Monday, September 4, 2017

ViaCyte Clinical Trial News: VC-01 is Fully Enrolled, VC-02 Starts

This blog posting covers two important pieces of news from ViaCyte.

ViaCyte's Phase-II Trial of VC-01 is Not Recruiting
(But What does that mean?)

I missed this news, when it was announced back in May 2017, but ViaCyte's Phase-II clinical trial of VC-01 is not recruiting more people.  I'm not sure if this is a "pause" between their phase-I group and their phase-II group, or if they have finished recruiting all people for both groups.  That's important because they are gathering effectiveness data for six months.  So whatever group they finished recruiting in May, they should have effectiveness data in November.  Effectiveness data for 15 people would be good, but from the full 65 people would be even better.  Since this trial is not blinded (and has no control group), they could publish their data as soon as they have it, if they want to.

Also, they are gathering safety data for two years, so that same group will finish gathering safety data in May 2019.  The same "15 people is good 65 people is better" and "with no control group, they can publish if they wish" applies to this safety data as well.

Clinical Trial Registery:

Differences Between ViaCyte's VC-01 and VC-02 Treatments

ViaCyte has started a clinical trial for their VC-02 stem cell implantation product, but as this treatment is not a cure (by my definition of "cure"), I will not be following it.  Don't mix up VC-02 with their earlier VC-01 product.  VC-01 is a potential cure, and I will follow it moving forward.

I found this confusing: why would a company test a non-cure after they had a cure already in the pipeline, and ahead of the non-cure?  Why even bother with the non-cure?

While VC-01 and VC-02 are encapsulated stem cells, the nature of the encapsulation is completely different.  VC-01 uses a "strong" encapsulation which prevents the body's immune system from attacking the new cells. This prevents both the normal rejection (ie. the foreign organ reaction), and type-1 rejection (ie. the malfunctioning autoantibody reaction) from attacking the new cells.  Therefore, VC-01 does not require anti-rejection drugs.  VC-02 uses a "weak" encapsulation which holds the stem cells together and in one place, and encourages new blood vessels to integrate into the encapsulation, but provides no immune protection.  People getting VC-02 will need to take anti-rejection drugs [d1].

Both VC-01 and VC-02 have the same cells inside.  They both start with ViaCyte's PEC-01 cells. These are created by harvesting human embryonic stem cells from a long-existing culture and treating them so they differentiate into pancreatic cells.  The cells that are inside the devices are these pancreatic cells.   (There are no "raw" stem cells in the device.)  This process is described on ViaCyte's web site here:

The obvious question is, why would any person with type-1 diabetes choose to be in the VC-02 trial, if they could be in the VC-01 trial?  The immunosuppression required by VC-02 has known bad side effects, and there are known risks in taking those drugs for decades.

First is that the VC-01 trial is not recruiting right now.  So if you want an encapsulated ViaCyte stem cell treatment right now, VC-02 is your only option.  I don't know if the VC-01 trial is completely enrolled, or if it will open up again, to gather a second group of patients.

Second is this: The ViaCyte team believes that the reason some implanted beta cells work and some fail is "vascularization".  Vascularization is the body's ability to grow blood vessels into the new beta cells so that they can get oxygen, remove waste products, and generally integrate with the host person.   ViaCyte believes that the encapsulation used in VC-01 will allow this vascularization and therefore be successful.   However, they also believe that VC-02 will have even better vascularization, and therefore an even higher chance of success.  So if someone currently has type-1 diabetes, they may choose to have VC-02 because it has a higher chance of success (even if this is a trade off against a known higher risk from the treatment).

The VC-02 Study

Although there is only one official clinical trial of VC-02, there are two patient groups within this trial (which they call "cohorts"), and these cohorts are really separate phase-I and phase-II trials. It's just that one clinical trial registry covers both. The first cohort will be 15 patients, all of whom will get a low dose version of the treatment. The second cohort will be 40 patients, all of whom will get a higher dose version of the treatment. There is no control group. They expect to finish the second cohort in Dec 2020.

They are collecting their primary safety data at 4 months post transplant, and primary effectiveness data (C-peptide data) at 6 months post transplant.

They are recruiting at two sites:

  • University of California San Diego, San Diego, California, United States, 92121
    Contact: Study Coordinator    1-844-317-STEM (7836)
  • University of Minnesota Recruiting, Minneapolis, Minnesota, United States, 55455
    Contact: Study Coordinator    612-626-4993

Clinical Trial Registry:
ViaCyte's FAQs:

Joshua Levy 
publicjoshualevy at gmail dot com
All the views expressed here are those of Joshua Levy, and nothing here is official JDRF or JDCA news, views, policies or opinions. My daughter has type-1 diabetes and participates in clinical trials, which might be discussed here. My blog contains a more complete non-conflict of interest statement. Thanks to everyone who helps with the blog.


Rick said...

I think VC-02 makes sense for many reasons. The best is that it is temporary and as we know temporary things, even new temporary things, might have a better chance of quicker FDA approval. I think the better way to look at it is this, why waste money on VC-02 if VC-01 was not showing progress?

Frank Meeuwissen said...

Here's the explanation from Viacyte's own website:

"Why is ViaCyte pursuing PEC-Direct product candidate now, when PEC-Encap is in clinical-stage testing?

The PEC-Encap product candidate is being tested in the clinic first because if it moves quickly in the clinic it could become a functional cure for all T1D patients. However, ViaCyte has also been developing the PEC-Direct product candidate in parallel, as a therapy for T1D patients that are at high risk of acute complications.

ViaCyte is making a great deal of progress with PEC-Encap, demonstrating that it has thus far been safe and well-tolerated, that the Encaptra device is immunoprotective (no evidence of allo- or auto-immune rejection or sensitization), and that long-term cell viability is feasible. While ViaCyte is not yet ready to move to the Phase 2 stage of clinical development with the PEC-Encap product candidate, the team continues to work towards that goal.

In the meantime, the observations with PEC-Encap are informing the development of PEC-Direct as an important first-generation product for the T1D patients with the highest unmet medical need. With multiple product candidates being investigated and developed, ViaCyte has a greater chance of helping diabetes patients that can potentially benefit from the islet cell replacement therapy technology as soon as possible. Given the potential therapeutic value of this novel beta cell replacement therapy, we feel it is important to get it to the patients with the most urgent unmet medical need as quickly as safely possible."

Male said...

I am disappointed you will not be following ViaCyte's VC-02 pec direct product human trial.