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The Sky’s The Limit For Micromet’s BiTE Technology’s Capability

Prohost Biotech - Tuesday, July 19, 2011

Micromet (MITI) added another important collaborator, Amgen (AMGN), to a long list of large and small drug developing companies that are attracted to Micromet’s BiTE technology. Amgen/Micromet agreement looks fair for both. It fits Amgen’s strategy of focusing on adding next-generation products to its pipeline and helps Micromet’s financial requirements during the development of its promising proprietary cancer programs. Amgen wanted to select from among three BiTE-based drugs against three undisclosed solid tumor targets. The giant biotech will pay upfront, milestone, and other payments in a deal that could be worth over $900 million for the two selected drugs, or half of this amount if it selects only one drug, in addition to double-digit royalties in the event of approvals and sales.

What is so unique about Micromet’s BiTE technology and drugs?

The whole story revolves around helping the immune system kill cancer cells. In the past two decades, serious attempts to energize the immune system and open its eye to see cancer and attack it as it does other body foreign invaders have exhausted many biotech vaccine companies’ budgets. After years of struggling, we finally witnessed the approval of the first therapeutic vaccine, Provenge developed by  Dendreon (DNDN) for prostate cancer. Other biotechnology firms working on therapeutic vaccines were encouraged by the news; yet investors remained skeptical.

Like the therapeutic vaccine firms, Micromet’s approach also aims at enabling the immune system to kill cancer cells. Yet, unlike the therapeutic vaccines that rely on immunogens to boost the immune system’s function, Micromet’s bi-specific T-cell engagers (BiTE) technology uses engineered fusion proteins made of fragments of two different monoclonal antibodies. The novel structure allows the simultaneous binding to the cytotoxic immune system cell and to the cancer cell. For example, the firm’s drug blinotumomab binds to the CD3 co-receptor on T cells and to the CD19 membrane protein on the surface of the cancerous B cells, hence, creating an immunological synapse between the immune system’s cytotoxic T cells and the cancer cells. By binding to CD3 co-receptor on the T cell, the antibody activates the immune system T cell and instigates the delivery of the T cell cytolytic proteins, perforins and granzymes, into the cancer cells. As a result, cancer cells commit apoptosis (programmed cell death).

So, without using a therapeutic vaccine, Micromet became capable of realizing the same objective as the therapeutic vaccine, i.e., enabling the immune system cytotoxic T cells to reach the cancer cells, attack them and deliver their toxins to kill them.

It is, indeed, an elegant approach. But elegant therapeutic approaches do not necessarily mean that it will work. Micromet validated its approach early on. It confirmed that in the presence of BiTE antibodies, T cells were capable of serially eliminating tumor cells. Moreover, it confirmed that the immune system T cells increase in number at the site of attack. These early validations were followed by a clinical validation from clinical trial results from Phase I trial of its drug blinatumomab on non-Hodgkin's lymphoma (NHL) and from Phase II clinical trial results on adult patients with acute lymphoblastic leukemia (ALL) who had relapsed following treatment with standard therapy. In this trial blinatumomab produced a high complete remission rate with 75% of patients (9 of 12) achieving a complete remission and compete remission with partial recovery of blood counts. All responding patients achieved a complete molecular response, or had no evidence of leukemic cells in their bone marrow, a key factor for patient survival.

What made these early validations attract many drug developers into signing collaborative agreements with Micromet to develop products based on the BiTE technology is that Philadelphia negative relapsed/refractory ALL is very difficult to treat and the current treatment, which consists of toxic chemotherapy drugs, fails to bring remission. Nine drug developers signed collaborative license agreements with Micromet. They include the large pharmaceutical companies Merck Serono; Bayer Schering Pharma; Sanofi-Aventis; Boehringer Ingelheim and a few days ago, Amgen followed suit.

What else?

Micromet launched a clinical development program to establish blinatumomab as a key component of treatment for adult and pediatric patients with early and advanced ALL. It initiated a European pivotal trial intended to confirm blinatumomab’s ability to eradicate leukemic cells in the bone marrow of ALL patients, the so-called minimal residual disease or MRD after receiving front-line chemotherapy. Most adult patients with MRD who do not receive a bone marrow transplant following front-line chemotherapy relapse and ultimately die of their disease. Moreover, Micromet established a phase 1/2 clinical trial in pediatric and adolescent patients with advanced stage ALL in both Europe and the United States. This trial builds on the experience of pediatric patients treated with blinatumomab on a compassionate-use basis.

Micromet’s pipeline has 11 products; eight of them are developed through the BiTE technology and 3 are conventional monoclonal antibodies. Probably good news is that the most advanced BiTE products are wholly owned by Micromet and the rest are partnered.

Financial: In March and November 2010, the firm had successfully raised a total of $145.8 million in net proceeds from two public offerings of common stock. Combined with revenues being received from collaborations, the cash is sufficient to advance and expand the firm’s clinical development programs. According to Micromet’s projections, the cash reserves will fund the firm’s operations into 2013.

All the above constitute reasons for optimism about Micromet. If the current optimism remains intact backed with good news from clinical trials, MITI’s value will definitely grow following the announcement of data from each trial. In the event of approval, we believe, the sky’s the limit for Micromet’s capability to cure cancers and generate income.

We do not own shares in Micromet and we do not intend to buy any for the next 3 months.

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