Author of

• 20188

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  P3.09 - Mesothelioma (ID 725)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Mesothelioma
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 24608

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    P3.09-010a - Late Response to Pembrolizumab in Advanced Biphasic Pleural Mesothelioma (ID 10129)

    09:30 - 09:30  |  Author(s): Z. Choudry
    • Abstract

    Background:
    Despite significant efforts, there have been limited advances in the treatment of advanced pleural mesothelioma since the discovery of a survival benefit for first line chemotherapy with cisplatin and pemetrexed. Immunotherapy with checkpoint inhibitors has offered a new potential therapeutic strategy. In the phase 1b clinical trial KEYNOTE-28, pembrolizumab showed modest activity with a partial response rate of 20% (five out of 25 patients) in PD-L1+ mesothelioma, with responses being prolonged.
    
    Method:
    Section not applicable
    
    Result:
    A previously well 69 year old male with a history of industrial asbestos exposure presented with increasing dyspnoea over a period of several weeks. His ECOG PS was two. His CT scan showed significant pleural rind and nodularity together with a small pleural effusion. A core biopsy confirmed biphasic mesothelioma. After three cycles of cisplatin and pemetrexed the patient had achieve a partial response by modified RECIST and resolution of his symptoms. However, after a further two cycles the tumour had progressed. The patient then received two cycles of pembrolizumab at a dose of 2mg/kg (self-funded). Imaging showed minor radiologic progression after two cycles. In the face of symptomatic deterioration the patient elected to cease active anticancer therapy. The patient returned after a three month period with an improvement in symptoms and a reduction in disease burden on imaging. Palliative radiotherapy was instituted to a single large lesion, and pembrolizumab was recommenced. The patient has shown further interval reduction in disease over a four month period, seven months since the original treatment with pembrolizumab, with ongoing response maintained at ten months.
    
    Conclusion:
    Atypical response patterns to immunotherapy in solid tumours are described, but are uncommon. Our patient showed both radiographic progression and symptom deterioration and hence stopped treatment in view of the natural history of mesothelioma. However, he has achieved a late response which has been sustained. It is important for clinicians to monitor patients after presumed progression on immunotherapy due to this phenomenon. Pseudoprogression has not previously been reported with pembrolizumab in mesothelioma. It has been described in the Phase II NivoMes trial using nivolumab, with three patients out of 38 showing this response pattern. The availability of paired biopsy specimens from a number of patients in the NivoMes study may allow for this phenomenon to be explored further.