FDA's Approval of Besremi Marks 'One of the Most Important Developments' in Treatment of Polycythemia Vera

The Food and Drug Administration (FDA) approved the use of the novel agent Besremi (ropeginterferon alfa-2b-njft) for adults with polycythemia vera (PV) in November 2021.

Dr. Naveen Pemmaraju, an associate professor in the Department of Leukemia at MD Anderson Cancer Center, said in an interview with CURE® that since the approval, “things are going well in terms of being able to prescribe the drug to get it to patients with polycythemia vera.” He noted, however, that “even post-approval, all of us need to watch out for toxicity (and) side effects.”

The FDA approval was based on research showing that after 7.5 years of treatment with Besremi, 61% of patients with PV in the clinical trial experienced a complete hematologic response, meaning they had a red blood cell volume of less than 45% without a recent blood draw, normal white blood cell and platelet counts, normal spleen size and no blood clots.

“This is one of the most important developments in our field of myeloproliferative neoplasms and polycythemia vera,” Pemmaraju said. “The approval of the novel agent … Besremi has already become an important tool in the clinic to consider for our patients.”

Besremi belongs to a drug class called interferons — a group of signaling proteins made and released in response to a virus — which Pemmaraju describes as “more patient friendly as compared to previous interferon formulations.” He explained that Besremi and other interferons are given to patients via injection every 2 weeks to every month eventually, unlike other drugs in the chronic disease space, which are usually given orally.

The ability to self-administer Besremi can be convenient for some patients, but there are still limitations, he noted.

“I think on the one hand, it is convenient because you can do it at home. But it’s not an oral ... so it does require some ability to understand how to do it properly. Sometimes people may need to involve a caregiver,” he explained, adding that patients also need to watch forreactions at the site of injection.

Still, the dosing of Besremi is more accommodating to patients, Pemmaraju said. Previously, some patients with PV may have received Pegasys (peginterferon alfa-2a), another interferon often given in this population, once every week. Besremi, however, is given once every two weeks and is later reduced to once monthly, he explained.

Besremi also demonstrated safe and effective long-term results versus what is considered the standard of care in this setting, Hydrea (hydroxyurea), which Pemmaraju called “pretty exciting.”

Patients with PV also have the treatment option of the Janus kinase inhibitor Jakafi (ruxolitinib) after Hydrea failure or intolerance. In addition, several ongoing clinical trials are evaluating new agents for this patient population.

“All of a sudden now, in the field of polycythemia vera in particular — which has not had a lot of drug development over the past 30 years — you are seeing quite a bit (of development) now,” Pemmaraju said.

As with any recently approved drug, it’s important to watch for side effects, especially in patients with PV because they experience symptoms and complications caused not only by treatments, but by the disease itself.

“With (the) excitement of a novel agent, you have to look out for a couple of things,” Pemmaraju said. “You have to look out for novel toxicities, you have to look out for cost of the drug and then you have to look out for access to the drug.

“Oftentimes FDA approval is not the end of the story.”

He added that as a drug class, interferons can cause some serious toxicities, such as problems with the thyroid and liver; problems with thinking and mood, including suicidal thoughts and psychiatric changes; and general PV side effects we must always be on the look out for, such as blood clotting and bleeding. Physicians also need to watch for drug-to-drug interactions — what other medications a patient is taking that might have a reaction with Besremi. It is important, he emphasized, for patients to have an open conversation with their physician about all of this.

Pemmaraju noted that the long-term findings demonstrate that Besremi is very safe and well tolerated.

“I think the strength of this data set is that you have such a long follow-up,” he said. “It’s very comforting to see that. You don’t always have that long-term follow-up before you have a drug in the clinic.”

Pemmaraju said that approvals like this in a rare cancer type such as PV are important to push research forward and keep hope alive.

“I think what it makes me reflect on is … that I’m proud to be in this field of rare diseases because no matter how rare a disease is, it’s affecting you, it’s affecting your loved one, your family member, your friend, your community,” he said. “So I’m pleased to see that research at this level (is) resulting in new pathways (and) new drugs approved for even the rarest of rare diseases.

“It gives a lot of hope to all of us — patients, caregivers (and) researchers — to keep going.”

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