Tomorrow 10/04, at 7:00 am ET, Sarepta Therapeutics (SRPT) with Dr. Mendell are hosting a conference call from Argentina at #WMS2018 the 23rd International Annual World Muscle Society meeting, to present and discuss new data from the micro-dystrophin gene-therapy study Ph1/2.
Link to SRPT webcast page: http://investorrelations.sarepta.com/events-and-presentations
Back in June 19th at the R&D day SRPT presented the biopsy data from the first 3 patients, along with the surprising CK levels as well. We are waiting for the 4th patient biopsy data to see the dystrophin-expression data and compare it to the first 3 patients. Also looking for a longer-term follow-up on the first 3 patients, as the data can include 6 months follow-up, while the first patient which dosed on 01/04/2018 can bring in as far as 9 months of follow-up vs. baseline.
I expect to see same or even better dystrophin-expression in the 4th patient, while in the first 3 patients the results were: Mean 38.2% micro-dystrophin as measured by Western blot compared to normal using Sarepta’s measurement or mean 53.7% using Nationwide Children Hospital- NCH’s method, which adjusted for fat and fibrotic tissue. Moreover; mean 76.2% of dystrophin-positive fibers – mean intensity of 74.5% vs. normal control and one vector copy per nucleus.
The next important data we also will look for is the “Functional Data” on NSAA- North Star Ambulatory Assessment as endpoint and its subgroups for the patients as far as 9 months vs. baseline, with the 100-meter Timed Test, the “Ascend and Descend 4 Steps Test”, Timed Up and Go test, Hand-held Dynamometry & more (NSAA has 17 item motor functional scale assessing abilities that are necessary to remain functionally ambulant).
The tough point in the case of the functional-data is the market interpretation to the results, while a stabilization on NSAA including several key efficacy parameters would be seen as de-risking for the gene-therapy study. The market will try to see how the 4 patients perform in the 100 meter test vs. healthy boys and DMD patients on steroids. We might see some off the chart discussion, but the presence of Dr. McDonald the world DMD expert will be helpful, he is independent and not involved with SRPT and the micro-Dystrophin study. Dr. McDonald can comment & add his standpoint and insight on the clinical results, adding from his long life experience with the DMD natural history.
At the R&D day SRPT presented another important data from the micro-Dystrophin study, the CK levels (creatine kinase, marker of muscle injury which is a key biomarker that is elevated as part of the Natural History of DMD) in all 3 patients declined 87% from the baseline to day 60, I expect the same or even better reduction in the 4th patient, but more important for us these days, is to get a look at the CK levels in all the 4 patients after a longer follow-up, and how the patients are doing in their daily life activity.
Disclosure: Author is Long SRPT