As abstracts rolled out for next month's American Society of Clinical Oncology (ASCO) meeting in Chicago, Glycomimetics Inc. whetted the appetite for more data from an ongoing phase II trial with E-selectin antagonist GMI-1271 in acute myeloid leukemia (AML).

"We will be sharing everything we know from the data cut" at ASCO and, later the same month, at the European Hematology Association (EHA) meeting in Madrid, Spain, CEO Rachel King promised during a conference call. Meanwhile, the results available so far pushed the Rockville, Md.-based company's stock (NASDAQ:GLYC) up 98.7 percent, or $5.30, to close Thursday at $10.67.

Canaccord analyst John Newman predicted that Wall Street will find pleasing the fuller results not yet publicly shared, since – as Glycomimetics also made known this week – the FDA has granted GMI-1271 breakthrough status. U.S. regulators have "likely seen more data than the public [has], and seem impressed enough" to assign special consideration to the candidate, he said.

AML patients treated with GMI-1271, combined with chemotherapy, continue to experience higher-than-expected remission rates and lower-than-expected induction-related mortality rates in both arms of the trial, the company said, adding that baseline expression of the E-selectin ligand biomarker on leukemia cells predicted clinical response and was tied to greater likelihood of achieving remission in the cohort of AML patients with relapsed/refractory (r/r) disease.

One arm of the study is treating newly diagnosed AML patients 60 years of age and older and the other targets adult patients with r/r. The enrollment of the cohort of newly diagnosed patients is complete; enrollment of the r/r group is expected to finish by midyear. Glycomimetics aims to enroll about 90 patients, of which about 25 have newly diagnosed disease and about 65 show r/r AML. First results of the study were reported at the EHA meeting last year in Copenhagen, and Glycomimetics provided an update at the December 2016 American Society of Hematology (ASH) meeting in San Diego.

Treatment continues to be well-tolerated, with no obvious incremental toxicity observed when GMI-1271 is added to chemo. "We did report in the newly diagnosed population, the older population, that we had two deaths of sepsis within the first 60 days on study," Chief Medical Officer (CMO) Helen Thackray said during the conference call. "It is actually, unfortunately, a population that has a very high rate of death from sepsis, and so two deaths in that group is not at all unusual. We've had no indication in the preclinical data or the clinical trial data reported publicly so far that there would be any increased risk of infection with this mechanism."

Thursday's update added nine evaluable patients to make a total of 42 in r/r AML, where GMI-1271 maintained its complete response (CR)/complete remission with incomplete blood count recovery rate of 45 percent, the same as reported at the ASH meeting. The standard of care for that form of the disease is MEC, or mitoxantrone, etoposide and Ara-C, which usually garners about a 19 percent CR rate. To date with GMI-1271, the median follow-up is 11 months, and a median overall survival of 7.6 months was reached. Based on data gained so far, the recommended phase II dose is 10 mg/kg. Glycomimetics is testing the compound in first-line AML, too, where the updated CR number came in slightly lower: 71 percent from 73 percent with an added six evaluable patients, noted Jefferies analyst Biren Amin. "The CR rate was 75 percent in de novo disease vs. 67 percent for secondary AML," he said in a report, citing GMI-1271 CR rates in first-line disease that are higher than current standard-of-care therapy, i.e., 7+3, or seven days of cytarabine and three days of daunorubicin. That regimen gains CR rates of 45 percent to 60 percent. Results with Glycomimetics' prospect "support further development of GMI-1271 in both of these indications," in Amin's view.

Selectins, known as adhesion molecules, recognize specific sugars on the surface on blood stem cells as well as other cells. Three types of selectins exist, and two of those types, P-selectin and E-selectin, are expressed on blood vessel cells in the bone marrow. Not only are blood stem cells stopped by selectins, but selectin itself is also one of the signaling molecules that affects its activity and further trajectory along the different paths a stem cell can take. The idea is that temporarily shutting down blood stem cells could protect them from becoming collateral damage in cancer therapies that target dividing cells. Such a temporary shutdown could reduce side effects, and it also might enable treatment to be more effective by enabling higher doses. (See BioWorld Today, Oct. 24, 2012.)

Apparently, it's working. During the call, Stifel analyst Stephen Willey raised what CMO Thackray called "a very interesting point" when he asked more about selectin as a biomarker. "Given the mitigation of chemo-induced toxicity, do you think there is even a need to preselect patients on the basis of E-selectin ligand expression, specifically in the relapsed/refractory setting?" he wanted to know. Thackray said that, "while we do see this relationship with respect to remission, we have not said anything about whether – and we wouldn't expect that it would be the case – patients would have to have higher levels of E-selectin ligand on their tumors in order to see a potentially beneficial effect during the induction chemotherapy. I'm just saying that based on our preclinical data, [where] we showed reductions in chemotherapy-induced mucositis which were quite pronounced in the animal models. We haven't disclosed data yet on that in the abstracts, but we will report what we know at ASCO" and at the upcoming EHA congress.

Asked about the potential phase III trial design in r/r disease – specifically, whether MEC or physician's choice would be the control arm – Thackray said that "we know from this trial the effects that we're seeing with MEC chemotherapy," and in preclinical work, enhanced survival vs. placebo turned up with other types of chemo as well. "We would want to discuss with the agency about the program going forward whether it's appropriate to treat, as we have, with MEC chemotherapy or perhaps broaden to other chemotherapy options available to physicians," she said. "The preclinical data would be supportive of a broader approach."

About sharing risk and expense in the larger experiment, CEO King was noncommittal, calling the moment "premature to make any comments about any specific partnering plans, but I would say it would certainly be our goal to preserve significant value within the company if we do engage in any partnerships around this program."

Other stock-moving abstracts disclosed by ASCO Thursday included phase I/II data with Wilmington, Del.-based Incyte Corp.'s ongoing ECHO-204 trial evaluating the safety and efficacy of epacadostat, a selective IDO1 enzyme inhibitor, in combination with Opdivo (nivolumab, Bristol-Myers Squibb Co.), a PD-1 immune checkpoint inhibitor. Efficacy data in patients with squamous cell carcinoma of the head and neck, melanoma, ovarian cancer and colorectal cancer, as well as overall safety data will be highlighted in an oral presentation at the Chicago meeting. J.P. Morgan analyst Cory Kasimov said in a report that the compound yielded "consistent and compelling evidence of efficacy across multiple tumor types (particularly lung and head-and-neck cancer)."

Shares (NASDAQ:INCY) closed Thursday at $128.80, up $8.31.

Studies of IDO inhibitors indoximod and navoximod from Newlink Genetics Corp., of Ames, Iowa, used in combination with other agents, were highlighted also. Indoximod, which is wholly owned by Newlink Genetics, has a proposed differentiated mechanism within the IDO pathway and acts as a tryptophan mimetic having a direct effect on immune cells to reverse immune suppression used by cancer to protect itself. Navoximod is a direct enzymatic inhibitor of IDO and is partnered with Roche Holding AG, of Basel, Switzerland. Results from a randomized, double-blind, placebo-controlled, multi-institutional phase II investigator-initiated study with indoximod in combination with the therapeutic cancer vaccine Provenge (sipuleucel-T, Valeant Pharmaceuticals International Inc.) for patients with metastatic, castration-resistant prostate cancer will be presented as a poster at ASCO. The navoximod data were characterized by Jefferies' Amin as "weak." Shares of Newlink (NASDAQ:NLNK) closed Thursday at $14.64, down $1.46.