Earlier this week, Geron announced that it would discontinue its stem cell clinical trials. It intends to focus its research efforts on its oncology programs.
While disappointing for those of us hoping to see Geron continue to advance its stem cell programs, this sort of action isn’t unusual for small biotech companies. With scarce resources, putting programs with longer time horizons on hold in favor of lower-hanging fruit that can pay off in the nearer term makes economic sense. It helps prevent the dilution of the shares, and preserves capital for advancing programs that can produce revenues sooner. It is a shareholder-friendly move.
Geron, however, will continue to follow stem cell-treated patients and accumulate data. Geron still holds valuable stem cell intellectual property. Patrick Cox, who follows the stem cell space closely, expects Geron’s stem cell intellectual property, much of it important and unrelated to the discontinued clinical programs, will generate revenue for the company in the long run.
Geron’s new CEO, by the way, has a history of successfully managing partnerships and acquisitions for small biotechnology firms under his care. He successfully sold a private biotech firm, Proteolix, in 2009 while serving as president and CEO. The same was the case when Dr. Scarlett served as CEO at Tercica Inc. in 2007.
Geron Advances Cancer Pipeline
Shortly after announcing the decision to discontinue the stem cell program, Geron released clinical data for its Phase I brain cancer drug, GRN1005.
As you probably know, many cancer drugs will not treat cancers located in the brain or central nervous system. The blood-brain barrier, which protects the brain from foreign substances, filters out many chemotherapy drugs and renders them ineffective.
GRN1005, however, takes the popular commercial chemotherapy compound, paclitaxel, and links it to a proprietary peptide molecule. Since many peptides — which are small protein molecules — are allowed to pass through the blood-brain barrier by the body, paclitaxel gets to hitch a ride into the brain, where it can then do its work on cancer tumors.
In the final Phase I results for GRN1005, Geron found the peptide/paclitaxel conjugate to be generally well tolerated, with toxicity similar to paclitaxel. Since paclitaxel itself is an approved product, this is good news. Phase I trials tend to focus on safety, and usually use various dosing levels to test tolerability in patients.
With GRN1005, 20% of patients with cancers that had spread to the brains from other parts of the body showed tumor shrinkage. Patients with gliomas, a type of brain cancer, showed a 6% response to the experimental compound. One patient treated with a high dose achieved complete response, which means that all signs of brain cancer were gone.
In addition, a substudy was undertaken in brain cancer patients shortly before they entered surgery. These patients received GRN1005 a few hours before surgical tumor removal. The excised tumors showed the presence of paclitaxel at higher concentrations than expected for patients that receive the ordinary version of the compound, which indicates that GRN1005 successfully crossed the blood-brain barrier. In addition, paclitaxel was present in these tumors in therapeutically active amounts.
Geron plans to initiate two Phase II clinical trials for GRN1005 soon, with data to become available in the first half of 2013.
Geron’s second compound, Imetelstat, is further advanced in the clinical trials process. It is in Phase II, with results expected next year. Imetelstat is designed to inhibit telomerase production in cancer cells. Telomerase, sometimes called the “immortalizing enzyme,” has its production permanently turned on in cancer cells. This allows cancer cells to duplicate and grow indefinitely. Inhibiting telomerase, on the other hand, breaks the cycle and causes cancer cells to behave more like healthy cells, which eventually age and die after a certain number of cell divisions.
Geron has two very promising nonstem cell clinical trial candidates and is continuing to run its drug discovery department. It has a new CEO that has focused the company’s efforts on the therapeutic programs likeliest to deliver results in the near term. He is looking to partner its stem cell assets with big pharmaceuticals and has a good track record at other firms.
The discontinuation of the stem cell program is actually good news from a business standpoint.
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