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We are conducting an EPM-treatment effectiveness study that will compare the treatment response between two drugs. The new drug is compared to a drug selected from those that are available commercially. The commercially available drug is called the Active, we will compare our treatment to an Active. The FDA’s Freedom of Information (FOI) Summary reports important information that was used to license a drug, this information is publicly available. The FOI’s found for EPM treatments show between 15 and 59% effectiveness. Studies were done in less than fifty evaluable horses. It is important to replicate the parameters used to determine effectiveness in the Active in order to compare the results between the studies.

The effectiveness of two products (ReBalance® and Protazil®) defined a successful treatment when the Western Blot test on CSF, compared before and after treatment, were negative. That means if a horse did not improve clinically, but antibodies weren’t detected by CSF-immunoblot after treatment, the horse was considered successfully treated. The ReBalance study used a total of 26 horses to determine effectiveness. Rebalance® was successful in 15% of the horses, that means 4.2 horses showed an improvement in clinical exam after 90 days. A few more ReBalance-treated horses, 42%, improved after 210 days. And, if clinical exam was evaluated with western blot conversion to negative as the criteria for success…at 210 days, a few more horses were considered successes. One interpretation is that if no antibodies were detected then the parasites are gone; the horse didn’t improve because there was irreversible neurological damage. Although commonly believed, that is not our working model of EPM. We believe that neuroinflammation can be reversed, if diagnosed and treated properly.

The Protazil® FOI shows 59% of horses are better at 48 days, unless a negative western blot test is included in the effectiveness analysis. In that case, effectiveness is 67%. An advantage to comparing our drug to Protazil® is the duration to an expected response. The FOI reports an improvement 20 days after the end of treatment, day 48. That is a darn site better than 90-210 days.

The folks testing Marquis® reported in their FOI that “Western Blot of the CSF did not appear to be a major factor in determining treatment success nor a reliable measure of treatment success”. They used gait exam as their assessment parameter and showed 59% improvement based on that exam.

Remember it was shown (Furr et. al. 2006) that prophylactic treatment with anti-protozoals delay antibody production in horses given oocysts as challenge, the challenge is similar to how horses are naturally infected. It was Dr. Furr and his co-workers that showed a delay in antibody production did not indicate that clinical signs would be prevented when horses were given ponazuril as a preventive treatment. The down side to Marquis® is 110 days to show an improvement, 82 days after the end of treatment, and that is a bit too long for our ideal comparison.

There is one notable reference in the new Marquis® flyer we just received and worth a digression from our current topic. The flier cites a paper published years before S. neurona was isolated from an EPM horse! This paper is offered as evidence that ponazuril “kills the parasite that causes EPM to stop it from inflicting further damage to the central nervous system (CNS)”! The paper really reports the effects of trianzinones on developmental stages of Eimeria in chickens, no mention of S. neurona, EPM or CNS stages of sarcocystis that cause EPM. Eimeria are coccidian parasites, don’t develop muscle cysts, and does not cause EPM. Eimeria is found and stays in the gut of a chicken. The flyer also cites coccidia in calves, lambs, and pigs as references. We side with Dr. Dirikolu (JAVMA, Vol 242, 2013) that reviews in vitro and in vivo studies to “clearly indicate the removal of triazines after appropriate treatment time results in regrowth of parasites…suggesting that stages are inhibited and retain the ability to begin development again once the drug is removed”. That means the action of the drug, in horses with S. neurona infections, is static, it doesn’t kill (cidal) all the stages. That is one explanation why horses relapse on this treatment. That is why it is important to test the drug against the species of organism in the animal species for which it was intended.

We are conducting the study, in horses, to show the field effectiveness against suspected S. neurona in horses. From the forgoing information our logical selection is Protazil® as our active placebo for our study. We will evaluate the clinical response to the treatment, not an antibody difference measured on a test before and after treatment.

We proposed a study using two treatments. Veterinarians call this kind of study an active control effectiveness study design, there is no placebo because the active control serves as the placebo. The advantage with this type of study is that a client feels more secure that a horse with EPM is getting a treatment and not a “sugar pill”. A veterinarian can enroll a horse and we have to have some assurance that there will be 4 cases/site over a couple of years. The site is the veterinarians practice.

Orogin® is a drug that is designed to treat Equine Protozoal Myeloencephalitis (EPM) due to S. neurona in horses. The Orogin® effectiveness study uses an active controlled parallel arm effectiveness design with animals randomly assigned to treatment groups and receive either the investigational drug (Orogin®) or the active control (Protazil®). The study for Orogin® is limited to 70 horses. This is a study that will be part of our Freedom of Information Summary and, because it is an FDA study, it has a few strings attached.

This is not a placebo controlled study, the horse will get a drug to treat EPM. The signed Owner Consent form, is required. The owner consent form informs the horse owner that this is an investigational drug. Your horse will not be considered for entry into the study without this form in place. If you haven't signed this form, you are not in this study. Horses can receive an alternate treatment at day 10, if there is no improvement. Any horse that is removed from the study drug before the end of the study will be called a treatment failure. The horses are examined again at 48 days, the expected time for Protazil® to exert an effect.

What does it take for a horse to qualify for enrollment? The documentation for qualification is called the Qualification Record. There are three conditions that must be met to qualify 1) the horse must have a provisional diagnosis of EPM due to Sarcocystis neurona. 2) The animal must exhibit a minimum of a Grade 2 deficit, and the easy one 3) the animal is 9.6 months to 30 years. A Grade 2 deficit is defined as “neurological deficit obvious at normal gaits or posture; signs are exacerbated with manipulative procedures.”

There is a second part for the qualification into the study and that is disqualification because there are situations that will disqualify a horse. The horse can't be in another study or be unsuitable for this study. The horse can't enroll if it has another disease. If the horse can't get up, grade 5, or the owner can't get medication into the horse (or multiple folks will treat the horse) it won't meet the study qualification standards.

There are some other forms (all one page with check boxes) for the veterinarian to fill out, the Physical Exam form at day 0 and 48, the Data Collection forms at day 0, 10, 27, and 48 and a Supplemental History form (these document the criteria used to support the diagnosis of EPM). There is a blood draw before treatment and day 10, the blood is collected in a couple of red top and lavender top tubes, accompanied by a Sample Collection form. Owners participate in the observations by completing check boxes on the Client Observation form that note behavior, appetite, respiration, and occurrence of diarrhea for 28 days, the end of the Protazil® therapy. Additional space is provided for owner comments.

So far, so good. But the first inclusion criteria, a provisional diagnosis of EPM, may be the most difficult requirement for this study. The diagnosis of EPM must be supported by testing, along with any other diagnostic testing used generally by the veterinarian for the horse. This ensures the diagnosis is correct. The FDA set the standard as CSF analysis by Western Blot to support the diagnosis.

We recognize that CSF taps are not generally obtained in the field and most veterinarians test serum, or don't test at all. We strongly hold that serum testing guides the correct treatment and that is so important. Hopefully data from this study will support that rationale, just like the Marquis® study, that CSF testing isn’t the best criteria to determine a horse that will respond to treatment. What we know now, that was not known a few years ago, is that diseases (like S. fayeri or autoimmune polyneuritis) look like EPM but will not respond to ReBalance®, Marquis®, or Protazil®. That is why treatinginflammation that is common to S. neurona, S. fayeri, or autoimmune polyneuritis is important. We want to use the serum analysis to make these points in our FOI.

However, until there is a paradigm shift at FDA the horse must have a CSF tap to participate. We provide a CE course (3 credits) and teach a technique to obtain a CSF tap, in the field, in a standing horse. Field sedation techniques, using drugs most veterinarians have on hand, allow a veterinarian to get a CSF sample from the side of the neck. With a bit of practice, the tap can be obtained in a couple of minutes. You can email us for the link or go to the Learn More tab and copy the link from the slide presentation that describes Pathogenes CE program. We will run the CSF testing at no cost.

We are far from finished in our quest to make EPM treatable and affordable and need your help with these studies. If you desire new equine treatments in the pipeline veterinarians and owners will need to be proactive. From idea, to models, to field testing and ultimate use, it's expensive and time consuming. It's also highly rewarding. This is our commitment to the horse community and any part you can play is appreciated. A veterinarian can call and discuss the protocol and time commitments.

 

We believe new treatments are transformational when talking about protozoal disease. What inspires transformational thoughts and ideas?  Some think it is a mysterious process, right out of the blue, a light comes on.  More likely, innovation springs from many years of questioning, hard work, vigorous testing, and careful analysis.

We have reached the proverbial 10,000 hours (ref: Malcolm Gladwell, Outliers) studying EPM, creating models, and we are ready for a final analysis.  Our research started using models that defined the disease process and indicated that we could develop a beneficial treatment.  Years later, it’s time to put the models aside and statistically test our model.  Our first placebo controlled study for NeuroQuel is available, limited to 60 horse owners.  This is a study that will be part of our Freedom of Information Summary and because it is an FDA study it has a few strings attached.

NeuroQuel is a drug that is designed to control the residual or recurrent clinical signs due to inflammation associated with Equine Protozoal Myeloencephalitis (EPM) following antiprotozoal therapy in horses.  The field study will enroll horses that have failed to improve, or have relapsed after licensed EPM treatment (Marquis, Protazil, or Rebalance). The horses will receive NeuroQuel and we will evaluate the response to the treatment.

This is a placebo controlled study.  The first form, the Owner Consent form, is required.  The owner consent form informs the horse owner that there is a chance (a statistically calculated chance, 1 out of 3) that the horse will receive a placebo treatment.  Your horse will not be considered for entry into the placebo controlled study without this form in place.  If you haven’t signed this form, you are not in this study.

Does the horse qualify for enrollment?  Not surprising, the documentation for qualification is called the Qualification Record. There are three conditions that must be met to qualify 1) the horse was previously diagnosed and treated for EPM.  2) The animal exhibits recurrent or residual clinical signs with a minimum of a Grade 2 deficit, and the easy one 3) the animal is 6 months or older weighing 600 pounds or more.  A Grade 2 deficit is defined as “a defect that is easily detected and exaggerated by backing, turning or neck extension.  The horse may sway at a walk.  There may be a wide based stance after tight circling.  The horse is weak on the tail pull-easily pulled off track and does not return to a normal walk for 3 steps.”

There is a second part for the qualification into the study.  There are situations that will un-qualify a horse.  The horse can’t be in another study or unsuitable for this study.  The horse can’t enroll if it has another disease.  If the horse can’t get up, or the owner can’t get medication into the horse (or multiple folks will treat the horse) it won’t meet the qualification criteria.

There are some other forms to fill out, the Physical Exam form, the Data Collection form at day 0 and day 14, and a Supplemental History form (these document the criteria used to support the original diagnosis of EPM).  There is a blood draw before and after treatment, the blood is collected in a couple of red top and lavender top tubes, accompanied by a Sample Collection form.  Owners participate in the observations by completing check boxes on the Client Observation form for behavior, appetite, respiration, and occurrence of diarrhea.  Additional space is provided for owner comments.

So far, so good.  But the first inclusion criteria is the most difficult requirement for this study.  The original diagnosis of EPM must be supported by testing and other diagnostic testing as needed. The FDA set the standard as CSF analysis to support the original diagnosis.  After bioassay for antibodies in the CSF the horse must have received a full course of an FDA approved treatment, per label instructions: dose, duration, and frequency, no loading doses or multiple treatments.  Treatment must be what the sponsor intended when they licensed their treatment.  Treatment must be within 90 days of enrollment.  At the end of the FDA approved treatment, if signs (minimum Grade 2) are present, then the horse will qualify for this study.  Also, if within 90 days the horse “relapses” with a Grade 2 deficit, then the horse will qualify for the study.

We recognize that CSF taps are not generally obtained in the field and most veterinarians  test serum, or don’t test at all.  We strongly hold that testing allows the selection of the correct treatment and can be accomplished by serum testing.  Hopefully data from this study will support that rationale, CSF taps aren’t the best criteria to determine a horse that will respond to treatment.

However, until there is a paradigm shift at FDA, we provide a CE course (3 credits) and teach a technique to obtain a CSF tap, in the field, in a standing horse.  Field sedation techniques, using drugs most veterinarians have on hand, allow a veterinarian to get a CSF sample from the neck.  With a bit of practice, the tap can be obtained in a couple of minutes. You can email us for the link or go to the Learn More tab and copy the link from the slide presentation that describes Pathogenes CE program.

We will continue to use models that advance our ideas because idea-modeling will result in more treatment options for horses and their caretakers.  For example we learned about the effect Sarcocystis fayeri, a common protozoal infection in horses, can have on neuromuscular disease.  Another example is the presence of autoimmune disease in horses, when treated early the horse can have several more years of useful life. A  limited enrollment, placebo controlled study gathers statistical data.  After the “reasonable expectation” of clinical benefit study a conditional license is issued and a larger field effectiveness study is conducted.

We are far from finished and need your to help in these studies if new equine treatments are desired in the pipeline.  From idea to models to field use, it’s expensive and time consuming.  It’s highly rewarding.  This is our commitment to the horse community and any part you can play is appreciated.

Pathogenes has many partners in our quest to bring a safe equine therapy to market.  We have scientific partners, financial partners, veterinary partners, horse owners, and the government.  The government is everyone's partner in business.   In return for income tax the FED provides infrastructure and many other services that fly under the radar.

Our partnership with the FED’s will allow us to bring two drugs to the equine community.  In return for their services we provide a percent of fees for the life of the commercialized product. As part of the drug licensing process the center for veterinary medicine provides milestone goals and a path to complete those goals.  Our path is directed by guidance information documents, GFI’s.  As we accomplish each goal, we take the next step.

Our first milestone was developing a treatment and providing information to FDA that equine protozoal myeloencephalitis (EPM) is an important, rare disease.  Unprofitable for big pharmaceutical companies to develop the treatment of EPM falls under the (orphan) drug act, or MUMS.  Pathogenes commitment is to provide a safe and effective therapy that all can afford and its designation under MUMS makes that possible.  The MUMS program provides help with submissions, fee waivers, and guidance so we can accomplish our goals. the FDA has a big say in the studies that we run to meet milestones that lead to commercialization.

Starting the next field trial with NeuroQuel is a milestone. Before we could move forward with our therapies we had to produce a drug that had rigorous scrutiny in the manufacturing process. Unlike compounding (one- drug one-animal, no quality control for the drug substance activity/stability in the product) an FDA licensed drug must be carefully evaluated--that means nearly a million dollars is associated with  production.  A drug manufactured in a facility compliant with cGMP’s is licensed because it has achieved the rigors of ingredient and production testing.

A next step is the NeuroQuel PLACEBO CONTROLLED FIELD TRIAL.  There seems to be misinformation about placebo controlled trials so here are some facts to clear the air:

  • You must enroll to be considered for a placebo controlled trial.  You must sign a paper informing you of the nature of the study and by enrolling you agree that you understand the conditions of the study.
  • Enrollment documents explain the statistical chances that you will receive a placebo or the active drug.  If you haven’t signed an enrollment document, you are not in a placebo controlled trial!
  • Enrollment requires that information is given back to the study monitor!  If you have not completed in-trial and end of trial forms you are not in a placebo controlled study.
  • A horse enrolled in the study must satisfy some entrance criteria.  Entrance criteria can include age, weight, and recent treatment history.  A huge entrance factor in our placebo controlled study is diagnosis of EPM.

The up-side of these controlled studies is the quality of the information that is given to FDA.  The down side may be the number of forms that have to be signed!  We spent the last couple of years training veterinarians about EPM.  We gave our trained veterinarians continuing education for their help and attention.  Most discovered some new things about their EPM case, veterinarians didn’t learn everything they needed to understand EPM in veterinary school!  Most importantly, we found diseases that mimic EPM.  We spent a few years developing tests to identify EPM-mimicking disease so that our study isn’t compromised.  The recognition of these EPM-mimicking diseases did lead to publications that educated those veterinarians that are current with EPM topics.  Effective treatment of some of these horses (that didn’t respond to commercialized EPM therapies because they didn’t have EPM) became possible.

We are contacting our trained veterinarians that treat horses with EPM so they may enroll horses that have failed on commercial EPM treatments.  NeuroQuel is for the treatment of horses with residual or relapsing signs due to EPM caused by S. neurona.  Horses eligible for enrollment in the placebo controlled NeuroQuel study include a diagnosis of EPM with a cerebrospinal fluid analysis (CSF test) followed by treatment with the label dose of a licensed antiprotozoal therapy (no compounded products or off label drugs) within 90 days of enrollment.  Other conditions include age and the degree of deficit.  If you have a horse that was diagnosed with EPM by CSF tap, has not completely responded to Marquis, Protozil, or ReBalance using the dose on the label and has residual signs you may have a case that will qualify for our study.

For full information on the enrollment of horses into the placebo controlled field study please check out the downloadable documents at http://pathogenes.com/w/faq/.  Or use the contact information at www.pathogenes.com and we can help with the enrollment process.  Enrollment in these studies will help bring our treatment to market and bring new information to the equine community.

If you have a horse that does not qualify, please give us a call. It is important to document the reason the animal couldn’t participate.

For more information about placebos and the “placebo effect” please consider http://www.wired.com/2009/08/ff-placebo-effect/

Reference paper: Ultrasound-guided cervical centesis to obtain cerebrospinal fluid in the standing horse  Anthony Pease, Ashley Behan, George Bohart Vet Radiol Ultrasound 2012 53(1) 92-5

In some cases a cerebrospinal fluid analysis is used to support a presumptive diagnosis of equine protozoal myeloencephalitis.  The presence of antibodies against S. neurona is considered, by some, as evidence that parasites are in the central nervous system.  Research done so far on on oocyst challenge infections fails to support this view.  We believe that the inflammatory component of the EPM syndrome should not be ignored.

There is a need to define cases that are associated with S. neurona and those that are unassociated with protozoa; for some clinicians a CSF tap may be the defining test.  Testing CSF fluid will help us obtain the data to make an assessment of the utility of CSF analysis in field selection of treatable cases of EPM in a statistically meaningful study.  We don’t charge for antibody determination on CSF fluid when it is submitted with a serum sample for SAG 1, 5, 6 testing.  The veterinarian-signed paperwork must accompany the submissions for the no charge CSF testing.

Resistance to field collection of CSF are justified.  The lumbosacral space is used for CSF collection in the standing horse.  The limits of this procedure are technical expertise, blood contamination, and the distance from the cranium, the proposed site of the lesion.  In the field the risk of trauma to the veterinarian is great due to the close proximity of the clinician to the rear limbs.

Alternatively, a sample can be obtained from the atlanto-occipital space under general anesthesia.  Experience with obtaining an AO tap is a plus with this technique.  The risk of injury during recovery from general anesthesia in an ataxic horse is high.  And transporting an ataxic animal is not advised.

 

The ultrasound-guided cervical centesis was used in normal horses in the above referenced paper and may be a viable alternative for field veterinarians that want a sample from an ataxic horse.  A brief survey of veterinarians indicates that this was not a procedure that is in common use for acquiring a CSF sample from an ataxic horse, therefore we are reviewing the procedure here. The hypothesis is  that obtaining a tap at C1-2, with assistance from ultrasound, may provide an alternative to collection of CSF in a standing horse.  The horses used in the Pease study were in stocks.  The horses were sedated with detomidine hydrochloride followed by morphine.  The area is aseptically prepared prior to the sample collection.  A nose twitch is used when the needle is placed.

A 10-4 MHz, microconvex curvilinear transducer (oriented dorsoventrally) is placed at the level of C1-2.  An 18g, 3.5 inch needle with stylet is advanced to the dura mater, in a dorsomedial direction approximately 4 cm through the dura mater (with the stylet) and into the subarachnoid space.  The CSF sample is then collected with gentle suction (changing syringes after the initial 5 ml decreases blood contamination).  Post collection observations are conducted for 48 hours.  We have a demonstration video of this procedure available on line. Call for information.

We are following that long road to FDA licenses with our two drugs.  One will be used to treat horses with EPM.  The second drug will be used for horses that didn’t fully respond to EPM treatment or are suffering what is commonly referred to as a “relapse”.  To accomplish our goals we conduct field studies.

Our studies are listed on our web pages and some common questions are answered there, if you have questions, please email us and we’ll answer by email.  One concern is about the placebo.  Some placebo controlled studies are required by FDA.  In these studies, two out of every three horses will get the test drug and one will get the placebo.  Before the horse is enrolled into the study the owner must fill out and sign the Owner Consent Form.  The form will clearly state if the trial involves a placebo, but the form won’t indicate which drug is being given.  We have a statistician determine the enrollment into each treatment group and that eliminates bias.

The treatment is given for 10 or 14 days.  At the end of 10 days of treatment, the veterinarian will decide what the next steps are for each animal.  The continuing education program we initiated has prepared the vet  to handle the cases to the utmost of our research--they are up to date on our emerging technology.

You can decide what study would best suit your particular case by evaluating the inclusion and exclusion criteria. We have a computer programed to evaluate the submission and  data and help guide the study decisions.  Sometimes horses just don’t fit.

The inclusion and exclusion criteria are important.  We won’t take any horses into the study that are down and unable to stand.  These horses have special needs that won’t be met participating in the study —but call us, we are most happy to share our expertise in these cases.  The serum samples from these horses are very valuable to us, even in the unfortunate circumstance the horse is lost.  The data from these horses can’t fulfill our FDA obligations, but we use the samples to develop new protocols that can help others.  We will include horses with a Grade 2-4 on the gait assessment just as it is defined on the submission form.  The next criteria is to determine the presence or absence of serum antibodies to S. neurona. The antibody will help us decide if the horse has Idiopathic encephalomyelitis or if the provisional diagnosis suggests S. neurona as the cause.

 

This is Ranger Scherer.  He lived on a farm that had a horse with EPM.  He was tested even though he is “pretty normal” for a 5-year old gangly teenage boy--lots of energy, a little bit naughty, but quite sweet!”  He sent in his vote:  No on CSF!  Here’s why:

We determined in 2002 (and published the data in 2003) that specific antibody testing can eliminate the need for collecting and testing spinal fluid (CSF) in experimentally challenged horses, in this study we published data from 6 horses.  Further studies that were blinded--we used board certified veterinary neurologists to do the clinical exams gave us more information.  We the split samples of serum and CSF from 57 of the challenged horses and compared our SAG 1 ELISA results (for serum and CSF) with testing run by the folks in Kentucky.  They got samples pre-challenge and every 30 days for 4 months.  The statistician analyzed the data and determined two things.  First, the antibody levels are consistent with duration of infection and not the number of organisms in the animal.  And second, that there was no statistical difference in determining disease by testing CSF.  We now employ two additional, highly specific antigens in our ELISA’s to determine the phenotype of the infection—CSF is not required for these tests either.  We will measure the antibody in CSF if you submit it to us, but we don’t require it.

If you choose to enter a horse into our studies, you may do so.  Recently, in a Brief Communication, J Vet Intern Med 2013:27:596-599, Johnson, Morrow and Sweeney determined that when evaluating IFAT and SAG 2, 4/3 “using serum results alone was least accurate for both test types.  The more accurate methods, such as the SAG2, 4/3 ELISA serum: CSF ratio, should be used.”  These thoughts were reiterated in J Vet Intern Med 2013;27:1193-1200.  We stand by their recommendations and will accept this test that they reported as more meaningful to detect exposure to S. neurona:  a serum/ CSF ratio.  The IFAT (serum) disagreed with the SAG 2 4/3 ELISA (serum) in one third of the samples, not unlike the results we obtained from EBI in our studies.  The published recommendation is that the IFAT should also be supported by CSF testing.

The reason we won’t go into depth on these papers, as we have done in the past, the point is moot.  We realize that a significant part of EPM is mediated by inflammation.  IgG tests don’t discern inflammation, thus don’t discern EPM.  An ELISA that detects S. neurona antibodies can determine past and current S. neurona infections and that is a start.  These infections can lead to EPM, but they aren’t diagnostic.