ASCO15: Analyst Calls ImmunoGen's Phase I Ovarian Cancer Data "Impressive"

Published: Jun 01, 2015

ASCO15: Analyst Calls ImmunoGen's Phase I Ovarian Cancer Data
June 1, 2015
By Mark Terry and Riley McDermid, Breaking News Staff

The American Society of Clinical Oncology (ASCO) 2015 Annual Meeting is bringing out a lot of good news, including impressive data from Waltham, Mass.-based ImmunoGen, Inc. , that showed 53 percent of patients in its ongoing Phase I trial for ovarian cancer saw a slowing of the disease.

The drug, IMGN-853, targets tumors that produce high levels of a protein called folate receptor alpha, which is about 2,000 to 3,000 of the approximately 21,300 women diagnosed annually with ovarian cancer.

The findings showed that the drug seemed to slow the growth of the cancer in 53 percent of patients receiving the treatment. A more typical response for existing chemotherapy drugs is 15 to 20 percent. In addition, previous trial data presented by ImmunoGen showed a 40 percent response rate. Of the 17 patients evaluated, ovarian cancer appeared to be eradicated and in eight there was measurable improvement.

Michael Schmidt, an analyst with Leerink Partners, described the results as “impressive” in a research note, but expressed some concerns about the side effects. Adverse events were called low grade, including diarrhea, blurred vision, nausea, vomiting, fatigue and abdominal pain.

ImmunoGen (NASDAQ: IMGN) (MP): Prelim. IMGN853 activity in Fra+ platinum-resistant ovarian cancer expansion cohort; no big surprises in MARIANNE abstract,” wrote Schmidt in a note to investors. “For '853, IMGN saw 4 PRs & 1 CA125 response in 10 pts treated at the Ph II dose (6mg/kg, Q3weeks). AEs still included ocular events & neuropathy, ‘the majority’ of which were Gr 1&2. Dose-finding in Part B (3 doses/4 weeks) continues; IMGN saw signs of activity (1/15 PRs & 3 CA125 response) in dose-escalation there. In MARIANNE, PFS was 13.7, 14.1 (p=0.31), & 15.2 (p=0.14) months in Herceptin+chemo, Kadcyla, & Kadcyla + Perjeta arms, respectively. Interestingly, PFS in the MARIANNE control arm was not far off vs. that in CLEOPATRA (12.4 months) despite significantly more prior adjuvant HER2-directed therapy use in MARIANNE. Herceptin + Perjeta produced an impressive 18.7 mo. PFS in CLEOPATRA.”

Initially the trial established the Phase II dose of mirvetuximab soravtansine, then was assessed for safety for the treatment of patients with FRa-positive platinum-resistant ovarian cancer. Of the 22 patients in the efficacy study, 17 were analyzed while the remaining five are still being studied and hadn’t hit their first assessment yet. Of the 17 patients, nine had an objective response to treatment.

“These initial clinical findings with mirvetuximab soravtansine in the treatment of patients with FRa-positive platinum-resistant ovarian cancer are highly encouraging,” said Kathleen Moore, Mai Eager Anderson Chair of Cancer Clinical Trials at the Stephenson Cancer Center at the University of Oklahoma HSC in a statement. “There is significant need for new therapies for patients with ovarian cancer, including platinum-resistant disease.”

Typical first-line therapy for ovarian cancer is platinum-based drugs, such as carboplatin (Bristol-Myers Squibb Company ) plus a taxane and other drugs. However, tumors can become resistant to platinum-based drugs.

The next step for ImmunoGen will be a Phase II trial. “Based on these findings, we are implementing a development plan designed to advance mirvetuximab soravtansine as quickly as possible while also recognizing the potential to benefit the greatest number of patients,” said Charles Morris, executive vice president and chief development officer of ImmunoGen in a statement. “We’re preparing to initiate a Phase II trial in late 2015 that will assess this ADC as a single-agent treatment for patients with FRa-positive platinum-resistant ovarian cancer. It is possible that this trial could be used for registration in this patient population.”

The company is also planning to test the drug in combination with other drugs a possible treatment for patients with ovarian cancer that have had less previous treatment, as well as in target-positive endometrial cancer.

In late November 2014, Roche announced that the U.S. Food and Drug Administration (FDA) had approved its drug Avastin with chemotherapy for the treatment of platinum-resistant, current ovarian cancer. This was based on the results from the Phase III AURELIA study.

ImmunoGen employs about 300 people and has one approved drug, Kadcyla, for breast cancer, and several others in various stages of development. However, almost all of those in development are in partnerships with other big pharmaceutical firms. If IMGN853 was approved, the company would nab all of the profits.

Will PfizerKline Become the Next Pharma Player?
The speculation surrounding a possible bid from Pfizer Inc. for struggling GlaxoSmithKline is heating up, after one closely-watched biotech analyst said in a note last week that Pfizer buying the company would “unlock access to its balance sheet and improve its tax situation.”

Gregg Gilbert, a biotech analyst at Deutsche Bank, wrote in a note to investors “Introducing PfizerKline” that he thinks a deal would be “materially accretive” for both companies. Gilbert estimated that a bid priced at $29.86 a share, via half stock and half cash, which would push up Pfizer’s earnings per share by 10 percent to 16 percent beginning in 2016.

“We believe that the company has a sense of urgency to create value by leveraging the power of its balance sheet to do needle-moving deals,” Gilbert wrote. “Since media reports in the past have pointed to the potential for a Pfizer/GSK combination, we are revisiting that theme.”

We want to know, dear readers, if you agree? Should Glaxo continue going it alone, or might Pfizer buy it and create one of the world’s largest pharma players in history?

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