By Doug Macron
After reorganizing itself into a purely European firm, Silence Therapeutics this week provided a few new details regarding its pipeline, stating that it remains on track to complete a phase Ia trial of its cancer therapy Atu-027 and to move a second cancer agent, Atu134, into human testing next year.
However, Silence did not mention an earlier-stage acute lung injury drug dubbed Atu111 that it had said earlier this year it would continue to develop on its own despite having previously said it would only do so with a partner.
The company also released its financial results for the first half of 2011, posting lower operating expenses that reflect its recent restructuring, and a drop in its net loss.
Silence was established in 2005 when UK-based SR Pharma acquired German RNAi drugs firm Atugen. When it acquired US-based Intradigm four years later, the company had operations in London, Berlin, and Redwood City, Calif.
However, in April Silence announced that its “geographical diversity” created “considerable operational difficulties, as well as increased operating costs,” and that it would therefore close its California operations and become a fully European company (GSN 4/28/2011). In conjunction with the reorganization, which was completed in August, then-CEO Philip Haworth, who was based in California, agreed to resign.
As Silence wound down its US activities, it continued to advance Atu027 through a phase Ia trial in patients with solid tumors. The drug is a blunt-ended siRNA targeting the protein kinase PKN-3, which is associated with cellular morphology and locomotion in endothelial and cancer cells.
In June, at the annual meeting of the American Society of Clinical Oncology, the company reported interim findings from that ongoing study (GSN 6/9/2011). Those data showed that Atu027 was well tolerated in all dosing cohorts up to 0.18 mg/kg, and that nine patients achieved stable disease after repeated treatment, with six of the cases confirmed after three months.
Of the patients with stable disease, one with neuroendocrine cancer showed partial regression of pulmonary metastases, while one patient with breast cancer showed a “slight regression” in liver metastases, according to Silence.
This week, the company said that patient recruitment in the phase Ia study is expected to wrap up in “early 2012,” and that it expects to release results from it in the middle of the year. The firm added that a previously disclosed phase Ib study of Atu027 is still expected to begin in the second half of 2012, and that it continues to explore partnership opportunities for the drug.
Earlier in the year, Haworth had told Gene Silence News that the phase Ib trial would be in patients with a specific solid tumor type, although he did not specify which one. Silence officials were not available for comment by press time.
Meantime, Silence continues to advance Atu134, which comprises siRNAs against CD31 in the endothelium of tumors. Like Atu027, Atu134 is delivered using Silence's proprietary AtuPlex liposomal delivery technology.
Silence said that it has completed studies of the drug in multiple animal models, finding that it “appears to have a profound impact in slowing the progression of solid tumors.” The company said it has begun producing drug materials for preclinical toxicology work that it plans to launch in the first half of 2012.
As disclosed earlier this year, Silence anticipates moving Atu134 into phase I testing in the second half of next year. However, the company plans to run those trials in Europe, not the US as previously planned.
Absent from Silence's pipeline overview was Atu111, which is based on a novel lung-delivery technology called drug-assembling cholesterol complex, or DACC.
Silence previously said that the technology can be used to achieve sustained knockdown of up to three weeks in the lung endothelium, but indicated that it would focus on its oncology candidates, leaving Atu111 as an “attractive opportunity for potential pharmaceutical partners.” Later, Silence said that it would advance the drug through preclinical development.
It was not immediately clear whether this is still the company's plan.
However, Silence's new CEO Thomas Christely, who previously served as COO, said in a statement that the firm has “expanded its proprietary delivery technologies … to now include DACC” and another approach called DBTC, which focuses on hepatic delivery
For the six-month period ended June 30, Silence's net loss fell to £3.4 million ($5.4 million) from £7.1 million in the same period a year earlier.
Contributing to the lower loss was a drop in research and development spending to £1.82 million from £4.4 million in the first six months of 2010, which included costs related to the closure of Silence's California facility, and a decline in administrative costs to £2 million from £3.2 million.
Revenues in the first half of 2011 dropped to £350,000 from £720,000 a year earlier, reflecting lower income from license partners and grants.
At the end of June, Silence had £6.5 million in cash and cash equivalents.
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