LOW-PV interim analysis: Ropeginterferon versus phlebotomy in low-risk polycythemia vera

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Published: 25 Jun 2020
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Prof Tiziano Barbui - FROM Research Foundation, Bergamo, Italy

Prof Tiziano Barbui speaks to ecancer in an online interview for the virtual EHA 2020 meeting.

He outlines the background, design and results of this phase II randomised trial (LOW-PV), which is comparing ropeginterferon versus phlebotomy in low-risk patients with polycythemia vera.

Prof Barbui concludes that ropeginterferon is safe and effective in the haematocrit on target in low-risk patients with polycythemia vera.

The question of my study was to see whether patients at low risk of thrombosis with a polycythemia vera can benefit from therapy with ropeginterferon to phlebotomy and aspirin that is the standard therapy in patients with polycythemia vera at low risk of thrombosis.

We did a clinical trial and we randomised patients with a low risk PV to the standard arm that is phlebotomy plus aspirin versus phlebotomy, aspirin on the top of we had ropeginterferon. This interferon has been approved by the European Medical Agency, EMA, very recently and it’s going to be used in Europe.

After one year of treatment we selected 100 patients who completed the entire course of one year. In these patients we did an analysis and this is called an interim analysis because after 100 patients that corresponds to two-thirds of patients that were pre-planned to be included in the trial. We found that this drug was able to keep the haematocrit on target, meaning that the great majority of patients were on target of haematocrit less than 45% in about 85-87 of these patients as compared with 60% of patients in the phlebotomy arm alone.

So at the end we decided and we concluded that this drug was able to be of benefit in these patients. Also because these patients had less need to be phlebotomised so that this is an important point because iron deficiency is associated with an increased need of phlebotomy. Moreover, patients in the treatment arm, treatment with ropeginterferon arm, were less with symptoms that were extremely better when you treat patients with ropeginterferon. So we concluded that also in low risk patients with polycythemia vera the addition to standard therapy of ropeginterferon can benefit the great majority of our patients.

Treatment in this disease and in other diseases should follow the guideline recommendations. Recommendations in PV are the following: you have to decide whether your patient is at low risk of thrombosis or at high risk of thrombosis. Low risk of thrombosis are patients less than 60 years old without a prior history of events, cardiovascular events. High risk are those with age over 60-65 or even younger but with a prior thrombosis. Patients with high risk should be treated with a cytoreductive therapy. On the contrary, patients at low risk guidelines recommend not to treat these patients with cytoreductive therapy because there is a concern that chemotherapy can induce secondary cancer or leukaemia. This was the reason why we tried to do a clinical trial and we did a clinical trial with a drug that is not leukaemogenic and not carcinogenic drug such as pegylated ropeginterferon.

The follow-up – after one year we documented a clear advantage for ropeginterferon in comparison with phlebotomy alone. The follow-up of this study will last two years. We completed one year and the results we presented are results after one year of follow-up. After two years of follow-up we will answer other questions that are secondary endpoint questions that include the quality of life after two years, quality of life in terms of remission of the disease and also the reduction of the JAK2 allele burden. We think that allele burden can be reduced by ropeginterferon but to answer this last question we need two years of follow-up.