Smoldering multiple myeloma is something of a quandary for doctors. Individuals with the condition have an overall risk of 10 percent per year of progressing to outright myeloma, which is a cancer of the plasma cells.

A 10 percent annual risk means that seven years after a diagnosis of smoldering multiple myeloma, half of individuals will have developed outright multiple myeloma.

Several factors can be used to predict whether smoldering multiple myeloma patients are at high or low risk of progressing to straightforward multiple myeloma, but they are not foolproof. Some patients never progress. And in the meantime, if patients with smoldering multiple myeloma are not exactly healthy, they are also not exactly sick.

"For the most part, people are symptom-free and are going about their daily lives," Doris Peterkin told BioWorld Today. So doctors are hesitant to treat patients with chemotherapies, which, at that stage, are likely to impair their quality of life more than the disease itself does.

Peterkin is CEO of OncoPep Inc., a Boston-based start-up that is developing a vaccine, PVX-140, for treatment of smoldering multiple myeloma. PVX-140 was developed at the Dana-Farber Cancer Institute by Kenneth Anderson and Nikhil Munshi, who co-founded OncoPep with Jooeun Bae, also of Dana-Farber.

Three treatment options exist for outright multiple myeloma – Millennium Pharmaceutical Inc.'s Velcade, (bortezomib), and Celgene Corp.'s Thalomid (thalidomide) and Revlimid (lenalidomide). But, ultimately, the disease remains largely incurable despite those options. At last year's meeting of the American Society for Hematology, Meletios Dimopoulos, who is a member of the International Myeloma Foundation's scientific advisory board, told the audience while presenting Phase III data on Merck & Co. Inc.'s experimental multiple myeloma drug vorinostat that "the overwhelming majority of patients will eventually develop resistant disease."

Given the fact that once patients have progressed from smoldering multiple myeloma to outright multiple myeloma, at which point the chances for truly curing them are slim, there is a lot of interest in seeing whether earlier intervention might be able to cure patients, or at least further extend their survival time. Currently, clinical trials are under way testing Revlimid in patients diagnosed with high-risk smoldering multiple myeloma, those who are likely develop outright multiple myeloma within two to three years.

But Peterkin said a vaccine approach is a good fit with smoldering multiple myeloma because it is a relatively gentle therapeutic approach.

Although the vaccine will need to be administered repeatedly, the treatment overall will be "more like what a patient would experience going in for a flu vaccine" than like a chemotherapy regimen, she said.

At the same time, administering the vaccine early probably increases the odds in its favor. In late-stage cancer, tumors usually have evolved in ways that make them less visible to the immune system, vaccinated or not. And simultaneously, in patients with advanced cancer – especially if they have been treated with chemotherapy that targets rapidly dividing cells – the immune system tends to be compromised already.

In contrast to Provenge (sipuleucel-T, Dendreon Inc.), which is the only approved cancer vaccine to date, Peterkin described PVX-140 as "more of an off-the-shelf approach." Provenge is an autologous transplantation – a patient's dendritic cells are harvested, stimulated with antigens outside the body and re-transfused. PVX-140 consists of three peptides that are specific to myeloma cells. In preclinical work, the vaccine was able to stimulate a strong T-cell response to multiple myeloma cells.

For now, Peterkin is a one-woman show at OncoPep. She is "the only employee" of the still otherwise virtual company, which plans to stay that way through Phase I trials. The company plans to start such a Phase I trial later in 2012.

For the time being, Peterkin said, PVX-140 is "really our sole development program." In the long run, OncoPep hopes to take its approach into other hematologic cancers. "But that's a bit down the road."