Cytokinetics shares slide on dosing snafu in ALS drug study

Shares of Cytokinetics ($CYTK) plunged more than 10% this morning after the biotech awkwardly explained a dosing snafu in its sizable midstage study for an experimental treatment for ALS, or Lou Gehrig's disease. Investigators say that a "program error" in the system used to designate patients for the drug or a placebo caused 58 people in the drug arm to get a sugar pill rather than tirasemtiv. And now they are following up with regulators to see if they may need to expand on patient enrollment as the biotech ponders tinkering with the study's timeline.

"Cytokinetics is in communication with regulatory authorities regarding how best to respond to the error in drug assignment in order to preserve the intended scientific value of BENEFIT-ALS," the company said in a release. "The company continues to enroll patients in the study under the current protocol and may amend the protocol to allow increased enrollment. Following further communications with regulatory authorities, Cytokinetics expects to provide updated guidance relating to the conduct of BENEFIT-ALS, which may include revisions to the timing of publicly available results from the study as well as to the projected costs of the study."

The dosing screw-up was flagged by Cytokinetics' data management vendor, but the developer didn't finger any of the contractors that were involved by name. It's common for most biotechs engaged in clinical research to line up outside specialists for trial work like this.

As of now, Cytokinetics says it has enrolled about 450 of the 500 patients they had sought when starting the Phase IIb study. The news jarred investors after a string of positive events, including back-to-back licensing deals with Amgen ($AMGN) and Astellas. A few days ago Astellas paid $40 million in upfront cash and near-term R&D support to team up with Cytokinetics on new research on treatments for muscle weakness while partnering on the early-stage program for CK-2127107. And the deal is back-ended with up to $450 million in milestones for successful development work.

Cytokinetics has been working on small molecules that can boost body muscle where it counts. It's retained all rights for tirasemtiv, though, hoping that it is in line to complete work on a drug designed to treat a disease that typically kills its victims three to 5 years after diagnosis.

- here's the press release