Alder BioPharmaceuticals® New Data Demonstrated Eptinezumab Increased Migraine-Free Intervals (Up to 32.5 days) and Improved Quality-of-Life Outcomes in Patients with Episodic Migraine

BOTHELL, Wash., April 25, 2018 -- Alder BioPharmaceuticals, Inc. (NASDAQ:ALDR), a biopharmaceutical company focused on developing novel therapeutic antibodies for the treatment of migraine, today announced new data from its PROMISE 1 Phase 3 clinical trial evaluating eptinezumab, Alder’s lead investigational product candidate for migraine prevention, in patients with episodic migraine. The clinical data demonstrated that following a quarterly infusion of eptinezumab, patients experienced a significant reduction in migraine days and improved quality-of-life outcomes. Detailed results will be presented today at the 70^th Annual American Academy of Neurology Meeting in Los Angeles.

“Today, a patient’s quality of life is limited by the fear of a potential migraine, which severely impacts their activities of daily living, family life and careers,” said Roger K. Cady, M.D., vice president of neurology of Alder. “The significant periods of freedom from migraine delivered in the trial represents a compelling attribute of eptinezumab’s clinical profile. These notable improvements reinforce our confidence in eptinezumab’s potential to be an important treatment option in migraine prevention.”

Key Points

• Patients with episodic migraine who on average had 8.6 days of migraine per month demonstrated significant reductions in migraine frequency over weeks 1‒12, associated with 300mg dose group
  - 29.7 percent of patients achieved a 75 percent or greater reduction in migraine days from baseline, compared to 16.2 percent for placebo, p<0.0007
• In a post hoc analysis, patients achieving a 75 percent or greater response rate had over an eight-fold increase in days between migraines
   - During weeks 1‒12, the median migraine-free interval between migraine days increased from 3.9 days at baseline to 32.5 days
• Achieving a 75 percent or greater response rate was associated with more meaningful improvements in bodily pain and physical function at week 12, as measured by a quality of life patient-reported survey (SF-36)

“The significant increase in monthly migraine-free days demonstrate the potential relief that eptinezumab can deliver to migraine patients,” said Dr. Richard Lipton, Director of the Montefiore Headache Center, Albert Einstein College of Medicine. “Further, as demonstrated by the quality of life survey results, patients experienced improvements in areas such as bodily pain and physical function, illustrating the opportunity eptinezumab may provide to patients suffering from migraine.”

The observed safety profile for PROMISE 1, to date, is consistent with previously reported eptinezumab studies. The most commonly reported adverse events occurring at an incidence of 5 percent or greater across all eptinezumab treatment groups were upper respiratory infection (10.5 percent), nasopharyngitis (common cold) (6.8 percent) and sinusitis (3.6 percent).

About Eptinezumab PROMISE Clinical Trial Program
PROMISE 1 (PRevention Of Migraine via Intravenous eptinezumab Safety and Efficacy 1) was a Phase 3 randomized, double-blind, placebo-controlled global trial evaluating the safety and efficacy of eptinezumab for episodic migraine prevention. In the study, 888 patients were randomized to receive eptinezumab (300 mg, 100 mg or 30mg), or placebo administered by infusion once every 12 weeks. To be eligible for the trial, patients must have experienced £14 headache days per month, of which at least four met the criteria for migraine. The primary endpoint was the mean change from baseline in monthly migraine days over the 12 week, double-blind treatment period. In June 2017, Alder announced that eptinezumab met the primary endpoint and key secondary endpoints in PROMISE 1 with very high statistical significance. See the press release for more information.

PROMISE 2 (PRevention Of Migraine via Intravenous ALD403 Safety and Efficacy 2) is a Phase 3, randomized, double-blind, placebo-controlled global trial evaluating the safety and efficacy of eptinezumab for chronic migraine prevention. In the study, 1,072 patients were randomized to receive eptinezumab (300 mg or 100 mg), or placebo administered by infusion once every 12 weeks. To be eligible for the trial, patients must have experienced at least 15 headache days per month, of which at least eight met criteria for migraine. Patients that participated in the trial had an average of 16.1 migraine days per month at baseline. The primary endpoint was the mean change from baseline in monthly migraine days over the 12 week, double-blind treatment period. Secondary study endpoints assessed through 12 weeks included reduction in migraine prevalence day 1 and days 1-28, reduction of at least 50%, 75%, and 100% from baseline in mean monthly migraine days, change from baseline in mean monthly acute migraine-specific medication days, and reductions from baseline in patient-reported impact scores on the Headache Impact Test (HIT-6). In January, Alder announced that eptinezumab met the primary endpoint and key secondary endpoints in PROMISE 2 with very high statistical significance. See the press release for more information.

About Eptinezumab
Eptinezumab is an investigational monoclonal antibody discovered and developed by Alder BioPharmaceuticals for migraine prevention. Eptinezumab is the only potent and selective anti-CGRP mAb administered by quarterly infusion for migraine prevention, delivering 100% bioavailability to immediately inhibit CGRP.² Eptinezumab has been studied in several global, randomized, double-blind, placebo-controlled studies to assess its safety and efficacy in migraine prevention.

About Migraine
Migraine affects 36 million Americans² and, worldwide, is considered the sixth-leading cause of days with disability³ and the third-leading cause of disability of people under the age of 50.⁴ The occurrence of migraine can be unpredictable with a profound impact on activities of daily living. This disease can last decades, often during what should be the most productive years of patients’ lives.² Migraine can remit or progress to chronic migraine over time and persist as chronic migraine for years or decades, but it commonly oscillates between periods of frequent episodic and chronic migraine. Current preventive treatments for migraine fail to meet the needs of most patients and most patients discontinue use within 6 months to 1 year due to lack of efficacy and/or side effects.^5,6 There is a significant need for new, effective, and well-tolerated treatment options.

About Alder BioPharmaceuticals, Inc.
Alder BioPharmaceuticals is a clinical-stage biopharmaceutical company focused on transforming the migraine treatment paradigm through the discovery, development and commercialization of novel therapeutic antibodies.  Alder’s lead product candidate, eptinezumab, is a monoclonal antibody (mAb) that inhibits calcitonin gene-related peptide (CGRP) and is currently in late-stage clinical development for the prevention of migraine. Unlike other CGRP inhibitors, eptinezumab was specifically designed as an infusion therapy to address significant patient need. Alder is also developing ALD1910, a preclinical mAb that inhibits pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) for migraine prevention. For more information, please visit www.alderbio.com.

Forward-Looking Statements
This press release contains forward-looking statements, including, without limitation, statements relating to: the continued development and clinical, therapeutic and commercial potential of eptinezumab; eptinezumab’s potential to be an important treatment option in migraine prevention; the impact of the referenced data and results presented; and the significant need for new treatment options. Words such as “will,” “compelling,” “notable,” “confidence,” “potential,” “option,” “opportunity,” “may,” “need,” or other similar expressions, identify forward-looking statements, but the absence of these words does not necessarily mean that a statement is not forward-looking. In addition, any statements that refer to expectations, projections or other characterizations of future events or circumstances are forward-looking statements. The forward-looking statements in this press release are based upon Alder's current plans, assumptions, beliefs, expectations, estimates and projections, and involve substantial risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in the forward-looking statements due to these risks and uncertainties as well as other factors, which include, without limitation: risks related to the potential failure of eptinezumab to demonstrate safety and efficacy in clinical testing; Alder's ability to conduct clinical trials and studies of eptinezumab sufficient to achieve a positive completion; the availability of data at the expected times; the clinical, therapeutic and commercial value of eptinezumab; risks and uncertainties related to regulatory application, review and approval processes and Alder's compliance with applicable legal and regulatory requirements; risks and uncertainties relating to the manufacture of eptinezumab; Alder's ability to obtain and protect intellectual property rights, and operate without infringing on the intellectual property rights of others; the uncertain timing and level of expenses associated with Alder's development and commercialization activities; the sufficiency of Alder's capital and other resources; market competition; changes in economic and business conditions; and other factors discussed under the caption "Risk Factors" in Alder's Annual Report on Form 10-K for the fiscal year ended December 31, 2017, which was filed with the Securities and Exchange Commission (SEC) on February 26, 2018, and is available on the SEC's website at www.sec.gov. Additional information will also be set forth in Alder's other reports and filings it will make with the SEC from time to time. The forward-looking statements made in this press release speak only as of the date of this press release. Alder expressly disclaims any duty, obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Alder's expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based.

References

1. Baker B, Schaeffler B, Cady R, et al; Rational design of a monoclonal antibody (mAb) inhibiting calcitonin gene-related peptide, ALD403 (eptinezumab), intended for the prevention of migraine. Poster presented at the American Academy of Neurology (AAN) 2017 Annual Meeting.
2. Lipton RB, Silberstein SD. Episodic and chronic migraine headache: breaking down barriers to optimal treatment and prevention. Headache. 2015; 55(S2):103-122.
3. Migraine Research Foundation. Migraine Facts. https://migraineresearchfoundation.org/about-migraine/migraine-facts/. Accessed April 16, 2018.
4. Steiner, TJ, Stovner, LJ, & Vos, T. GBD 2015: Migraine is the third cause of disability in under 50s. The Journal of Headache and Pain, 2016;17(1).
5. Bigal ME, Krymchantowski AV, Lipton RB. Barriers to satisfactory migraine outcomes. What have we learned, where do we Stand? Headache. 2009;49(7):1028—1041.
6. Hepp, Z, Dodick DW, Varon SF, et al. Adherence to oral migraine-preventive medications among patients with chronic migraine. Cephalalgia 2015;35(6):477-88.

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