Symptom burden and quality of life in patients with high-risk essential thrombocythaemia and polycythaemia vera receiving hydroxyurea or pegylated interferon alfa-2a: a post-hoc analysis of the MPN-RC 111 and 112 trials

Background: Patients with essential thrombocythaemia or polycythaemia vera have several symptoms that can worsen their quality of life. We aimed to assess how symptom burden changes over time with cytoreductive therapy. Methods: We performed a post-hoc analysis of data from MPN-RC 111—a single-arm, open-label, phase 2, multicentre trial at 17 hospitals and cancer centres in Italy and the USA, evaluating the clinical–haematological response to pegylated interferon alfa-2a in patients who were resistant or intolerant to hydroxyurea (NCT01259817)—and MPN-RC 112—a randomised, open-label, phase 3, multicentre trial at 25 hospitals and cancer centres in France, Germany, Israel, Italy, the UK, and the USA, comparing the clinical–haematological response to pegylated interferon alfa-2a versus hydroxyurea in therapy-naive patients with either high-risk essential thrombocythaemia or polycythaemia vera (NCT01258856). Patients completed the Myeloproliferative Neoplasm Symptom Assessment Form (MPN-SAF) and the European Organisation for the Research and Treatment of Cancer Core Quality of Life Questionnaire through 12 months after initiation of treatment as secondary endpoints. In this post-hoc analysis, we examined the association of symptom burden with the clinical–haematological response at 12 months and the effect of baseline symptom burden (ie, high burden [total symptom score ≥20] vs low burden [total symptom score <20]) on subsequent changes in symptoms, estimated via mixed models. A clinically significant improvement in symptom burden was defined as 50% or greater improvement in the MPN-SAF total symptom score from baseline to 12 months in patients with a total symptom score greater than zero at baseline. Findings: 135 patients were enrolled in MPN-RC 111 between Feb 15, 2012, and Dec 23, 2015, and 168 were enrolled in MPN-RC 112 between Sept 24, 2011, and June 30, 2016. For this analysis, we included data from 114 patients from MPN-RC 111 (64 [56%] with essential thrombocythaemia and 50 [44%] with polycythaemia vera; 56 [49%] were female, and 100 [91%] of 110 were white) and 166 patients from MPN-RC 112 (79 [48%] with essential thrombocythaemia and 87 [52%] with polycythaemia vera; 68 [41%] were female, and 145 [93%] of 156 were white). At 12 months, a clinically significant improvement in symptom burden was reported by 12 (32%) of 38 complete responders and seven (20%) of 35 partial responders treated with pegylated interferon alfa-2a in MPN-RC 111; five (19%) of 27 complete responders and six (18%) of 34 partial responders treated with pegylated interferon alfa-2a in MPN-112; and eight (27%) of 30 complete responders and six (22%) of 27 partial responders treated with hydroxyurea in MPN-112. More complete and partial responders reported a clinically significant improvement than did non-responders (44 [22%] of 191 complete and partial responders vs four [5%] of 76 non-responders; Fisher's exact p=0·0003). Symptom burden improved between 3 and 12 months in patients with high baseline symptom burden, both those treated with pegylated interferon alfa-2a (mean total symptom score change –10·2, 95% CI –13·2 to –7·2) and those treated with hydroxyurea (–6·8, –11·2 to –2·4). However, symptom burden worsened between 3 and 12 months in patients with low baseline symptom burden (patients treated with pegylated interferon alfa-2a: mean total symptom score change 3·2, 95% CI 0·9 to 5·4; patients treated with hydroxyurea: 3·4, 0·6 to 6·2). Interpretation: Results can inform treatment decisions, including treatment timing and goals in managing essential thrombocythaemia and polycythaemia vera, because measuring symptom burden from the patient perspective is crucial to understanding treatment efficacy and tolerability. Funding: US National Cancer Institute of the National Institutes of Health, and Roche Genentech.