Efficacy and safety of dostarlimab in elderly patients with multiple comorbidities and allergic diathesis: case report.

Background: Several studies have demonstrated the effectiveness of anti-programmed death-1 (PD-1) drugs in patients suffering from deficient mismatch repair/microsatellite instability (dMMR/MSI) endometrial cancer (EC). The phase III Ruby study, showed benefit in progression-free survival (PFS) for patients with stage III-IV EC, both MSI-high/dMMR (MSI-H/dMMR) and mismatch repair proficient/microsatellite stable (pMMR/MSS), treated upfront with chemotherapy in combination with dostarlimab. Even earlier, the GARNET trial, which enrolled patients with advanced or relapsed EC with dMMR and/or MSI progressing on prior platinum therapy to receive dostarlimab, reported overall response rate (ORR) of 43.5% with a manageable safety profile. We report on the case of an elderly patient with many pathologies treated with dostarlimab.

Case description: A 75-year-old woman with EC (MSI-H) with pulmonary and bone metastasis progressed on first line chemotherapy platinum-containing, was treated with dostarlimab as monotherapy. Medical history was positive for arterial hypertension, autoimmune thrombocytopenia and allergy to amoxicillin and levofloxacin. After the second administration of dostarlimab, our patient showed a dramatic improvement of her clinical conditions. The clinical response was confirmed by radiological response on the basis of the results of a computed tomography (CT) scan performed in March 2023 that showed a reduction of the pelvic mass and pulmonary secondaries. No toxicities related to autoimmune thrombocytopenia occurred. The experienced grade 2 infusion reaction, resolved with the suspension of the drug and the administration of an antihistaminic drug; then we resumed dostarlimab doubling the administration time.

Conclusions: The administration of dostarlimab is safe and feasible in elderly people with multiple pathologies and multiple allergies with recurrent dMMR/MSI EC. The drug is well tolerated and able to give a good quality of life to patients.