A big star of the American Society of Clinical Oncology meeting this past weekend was ipilumumab, a drug that was designed to enhance the immune system and Bristol-Myers Squibb presented data showing patients with advanced melanoma lived significantly longer on the treatment. There were some caveats, though, such as serious side effects and that the study compared the medicine to a vaccine, not a placebo, suggesting an issue with the vaccine led to the outcome.

The study, which followed 676 patients who failed to benefit from two existing treatments -interleukin-2 or dacarbazine, found that patients taking ipilimumab lived an average of 10 months, compared with 6.4 months (read the study in The New England Journal of Medicine). Immune therapy may be controversial, but some Wall Street analysts expect big things. Here is what a few are saying…

“The design of this ipi study had left us skeptical on the chances that it would be sufficient for approval, given the low dose and the use of the vaccine as a comparison,” writes Credit Suisse analyst Catherine Arnold in a research note. “While some regulatory risk still exists, especially in regards to understanding what benefit (or possible harm) the vaccine provides, at minimum the probability of success (POS) for the drug reaching the market has now increased, and this study may be enough for it to be approved without the results of the ongoing study of ipi in 1st line use. We increase our POS to 80 percent and increase our 2015 global revenue estimate to $720 million (from $500 million).”

“Iipilimumab is the first drug to actually show a significant survival advantage in treating refractory metastatic melanoma. Because of this impressive improvement, we now assume ipilimumab will be a straightforward approval for the FDA and that the drug will gain significant market share in melanoma,” writes Jon LeCroy of Hapoalim Securities, in an investor note. Our new 2014 worldwide sales estimate for ipilimumab is $1.050 billion, up from $350 million, previously.”

“Full results of the ‘020 study of ipilimumab published in the NEJM yesterday showed an impressive and consistent improvement in median overall survival in both ipilimumab plus the vaccine and the drug alone arm vs. the vaccine arm…To our knowledge, this is the first Ph III study of an experimental medication to demonstrate a statistically significant benefit in median overall survival for the treatment of metastatic melanoma, and definitively the first study to show a statistically significant improvement in the 2nd line setting,” wrote Seamus Fernandez in a note. “Since the ‘020 study doesn’t have a true
active control arm or a comparison to placebo, a comparison to historical controls will be important to regulators. In that context, median overall survival in the vaccine “control” arm of 6.4 months was
quite low and requires additional explanation.”