More Safety Questions for Glaxo DMD Drug; Sarepta Meets With FDA Soon

P/>BOSTON ( TheStreet) -- A GlaxoSmithKline ( GSK) scientist, Dr. Rohit Batta, may have been trying to soothe the nerves of Duchenne muscular dystrophy parents when he provided another update about drisapersen on Monday. I believe he raised even more concerns about the experimental drug's safety profile.

Here's the passage from Batta's email, sent to Parent Project Muscular Dystrophy, that stood out to me:

The story that appeared on the investor website highlighted the point that a small number of boys in the clinical trial programme were hospitalised due to thrombocytopenia (a decrease in the number of platelets or small cells that help blood to clot) and proteinuria (excessive protein in the urine). The boys have all recovered, following withdrawal of drisapersen and appropriate medical management. My emphasis in bold.

Toxicity requiring treatment with drisapersen to be stopped is not good thing! Drug withdrawal is more serious than if treatment was merely interrupted.

Batta adds:

It is important to note that it is usual practice for an investigator to admit a boy to hospital if necessary, for the boy to be appropriately treated and to recover.

Fine, but Batta is totally downplaying the seriousness of these toxicities. The boys required hospitalization! Yes, they recovered -- and that's a good thing -- but why is drisapersen causing some boys -- even a small number -- to be hospitalized for thrombocytopenia and proteinuria?

GlaxoSmithKline has much more safety data on drisapersen already collected from a completed phase II study but has so far declined to make it public. Perhaps it's time to do that.

My story from last week on the patients hospitalized after drisapersen therapy can be found here.

Meantime, Sarepta Therapeutics ( SRPT) , presenting this afternoon at an investor conference in Boston, said its meeting with the FDA has not yet taken place but will before the end of March. The company is being coy about the exact date.

Most importantly, Sarepta said it will make a public announcement about the outcome of this FDA meeting no later than 30 days after the meeting concludes. That means we'll know if eteplirsen qualifies for accelerated approval by April 30, at the latest.

Let the run-up begin.

Sarepta also said it is looking for a medical meeting venue "in the coming months" to present 74-week data from the eteplirsen phase II trial.

Question: If the 74-week data were bad (patients treated with eteplirsen losing significant muscle function as measured by the 6-minute walk test) wouldn't it be considered a material event, and as such, need to be disseminated to investors immediately?

I think so, so Sarepta not rushing to disclose 74-week eteplirsen data is a good thing, suggesting that the durability of the drug's benefit is being maintained.

-- Reported by Adam Feuerstein in Boston.

Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback; click here to send him an email.