You are now leaving and being directed to a site not maintained by Arena. Arena is not responsible for content or privacy policies on other sites.
Cancel Ok



Arena Pharmaceuticals is focused on delivering important medicines to patients and we’re grateful that you have joined us on our journey to date. We are excited to share that Arena Pharmaceuticals has entered into an agreement to be acquired by Pfizer.  A press release with transaction information can be found here.

We are committed to executing a smooth transition. Between now and the closing date, operations at Arena will not change. We do not expect changes to your relationship with Arena and your contacts will remain the same. Arena will continue to enroll studies and drive forward on our stated timelines. Thank you for the strong partnership that we have with both you and your site as we make this transition with the highest professional standards.


Feel free to share this information with your teams. See our FAQ and please contact your Arena Clinical Trial Manager if you have any additional questions.



Q: Will the study contact(s) for my trial change?

A: No. For the current time, all contacts will remain the same. If these change in the future, we will provide notification.


Q: May I share any information or documents related to Arena clinical trials with Pfizer or their CROs?

A:  All documents should not be shared with anyone outside of Arena or current our designated CRO until further notice, which will occur following closing of the transaction.


Q: Should I respond to any direct communications received from Pfizer about Arena or Arena’s clinical trials?

A: If you receive any questions or requests from Pfizer, their CROs or other representatives, do not respond and please notify Arena immediately.


Q: Will the clinical trial agreement between my site and Arena be amended or assigned to Pfizer?

A: Not at this time.


Q: Should I continue to maintain my record keeping and investigational drug retention responsibilities for this study? 

A: Yes, nothing changes in terms of current trial conduct.


Q: If I have a pertinent financial disclosure update to make (e.g., equity interest, etc.) due to this announcement, should I inform Arena? 

A: At this time, you should not change any processes you’re currently using to report financial disclosures with respect to Arena.


Q: Will my CRO change?

A: No, the current CRO that is running your trial will remain during the transition of Sponsorship.


Q:  Will I be paid for the work performed?

A: Yes, all contracts will remain in effect and follow the same payment schedules.


Q: Will the sponsor of my study be changing from Arena to Pfizer?

A: The current relationship that Arena has with FDA or any other Health Authority is not impacted by this announcement. Specific details related to regulatory operations will be further informed following closing of the transaction with Pfizer.


Q: As an investigator in an Arena-sponsored study, will I have to change the way I report safety-related events observed in the study?

A: No. You should not change any processes you’re currently using to report safety-related events.


Q: Do I need to inform my local Ethics Committee of this announcement?

A: Until the closing of the transaction, it is not necessary to inform your local EC.  We will update you on appropriate communication when the transition occurs.




Cautionary Statement Regarding Forward-Looking Statements

This communication and any documents referred to in this communication contain certain forward-looking statements within the meaning of the federal securities laws with respect to the proposed transaction between Pfizer and Arena, including, but not limited to, statements regarding the expected benefits of the proposed transaction and the anticipated timing of the proposed transaction, strategies, objectives and the products and markets of each company. These forward-looking statements generally are identified by the words “believe,” “predict,” “target,” “contemplate,” “potential,” “project,” “expect,” “anticipate,” “estimate,” “intend,” “strategy,” “future,” “opportunity,” “plan,” “may,” “should,” “will,” “would,” “could,” “will be,” “will continue,” “will likely result,” and similar expressions. Forward-looking statements are predictions, projections and other statements about future events that are based on current expectations and assumptions and, as a result, are subject to risks and uncertainties. Many factors could cause actual future events to differ materially from the forward-looking statements in this communication, including but not limited to: (i) the risk that the proposed transaction may not be completed in a timely manner or at all, (ii) the failure to satisfy the conditions to the consummation of the proposed transaction, including the adoption of the Merger Agreement by the stockholders of Arena and the receipt of certain governmental and regulatory approvals, (iii) the occurrence of any event, change or other circumstance that could give rise to the termination of the Merger Agreement, (iv) the effect of the announcement or pendency of the proposed transaction on Arena’s business relationships, operating results, and business generally, (v) risks that the proposed transaction disrupts current plans and operations of Arena or Pfizer and potential difficulties in Arena employee retention as a result of the proposed transaction, (vi) risks related to diverting management’s attention from Arena’s ongoing business operations, and (vii) the outcome of any legal proceedings that may be instituted against Pfizer or against Arena related to the Merger Agreement or the proposed transaction. The risks and uncertainties may be amplified by the COVID-19 pandemic (and related variants), which has caused significant economic uncertainty. The extent to which the COVID-19 pandemic (and related variants) impacts Arena’s businesses, operations, and financial results, including the duration and magnitude of such effects, will depend on numerous factors, which are unpredictable, including, but not limited to, the duration and spread of the outbreak, its severity, the actions to contain the virus or treat its impact, and how quickly and to what extent normal economic and operating conditions can resume. The foregoing list of factors is not exhaustive. You should carefully consider the foregoing factors and the other risks and uncertainties that affect the businesses of Pfizer and Arena described in the “Risk Factors” section of their respective Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q and other documents filed by either of them from time to time with the SEC. These filings identify and address other important risks and uncertainties that could cause actual events and results to differ materially from those contained in the forward-looking statements. Forward-looking statements speak only as of the date they are made. Readers are cautioned not to put undue reliance on forward-looking statements, and Arena assumes no obligation to, and does not intend to, update or revise these forward-looking statements, whether as a result of new information, future events, or otherwise, unless required by law. Arena gives no assurance that it will achieve its expectations.


Additional Information and Where to Find It

In connection with the proposed transaction, Arena will be filing documents with the SEC, including preliminary and definitive proxy statements relating to the proposed transaction. The definitive proxy statement will be mailed to Arena’s stockholders in connection with the proposed transaction. This communication is not a substitute for the proxy statement or any other document that may be filed by Arena with the SEC. BEFORE MAKING ANY VOTING DECISION, INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE PRELIMINARY AND DEFINITIVE PROXY STATEMENTS AND ANY OTHER DOCUMENTS TO BE FILED WITH THE SEC IN CONNECTION WITH THE PROPOSED TRANSACTION OR INCORPORATED BY REFERENCE IN THE PROXY STATEMENT WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED TRANSACTION. Any vote in respect of resolutions to be proposed at Arena’s stockholder meeting to approve the proposed transaction or other responses in relation to the proposed transaction should be made only on the basis of the information contained in Arena’s proxy statement. Investors and security holders may obtain free copies of these documents (when they are available) and other related documents filed with the SEC at the SEC’s web site at, on Arena’s website at or by contacting Arena Investor Relations at (858) 453-7200.


No Offer or Solicitation

This communication is for information purposes only and is not intended to and does not constitute, or form part of, an offer, invitation or the solicitation of an offer or invitation to purchase, otherwise acquire, subscribe for, sell or otherwise dispose of any securities, or the solicitation of any vote or approval in any jurisdiction, pursuant to the proposed transaction or otherwise, nor shall there be any sale, issuance or transfer of securities in any jurisdiction in contravention of applicable law.


Participants in the Solicitation

Arena and certain of its directors, executive officers and employees may be deemed to be participants in the solicitation of proxies in connection with the proposed transaction. Information about Arena’s directors and executive officers in the proposed transaction will be included in the proxy statement described above. These documents are available free of charge at the SEC’s web site at and by going to Arena’s website at