These 4 meds were fast-tracked by the FDA in 2021

The FDA’s Fast Track program expedites the development and review of novel drugs/biologics that help with severe conditions and fulfill unmet needs. Sponsors usually request Fast Track Designation when obtaining permission from the FDA to administer an investigational drug or biologic to human participants when submitting the Investigational New Drug (IND) Application.

The number of requests for Fast Track Designations has been trending upward in recent years. In 2018, for example, there were 217 requests received, with 145 granted; in 2019, 151 of 255 requests were granted; and in 2020, 187 of 280 requests were granted.

Here’s a detailed list of some drugs that were fast-tracked in 2021.

Rylaze 

This biologic is approved for the treatment of acute lymphoblastic leukemia (ALL) and lymphoblastic lymphoma (LBL) in adults and children aged 1 month or older who are hypersensitive to E. coli-derived asparaginase.

Nearly 15% of children with ALL develop an allergy to the chemotherapy drug pegaspargase, which is a key component in ALL treatment and a form of asparaginase. Allergic reactions can lead to a phenomenon known as silent inactivation, which neutralizes asparaginase in the blood. 

If allergy occurs with pegaspargase, physicians usually switch to the biologic agent erwinia asparaginase. Issues with manufacturing, however, have resulted in global shortages of this agent.

Rylaze (asparaginase erwinia chrysanthemi [recombinant]-rywn) is the newest iteration in this class. It was developed to compensate for manufacturing shortages of erwinia asparaginase.

As a group, asparaginases can lead to liver damage, infection, allergic reactions, and more, with 55% of recipients exhibiting severe reactions.

Tembexa

Even though smallpox was eradicated in 1980, the FDA approved Tembexa (brincidofovir) as a medical countermeasure in the event that the variola virus becomes weaponized.

The variola virus was spread by direct contact and manifested between 10 and 14 days after infection, with symptoms such as fever, fatigue, and aches, as well as a rash that developed into pus-filled sores, which crusted and scarred. Complications of the infection included encephalitis and corneal ulcerations, as well as blindness.

Tembexa is an antiviral drug that is a lipid conjugate formed to mimic natural lipids in endogenous lipid-uptake pathways. Once in cells, brincidofovir is metabolized to release cidofovir, an antiviral agent. When cidofovir is added to an elongating viral DNA chain, viral DNA synthesis abates.

The efficacy of Tembexa was based on preclinical studies in animal models infected with a virus akin to the variola virus. Safety information was derived from a clinical trial in which the drug was used for a non-smallpox indication: patients undergoing hematopoietic stem cell transplantation. Common adverse effects include diarrhea, vomiting, and stomach pain.

Brexafemme

Brexafemme (ibrexafungerp) is the first antifungal with a novel mechanism of action in the past two decades. The last class—echinocandins—hit the market in 2001. 

This first-in-class triterpenoid antifungal is indicated for the treatment of vulvovaginal candidiasis. It inhibits the biosynthesis of β-(1,3)-D-glucan, which is part of the fungal cell wall. Like the echinocandins, it combats Candida and Aspergillus species. It boasts enviable safety/tolerability, few drug-drug interactions, and penetrates tissue well. This drug is available in an oral formulation. 

Importantly, Brexafemme is a CYP3A substrate and inhibitor. When used with CYP3A inhibitors, its dose should be decreased. Conversely, CYP3A inducers should be eschewed when this antifungal is used. This agent could be a teratogen, and should be avoided in pregnant women.

According to an article published in NEJM Journal Watch, possible off-label indications could include the treatment of severe, invasive fungal infections.

Trodelvy

Trodelvy (sacituzumab govitecan) was fast-tracked for the treatment of adults with triple-negative breast cancer that has metastasized. Patients must have previously received at least two therapies before taking the drug.

In an FDA press release from April 2021, Richard Pazdur, MD, director of the FDA’s Oncology Center of Excellence stated: “Metastatic triple-negative breast cancer is an aggressive form of breast cancer with limited treatment options. Chemotherapy has been the mainstay of treatment for triple-negative breast cancer. The approval of Trodelvy today represents a new targeted therapy for patients living with this aggressive malignancy. There is intense interest in finding new medications to help treat metastatic triple-negative breast cancer. Today’s approval provides patients who’ve already tried two prior therapies with a new option.”

This Trop-2-directed antibody plus topoisomerase inhibitor drug conjugate hones in on the Trop-2 receptor, which facilitates cancer growth and spread. The topoisomerase inhibitor exhibits toxicity toward cancer. 

In clinical trials, the objective response rate (ORR) was 33.3%, and the median duration of response was 7.7 months. This agent has a Boxed Warning for severe neutropenia and severe diarrhea.