A clinical study of tremelimumab, alone or in combination with olaparib, for recurrent epithelial ovarian cancer

Objective

PARP inhibitors may work synergistically to improve the efficacy of immunotherapy in patients with epithelial ovarian cancer (EOC). We performed a parallel-arm study of tremelimumab, alone or with olaparib, in patients with recurrent EOC.

Methods

Eligibility criteria included measurable disease and progression <12 months from last platinum. Participants were randomized to Arm A (tremelimumab monotherapy, 10 mg/kg/dose intravenously [IV]) or Arm B (dose level 1 [DL1] olaparib orally 150 mg twice daily with tremelimumab IV 3 mg/kg/dose and DL2 olaparib orally 150 mg twice daily with tremelimumab IV 10 mg/kg/dose). Primary objectives were safety, change in peripheral ICOS⁺ T cells, and identification of optimal dose combination.

Results

Among 24 total patients (12 on Arm A, 6 on Arm B-DL1, 6 on Arm B-DL2), the most common grade 3 toxicities were rash (13 %), immune-mediated hepatitis (8 %), and colitis (8 %). No grade ≥ 4 toxicities were identified. No dose-limiting toxicities were identified. One patient (Arm B-DL2) experienced a partial response; no complete responses were observed. Ten patients (7 on Arm A, 2 on Arm B-DL2, and 1 on Arm B-DL1) had a best response of stable disease. There was a significant increase in CD4⁺ICOS⁺ and CD8⁺ICOS⁺ T cells at both C1D15 and C1D22 in groups treated with tremelimumab IV 10 mg/kg/dose, but not in those treated with tremelimumab 3 mg/kg/dose.

Conclusions

Tremelimumab IV 10 mg/kg/dose with olaparib 150 mg orally twice daily was safe and feasible. Tremelimumab 10 mg/kg/dose (as opposed to 3 mg/kg/dose) was required for immune activation, although this did not translate into clinical responses.