TUSTIN, Calif. (

TheStreet

) --

Radient Pharmaceuticals

(RPC)

said Wednesday that its Onko-Sure cancer-monitoring test performed better than an older, competing test in detecting early-stage colon cancer, but the company didn't disclose how the performance of the two tests compared across all stages of colon cancer.

The new but limited disclosure about Onko-Sure's performance comes from what Radient described as the "final data set analysis" of a U.S. clinical validation study. This study was designed to compare the efficacy of Onko-Sure against the carcinoembryonic antigen (CEA) test. Both Onko-Sure and CEA are approved in the U.S. as lab tests that doctors can use to monitor the progression of colon cancer in previously diagnosed patients.

Radient's Onko-Sure test "can be up to 17% more effective" at detecting colon cancer in stages I and II compared to the CEA test, the company said Wednesday. Radient did not say whether this 17% advantage was statistically significant, nor were important and relevant details provided such as the comparable sensitivity and specificity of the Onko-Sure and CEA tests, respectively.

When Radient released interim results from this same study on March 31, the company said Onko-Sure demonstrated a "significant advantage" over the CEA test in detecting early-stage colon cancer.

The Onko-Sure study was designed to test blood samples taken from 976 patients with all stages of colon cancer. Radient has not disclosed how Onko-Sure performed relative to the CEA test when all the colon cancer patient blood samples were analyzed. Radient did not give an explanation Wednesday for releasing partial results from the study's final analysis.

The combined use of Onko-Sure and CEA was more sensitive at detecting colon cancer progression than the use of either test by itself, Radient said Wednesday in a repeat of a claim made when the company announced preliminary results on March 31.

This Onko-Sure clinical validation study is the same one that Radient previously claimed was being conducted with the prestigious Mayo Clinic research hospital. As first reported by

TheStreet

in March, the Mayo Clinic said it did not work with Radient on the Onko-Sure clinical trial, explaining that it only sold blood samples to Radient for use in the Onko-Sure study.

The Mayo Clinic name is missing from Wednesday's announcement. Instead, Radient says that the Onko-Sure study was "conducted in collaboration with a well-recognized, large third-party not-for-profit group practice and its affiliates."

Much of what Radient disclosed about Onko-Sure's advantage over CEA in patients with early-stage colon cancer was already known but has not helped the company turn Onko-Sure into a commercially viable cancer diagnostic. Radient published a similar study last year essentially reaching the same conclusion, although CEA's performance overall was superior to that of Onko-Sure.

Onko-Sure sales for the first nine months of 2010 totaled $116,000, a 15% decrease from sales in the first nine months of 2009. Radient has delayed the release of fourth-quarter 2010 financials, including its 10-K annual report with the

Securities and Exchange Commission

.

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Radient continues to operate under the threat of delisting by the NYSE Amex. Last week, the exchange granted Radient another extension, until June 23, to meet listing standards.

Ahead of the the release of the Onko-Sure study results, Radient shares closed Wednesday at 42 cents. The stock was up 19 cents, or 45%, to 61 cents, in after-hours trading. Even with that bump, Radient shares are still down 64% from their high of $1.67 reached in early January.

Radient is also in danger of defaulting on $8.4 million in convertible debt issued to five investors in a private-equity financing that closed on Jan. 31, according to a preliminary proxy statement filed with the SEC in February.

Under terms of the financing deal, Radient is required to hold a shareholders meeting no later than April 30 to approve the issuance of stock and warrants to the five investors who currently exceed the company's anti-dilution safeguards, Radient disclosed in its SEC filing.

Radient has made no plans to schedule a shareholder vote before the April 30 deadline. If Radient defaults on the financing agreement, the investors could force the company to immediately repay the $8.4 million in convertible notes. The investors could also take a more conciliatory line and seek to renegotiate terms of the financing arrangement.

Radient has delayed release of its year-end 2010 financial and its 10-K annual report, but the company did say last week that it expects to report a net loss in the range of $68 million to $74 million in 2010 compared with a net loss of $17 million in 2009.

-- Written by Adam Feuerstein in Boston.

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