Introduction:
- Henoch-Schonlein Purpura (HSP) is a small-vessel vasculitis. It is associated with
IgA-dominant immune deposits in the skin, gut, and kidney and is thus called IgA
vasculitis.
- Purpuric skin rash, abdominal pain or renal involvement, and arthritis are the most
common symptoms.
- Almost two-thirds of the cases are an allergic reaction to targeted therapy or occur in
the aftermath of an infection.
- Hormone (HR) positive and Human Epidermal Growth Factor Receptor 2 (HER2)
negative breast cancers are treated with cyclin-dependent kinases 4/6 (CDK4/6)
inhibitors.
- While there is no previous report of HSP in adults treated with CDK4/6 inhibitors,
this study presents a case of HSP in an Abemaciclib-treated advanced breast cancer
patient.
Case Presentation:
- A 65-years-old female was diagnosed with a stage IV HR+/HER2- breast cancer and
lung, liver, and bone metastasis.
- She had hypertension at the time of diagnosis, which was treated with ACE inhibitors.
- The first line of treatment was a combination of Abemaciclib 300 mg daily (a
CDK4/6 inhibitor) and Letrozole.
- She had a good response without any serious side effects.
- However, in 4 months, she complained of joint pain, severe asthenia, fever, and
spreading purpuric papules on lower limbs.
- The tests revealed nephritic syndrome with progressive renal failure, microhematuria,
and proteinuria.
- Based on the spread of the purpura to the sides and buttocks in the next few hours,
the clinicians suspected HSP.
- The patient was treated with intravenous dexamethasone 1 mg/kg body weight and
systemic antibiotics.
- The blood and serological tests concluded negative for HSP.
- However, light microscopy confirmed the diagnosis of Abemaciclib-induced HSP
when it showed mesangial hypercellularity with diffuse IgA and C3 deposits in the
mesangiu.
- The patient was discharged after 15 days after a corticosteroid tapering and regulating
the renal function.
- She was started on a low-dose Abemaciclib after a month and exhibited no side
effects thereafter.
Discussion:
- It is predicted that Abemaciclib could have triggered an abnormal IgA-mediated
immune response against the small vascular walls endothelial cells.
- Abemaciclib-treated patients have shown PD-L1, PD-L2 upregulation, an increase of
IFNγ-dependent enzymes, and an upregulation of MHC class I and II in pre-clinical
studies.
- Based on the limited evidence and reports, the incidence of HSP in Abemaciclib is
rare.
- However, with the integration of Abemaciclib in breast cancer treatment, oncologists
must consider the possibility of HSP occurrence.
- Monitoring for early detection and appropriate treatment is required in these patients
to avoid further complications.