Abstract Body (Do not enter title and authors here): Background: Pulmonary tumor thrombotic microangiopathy (PTTM) is a cancer-associated pulmonary artery embolism-like condition with a poor prognosis that is fatal in a short time due to pulmonary hypertension and respiratory and right heart failure. Although the incidence of cancer is increasing in Japan, the prognosis has been improving due to advances in treatment, so that PTTM would be fatal and has a significant impact on the prognosis of patients with cancer. Several reports have shown that imatinib, a tyrosine kinase inhibitor, is effective in the treatment of PTTM, however, there is no established evidence for efficacy and safety in using imatinib in PTTM therapy. The purpose of this trial is to evaluate the safety and efficacy of imatinib administration in patients complicated with PTTM.
Study Design/Methods: This was a multicenter, open-label, exploratory clinical trial (jRCTs031210263). Inclusion criteria were 20 years of age or older adults with a burden of cancer, right heart catheterization or echocardiography showing pulmonary hypertension (mean pulmonary artery pressure ≧25 mmHg or estimated right ventricular systolic pressure ≧40 mmHg), and progressive hypoxemia. In parallel with this prospective trial, we conducted a multicenter retrospective registry study of PTTM and patients enrolled in this retrospective registry who did not receive imatinib were set as the control group. Intervention: Participants received dose of oral imatinib 200 mg once daily. Primary endpoint: overall survival after imatinib administration. Secondary endpoints: hemodynamics, BNP levels, quality of life, 6-minute walk distance, imatinib blood levels at the second week of treatment, and time to rehospitalization.
Results: In total, 11 PTTM patients were enrolled and treated with imatinib, and over 100 PTTM patients without imatinib administration were registered as historical control.
Conclusion: We report the primary endpoint of this multicenter exploratory clinical trial of the efficacy and safety of imatinib in patients with PTTM.