April 30 (Reuters) - Nymox Pharmaceutical Corp said its experimental prostate cancer drug reduced the progression of cancer in patients, but it could not determine if the study succeeded in meeting pre-determined goals due to a high rate of incorrect biopsies.

In the mid-stage study, patients receiving a single injection of the drug, NX-1207, had less cancer progression in the treated area than in untreated patients.

The main goal of the trial was to show a significantly higher number of patients with undetectable prostate cancer after 45 days of treatment, compared to untreated patients.

However, the company was unable to assess the drug's benefit because of a high percentage of false negative biopsies - a result suggesting there is no cancer present when it actually is - in the untreated patients' group.

Nymox's shares were down 3 percent at $4.98 in morning trading on the Nasdaq.

(Reporting by Esha Dey in Bangalore; Editing by Maju Samuel)