NEW YORK (AP) — Shares of Synta Pharmaceuticals Corp. lost more than a third of their value Monday after the company reported new details from a clinical trial of its cancer drug ganetespib that disappointed investors.

The trial was designed to study ganetespib as a secondary treatment for adenocarcinoma, a type of non-small cell lung cancer. Synta said patients who were treated with ganetespib and the chemotherapy drug docetaxel had median survival of 9.8 months after treatment, compared to 7.4 months for patients treated with docetaxel alone. The ganetespib patients had median survival of 4.5 months before death or the resumption of disease progression, compared to 3.2 months for the docetaxel group.

The Lexington, Mass., company said the results were stronger if patients who quickly got worse during their initial treatment — which happened before the trial — are excluded. It said those patients had median survival of 10.7 months when treated with ganetespib and 6.4 months when treated with docetaxel alone.

Synta said in October that patients treated with ganetespib had longer overall survival and time-to-disease-progression. Earlier this year the company started enrolling patients in a late-stage trial of ganetespib, and it expects to report results in 2014. That trial includes patients who quickly got worse during their first round of treatment.

Synta has no approved drugs.

Shares of Synta fell $2.51, or 34 percent, to close at $4.87. The stock has traded $4.40 and between $11.88 in the last 52 weeks.