Can a patient with active herpes zoster (shingles) receive Phesgo (pertuzumab and trastuzumab)

Phesgo Administration in Patients with Active Shingles

Phesgo (pertuzumab and trastuzumab) should not be administered to patients with active herpes zoster (shingles) infection. Treatment should be delayed until the shingles infection has completely resolved.

Rationale for Recommendation

Immunosuppression Considerations

• Phesgo contains pertuzumab and trastuzumab, which are monoclonal antibodies targeting HER2 that can potentially affect immune function.
• Active herpes zoster represents an active viral infection that could:
  1. Worsen with immunosuppressive therapy
  2. Potentially disseminate to other areas including visceral organs
  3. Lead to complications such as postherpetic neuralgia

Guidelines Supporting This Recommendation

The NCCN Guidelines for Prevention and Treatment of Cancer-Related Infections (2024) specifically recommend:

• Prophylactic antiviral therapy for all patients receiving antibody-based therapies 1
• Herpes zoster prophylaxis for patients receiving antibody therapies like daratumumab, isatuximab-irfc, or elotuzumab 1

These recommendations highlight the recognized risk of herpes virus reactivation with antibody therapies, suggesting caution with active infection.

Management Approach

For Patients with Active Shingles:

1. Delay Phesgo administration until complete resolution of the shingles episode 2
2. Treat the active shingles infection with appropriate antiviral therapy:
   • Acyclovir, valacyclovir, or famciclovir, ideally started within 72 hours of rash onset 3
   • Continue treatment until lesions have crusted over and are healing

When to Resume Phesgo:

• Resume Phesgo only after complete resolution of active shingles lesions
• No specific waiting period is mandated after resolution, but ensure all lesions are completely healed

Prevention Strategies After Resolution

After the shingles episode has resolved and before resuming Phesgo:

1. Consider recombinant zoster vaccine (Shingrix):

   • Recommended for adults ≥50 years and immunocompromised adults ≥18 years 1
   • Two-dose series with shortened interval (1-2 months apart) for immunocompromised patients 2
   • Previous shingles episode is not a contraindication to vaccination 2
   • Must wait until acute shingles episode has completely resolved before vaccination 2

2. Prophylactic antiviral therapy:

   • Consider prophylactic antivirals during Phesgo treatment to prevent recurrence
   • Particularly important for patients with history of herpes zoster reactivation

Important Caveats

• Timing of vaccination: If planning to administer Shingrix after shingles resolution, the vaccine should be given at least 4 weeks before resuming Phesgo 1
• Monitoring: Once Phesgo is resumed, closely monitor for signs of herpes zoster recurrence
• Risk assessment: Patients with multiple risk factors for herpes zoster (advanced age, prior episodes, immunosuppression) may benefit from longer-term prophylaxis

Conclusion

The presence of active shingles is a contraindication to receiving Phesgo. Treatment should focus on resolving the shingles infection first, followed by appropriate preventive measures before resuming Phesgo therapy. This approach minimizes the risk of disseminated infection and complications while ensuring optimal cancer treatment once the infection has resolved.