Hi there,

I'm afraid that the only possible way is through promo codes. If I am not mistaken the person who wants to buy your app in Bulk wants to give it out to patients individually correct? Not that it is a hospital or such where they could simply use the same apple ID to login and put it on all their devices.
From my experience the only solution is through promo codes unless you release the app for free and approach a different monetization model.
I would love to have some specifics to perhaps help you out a bit further, I am currently offering a one time 15 minute free call so just go there https://clarity.fm/giulianosenese/free15
and schedule a call if you need it!

You have two other solutions. You could build the app with an entreprise itunes account ($500/year) and people would just have to download it from a webpage (no app store required). You would have to protect this page though, so that only patient can download it.

The other solution is more a hack. You could use apple beta program (testflight on itunes connect). With this, you can distribute the app up to 1000 people, you just need their email. It's a little more complicated, and it's more a hack than a real solution.

I would love to help you out a bit further, https://clarity.fm/matthieurouif
and schedule a call if you want.

+1 to what Matt. said. Enterprise account would likely be the most cost-effective solution. Here's the documentation from Apple: https://developer.apple.com/library/ios/#featuredarticles/FA_Wireless_Enterprise_App_Distribution/Introduction/Introduction.html.

There's is another alternative out there. After all, Starbucks gives away thousands of promo codes to paid apps all the time. I've been a developer on the other side of those giveaways—meaning, Starbucks featured our app.

Hope this helps,
Austin

Through Apple’s VPP, coupled with the B2B program, developers can offer bulk orders of customized applications that are tailored to a buyer’s needs. The purchasing organization needs to be a US based company with a registered Apple ID, but an appropriate business partner can act as an intermediary to complete the purchase. The bulk order is delivered in the form of a spreadsheet containing iTunes promo codes, allowing the buyer to easily distribute the apps. By redeeming these codes, B2B users can download the customized version of the app that normal iTunes users can’t access. You can get more information here: https://www.apple.com/business/docs/site/Apple_Business_Manager_Getting_Started_Guide.pdf

Besides if you do have any questions give me a call: https://clarity.fm/joy-brotonath