Ibalizumab (Trogarzo) Has a Reasonable Chance of FDA Approval

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Trogarzo (ibalizumab), a novel HIV medication, has a PDUFA action date of 4/3/2018.

In one form or another, Trogarzo’s history of preclinical development goes back to 1993. In the early 2000s a phase I clinical trial for the drug was run by Tanox Inc., a U.S. biopharmaceutical company.

Tanox was acquired by Genentech, Inc. in 2006. By 2007, TaiMed Biologics Inc. (a Taiwanese firm) licensed the medication from Genentech.


In 2003, the FDA granted ibalizumab Fast Track status, then Orphan Drug designation in 2014, and Breakthrough Therapy designation in 2015. Combined, this means:

  1. Ibalizumab has been recognized as a drug that is intended to treat a serious or life threatening condition (HIV/AIDS in this case).
  1. The FDA recognizes that ibalizumab has the potential to safely and effectively treat a condition (or subset thereof) that affects fewer than 200,000 people in the U.S. Ibalizumab is most likely going to be used in patients who have HIV that is resistant to other medications.
  1. Preliminary evidence suggests that ibalizumab may be substantially better in one or more relevant ways when compared to existing treatments for HIV.
  1. TaiMed can submit information in its Biologics License Application (BLA) for FDA review as it comes in, instead of submitting it all at once as most companies do when seeking FDA approval.
  1. As a result, the FDA will work along the way to speed up the development and review of this drug with greater organizational commitment. In other words, the FDA will work quickly yet just as thoroughly in order to get this drug approved so long as it’s truly safe and effective.


In 2016, Theratechnologies Inc. (Ticker: THERF) and TaiMed Biologics Inc. partnered to market and distribute ibalizumab (Trogarzo) in the U.S. and Canada.

A year later, the two companies reached an agreement whereby THERF obtained the commercial rights to Trogarzo in other territories, including the European Union and Russia.

In June of 2017, the FDA granted Trogarzo priority review for its BLA, with an expected PDUFA action date of January 3, 2018. This was delayed until April 3, 2018.

That’s because in October of 2017, the FDA requested TaiMed submit additional manufacturing information. TaiMed complied and the FDA had to extend the action date because the information TaiMed provided constituted a major amendment it needed more time to review.


Fluorescent Antibodies

Antibodies bound to a green fluorescent molecule have attached to a very specific portion of each cell in this image.

Trogarzo is the trade name for an HIV medication known generically as ibalizumab. During its very long history of development, Trogarzo has alternatively been referred to as TMB-355, TNX-355, and hu5A8.

Trogarzo is a monoclonal antibody. Antibodies are protein molecules produced by white blood cells in our body known as plasma cells.

Naturally, antibodies attach to very specific portions of something the body considers to be foreign, like a virus. After attachment, the antibody can trigger a sequence of molecular events that destroy the virus.

Alternatively, the antibody may serve as a beacon for other white blood cells to come and destroy the virus instead.

The fact that Trogarzo is a monoclonal medication means that all of the antibodies found in Trogarzo are exactly the same. As a result, all of the antibodies in Trogarzo bind to the same exact spot on a cell.


HIV & T Cells

In this image, HIV viruses (green) are seen escaping a T cell (blue).

Trogarzo is designed to treat people infected with the human immunodeficiency virus (HIV); the virus responsible for causing AIDS.

HIV uses white blood cells, known as CD4+ T cells, to replicate itself in the human body. HIV also destroys these same T cells via numerous different mechanisms.

This is a serious problem because T cells are responsible for keeping us safe from other infections. And so, as a person loses more and more T cells due to HIV, they risk succumbing to infections caused by other microorganisms.

So this is where Trogarzo comes in.

Unlike natural antibodies, which would normally attach to foreign entities like viruses, Trogarzo has been genetically engineered to attach to a specific part of the T cell that’s known as the CD4 T cell receptor.

The T cell receptor is like a “lock” to a T cell. HIV must first open this main lock in order to be able to insert the keys to “co-locks” thereafter.

Trogarzo doesn’t stop HIV from inserting its key into the main lock. However, Trogarzo jams this lock and prevents HIV from opening up the co-locks thereafter as a result. This is why Trogarzo is known as an “entry inhibitor”.

Since the HIV can’t enter the T cell, it can’t multiply itself and destroy the T cell in the process. Consequently, Trogarzo helps decrease the destruction of T cells and may decrease the chances a person with HIV/AIDS will come down with a lethal infection.


Monoclonal antibodies like Trogarzo have some major potential advantages when compared to traditional HIV medications:

  1. They last a long time in the body. This means they don’t have to be administered to patients very frequently. This helps improve patient adherence and quality of life.
  1. They can help treat HIV without suppressing the immune system. In fact, they might boost the immune system by stopping the destruction of T cells in the body.
  1. They can cut down on the number of significant side effects.

Potential disadvantages compared to other HIV medications include:

  1. The need to inject such medications into the body. They can’t be taken orally because they are pretty fragile and won’t survive the digestive processes in our stomach and intestines.
  1. Fluctuating pharmacokinetics (PK). Practically speaking, this implies it can be hard to figure out an effective dose for such a medication.
  1. A high cost of manufacture, passed on to consumers.


We’ll summarize the many known findings of phase I, II, and III clinical trials on ibalizumab as follows:

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Published: 2/21/2018

Last Updated: 2/21/2018

No one associated with this article has any financial stake in, or ties to, THERF.