It’s a complicated process for a pharmaceutical Sponsor company to screen potential new CDMO partners for an API or drug product development program. The first priority is to find several potential CDMOs with the location and capabilities that match the scope of your project. It’s possible to find multiple good options, so the next challenge is to select the best fit. 

Now you’ve interviewed your top candidate company by phone—and they look promising! Similar to hiring a new employee, it’s important to check the professional references of your CDMO. It’s quite reasonable to ask this attractive CDMO for references from other Sponsors who have worked with them in the past.

How do you get the most out of that CDMO Reference Check phone call?

Why Check CDMO References?

A wise hiring manager would certainly check professional references before hiring a new executive. A smart investor would absolutely conduct Due Diligence before funding a startup company. In the same way, references are a critical last step when selecting a CDMO. 

Like hiring and investing, selecting a CDMO partner will begin a relationship that should last several years and require substantial cash. This will be a relationship you don’t want to undo, once begun. Reference checks are a great way to qualify the soft skills of a potential partner.

Clients should be comfortable requesting references from a potential CDMO partner before they sign a Letter of Intent or Contract. 

There are many steps in the CDMO screening process: Creating an RFP, reviewing the CDMO’s proposal, interviewing the CDMO project team by phone, researching their business & financial stability, carefully examining their responses to a Quality Questionnaire, and planning an onsite Quality and technical audit. 

The opinions of past customers is another piece of available input that can inform the decision-making process. Somebody’s recent real-world experience with this CDMO can distinguish a good partner from a great partner.

Asking the CDMO for References

CDMOs are routinely asked for references toward the end of the screening process. It’s fine to “pressure test” a CDMO and ask them to demonstrate why they are the best fit for your project. 

Speaking with their reference requires a different attitude. The reference is doing a favor for their CDMO, so it’s best to approach the reference with a cordial tone. Think of it as visiting a friend’s grandmother while showing your best behavior. 

Be respectful of the time the Reference is offering and keep the conversation focused on key topics.

When requesting a reference, ask the CDMO to recommend someone that is similar to your company. In an ideal case, the Reference should have had a recent development program like yours. Hopefully they are the same size, with similar budgeting, same risk culture as yours, with similar API chemistries and/or drug product formulations in their development program. It may not be possible to get an exact match, but the more you have in common with the reference, the better. It’s helpful to start with a wish list when asking the candidate CDMO for the ideal Reference.

Characteristics of an Ideal CMC-CDMO Reference

When looking at the characteristics of an ideal CMD-CDMO reference (Table 1), not all references offer the same level of insight. The most valuable conversations come from individuals whose experience closely mirrors your own—both in terms of the work performed and the environment in which it was executed. Recency matters. A reference who has completed a project within the past year—or is currently engaged in one that has been running for several months—will have a much clearer, more relevant perspective on how the CDMO operates today.

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Table 1. Characteristics of an Ideal CMC-CDMO Reference

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Equally important is site specificity. Large CDMOs often operate across multiple facilities, and performance can vary meaningfully between sites and even between project teams. A reference tied directly to the same site you intend to use provides a far more reliable indicator of what your own experience is likely to be.

The individual should have been hands-on and closely involved in the work. Roles such as CMC team leads, project managers, and functional leads in formulation, analytical, or manufacturing tend to offer the most comprehensive perspective.

Technical alignment is another key filter. The closer the reference’s project is to yours—in API chemistry, manufacturing processes, dosage form, excipients, and formulation approach—the more meaningful their feedback becomes.

Beyond technical considerations, organizational alignment should not be overlooked. Budget expectations, risk tolerance, and company culture all shape how a sponsor engages with a CDMO. A reference operating under similar constraints will provide more actionable insights.

Ultimately, the right reference should be able to speak candidly about cost accuracy, timelines, team performance, GMP culture, change orders, and the quality of final deliverables.

Logistics of the Call

Generally, the client and Reference will connect first by email, then a specific date and time is arranged for a brief conversation by phone (voice, Zoom, Teams). 

A missed connection is somewhat common, so be prepared to reschedule at the last minute. If the Reference has an emergency at their company, then please accommodate their schedule.

The Reference may have limited time for this, so a 30-minute call is typical. Plan to stop a few minutes early. 

Preparing for the Conversation

A formal calendar meeting invitation from you should define the length of the call and confirm the invitation has been accepted by the Reference. Provide a skeleton Agenda to the Reference before the call.

An Agenda for the meeting is a good idea because it sets expectations and comforts the Reference that the call will be productive. It demonstrates that you are not wasting their time. Include a few topics in the Agenda to prompt discussions during the call. Formatting these in the form of a question is OK if they don’t tax the Reference. 

Avoid sending the Reference any forms to be completed. This method is burdensome and highly unpopular. 

Most likely, the Reference will spend very little time preparing before the Reference Check call. They will be sharing their experiences spontaneously, based on recent memory.

Research the Reference and the reference’s employer in the news, blogs, and trade magazines before the call. Consider if they are tied to a public partnership with this CDMO. LinkedIn may provide more details about the Reference’s education, current role, and industry experience.

It’s OK to invite one or two of your experienced SMEs into the call. Be cautious of including too many people on either side, because this will dilute the conversations and hinder open and honest expression. If more than one person is on the call, then designate one person as the lead and let the others observe with minimal questions. 

Prepare yourself and your team. Ask open ended questions and allow the discussion to flow. Remind everybody that you are trying to harvest objective evidence of the past performance of this CDMO and importantly, tease out any intangibles you can pick up as well.

Confidentiality

References may be reluctant to discuss certain specifics regarding their project. Be respectful of their boundaries, especially if some answers are intentionally vague about technical topics related to potential Intellectual Property (IP) or Trade Secrets.  Focus on the Reference’s opinion about the CDMO’s efficiency, technical competence, and culture (especially their attitude towards customers) since these topics are always fair game.

What to Ask

Every development program, CMC team, and Sponsor’s baseline expectations of their candidate CDMO is different, so there is no one-size-fits-all set of questions. The Reference will be expecting the predictable questions. Some questions (especially around pricing vs value) must be asked with diplomacy to elicit an answer that helps you. 

Start with a basic list (Table 2), then whittle it down. Encourage your project team to edit and customize the scope as part of your preparation for the call.

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Table 2A. Example Questions for CMC-CDMO References: Evaluation & Fit

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Table 2B. Example Questions for CMC-CDMO References: Execution & Performance

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It is best to ask a mix of specific and open-ended questions. Classic interview question formats like “Describe a time that….” or “What surprised you about ……” invite and unearth very helpful stories.

Most refence conversations are 30 minutes or less, so target your most important questions first. Have extra questions ready for the Reference and let the conversation permit some amount of spontaneity.

Near the end of the call ask the Reference if there were any major experiences in their relationship with the CDMO that were not discussed. A great way to conclude is to ask “Is there anything you consider important that we haven’t already discussed?” or “If you were going to start this project again from the beginning, is there anything you would have done differently?” Be flexible if the Reference circles back and expands on an earlier topic. 

Your Internal Debriefing After the Reference Check Call

If two of your SMEs were on the Reference Check call with you, there may be three different reactions to the call. Ask your SME attendees to share their notes with you and possibly your wider project team members.

Arrange an internal call after the Reference Check to confirm everybody who attended is on the same page, especially about their opinions regarding the subjective observations. Invite your other core CMC support SMEs (who were not on the Reference Check call) to this debrief so they can hear and absorb the stories. 

As you move to close the debriefing meeting, capture a few brief and frank summary bullet statements for internal use only. 

Feedback

It is expected courtesy for the Sponsor to tell the candidate CDMO that the Reference Check call has been completed and when it took place. The content of the Reference Check itself is a private conversation. The Sponsor may not choose to give specific feedback to the CDMO about the Reference Check call and that’s OK.

If the Sponsor ultimately chooses another candidate, then the passed over CDMO would certainly welcome feedback about the overall screening process, the competitiveness of their quote, and the takeaways from the Reference Check call. Again, sharing any of these is entirely at the discretion of the Sponsor.

In Summary

Like going on a job interview, it is important to take the CMC-CDMO Reference Check seriously (Table 3) and to be prepared. First make sure you are talking to the right person, then focus on the topics that matter most to you.

Be flexible if the conversation goes in an unexpected direction. Show respect and gratitude to the Reference because it’s not their day job to be fielding your questions. Draw out both objective and subjective opinions from the Reference and take real time notes. Debrief with your full CMC team afterwards and summarize points of team consensus. A good reference check will build confidence that you are selecting the CDMO that best fits your project.

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Table 3. Top 10 Best Practices for Contacting CMC-CDMO References

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