Actinium Pharmaceuticals' Iomab-B Will Not Repeat Bexxar's Past


Bexxar's troubling past may be causing consternation for investors, analysts, and journalists that may have otherwise taken interest in potential radioimmunotherapy (RIT) drugs.

For ATNM's Iomab-B, there are very important differences to Bexxar, which I believe makes the case for a successful commercial launch and sustained sales of Iomab-B if FDA approved.

The company's Iomab-B should be looked on favorably by the FDA because of its safety and tolerance in over 250 patients. So, no prolonged approval process is expected.

Let me begin by disclosing that I'm a shareholder of Actinium Pharmaceuticals (NYSEMKT:ATNM). My name is Erik Neelsen, and I'm an RN by profession. I have not been paid to write this article nor am I an employee of Actinium Pharmaceuticals.


I want to start with a brief history of Bexxar. This is a drug that combines tositumomab with iodine-131. Corixa obtained Bexxar from Coulter Pharmaceutical in 2000. GlaxoSmithKline (NYSE:GSK) partnered with Corixa to market and manufacture Bexxar. Bexxar targets the CD20 protein marker for non-Hodgkin's lymphoma in patients who had not responded well to a chemo and Rituxan combo. The drug had success as 29% of these patients went into complete remission (CR) for a median time period of 25 months. But Bexxar had some safety and efficacy questions that may have caused the FDA to wait so long (four years) before approving the drug in 2003, which allowed the chemo and Rituxan combo to become the standard of care in that market. Also, in a 2011 study, Bexxar was found to have no statistically significant improvement compared to Rituxan when each was combined with chemo. Here are further events that point to where Bexxar went wrong - once the drug was approved, the patient's oncologist had to refer his/her patient to a nuclear med pharmacy or radiation oncologist that could handle Bexxar, so the patient's oncologist and his/her related infusion center lost money by referring their patient. But there were also problems with supply and reimbursement which didn't help Bexxar's case with these same oncologists. Bexxar was discontinued by GSK after sales dwindled.


Now, let's take a look at Iomab-B and find out why it is has a better outlook. First, let's get an overview on Iomab-B. The drug is a radioimmunoconjugate combining iodine-131 with an anti-CD45 monoclonal antibody that targets the CD45 antigen found on virtually all leukocytes, including myeloid precursors in bone marrow and mature lymphocytes in lymph nodes as well as more than 90% of AML samples. This provides a high number of antibody-binding sites in these tissues for patients in remission or relapse.

Iomab-B is initially targeting a very specific group of patients (relapse/refractory elderly AML) that will not require a referral to a specialist pharmacy or physician. In a phase 2 unpublished clinical trial conducted at the Fred Hutchinson Cancer Research Center, 27/27 patients diagnosed with relapsed/refractory acute myeloid leukemia patients over age 50 years achieved CR when given Iomab-B in preparation for a Bone Marrow Transplant (BMT). Out of those 27 patients, 100% were engrafted by day 28 following a BMT. Overall survival (OS) for the Iomab-B/BMT cohort were 30% OS at 1 year and 19% OS at 2 years. For the patient cohort undergoing current BMT (10 patients), 1yr OS was 10% and 2yr OS was 0%. For patients treated with just chemotherapy, 1yr OS was 10% and 2yr OS was 0%. In another cohort of patients with poor cytogenetics, the results were more impressive with patients who were treated with Iomab-B/BMT having 1yr OS of 33% and 2yr OS of 19% compared to the BMT/chemo cohort with 1yr OS of 3% and 2yr OS of 0%.

Why Iomab-B Is Different

First, the physician needs to choose the best drug that can get their patient to a CR for a BMT. The upcoming Iomab-B phase 3 trial will answer the question of which treatment (chemo or Iomab-B) works best. In both instances (chemo and Iomab), the patient is in the hospital while receiving treatment, so no conflict of interest exists in terms of where the patient is treated.

Second, Iomab-B is safe as most adverse events were classified as Grade 2 or less such as infusion site reactions, chills, and nausea. The distribution of Iomab is mostly restricted to bone marrow, the spleen, and liver. Iomab targets CD45 which is almost universally expressed on AML cells and stem cells and spares red cells and other tissues from damage. This is why these elderly relapsed AML patients can tolerate Iomab better than chemotherapy. Iomab-B is a targeted therapy.

Third, according to Dr. Roland Turck, the CD45 mAb clinical sample production will already be scaled for commercial use by the time of launch. The 30 participating centers in the upcoming phase 3 trial will be able to immediately use Iomab commercially on day 1 of FDA approval. So in essence, there is no "ramping up" period for sales at these centers. And here is the main point to remember - the number of BMT centers (30) in this trial represent a majority of the BMT market in the US. Incredibly, because of the concentration of this market, Iomab-B could actually dominate this segment of BMT from day 1 of FDA approval.

In the latest KOL (Key Opinion Leaders) event held in May of this year, CEO Dr. Kaushik Dave of ATNM disclosed in the Q&A session that all gating items (for phase 3) were complete except for putting data down on paper. He also pointed out that the company would "take its time" completing this task and subsequently submit an IND to begin the trial. While investors may frown on this (taking their time), I think it's prudent for the company to be cautious and not make mistakes that could echo Bexxar's errors. On the reimbursement issue, Dr. Turck points out that 20% of the participating hospitals are PPS exempt. And according to Dr. Dave, the company will be collecting data during the trial to prove the economic advantage Iomab has over chemotherapy. Iomab is estimated to be priced at $85,000 while chemotherapy costs between $50-200K for this indication (dependent on how many rounds of chemo needed to achieve CR). In addition, with chemotherapy, the patient experiences a longer hospital stay, which can increase total costs as Iomab-B can get a patient to BMT in 10 days versus chemotherapy's 28-42 days.


Looking at the financials, as of March 31, 2015, Actinium had over $19 million in cash and has since raised another $5 million from investor Dr. Phillip Frost. Expenses incurred by the company in 2014 was just under $25 million. The company will need at least around $60 million to cover operating expenses and the upcoming phase 3 trial over the next 30 months, so share offerings or a partnership will be needed.

Supply And Manufacturing

Actinium has a contract with Goodwin Biotechnology, Inc. to manufacture CD45 mAb for the upcoming phase 3 trial for $3.3 million. Actinium also states in the 10-K that iodine-131 is readily available from a number of qualified pharmaceutical vendors.

Paid Promotion Concerns

The company has been scrutinized recently for a paid promotion highlighted in particular by Adam Feuerstein of The ad cost $60k for one week of promoting the company. It was paid by Edge Media LLC to Small Cap Specialist LLC, which is a parent company of Small Cap Street who actually ran the ad. I view paid promotions as nothing more than outsourced marketing. Nearly all companies participate in some form of promoting their product either through an in-house marketing department or outsourced to a specialized marketing company.

For small/microcap biotechs, it seems taboo to promote your company since investors/patients/healthcare personnel should follow your company based solely on the trial results and marketability of the drug candidate. I think that is a reasonable point of view. However, Actinium's Iomab-B has had outstanding results to date, but has not received much attention in the biotech community, as evidenced by Mr. Feuerstein stating he never heard of the company before the promotion discovery and incoming tweets about ATNM. So this presents a difficult dilemma for the company. Does it just perform day-to-day operations with no promotions other than attending conferences, or does it promote the company through back channels? I want to state that I publicly chastised management on Twitter for paying for the ads in part, because I think it didn't need to engage in promotion. I and many others were beginning to discover the company (I found it in a tweet, not an ad). But, I can see to some degree why management felt it needed to promote Iomab/Actimab to obtain funding for upcoming trials and general operations. Was it an amateurish move to engage in promotions? Perhaps. But, that mishap on management's part hasn't put me off on the potential of Iomab-B. Sometime after this miscue, Dr. Phillip Frost led a group of investors to purchase $5 million of ATNM stock at $2.60/share. Was he led to buy into the company by a paid promotion? I seriously doubt it. I suspect he has also recognized real potential in this company.


Risks on investing in Actinium Pharmaceuticals are several including an inability to fund operations/phase 3 trial, supply shortage of I-131 as the US imports all I-131 (however, SHINE Medical may be an alternative domestic source in 2018), phase 3 trial results not meeting endpoints (primary durable CR in six months, secondary OS 1yr), and a general mismanagement of resources.

Thesis For Investment

Iomab-B offers the patient a faster pathway to BMT (10 days vs. 28-42 days) with less side effects than chemotherapy. The company has made an astute decision by consulting Dr. Turck to help ensure the commercial viability of Iomab-B. In contrast to Bexxar, Iomab-B should have a much easier transition from the clinical trial stage to commercial stage by virtue of the BMT market concentration and uniqueness of the drug itself. There is no other treatment that comes close to mimicking Iomab-B for its respective market. A BMT offers the only cure for these AML patients. And since Iomab-B offers many of these "worst of the worst" patients their only chance for getting a BMT, the drug itself could be a cure for many elderly AML patients as ATNM's Dr. Dragan Cicic stated in the KOL May event. A drug that may provide a potential cure is reason enough to buy into ATNM. Aside from Iomab-B's initial indication, Dr Hillard Lazarus alluded to the possibility for Iomab-B to potentially treat "any white cell that has become malignant" in that same KOL May event during the Q&A session. That statement implies an immense potential for sales in future indications for Iomab-B.

Disclosure: I am/we are long ATNM.

I wrote this article myself, and it expresses my own opinions. I am not receiving compensation for it. I have no business relationship with any company whose stock is mentioned in this article.

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