Rituxan Biosimilar

Results from the Phase 3 clinical trial called REFLECTIONS B3281006 were announced a few days ago. The trial compares Rituxan with a biosimilar called PF-05280586. The study found that the biosimilar had an Overall response rate that was the equivalent of Rituxan's.

Some reminders: A biosimilar is kind of like a generic version of a drug. However, a drug is created with a chemical formula. After a certain period of time, a drug loses the patent protections that are given to the company that developed it. Once those protections are gone, other companies can develop generic versions of the drug and sell them under a different name. It's relatively easy to do once they figure out the chemical formula.

A biosimilar works in the same general way. When the patent protection for Rituxan expired, other companies could come in and make their own version.

The difficulty is, Rituxan is not a drug. It's a biological treatment. That means the manufacturer can't just go to the chemical store and mix some up. Biological treatments are made from living things. And living things are complicated. So making copies of them are complicated, too.

It's certainly possible to make a biosimilar, but it takes some time, and you have to show that you did it right, and that patients taking it will get the same benefits, without harsher side effects, than those who take the original.

And that's what's happening in the REFLECTIONS B3281006 trial. There were 394 participants in the trial, all of whom had low tumor burden Follicular Lymphoma, and had not yet received any treatment. Half of the patients were given Rituxan, and half were given the biosimilar. The initial results show that the Over Response rate was the same for both.

So far, that's all the manufacturer of the biosimilar is saying. They plan to present more data at a future medical conference (maybe ASCO in June? That's just my guess -- the timing seems right). I assume they will use the results of this trial to seek FDA approval.

This would be the second Rituxan biosimilar to seek FDA approval, assuming they do seek it. The first was Rixathon. The application for Rixathon went to the FDA last September. Rixathon has already been approved by the European Commission.

So what does this mean for Follicular Lymphoma patients?

The biggest reason for a company to develop a biosimilar is that it will make them some money. Rituxan is one of  the most popular blood cancer treatments in the world. It is on the World Health organizations list of Essential Medicines. It has made its manufacturer a lot of money.

Getting a piece of that with a biosimilar will make someone else a lot of money, too. And it will do it, of course, by charging less. Just like a generic version of a drug is cheaper, so will (it is assumed) a generic version of a biosimilar.

For patients, that could be very good news. Rituxan isn't cheap -- no cancer treatment is. Lower costs could help a lot of patients. Insurance companies must be less reluctant to add Rituxan to chemo, or to allow an extra round on its own. And lower costs all around show (it is assumed) reduce insurance costs for patients.

It will be interesting to see how biosimilars play out, once they are approved. Will insurance companies insist on them? Will doctors, if given a choice, stay with what they know (Rituxan) rather then the newer biosimilar? Will patients have an opinion? Will any switch to biosimilars happen right away, or will the people who choose them wait for more longer-term results of studies?


Time will tell. But my own personal opinion, as a patient, is that more options for us is usually a good thing.