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Anthony M. Hunter, MD, discusses study findings showing that many patients with polycythemia vera do not receive treatment in line with NCCN guidelines.

Many patients with polycythemia vera (PV) in the United States are not receiving treatments in line with National Comprehensive Cancer Network guidelines, and many who receive treatment have a suboptimal response, researchers reported in Current Medical Research and Opinion.

In a retrospective observational study, researchers analyzed the health records of 5,871 patients with PV. Nearly all patients (88.0%) had received hydroxyurea for PV, and 67.0% were currently being treated with hydroxyurea.

At 6 months, 56.9% of patients who received pharmacologic cytoreductive treatment had a suboptimal response. Five-year survival was 81.5% and 84.3% among patients with suboptimal and optimal responses to hydroxyurea, respectively.

Although not statistically different, these results suggest the potential for survival benefits with longer follow-up, the study authors noted.

“This finding suggests that patients with PV may need medication dosage adjustments, improved management of their treatment side effects, or alternative treatments sooner than is currently common,” they wrote.

 An Uninvolved Expert’s Perspective

Hematologist Anthony M. Hunter, MD, who was not involved in the study, spoke with Physician’s Weekly (PW) about the results and how they may affect patient management.

 PW: What are the key takeaways for clinicians?

Anthony M. Hunter, MD: I find several details particularly noteworthy. First, nearly half the patients in the study were not treated according to accepted guidelines. Only 55% of high-risk patients were treated with pharmacologic cytoreductive therapy. This is notable, given that standard treatment guidelines, including National Comprehensive Cancer Network guidelines, recommend all high-risk patients receive such therapy.

Secondly, of those patients who were treated, just over half had a suboptimal response as defined by inadequate control of blood counts. This suggests that even those who were appropriately started on therapy still did not demonstrate adequate control of their disease, highlighting the need for better dose optimization of cytoreductive therapies and/or the need to transition to second-line agents if first-line therapy is ineffective.

Lastly, the choice of cytoreductive therapy, not surprisingly, demonstrates hydroxyurea as the most utilized therapy, but interferon use was essentially absent, demonstrating the minimal uptake of this established and effective therapy in community practice in the US.

These results are largely aligned with other real-world studies of PV patients in the US, including the large group of high-risk patients not treated with cytoreductive therapies, as well as the demonstration of ongoing inadequate blood count control in PV patients. While not surprising given this prior data, it remains somewhat perplexing to see this substantial group of patients not being treated according to established guidelines, which have remained largely unchanged for years.

Why was it important to do this study?

PV is a relatively uncommon disease across hematology and oncology. It is important to evaluate practice patterns in routine community oncology practices and document alignment with optimal, guideline-based care. This helps us better understand deficiencies in PV care so additional resources and education can be targeted to improve patient outcomes.  

How could the findings affect patient management?

The observational study doesn’t highlight new therapies, compare outcomes with existing therapies, or impact treatment guidelines. However, the study demonstrates the substantial number of patients with suboptimal disease control.

This suggests that the outcomes for patients with PV in the US could be positively impacted simply by stricter adherence to established treatment guidelines, and it highlights the need for ongoing disease education. The demonstration of more than 50% of patients on hydroxyurea with inadequate blood count control also demonstrates that, in addition to better optimization of this frontline therapy, increased utilization of additional cytoreductive therapies (interferons and ruxolitinib) and development of additional therapeutic options are needed.

What related research might you recommend?

 Numerous questions in PV remain unanswered that more robust real-world data could address. But as with this study, such questions are often limited by the available data.

To better understand treatment patterns and how we can increase adherence to guidelines, it would be important to delve into the reasons why patients in this study were or were not treated with cytoreductive therapies.

Several factors could also be looked at regarding suboptimal treatment response, such as the selected starting dose, dose titrations, changes to a second-line agent, as well as evaluation at additional timepoints. Longer-term follow-up would also be important to determine the impact of inadequate disease control (lack of therapy or response) on long-term thrombosis and survival outcomes.