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Investors will get a first look at data from an early study of


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imetelstat in myelofibrosis on Thursday when the American Society of Hematology makes research abstracts to its December annual meeting available online.

At this risk of overselling, these imetelstat data are super important because they will either justify Geron's incredible 180% stock surge over the past two months or make a fool of those who believed (naively) Geron might be capable of reversing more than two decades of drug development futility.

Imetelstat, a telomerase inhibitor, is Geron's last chance.

Yet there is legitimate buzz surrounding imetelstat going into Thursday's ASH abstract release because the drug may have legitimate disease-modifying potential in bone marrow cancers like myelofibrosis.


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Jakafi is approved to treat myelofibrosis but only provides symptomatic relief -- mainly by reducing the size of a patient's enlarged spleen, a hallmark of the disease.

Imetelstat, on the other hand, may prove to be effective in the bone marrow, meaning the drug could to slow or even stop the malignancies which cause diseases like myelofibrosis.

Here's a simple way to think about imetelstat's potential: Neither Jakafi nor any other similar (JAK inhibitor) drugs being studied in myelofibrosis today are capable of producing a complete remission (CR) or partial remission (PR). At best, these drugs only provide clinical improvement (CI) in myelofibrosis patients.

When the imetelstat ASH abstract is released Thursday, investors will be looking for concrete evidence of patients with CRs or PRs following treatment.

The imetelstat study to be unveiled the ASH meeting is not being run by Geron but instead by noted myelofibrosis expert Dr. Ayalew Tefferi of the Mayo Clinic. Tefferi is also a bit controversial for publicly disdaining Jakafi.

Incyte doesn't send him Christmas cards.

What Wall Street knows about the outcome of the imetelstat study to date comes from Geron passing along hints based on what Teferri tells the company.

Here's the Geron slide from its most recent corporate presentation that has investors intrigued:

In Cohort A, which enrolled 11 myelofibrosis patients, two or more responses were observed. This allowed the study to enroll another 11 patients in Cohort B, where once again, two or more responses were recorded. A third cohort of patients is now enrolling.

Geron has not disclosed the nature of these imetelstat responses, which is why the reveal of the ASH abstract on Thursday is such a big deal.

Investors want to see partial remissions (PRs) in the imetelsat abstract. Complete remissions (CRs) would be amazing but perhaps less likely because the drug's mechanism of action isn't well suited to reducing spleen size.

So, look for PRs in the ASH abstract. The more PRs, the better, and the more likely Geron's stock rally will continue. Just note that at Monday's close of $4.01, Geron is already worth more than $500 million, raising the risk of a stock sell off regardless of how good the imetelstat data look.

Compounded by the high likelihood Geron raises money to fund future imetelstat studies.

But Geron shares will almost certainly fall -- and far -- if imetelstat only manages to produce clinical improvements (CIs) in the Tefferi study. This outcome won't differentiate imetelstat enough from Jakafi to matter much.

For those interested in how CIs, PRs and CRs are measured in myelofibrosis studies, here's an outline, courtesy of Geron:

-- Reported by Adam Feuerstein in Boston.

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Adam Feuerstein writes regularly for TheStreet. In keeping with company editorial policy, he doesn't own or short individual stocks, although he owns stock in TheStreet. He also doesn't invest in hedge funds or other private investment partnerships. Feuerstein appreciates your feedback;

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