Biohaven Announces Expanded Safety And Preliminary Preventive Efficacy Data From Ongoing Long-Term Safety Study, And Presents Case Reports Of Using Rimegepant To Successfully Treat Breakthrough Migraine Attacks In Patients Taking Preventive CGRP

• Over 105,000 doses of rimegepant 75 mg have been administered in over 1,780 migraine patients in the long-term safety study to date
• Safety profile remains favorable with no liver safety signal detected as assessed by an external liver safety panel, including patients in the scheduled, high frequency dosing cohort
• In the completed scheduled dosing cohort, 48.4% of patients treated with rimegepant every other day experienced a ≥50% reduction from baseline during month 3 in the frequency of monthly moderate to severe migraine days
• First clinical experience supporting the potential of oral rimegepant to be safe and effective for the treatment of breakthrough migraine attacks on the background of injectable CGRP-targeting monoclonal antibodies

NEW HAVEN, Conn., May 7, 2019 /PRNewswire/ -- Biohaven Pharmaceutical Holding Company Ltd. (NYSE: BHVN) today announced additional safety and preliminary efficacy results from its ongoing long-term, open-label safety study of its oral calcitonin gene-related peptide (CGRP) receptor antagonist, rimegepant. Based upon this interim analysis of Study BHV3000-201 (NCT03266588 or "Study 201"), database cutoff of February 20, 2019, rimegepant was well tolerated with long-term dosing up to one year in patients with migraine. Thus far, 105,192 doses of rimegepant 75 mg was administered up to once daily to over 1,780 patients with migraine. Interim hepatic data were reviewed by an external independent panel of liver experts who concluded that there was no liver safety signal and compared to placebo arms of other migraine treatments, there was a very low incidence of overall elevations of liver laboratory abnormalities (1% incidence of serum ALT or AST > 3x the upper limit of normal (ULN) through the data analysis cut-off date).

Biohaven, for the first time, also reported the safety and preliminary efficacy data from the scheduled dosing cohort. In this cohort of patients with a history of 4 to 14 moderate to severe migraine attacks per month, patients were treated with rimegepant 75 mg every other day for up to 12 consecutive weeks. Patients in this cohort could also supplement their scheduled rimegepant dosing with additional as-needed (or PRN) dosing on nonscheduled dosing days. In this cohort, 286 patients received a total of 11,296 doses of rimegepant 75 mg tablets at least every other day, with median number of tablets per 4 week period of 14.2. During the on-treatment period, no rimegepant-treated patients (N=281) experienced ALT or AST levels >3x the ULN. There were also no rimegepant-treated patients who experienced alkaline phosphatase or bilirubin >2x the ULN. With regard to efficacy, 48.4% of subjects in the scheduled dosing cohort experienced a ≥50% reduction in the frequency of monthly migraine days with moderate-to-severe pain intensity during the third month of treatment.

The company also presented the first clinical reports suggesting that oral rimegepant has the potential to be safe and consistently effective for the treatment of breakthrough migraine attacks in patients taking injectable CGRP-targeting monoclonal antibody (mAb) preventive therapy. One patient prescribed erenumab and another taking fremanezumab for prevention successfully treated breakthrough migraine attacks with oral rimegepant 75 mg without requiring additional acute treatments during those episodes. No treatment-related adverse events (AEs) occurred with oral rimegepant in combination with erenumab or fremanezumab in these two patients. These cases report that use of oral rimegepant treated breakthrough migraine attacks in patients taking mAbs with different mechanisms of action: erenumab targets the CGRP receptor while fremanezumab targets the circulating CGRP ligand.

About Rimegepant
Rimegepant is Biohaven's orally-dosed calcitonin gene-related peptide (CGRP) receptor antagonist, which the Company is developing as a treatment for migraine. Rimegepant represents a novel mechanism that targets the underlying pathophysiology of migraine without causing vasoconstriction. The efficacy and safety profile of rimegepant for the acute treatment of migraine has now been established across four randomized controlled trials to date: the three completed pivotal Phase 3 trials, and a Phase 2b trial. The co-primary endpoints achieved in the three Phase 3 trials are consistent with regulatory guidance from the U.S. Food and Drug Administration (FDA).

About Biohaven
Biohaven is a clinical-stage biopharmaceutical company with a portfolio of innovative, late-stage product candidates targeting neurological diseases, including rare disorders. Biohaven has combined internal development and research with intellectual property licensed from companies and institutions including Bristol-Myers Squibb Company, AstraZeneca AB, Yale University, Catalent, ALS Biopharma LLC and Massachusetts General Hospital. Currently, Biohaven's lead development programs include multiple compounds across its CGRP receptor antagonist, glutamate modulation and myeloperoxidase inhibition platforms. More information about Biohaven is available at www.biohavenpharma.com.

Forward-Looking Statements
This news release includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements involve substantial risks and uncertainties, including statements that are based on the current expectations and assumptions of the Company's management. All statements, other than statements of historical facts, included in this press release regarding the Company's business and product candidate plans and objectives are forward-looking statements. Forward-looking statements include those related to: the expected timing, commencement and outcomes of the Company's planned and ongoing clinical trials, the potential of rimegepant to be a safe and effective treatment for breakthrough migraine attacks in certain patient populations, the timing of planned interactions and filings with the FDA, the timing and outcome of expected regulatory filings, the potential commercialization of the Company's product candidates and the potential for the Company's product candidates to be first in class or best in class therapies. The use of certain words, including "believe", "continue", "may", "on track", "expects," "planned" and "will" and similar expressions, are intended to identify forward-looking statements. Various important factors could cause actual results or events to differ materially from those that may be expressed or implied by our forward-looking statements. Additional important factors to be considered in connection with forward-looking statements are described in the "Risk Factors" section of the Company's Annual Report on Form 10-K filed with the Securities and Exchange Commission on February 28, 2019. The forward-looking statements are made as of this date and the Company does not undertake any obligation to update any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law.

For further information, contact Dr. Vlad Coric, Chief Executive Officer, at Vlad.Coric@biohavenpharma.com

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Company Codes: NYSE:BHVN