SIPPET Study: Relevance to the Developing World

As the Annual Congress of the World Federation of Hemophilia concluded in Orlando, Florida I want to shift your attention to and comment on the significance of the SIPPET study to the developing world.

It is fair to say that a majority of the persons with a bleeding disorder live in the developing world and a majority in this group is yet to be diagnosed.  This is a very powerful statement and it is true.  The findings of the SIPPET study (SIPPET) have a whole different meaning to the developing world.  Let us revisit some of the premise of the SIPPET first, focusing on keywords used. Subjects in SIPPET were 'PUPs' (previously untreated patients) who were 'Toddlers' (<6 years old).

In the developing world PUPs and Toddlers are not mutually exclusive. I mean PUPs are not always Toddlers.

What was the definition of PUPs in SIPPET?  PUPs were defined as: "no previous treatment with any factor VIII concentrate, no treatment or minimal treatment (<5 times) with blood components (whole blood, fresh-frozen plasma, packed red cells, platelets, or cryoprecipitate), no treatment with investigational drugs, and a negative test for factor VIII inhibitors at the central laboratory."

By this definition a majority of the diagnosed bleeders in the developing world are PUPs.  This is due to the cost and chronic scarcity of purified (plasma or recombinant) factor in the developing world.  For example, I was a PUP until 29 years of age (in India) until I received my first dose of monoclonal antibody affinity-purified Factor VIII which I received in the US.  There are many PUPs in the developing world.  Some younger, some older.  These PUPs are not 'toddlers'.  Once again this is among the diagnosed bleeders.  In the undiagnosed population, ALL ARE PUPS irrespective of age!!
It is important to follow the adult PUP population in the developing world and chart their genetics and inhibitor development- a 'SIPPET' in adult PUPs.  Are the findings in this population are similar to those on toddlers?


Personal stories
I have previously written about my life in India with hemophilia.  After studying the SIPPET paper and knowing that by definition I was a PUP and on recombinant Factor why I did not develop an inhibitor (thankfully!)?  Here are my thoughts.  Yes, as a PUP, I started on purified plasma-derived Factor VIII.  Recombinant FVIII was not available in the early '90s.  After 4-5 years on this I switched to recombinant Factor in the mid-90s.  I do not have an inhibitor to FVIII as of today.


In the case of another Indian I know; he was diagnosed at the age of 25 and had received minimal treatment for hemophilia until he came to the US at 27.  By SIPPET definition he is a PUP. He started on Recombinant FVIII.  A Factor VIII recovery study showed the recovery was poor. Inhibitor analysis led to him being diagnosed with an inhibitor.


I am by no means suggesting any pattern of inhibitor development depending on treatment with plasma-derived or recombinant FVIII.  These anecdotes goes to validate that inhibitors can develop in PUPs of any age. The cost of treating and the consequences of not diagnosing and therefore not treating an inhibitor in bleeding disorders is too high to leave SIPPET to toddlers alone. A SIPPET-like study in PUP adults is warranted.

SIPPET Study: Relevance to the Developing World

As the Annual Congress of the World Federation of Hemophilia concluded in Orlando, Florida I want to shift your attention to and comment on the significance of the SIPPET study to the developing world.

It is fair to say that a majority of the persons with a bleeding disorder live in the developing world and a majority in this group is yet to be diagnosed.  This is a very powerful statement and it is true.  The findings of the SIPPET study (SIPPET) have a whole different meaning to the developing world.  Let us revisit some of the premise of the SIPPET first, focusing on keywords used. Subjects in SIPPET were 'PUPs' (previously untreated patients) who were 'Toddlers' (<6 years old).

In the developing world PUPs and Toddlers are not mutually exclusive. I mean PUPs are not always Toddlers.

What was the definition of PUPs in SIPPET?  PUPs were defined as: "no previous treatment with any factor VIII concentrate, no treatment or minimal treatment (<5 times) with blood components (whole blood, fresh-frozen plasma, packed red cells, platelets, or cryoprecipitate), no treatment with investigational drugs, and a negative test for factor VIII inhibitors at the central laboratory."

By this definition a majority of the diagnosed bleeders in the developing world are PUPs.  This is due to the cost and chronic scarcity of purified (plasma or recombinant) factor in the developing world.  For example, I was a PUP until 29 years of age (in India) until I received my first dose of monoclonal antibody affinity-purified Factor VIII which I received in the US.  There are many PUPs in the developing world.  Some younger, some older.  These PUPs are not 'toddlers'.  Once again this is among the diagnosed bleeders.  In the undiagnosed population, ALL ARE PUPS irrespective of age!!
It is important to follow the adult PUP population in the developing world and chart their genetics and inhibitor development- a 'SIPPET' in adult PUPs.  Are the findings in this population are similar to those on toddlers?


Personal stories
I have previously written about my life in India with hemophilia.  After studying the SIPPET paper and knowing that by definition I was a PUP and on recombinant Factor why I did not develop an inhibitor (thankfully!)?  Here are my thoughts.  Yes, as a PUP, I started on purified plasma-derived Factor VIII.  Recombinant FVIII was not available in the early '90s.  After 4-5 years on this I switched to recombinant Factor in the mid-90s.  I do not have an inhibitor to FVIII as of today.


In the case of another Indian I know; he was diagnosed at the age of 25 and had received minimal treatment for hemophilia until he came to the US at 27.  By SIPPET definition he is a PUP. He started on Recombinant FVIII.  A Factor VIII recovery study showed the recovery was poor. Inhibitor analysis led to him being diagnosed with an inhibitor.


I am by no means suggesting any pattern of inhibitor development depending on treatment with plasma-derived or recombinant FVIII.  These anecdotes goes to validate that inhibitors can develop in PUPs of any age. The cost of treating and the consequences of not diagnosing and therefore not treating an inhibitor in bleeding disorders is too high to leave SIPPET to toddlers alone. A SIPPET-like study in PUP adults is warranted.

SIPPET The MASAC response:Recommendation Document #243: My thoughts and questions

What if MASAC?

A few of my readers, primarily those not residing in the US, have asked what is MASAC? The acronym stands for Medical And Scientific Advisory Committee.  Per the National Hemophilia Foundation (NHF), a national US based organization, MASAC was developed to advance clinical care and promote hemophilia research.  You can read more about MASAC's role and its previous recommendations here.

MASAC on SIPPET

Over the past 7 months the hemophilia community speculated on what the SIPPET study was and what its results really meant to them. Now MASAC is here with its recommendations on SIPPET in MASAC document # 243.

Here are some of the fundamental facts based which I make my comment:

• SIPPET studied only toddlers with Hemophilia A (Factor VIII deficiency)
• SIPPET studied only previously untreated patients (PUPs).
• Only 18 of 251 PUPs studied were from the US.
• MASAC as an advisory committee is part of the National Hemophilia Foundation (NHF), a US based national organization. MASAC makes recommendations for patient care in the US.
• I have Hemophilia A, am 55 years old, without inhibitor (never had one). I have used recombinant FVIII for over 20 years.

In the season of disclaimers and disclosures, I have the following claimer: These are solely my opinions. I have not received any funds from plasma-derived or recombinant product manufacturers to express my thoughts.

So let's get right to it. Like everyone else who is SIPPET-aware in the hemophilia community, I too waited to hear what MASAC had to say. Initially, I had set very high expectations for MASAC. I expected a clear-cut opinion - If you fall in this category... do this, else do that. Very quickly, I lowered my sights. I suspected MASAC could not show a preference of one product over another. Very fair. Then how would they respond to increased incidence of inhibitors using recombinant products.

They released a statement on Jun 28, 2016. Here are the bullets from MASACs recommendation and in italics are my thoughts.

MASAC Recommendations

Based on currently available evidence, MASAC makes the following recommendations:

1. Individuals with greater than 50 exposure days (ED) to any recombinant product (i.e. Previously
Treated Patients or PTPs) should consider remaining on their current product, since multiple
clinical studies have shown that their risk for inhibitor development with any FVIII product is
markedly diminished after 50 EDs
Well, I fall in this category. Here the indication is to not 'rock the boat'. If you are treating with product X, stay with the same. Sounds good to me and in line with my plans. I am also delighted to know that my chances of developing an inhibitor is low to none. All round good news for me. But then what about that new product that has a longer half-life; the one in the horizon that is injected subcutaneously; the one with a cryptic name, ALN-AT3 (reminded me of R2-D2). There are numerous products in the works (a.k.a pipeline). If someone such as me, stays on his/her product based on MASAC, who would be on the new products. PUPs? At my clinic visit my hematologist shares her experience with new products and recommends a me to switch. Should I? What if I develop an inhibitor after the switch? Can my hematologist answer this question, can MASAC? Clearly, the answer is 'maybe not'. Inhibitors are truly an unknown. I do not believe that predisposition to inhibitors is geographic or ethnic. 

2. Individuals with more than zero and less than 50 exposure days should consider staying on
their current recombinant FVIII product, since the differences between SIPPET and
numerous other studies may not warrant switching patients who have already initiated a
treatment regimen.
Once again, if I understand this guideline, no product switch is recommended (' consider staying on their current recombinant FVIII product') to this group of patients. Then who gets to try out the products in the pipeline? PUPs, again? MASAC document states "PUP studies have been published for each new FVIII product introduced to the market in the past 25 years.". Has this data been shared with the consumer- either by the manufacturer or the national organizations (NHF, HFA). Is it hosted online for me to view. Such data would help me and many others like me choose a product to switch to. This bullet also directly addresses 'current recombinant FVIII product' users. What is recommended to non-recombinant users, having less than 50 exposure days? I would like to see MASAC address this population.


3. Newly diagnosed individuals and their caregivers should consider the new data from the
SIPPET study in the context of all the accumulated data on inhibitor formation in PUPs and
the pathogen safety risk/benefit of the two product classes and consider the following
options:
a. Initiate therapy with a pdFVIII/VWF product in all PUPs.
b. Initiate therapy with a rFVIII product as previously recommended by MASAC (6).
c. Initiate therapy with a newer rFVIII product.

For once, MASAC's recommendation is clear to me with 3 (a). All PUPs 'treat with pdFVIII/VWF product '. MASAC members have spoken and given good direction, based on the cumulative wisdom gathered from the universe of hemophilia research and their own medical experiences, weighing in on the results from SIPPET. I was excited to read this. Then, it got murky with 3(b) and 3(c). What is MASAC really recommending to PUPs or 'Newly diagnosed individuals'. Is it pdFVIII/VWF or is it rFVIII or is it R2-D2, ACE910 (new products)?  If they are indeed saying that PUPs pick any product have they really considered the results from the SIPPET study.  Perhaps they are waiting for a similar study exclusively on US based patients.

The referenced document (6) in 3(b) is titled:

       6. MASAC Recommendation regarding the use of recombinant clotting factor products with
        respect to pathogen transmission. MASAC Document #169, 2006

I have always known recombinant products to be safer than plasma-derived. MASAC does acknowledge this fact, though it also cautions us on the potential transmission of the new and emerging viruses such as Zika, SARS in a pdFVIII/VWF product. So, once again, is MASAC saying that these viruses could pass through the manufacturing stages, in theory, and infect? So now has it come down to the debate of choosing between Inhibitors vs. virus, for PUPs and newly diagnosed? Who will take the final decision? The family of the PUP who in all likelihood knows very little about these nuances OR the medical team? If it is the medical team, for the care to be standardized across treatment centers they will need clearer direction from MASAC or data from prospective studies. Perhaps MASAC is looking for additional SIPPET-like clinical trials conducted in the US before they can do this (I know I am repeating this). For now, recommending 3(b) and 3(c) alongside 3(a) to PUPs is confusing.

4. Regardless of which option is chosen, all PUPs should be enrolled in the ATHN data collection system or a clinical trial to assess outcomes.

As I alluded to above is data collection through HTCs for ATHN being analyzed for new inhibitor development as part of a clinical trial. If so, then there is data available from US based studies and MASAC can release a statement on it. Such a report, even if interim, would promote willingness in the community to enroll PUPs. If not, then it is simply a reminder to enroll PUPs and has little to do with 'MASAC on SIPPET'.

5. For all classes of treatment products, the risk for inhibitor formation in PUPs is unacceptably high. All efforts by government, HTCs, patient advocates, and industry should be directed at reducing the risk of inhibitor formation.

I agree here. An incidence of inhibitors, even at 26.8%, is too high a number, with a lot of implications. There are products in the horizon which help clotting in inhibitor patients by bypassing inhibitors. These are exciting times as Dr. Glenn Pierce wrote in PEN magazine.

In Summary

With this document MASAC have covered all patients under their oversight who receive FVIII products- PUPs and non-PUPs.  They agree that inhibitors have been on the rise since the introduction of recombinant products in 1992.  They attribute this to closer monitoring of inhibitor development and more sensitive assays since the 90s.  They acknowledge that the SIPPET study was across a diverse patient population while previous, similar studies were in primarily "Caucasians".  SIPPET has studied only a small number of patients (16%) on 3rd generation recombinant product, which a majority of the US based patients are such products, recommending that the community do not extrapolate the SIPPET results to newer and in-pipeline products.


They have stated also that all new products are studied on PUPs.  Where is this data?  Were inhibitor development studied over 50 exposure doses? MASAC points to the fact that in the SIPPET study did not follow patients after 50 EDs.  Well, the study was terminated prematurely due to a World Federation of Hemophilia announcement to consider not using Kogenate FS, for newly diagnosed patients with Hemophilia A, when other, safer, clotting-factor concentrates are available. This was due to higher risk of inhibitors.


MASAC suggests that 'risk of inhibitor development must be weighed against transmission of pathogens via pdFVIII/VWF'.  Here they are re-stating the obvious- do a risk-benefit analysis.  But, who does this analysis? Is it the patient? How does he/she figure this out if he/she plans to switch to a newer product. If it is the doctor, does he have all the inhibitor development data to faithfully perform this analysis?  I am aware of a few new products available to me to switch to right now or coming soon. Where do I find the information I need to make the decision to switch with confidence?


If you, my reader, has similar or additional questions or answers I'd love to hear from you in the comments section below or in an email.

EHC on SIPPET

The European Haemophilia Consortium (EHC) has 45 National Member Organisations (NMOs) from 27 Member States of the European Union (EU) and most Member States of the Council of Europe. Simplified, EHC is the NHF equivalent of the EU. EHC has posted their own response to the SIPPET study here.


Brexit impact on hemophilia care in Europe


The European Association for Haemophilia and Allied Disorders (EAHAD) is a multi-disciplinary association of healthcare professionals who provide care for individuals with haemophilia and other bleeding disorders. Its members include hematologists, nurses, physiotherapists, laboratory scientists and researchers from across Europe. The Brexit vote on June 24, 2016 and UK's decision to part from the EU could have an impact on collaborations between the different member states and UK. To minimize this impact the president of EAHAD published this letter on June 28, 2016.
 


Next post: What does SIPPET mean to the developing world?  Who is a PUP in the developing world?

SIPPET Study simplified

The Study
SIPPET is an acronym for 'Study on Inhibitors in Plasma-Product Exposed Toddlers'.  The SIPPET study, published in The New England Journal of Medicine (NEJM), is a clinical trial conducted on male toddlers under age 6 diagnosed with Factor VIII deficiency with anti-coagulant activity of < 1IU/dl and no inhibitors. The principal investigators were based in Milan, Italy, however this study was conducted (between 2010-2015) in 5 countries (India, Egypt, Iran, USA, other).  Prior to this study participants had received either no treatment or minimal treatment with blood products (whole blood, FFP, packed red cells, platelets or cryoprecipitate). 

The Products
The Factor products used in this study varied based on what was licensed for use in the country.  One plasma-derived (Pd) and 1 recombinant (Re) product was used in each country.  Patients were randomly assigned to one or the other product. The Pd products used were:  Alphanate and Fanhdi (Grifols), Emoclot (Kedrion Biopharma), and Factane (LFB Biomedicaments ). The Re products were: Recombinate and Advate (Baxalta), Kogenate FS (Bayer AG) and ReFacto AF (Pfizer).

The Study Design
The investigators had determined, based on some statistical analyses, that a sample size of 300 would be sufficient, accounting for a 10% dropout rate.  The steering committee overseeing the trial decided to terminate the trial in May 2015.  This was done in response to announcement by the World Federation of Hemophilia to consider not using Kogenate FS, for newly diagnosed patients with Hemophilia A, when other, safer, clotting-factor concentrates are available. This was due to higher risk of inhibitors.  I assume this put some limits on conducting the trial in certain countries, possibly due to product licensing issues.


Even though they did start with 303 patients assessed for eligibility, 264 were randomized to receive either Pd or Re Factor VIII. A further pared down patient number- 125 in the Pd group and 126 in the Re group were analyzed. The investigators then characterized these patients based on country, age at first treatment, type of mutation, mutation status (null, not-null), family history of hemophilia, family history of inhibitor development, race or ethnic group, previous treatment, type of treatment (on-demand, standard prophylaxis, modified 'once weekly' prophylaxis and brand of Factor VII used. They have further monitored the inhibitor development characteristics based on type of inhibitor ( all, titer- high/low/peak, persistent/transient) and time of development based on exposure days. A data was analyzed for their statistically differences between the two patient groups.


The Results and Interpretations
The results from the analysis of regression models, have lead the authors of this study to conclude that the rate of inhibitor development was 87% higher with recombinant factor VIII than with plasma-derived factor VIII.  In the editorial, in the same issue of NEJM, Donna DiMichele MD wrote:

"these data must now be integrated globally into the multifactorial decision-making processes underlying product selection for at-risk children with severe hemophilia A. The results are scientifically compelling. Endocytosis, clearance, and antigen presentation are affected by factor VIII protein glycosylation and von Willebrand factor association. That both glycosylation and association with von Willebrand factor are altered by recombinant technology lends immunologic plausibility to the implication that the product source plays a role in inhibitor generation and provides valuable mechanistic insight into the conundrum of factor VIII immunogenicity."



The following is my interpretation of this quote: The results from this study are compelling. the recommendation is to select the product source carefully before starting to treat at-risk (for inhibitors) children with severe Hemophilia A.  Dr. DiMichele refers to an article based on which she surmises that the source of the Factor (in this case Recombinant vs. plasma-derived) could make a difference in the immune response developed to Factor.  The chemical structure of recombinant Factor is different from that in plasma-derived. Further, von Willebrand factor is missing in the recombinant product.  These chemical differences in the Factor VIII structure may lead the inhibitor development noted in the SIPPET study.

The Study Author's Disclosure
To address potential conflicts of interest, the authors have disclosed that Grifols, Kedrion Biopharma and LFB have provided grants to the Angelo Bianchi Bonomi Foundation.  This Foundation is the primary funding agency for this study.  However, they had no input in the trial design; protocol preparation; patient recruitment; data collection, handling, and interpretation; or writing of this publication. The full disclosure by corresponding author, Dr. Peyvandi is available for review here.


Coming soon
What does this study result mean to the patient or the caregiver?  Has this trial answered any question conclusively or has it opened up new ones?  Whom can you look to for answers?