ASCO preview: What's the outlook for cancer vaccines?

Courtesy of Daniel Schwen

The cancer vaccine field has seen its share of late-stage disappointments and outright flops, with many experimental therapies only showing modest increases in survival. But a number of hopefuls are lining up to present new research backing their experimental shots at this year's upcoming American Society of Clinical Oncology Annual Meeting in Chicago.

Most recently, Amgen ($AMGN) revealed in April that its promising melanoma vaccine T-Vec missed statistical significance for improving overall survival in a top-line analysis of its Phase III study. Before that, GlaxoSmithKline ($GSK) announced in March that its MAGE-A3 jab failed to hit a pair of primary endpoints for non-small cell lung cancer.

Oncothyreon ($ONTY), Ziopharm ($ZIOP) and Keryx ($KERX) also had promising treatments with analyses delayed by slow death rates, and all eventually failed in the clinic.

Then there's Northwest Biotherapeutics' ($NWBO) dendritic brain cancer vaccine, which has been a source of controversy with skeptics claiming the company hasn't produced any clinically decisive study results. NewLink Genetics ($NLNK) has also generated skepticism from investors over the biotech's decision to carry on with a Phase III trial of its pancreatic cancer vaccine after omitting efficacy data in a mid-trial review.

Dendreon's ($DNDN) Provenge for hormone-refractory prostate cancer remains the only approved therapeutic cancer vaccine available to patients, but the company has struggled to drum up sales for its oncolytic immunotherapy.

Cancer vaccines are intended either to treat existing cancers--called therapeutic vaccines--or to prevent the development of cancer--known as prophylactic vaccines. These vaccines work in the same way as other vaccines: by priming a person's immune system to attack the disease. But attacking cancer is more complicated than tackling viruses, because cancer cells are the body's own cells, making it difficult to "teach" a person's immune system to pinpoint the cancerous ones.

Despite more setbacks than successes in the field, some new players are heading to ASCO with early-stage clinical trial data to attract investors and court partnerships.

  • Immunovaccine: Out of Halifax, Nova Scotia, Immunovaccine is bringing positive clinical data to ASCO on the company's lead cancer vaccine candidate, DPX-Survivac, for ovarian cancer. Results from the Phase I/Ib clinical study show that the therapy was well tolerated with proven immunogenicity. One patient experienced both a reduction in tumor size--by at least 30%--as well as a reduction in levels of a commonly used ovarian cancer biomarker, the biotech reports. Immunovaccine says it will launch a randomized, 250-patient Phase II trial of DPX-Survivac for the treatment of ovarian cancer this year. Immunovaccine presented early results from a Phase I trial last year at ASCO, showing that DPX-Survivac spurred T cell immune responses against the tumor-associated protein survivin.Abstract
  • Generex: Toronto-based Generex will give two presentations on its experimental breast cancer vaccine AE37, designed to generate a robust response to the breast cancer linked protein HER2. An interim analysis of a Phase II study of AE37 revealed a strong trend in reduction of relapse in patients with low to intermediate levels of HER2 expression. The company's first research abstract shows that in these patients the AE37 vaccine displayed a 40% decrease in the risk of relapse in patients, while those with triple negative breast cancer exhibited a 60% decreased risk. The second abstract shows a correlation between the magnitude of immunological response to AE37 and the tendency to relapse. Previous data presented last year at ASCO indicated that AE37 immunized patients showed increased T cell activation. Abstract 1 | Abstract 2
  • Etubics: Data from a Phase I/II trial conducted by Seattle-based Etubics show that the biotech's vaccine for metastatic colorectal cancer, ETBX-011, was well tolerated at all doses and no patients dropped out of the trial due to treatment. Previously, the company reported that immune responses were observed in the majority of patients and median overall survival was 11 months. In its latest results, the company says 44% of patients survived at 12-month follow-up and 28% at 18 months following treatments. The company is launching a multicenter Phase IIb trial to further evaluate ETBX-011's clinical effectiveness. In April, Etubics won a $4.4 million grant from the National Institute of Allergy and Infectious Diseases (NIAID) to develop a universal influenza vaccine. Abstract
  • Bellicum Pharmaceuticals: Houston, TX-based Bellicum is presenting data from an ongoing Phase I trial of its BPX-201 candidate--dubbed DeCIDe--in chemo-naive metastatic castrate-resistant prostate cancer, boasting that the vaccine shows "promising activity" when it was administered with the small molecule AP1903 in the 18 men enrolled in the trial. BPX-201 consists of a patient's own matured dendritic cells engineered with the DeCIDe "on switch" and is trained to target prostate cancer cells. When AP1903 is administered intravenously 24 hours after each dose of the vaccine, the "on switch" in the injected cells is activated, signaling the body's T cells to attack the cancer. In January, Bellicum bagged a $14.7 million Series B round of financing to help it expand an ongoing Phase I/II study of another one of its experimental cell therapies, BPX-501--known as CaspaCIDe. Abstract