FDA Approves New Asparaginase Product for Leukemia

M. Alexander Otto, MMS, PA

July 02, 2021

The US Food and Drug Administration (FDA) has approved a new version of asparaginase for use in children and adults who have developed hypersensitivity to asparaginase derived from Escherichia coli.

The new product is Jazz Pharmaceutical's Rylaze (asparaginase erwinia chrysanthemi [recombinant]-rywn), and it is approved for use in the treatment of acute lymphoblastic leukemia and lymphoblastic lymphoma.

Asparaginase, an enzyme that helps kill blood cancer cells, is a key component of chemotherapy for both conditions.

The problem is that about 20% of patients become allergic to the standard option, asparaginase derived from E coli.

The only alternative until now has been Erwinaze (also distributed by Jazz Pharmaceuticals), which, like Rylaze, is derived from Erwinia chrysanthemi, a plant pathogen related to E coli.

However, Erwinaze has been bedeviled by manufacturing problems and has been in short supply since 2016.

The situation has been "extremely disconcerting to patients, families and providers," and the hope is that Rylaze will "provide a consistently sourced alternative," Gregory Reaman, MD, the FDA's associate director of pediatric oncology, said in a press release.

Rylaze will hit the US market in mid-July. Jazz has been a distributor of Erwinaze as well, but it released its last batch in May, according to a spokesperson.

The key difference between the two products is that the asparaginase in Erwinaze is derived directly from Erwinia chrysanthemi, whereas the aspariginase in Rylaze is a recombinant product produced by different bacteria that have been genetically altered with Erwinia chrysanthemi DNA.

The approval for Rylaze was based on a study involving 102 patients (median age, 10 years) who developed hypersensitivity to E coli–derived enzyme or "silent inactivation" from neutralizing antibodies. In the study, almost 94% of patients achieved asparaginase target activity levels at the approved dosage of 25 mg/m2 IM every 48 hours. The study is ongoing, and investigators are currently evaluating IV dosing.

The most common side effects are hypersensitivity reactions, blood clots, hemorrhage, and pancreatic and liver toxicity. There is also a risk for fetal harm, so labeling advises women to use effective nonhormonal contraception during treatment and for 3 months afterward.

M. Alexander Otto is a physician assistant with a master's degree in medical science, and an award-winning medical journalist who has worked forseveral major news outlets before joining Medscape. Email: aotto@mdedge.com.

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