(Adds details, analyst comment, sales estimates; updates shares)
Sept 7 (Reuters) - Bristol-Myers Squibb Co said on Thursday the success of its combination therapy to improve overall survival in kidney cancer patients helped it end the trial early, despite having reported mixed results on other main goals earlier.
The drugmaker said a combination of Opdivo and Yervoy, its two main drugs, showed superior overall survival rates in previously untreated patients with advanced or metastatic renal cell carcinoma, than those given a standard-of-care drug.
Last month, Bristol-Myers said the combination treatment had failed to improve progression-free survival in patients, but had succeeded in reducing the size of their tumors.
The trials to monitor overall survival rates were to run through the second half of 2019, according to Cowen and Co. Bristol-Myers said they were stopped early after the successful results in a planned interim analysis.
"We believe the overall survival benefit likely confirms the durability of the signal seen on progression-free survival, leading to a very high likelihood of approval," Leerink Research analyst Seamus Fernandez wrote in a client note.
Bristol-Myers shares were up 1.6 percent at $60.82 in premarket trading on Thursday.
Cowen and Co analysts estimate Opdivo could generate sales of $12.36 billion in 2022, of which renal cell carcinoma would account for about $1.7 billion.
Renal cell carcinoma is the most common type of kidney cancer in adults, accounting for more than 100,000 deaths worldwide each year, Bristol-Myers estimates.
Most immuno-oncology trials now incorporate overall survival as a primary endpoint, arguing that progression-free survival may not be the best measure given the unique way in which the therapies work, Bernstein analyst Timothy Anderson said.
Still, Bristol-Myers' Opdivo failed to prolong survival in previously untreated patients with non-small cell lung cancer, the largest cancer market, according to test results earlier this year.
That led to Merck & Co Inc's Keytruda getting a leg up in the key immuno-oncology field and Bristol-Myers' becoming the target of activist investors.
U.S. health regulators had, on Wednesday, placed a partial hold on three trials testing Opdivo in combination with other medicines for multiple myeloma due to risks seen in similar studies involving a rival drug. (Reporting by Divya Grover in Bengaluru; Editing by Savio D'Souza)