The tally of biomedical innovation bills trickling through the U.S. Senate got an update yesterday: 18 down, with at least one more to go. Lawmakers on the Health, Education, Labor and Pensions (HELP) committee held the last of three meetings to approve bills that, once bundled together, will form a companion to the House of Representatives’s mammoth 21st Century Cures bill. That legislation, which the House passed this past July aims to spur medical breakthroughs through reforms at the National Institutes of Health (NIH) and the Food and Drug Administration.

But a final piece of the puzzle—a Senate agreement on how to increase funding for those agencies, and by how much—is still missing. The House version of 21st Century Cures includes $8.75 billion in so-called mandatory spending for NIH, dedicated money not subject to annual appropriations which would be provided by selling oil from the nation’s Strategic Petroleum Reserve.

Republicans in the Senate, however, initially balked at the idea of mandatory funding. But a chorus of Democratic lawmakers on the HELP committee—the loudest among them Senator Elizabeth Warren (D–MA)—insisted that no innovation bill would get their support without such funding.

The chair of the HELP committee, Senator Lamar Alexander (R–TN), has been supportive of mandatory funding, but has noted that his committee doesn’t have the jurisdiction to call for selling off petroleum reserves to pay for the spending. Still, he told the committee yesterday he was still optimistic about devising a funding plan that could win a majority vote in the full Senate. “I don’t have any intention of taking the work product of this committee to the floor without having a bipartisan agreement … about a surge in funding for the National Institutes of Health,” he told the committee. “Without that agreement, we don’t get this bill. But without this bill, we don’t get mandatory funding either.”

The leader of another key Senate panel signaled at a hearing today that he may be open to such “surge” funding. Senator Roy Blunt (R–MO), chair of the Senate appropriations subcommittee that oversees NIH’s budget, reiterated his opposition to a White House proposal to use mandatory funding for NIH’s regular budget in 2017, calling it “risky.” But he said he and Alexander have discussed a short-term “surge focused on specific projects,” which “might be different.”

NIH Director Francis Collins later explained in response to a question from Alexander—who also sits on the spending panel—that the agency thinks it could spend such a special fund on five specific areas without facing a “cliff” when the money runs out. NIH could submit a “workplan” with “timetables” and “specific dollar figures,” Collins said.

Among the measures that the HELP panel approved yesterday were a bill broadly authorizing President Obama’s Precision Medicine Initiative, another that cuts down on administrative requirements for NIH employees, and a long-discussed proposal to speed the regulatory approval of antibiotics for serious infections in limited populations.

Committee staff is now working to assemble those and related bills into a final Cures package. Alexander has indicated the final bill could be available as early as next week, and said yesterday that Senate Majority Leader Mitch McConnell (R–KY) has agreed to schedule a floor vote on the bill if the committee can produce it.

With reporting by Jocelyn Kaiser.