The Benefit/Risk Profile of AOP2014 in Low-risk Patients With PV (Low-PV)

It is an independent, investigator-generated, pragmatic trial including adult PV patients (aged 18-60) diagnosed according to World Health Organization 2008 criteria within the last 3 years before inclusion, without history of thrombosis and younger than 60 years ('low risk' patients).

Eligible patients are randomized to be treated with the best available therapy (recommended for this risk class, standard arm) based on phlebotomy including administration of low-dose (100 mg/daily) of acetylsalicylic acid (ASA, when there are not contraindications) OR Pegylated Proline-Interferon alpha-2b (AOP2014) every 2 weeks in addition to the recommended available regimen (experimental arm), for up to 12 months. The allocation of patients to study arms is 1:1 and stratification at randomization will be performed according to age category (< 50 years old or > 50 years old) and time from diagnosis (naϊve or non-naϊve). Naive patients are defined as new cases coming to observation, diagnosed for the first time just before study entry and never treated; non-naive patients are old cases (diagnosis not older than 3 years before study entry) undergoing therapy with phlebotomy and/or low doses of ASA.

Primary endpoint (PEp) is defined by the proportion (%) of patients who maintain the median value of hematocrit (HCT) below 45% during 12 months of treatment in each arm, without progression of disease and no need of any extra-protocol cytoreductive drug (responder patients).

Secondary endpoints include evaluation of hematological and molecular response, histological remission and safety profile of the protocol therapy.

Before randomization all patients undergo phlebotomies in order to reach an HCT below 45%.

After randomization, according to current common clinical practice the regimen of phlebotomies must be selected accordingly to maintain the recommended level of HCT< 45%. Once normalization of the HCT has been achieved, blood counts at regular intervals (every 4 weeks) will establish the frequency of future phlebotomies. Sufficient blood is recommended to be removed in order maintain the hematocrit below 45%. Supplemental iron therapy should not be administered.

All patients receive low-dose of ASA (100 mg/daily) as recommended by the current guidelines for low-risk subjects with PV.

Patients allocated in the experimental group receive in addition a pre-filled auto-injection pen for the subcutaneous auto-administration (into the abdominal skin or the thigh) of 100 µg of Pegylated Proline-Interferon alpha-2b (AOP2014) once every 14 days.

Patient visits are scheduled every month (4 weeks) for 12 months to assess and perform a reliable calculation of the primary end-point (% of patients with median HCT levels <45%).

At each monthly visit a pre-filled auto-injection pen is delivered to the patients who have been randomized in the experimental arm.

Assuming an expected drop-out rate of 12%, a total sample size of 150 patients (75 randomized in each group) will be randomized to reject the null hypothesis that the proportion of patients achieving the primary endpoint is 50% in favor of the alternative hypothesis that this proportion is 75% when AOP2014 is added to the phlebotomy based- therapy, with a power of 80% and an alpha error of 0.05 (two-tailed).

Two interim-analysis are planned when 50 and 100 of randomized patients have completed the 12 months study, respectively, in order to evaluate and supervise both safety and primary endpoint. The Lan and DeMets (1983) spending function with O'Brien-Fleming type boundaries will be employed to preserve the overall two-sided type I error rate for effectiveness at the 0.05 level, regardless of the timing of the analysis.

The results of the second interim analysis carried out at in April 2020 indicated a significant higher efficacy of the experimental arm than standard arm. The composite primary end-point was reached in 84% in patients of Ropeginterferon arm vs. 60% in standard arm (p=0.008, Odds Ratio=3.5, 95% CI: 1.3-10.4). This result, according to the statistical evaluation for futility and efficacy, reveals that , the null hypothesis is already been proven with first 100 patients randomized and cannot change in the future when 150 patients will enter the study. Therefore the data safety monitoring board and the steering committee agree that the accrual of new patients can be interrupted with 127 patients included.

The primary endpoint assessment is performed after the completion of the first 12 months of therapy for all subjects enrolled ('core study').

A period of 12 months is expected for completion of the enrolment / randomization phase. The 'core study' itself will take 12 months of treatment per patient.

Based on results from the 'core study' the extension phase will continue as follows:

1. After 12 month patients who meet the primary endpoint following either conventional or experimental therapy will enter the extension phase and remain on their current regimen.
2. non-responders, not meeting the primary endpoint after 12 months of conventional therapy will be switched to the experimental treatment.
3. non-responder, not meeting the primary endpoint after 12 months of experimental therapy will be switched to conventional treatment.

This extension phase will last for another 12 months from the Last Visit Last Patient included (LVLP) into the core study (matching cases 1 and 2 as defined above). Based on this, the overall length of the study is expected to cover a period of 36 months from the First Patient Included (FPI).