 3
• In the YOSEMITE/RHINE trials, 79.7% of eyes without complications achieved dosing intervals ≥12 weeks with faricimab. 5

Risks of Premature Discontinuation

Stopping treatment prematurely carries significant risks: 3, 1

• Premature discontinuation could lead to recurrence of macular edema and subsequent permanent vision loss. 3
• The DRCR.net protocol emphasizes that injections should be resumed if edema recurs or worsens after withholding treatment. 2, 1
• Untreated or inadequately treated DME carries significant risks of irreversible vision loss. 1

Faricimab-Specific Advantages

Faricimab offers specific benefits over other anti-VEGF agents: 6, 5, 7, 8

• Faricimab demonstrated 52% lower risk of epiretinal membrane formation compared to aflibercept over 100 weeks (3.8% vs 7.6%), which can impact long-term visual outcomes. 5
• Real-world evidence shows faricimab extends treatment intervals in refractory cases, with mean recurrence intervals extending from 5.8 to 10.8 weeks when switching from ranibizumab/aflibercept. 6
• Faricimab's dual mechanism (anti-VEGF-A and anti-angiopoietin-2) provides superior durability, allowing extended dosing intervals while maintaining efficacy. 7, 8

Critical Monitoring Parameters

To determine ongoing medical necessity, assess at each visit:

• Visual acuity changes (improvement defined as ≥5 letters or ~1 line gain) 2
• OCT central subfield thickness (improvement defined as ≥10% reduction) 2
• Presence of intraretinal or subretinal fluid on OCT 1
• Development of complications (epiretinal membrane, vitreous hemorrhage) 5

Common Pitfalls to Avoid

• Do not discontinue treatment based solely on good visual acuity if anatomic edema persists, as this predisposes to future vision loss. 1
• Do not extend intervals too aggressively before completing at least 6 monthly injections, as early responders may still benefit from additional loading doses. 1
• Do not ignore the contralateral eye – bilateral disease requires individualized treatment plans for each eye based on its specific response. 2
• Do not delay adding focal laser if edema persists beyond 24 weeks without improvement, as combination therapy may be necessary. 2