Abstract 130P
Background
OIIS is a rare but potentially fatal complication caused by a type II antibody-mediated hypersensitivity reaction (HSR), with different clinical presentations including autoimmune haemolytic anaemia, acute immune thrombocytopenia (AIT), Evans Syndrome (ES) and thrombotic microangiopathy (TMA). Our study aimed to characterise pts diagnosed with OIIS at the Drug Hypersensitivity and Desensitisation Centre (DHDC) of a comprehensive cancer institution, for prioritising risk assessment prior to oxaliplatin (OXL) re-exposure.
Methods
We conducted an observational study with retrospective analysis of prospectively collected data focusing on CRC pts with HSR to OXL; those meeting OIIS criteria were included. OIIS subtypes were assessed with post-reaction analyses to identify cytopenias, haemolysis and signs of organ damage. Indirect immunofluorescence test via flow cytometry was performed to identify the presence of OXL-dependent antibodies. Risk was stratified based on the severity of the HSR, and pts with a favourable risk and no therapeutic alternatives were re-exposed to OXL under closed monitoring by the DHDC.
Results
Between June 2019 and December 2023, 14 OIIS were diagnosed. Four (28.5%) were female, median age was 62.9 (51-73) and median cumulative OXL cycles was 19 (13-34). OIIS presented during OXL rechallenge and symptoms onset was immediate in all pts with back pain, chills and fever being the most frequent. Four pts underwent OXL re-exposure without major complications. Pts characteristics are shown in the table. Table: 130P
Pt's characteristics
| Patient | Sex, age | Number of cycles | Platelet drop (%) | OXL AP-Ab(+) | Haemolysis | DAT (+) | Clinical presentation | Re-exposure |
| 1 | F, 64 | 19 | 78 | Y | Y | Y | ES | N |
| 2 | F, 59 | 34 | 85 | Y | N | Y | AIT | N |
| 3 | F, 62 | 15 | 40 | Y | Y | Y | ES | Y |
| 4 | M, 51 | 22 | 68 | Y | N | N | AIT | Y |
| 5 | M, 65 | 19 | 33 | Y | N | N | AIT | N |
| 6 | M, 53 | 13 | 55 | NA | Y | Y | ES | Y |
| 7 | M, 66 | 24 | 36 | NA | Y | N | ES | N |
| 8 | M, 64 | 13 | 83 | NA | Y | N | TMA | N |
| 9 | F, 63 | 20 | 79 | NA | Y | N | ES | N |
| 10 | M, 73 | 15 | 91 | NA | N | N | AIT | N |
| 11 | M, 68 | 20 | 64 | NA | N | Y | TMA | N |
| 12 | M, 60 | 20 | 30 | NA | N | Y | AIT | Y |
| 13 | M, 65 | 19 | 54 | NA | NA | NA | AIT | N |
| 14 | M, 68 | 19 | 41 | NA | Y | Y | ES | N |
AP-Ab: OXL-dependant anti-platelet antibodies, DAT: direct antiglobulin test, Y: yes, N: no, NA: not available
Conclusions
Despite the limited population, this case series highlights the importance of OIIS awareness in daily practice and supports the feasibility of OXL re-exposure under a well-established protocol in a highly specialised allergy unit.
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
J.C. Ruffinelli Rodriguez: Financial Interests, Personal, Invited Speaker: Amgen; Other, Travel and accommodation: MSD, Merck, Advanced Accelerator Applications. C. Santos Vivas: Financial Interests, Personal, Advisory Board: Sanofi, Amgen, Pierre Fabre; Financial Interests, Personal, Other, Travel and accommodation: Merck KGaA, Merck. All other authors have declared no conflicts of interest.