Eli Lilly & Co (LLY.N) and Bristol-Myers Squibb Co (BMY.N) said on Wednesday they have stopped enrollment in one of two late-stage trials of an experimental lung cancer drug due to concerns it may be linked with blood clots.

The Phase III trial, known as INSPIRE, is testing the drug, necitumumab, as a first-line treatment for patients with advanced non-squamous non-small cell lung cancer.

An independent Data Monitoring Committee recommended that no new or recently enrolled patients continue treatment in the trial because of concerns related to thromboembolism, or blood clots.

Patients who have already received two or more cycles of necitumumab appear to have a lower ongoing risk and these patients may choose to remain on the trial, after being informed of the additional potential risks.

The drug continues to be studied in a Phase III trial named SQUIRE. This study is evaluating necitumumab as a potential treatment for a different type of lung cancer called squamous non-small cell lung cancer.

The INSPIRE trial is testing necitumumab in combination with Lilly's cancer drug Alimta and the chemotherapy drug cisplatin. The SQUIRE trial is testing necitumumab in combination with cisplatin and Lilly's chemotherapy drug Gemzar.

Lilly and Bristol-Myers share development costs and any potential commercialization costs within the United States, Canada and Japan. Lilly has exclusive commercialization rights in all other countries.

Lilly's shares were almost unchanged at $35.26 in late morning trading on the New York Stock Exchange. Bristol-Myers' shares were up 0.3 percent at $25.34.