The US Food and Drug Administration (FDA) approved several drugs in November and December relevant to conditions treated by nurse practitioners and PAs. Approvals include treatments for polycythemia vera, hepatitis B, achondroplasia, and cancers therapies.


Besremi® for Polycythemia Vera

Besremi® (ropeginterferon alfa-2b-njft) injection was approved by the FDA to treat adults with polycythemia vera, a rare blood disease that causes the overproduction of red blood cells. The excess cells thicken the blood, slowing blood flow and increasing the chance of blood clots, noted the FDA.

Besremi is the first FDA-approved medication for polycythemia vera that patients can take regardless of their treatment history and the first interferon therapy specifically approved for polycythemia vera.

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The effectiveness and safety of Besremi were evaluated in a multicenter trial that lasted 7.5 years. In this trial, 51 adults with polycythemia vera received Besremi for an average of 5 years. Besremi’s effectiveness was assessed by looking at how many patients had a red blood cell volume of less than 45% without a recent phlebotomy, normal white cell counts and platelet counts, a normal spleen size, and no blood clots. Overall, 61% of patients had a complete hematologic response.

CytaluxTM to Detect Malignant Lesions

CytaluxTM (pafolacianine) is a fluorescence imaging agent that was approved by the FDA for use in adult patients with ovarian cancer to detect malignant lesions. Infused 1 hour before surgery, Cytalux binds to folate receptor (FR)-expressing cancer cells and illuminates under near-infrared light during surgical procedures.

The American Cancer Society estimated there were more than 21,000 new cases of ovarian cancer and more than 13,000 deaths from this disease in 2021, making it the deadliest of all female reproductive system cancers.

The approval was based on a randomized phase 3 trial designed to evaluate the safety and efficacy of Cytalux in patients with ovarian cancer or with a high clinical suspicion of ovarian cancer. Of the 134 women (aged 33 to 81 years) who received a dose of Cytalux and were evaluated under both normal and fluorescent light during surgery, 26.9% had at least 1 cancerous lesion detected that was not observed by standard visual or tactile inspection.

Cytalux had previously been granted orphan-drug, priority, and fast track designations. The product is supplied in single-dose vials containing 3.2 mg/1.6 mL (2 mg/mL) pafolacianine.

VoxzogoTM for Achondroplasia in Children

The FDA has granted accelerated approval for VoxzogoTM (vosoritide) injection to improve linear growth in children 5 years and older with achondroplasia and open epiphyses. This is the first drug approved for achondroplasia, the most common form of dwarfism.

People with achondroplasia have a genetic mutation that causes fibroblast growth factor receptor 3 to be overly active, which prevents normal bone growth. Voxzogo works by binding to natriuretic peptide receptor-B that reduces the growth regulation gene’s activity and stimulates bone growth.

Approval was based on a multicenter, randomized, double-blind, placebo-controlled, phase 3 study that evaluated safety and efficacy in 121 children aged 5 to 14.9 years. Patients who received vosoritide in the study grew an average of 1.57 cm/year taller than those in the placebo group. The study lasted 52 weeks after which patients were eligible to enroll in an open-label extension study. 

The most common adverse reactions reported were injection site erythema, injection site swelling, vomiting, injection site urticaria, arthralgia, decreased blood pressure, and gastroenteritis and occurred in less than 10% of participants.

Voxzogo is supplied in 0.4 mg, 0.56 mg, or 1.2 mg lyophilized powder in single-dose vials.

FyarroTM for Malignant Perivascular Epithelioid Cell Tumor

FyarroTM was approved by the FDA for treatment of locally advanced unresectable or metastatic perivascular epithelioid cell tumor (PEComa), a form of uterine sarcoma, in patients 18 years and older.

Approval was based on data from the multicenter phase 2 AMPECT study that evaluated the safety and efficacy of the drug in 34 patients diagnosed with advanced malignant PEComa. During the trial, patients received Fyarro intravenously weekly until disease progression or unacceptable toxicity.  

Overall, 92% of patients had a response that lasted at least 6 months, 67% had a response lasting 12 months, and 58% had a response lasting at least 2 years.

The most common adverse reactions associated with Fyarro were stomatitis, fatigue, rash, infection, nausea, edema, diarrhea, musculoskeletal pain, decreased weight, decreased appetite, cough, vomiting, and dysgeusia. 


PreHevbrioTM Vaccine for Hepatitis B

The FDA has approved PreHevbrioTM for prevention of hepatitis B virus (HBV) infection in patients 18 years and older.

PreHevbrio is the first FDA-approved 3-antigen hepatitis B vaccine. It contains the S, pre-S2, and pre-S1 HBV surface antigens to prevent infection caused by all known subtypes of HBV. Approval was based on data collected from 2 randomized, double-blind, phase 3 studies.

The drug is supplied in single-dose vials containing 1.0 mL. The vaccine is administered via intramuscular injection as a series of 3 doses (0, 1, 6 months) and the most common reactions were injection site pain and tenderness, headache, fatigue, and myalgia. The most serious adverse reactions were severe allergic reactions.

Rituxan® for Pediatric Hematologic Cancers

First approved in 1997, Rituxan® (rituximab) has most recently been approved by the FDA to be used in combination with chemotherapy for pediatric patients 6 months and older diagnosed with advanced stage CD20-positive, diffuse large B-cell lymphoma (DLBCL), Burkitt lymphoma (BL), Burkitt-like lymphoma (BLL), or mature B-cell acute leukemia (B-AL). 

Approval was based on a study that evaluated the safety and efficacy of the agent in 362 patients with previously untreated cancer. Patients were randomly assigned Lymphome Malin B (LMB) chemotherapy (corticosteroids, vincristine, cyclophosphamide, high-dose methotrexate, cytarabine, doxorubicin, etoposide, and triple-drug [methotrexate/cytarabine/corticosteroid] intrathecal therapy) or Rituxan plus LMB chemotherapy.

The most common adverse reactions reported were febrile neutropenia, stomatitis, enteritis, sepsis, increased alanine aminotransferase, and hypokalemia.


1. Besremi. Prescribing information. PharmaEssentia Corporation; 2021. Accessed December 13, 2021.

2. Cytalux. Prescribing information. On Target Laboratories, Inc; 2021. Accessed November 10, 2021.

3. Voxzogo. Prescribing information. BioMarin; 2021. Accessed November 10, 2021.

4. Fyarro. Prescribing information. Aadi Bioscience; 2021. Accessed November 10, 2021.

5. PreHevbrio. Prescribing information. VBI vaccines; 2021. Accessed November 10, 2021.

6. Rituxan. Prescribing information. Genentech; 2021. Accessed November 10, 2021.